Remove vendored dependencies

While it appears that by now we actually can get successful builds
without Cargo insisting on Internet access by virtue of using the
--frozen flag, maintaining vendored dependencies is somewhat of a pain
point. This state will also get worse with upcoming changes that replace
argparse in favor of structopt and pull in a slew of new dependencies by
doing so. Then there is also the repository structure aspect, which is
non-standard due to the way we vendor dependencies and a potential
source of confusion.
In order to fix these problems, this change removes all the vendored
dependencies we have.

Delete subrepo argparse/:argparse
Delete subrepo base32/:base32
Delete subrepo cc/:cc
Delete subrepo cfg-if/:cfg-if
Delete subrepo getrandom/:getrandom
Delete subrepo lazy-static/:lazy-static
Delete subrepo libc/:libc
Delete subrepo nitrokey-sys/:nitrokey-sys
Delete subrepo nitrokey/:nitrokey
Delete subrepo rand/:rand

11 files changed, 0 insertions, 3602 deletions

diff --git a/nitrokey/src/auth.rs b/nitrokey/src/auth.rs
deleted file mode 100644
index cab1021..0000000
--- a/nitrokey/src/auth.rs
+++ /dev/null
@@ -1,437 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::convert::TryFrom as _;
-use std::marker;
-use std::ops;
-use std::os::raw::c_char;
-use std::os::raw::c_int;
-
-use nitrokey_sys;
-
-use crate::config::{Config, RawConfig};
-use crate::device::{Device, DeviceWrapper, Pro, Storage};
-use crate::error::Error;
-use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData, RawOtpSlotData};
-use crate::util::{generate_password, get_command_result, get_cstring, result_from_string};
-
-static TEMPORARY_PASSWORD_LENGTH: usize = 25;
-
-/// Provides methods to authenticate as a user or as an admin using a PIN.  The authenticated
-/// methods will consume the current device instance.  On success, they return the authenticated
-/// device.  Otherwise, they return the current unauthenticated device and the error code.
-pub trait Authenticate<'a> {
-    /// Performs user authentication.  This method consumes the device.  If successful, an
-    /// authenticated device is returned.  Otherwise, the current unauthenticated device and the
-    /// error are returned.
-    ///
-    /// This method generates a random temporary password that is used for all operations that
-    /// require user access.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided user password contains a null byte
-    /// - [`RngError`][] if the generation of the temporary password failed
-    /// - [`WrongPassword`][] if the provided user password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, DeviceWrapper, User};
-    /// # use nitrokey::Error;
-    ///
-    /// fn perform_user_task<'a>(device: &User<'a, DeviceWrapper<'a>>) {}
-    /// fn perform_other_task(device: &DeviceWrapper) {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let device = match device.authenticate_user("123456") {
-    ///     Ok(user) => {
-    ///         perform_user_task(&user);
-    ///         user.device()
-    ///     },
-    ///     Err((device, err)) => {
-    ///         eprintln!("Could not authenticate as user: {}", err);
-    ///         device
-    ///     },
-    /// };
-    /// perform_other_task(&device);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`RngError`]: enum.CommandError.html#variant.RngError
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn authenticate_user(self, password: &str) -> Result<User<'a, Self>, (Self, Error)>
-    where
-        Self: Device<'a> + Sized;
-
-    /// Performs admin authentication.  This method consumes the device.  If successful, an
-    /// authenticated device is returned.  Otherwise, the current unauthenticated device and the
-    /// error are returned.
-    ///
-    /// This method generates a random temporary password that is used for all operations that
-    /// require admin access.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided admin password contains a null byte
-    /// - [`RngError`][] if the generation of the temporary password failed
-    /// - [`WrongPassword`][] if the provided admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, Admin, DeviceWrapper};
-    /// # use nitrokey::Error;
-    ///
-    /// fn perform_admin_task<'a>(device: &Admin<'a, DeviceWrapper<'a>>) {}
-    /// fn perform_other_task(device: &DeviceWrapper) {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let device = match device.authenticate_admin("123456") {
-    ///     Ok(admin) => {
-    ///         perform_admin_task(&admin);
-    ///         admin.device()
-    ///     },
-    ///     Err((device, err)) => {
-    ///         eprintln!("Could not authenticate as admin: {}", err);
-    ///         device
-    ///     },
-    /// };
-    /// perform_other_task(&device);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`RngError`]: enum.CommandError.html#variant.RngError
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn authenticate_admin(self, password: &str) -> Result<Admin<'a, Self>, (Self, Error)>
-    where
-        Self: Device<'a> + Sized;
-}
-
-trait AuthenticatedDevice<T> {
-    fn new(device: T, temp_password: Vec<u8>) -> Self;
-
-    fn temp_password_ptr(&self) -> *const c_char;
-}
-
-/// A Nitrokey device with user authentication.
-///
-/// To obtain an instance of this struct, use the [`authenticate_user`][] method from the
-/// [`Authenticate`][] trait.  To get back to an unauthenticated device, use the [`device`][]
-/// method.
-///
-/// [`Authenticate`]: trait.Authenticate.html
-/// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
-/// [`device`]: #method.device
-#[derive(Debug)]
-pub struct User<'a, T: Device<'a>> {
-    device: T,
-    temp_password: Vec<u8>,
-    marker: marker::PhantomData<&'a T>,
-}
-
-/// A Nitrokey device with admin authentication.
-///
-/// To obtain an instance of this struct, use the [`authenticate_admin`][] method from the
-/// [`Authenticate`][] trait.  To get back to an unauthenticated device, use the [`device`][]
-/// method.
-///
-/// [`Authenticate`]: trait.Authenticate.html
-/// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
-/// [`device`]: #method.device
-#[derive(Debug)]
-pub struct Admin<'a, T: Device<'a>> {
-    device: T,
-    temp_password: Vec<u8>,
-    marker: marker::PhantomData<&'a T>,
-}
-
-fn authenticate<'a, D, A, T>(device: D, password: &str, callback: T) -> Result<A, (D, Error)>
-where
-    D: Device<'a>,
-    A: AuthenticatedDevice<D>,
-    T: Fn(*const c_char, *const c_char) -> c_int,
-{
-    let temp_password = match generate_password(TEMPORARY_PASSWORD_LENGTH) {
-        Ok(temp_password) => temp_password,
-        Err(err) => return Err((device, err)),
-    };
-    let password = match get_cstring(password) {
-        Ok(password) => password,
-        Err(err) => return Err((device, err)),
-    };
-    let password_ptr = password.as_ptr();
-    let temp_password_ptr = temp_password.as_ptr() as *const c_char;
-    match callback(password_ptr, temp_password_ptr) {
-        0 => Ok(A::new(device, temp_password)),
-        rv => Err((device, Error::from(rv))),
-    }
-}
-
-fn authenticate_user_wrapper<'a, T, C>(
-    device: T,
-    constructor: C,
-    password: &str,
-) -> Result<User<'a, DeviceWrapper<'a>>, (DeviceWrapper<'a>, Error)>
-where
-    T: Device<'a> + 'a,
-    C: Fn(T) -> DeviceWrapper<'a>,
-{
-    let result = device.authenticate_user(password);
-    match result {
-        Ok(user) => Ok(User::new(constructor(user.device), user.temp_password)),
-        Err((device, err)) => Err((constructor(device), err)),
-    }
-}
-
-fn authenticate_admin_wrapper<'a, T, C>(
-    device: T,
-    constructor: C,
-    password: &str,
-) -> Result<Admin<'a, DeviceWrapper<'a>>, (DeviceWrapper<'a>, Error)>
-where
-    T: Device<'a> + 'a,
-    C: Fn(T) -> DeviceWrapper<'a>,
-{
-    let result = device.authenticate_admin(password);
-    match result {
-        Ok(user) => Ok(Admin::new(constructor(user.device), user.temp_password)),
-        Err((device, err)) => Err((constructor(device), err)),
-    }
-}
-
-impl<'a, T: Device<'a>> User<'a, T> {
-    /// Forgets the user authentication and returns an unauthenticated device.  This method
-    /// consumes the authenticated device.  It does not perform any actual commands on the
-    /// Nitrokey.
-    pub fn device(self) -> T {
-        self.device
-    }
-}
-
-impl<'a, T: Device<'a>> ops::Deref for User<'a, T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.device
-    }
-}
-
-impl<'a, T: Device<'a>> ops::DerefMut for User<'a, T> {
-    fn deref_mut(&mut self) -> &mut T {
-        &mut self.device
-    }
-}
-
-impl<'a, T: Device<'a>> GenerateOtp for User<'a, T> {
-    fn get_hotp_code(&mut self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe {
-            nitrokey_sys::NK_get_hotp_code_PIN(slot, self.temp_password_ptr())
-        })
-    }
-
-    fn get_totp_code(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe {
-            nitrokey_sys::NK_get_totp_code_PIN(slot, 0, 0, 0, self.temp_password_ptr())
-        })
-    }
-}
-
-impl<'a, T: Device<'a>> AuthenticatedDevice<T> for User<'a, T> {
-    fn new(device: T, temp_password: Vec<u8>) -> Self {
-        User {
-            device,
-            temp_password,
-            marker: marker::PhantomData,
-        }
-    }
-
-    fn temp_password_ptr(&self) -> *const c_char {
-        self.temp_password.as_ptr() as *const c_char
-    }
-}
-
-impl<'a, T: Device<'a>> ops::Deref for Admin<'a, T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.device
-    }
-}
-
-impl<'a, T: Device<'a>> ops::DerefMut for Admin<'a, T> {
-    fn deref_mut(&mut self) -> &mut T {
-        &mut self.device
-    }
-}
-
-impl<'a, T: Device<'a>> Admin<'a, T> {
-    /// Forgets the user authentication and returns an unauthenticated device.  This method
-    /// consumes the authenticated device.  It does not perform any actual commands on the
-    /// Nitrokey.
-    pub fn device(self) -> T {
-        self.device
-    }
-
-    /// Writes the given configuration to the Nitrokey device.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the provided numlock, capslock or scrolllock slot is larger than two
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, Config};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let config = Config::new(None, None, None, false);
-    /// match device.authenticate_admin("12345678") {
-    ///     Ok(mut admin) => {
-    ///         admin.write_config(config);
-    ///         ()
-    ///     },
-    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    pub fn write_config(&mut self, config: Config) -> Result<(), Error> {
-        let raw_config = RawConfig::try_from(config)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_write_config(
-                raw_config.numlock,
-                raw_config.capslock,
-                raw_config.scrollock,
-                raw_config.user_password,
-                false,
-                self.temp_password_ptr(),
-            )
-        })
-    }
-}
-
-impl<'a, T: Device<'a>> ConfigureOtp for Admin<'a, T> {
-    fn write_hotp_slot(&mut self, data: OtpSlotData, counter: u64) -> Result<(), Error> {
-        let raw_data = RawOtpSlotData::new(data)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_write_hotp_slot(
-                raw_data.number,
-                raw_data.name.as_ptr(),
-                raw_data.secret.as_ptr(),
-                counter,
-                raw_data.mode == OtpMode::EightDigits,
-                raw_data.use_enter,
-                raw_data.use_token_id,
-                raw_data.token_id.as_ptr(),
-                self.temp_password_ptr(),
-            )
-        })
-    }
-
-    fn write_totp_slot(&mut self, data: OtpSlotData, time_window: u16) -> Result<(), Error> {
-        let raw_data = RawOtpSlotData::new(data)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_write_totp_slot(
-                raw_data.number,
-                raw_data.name.as_ptr(),
-                raw_data.secret.as_ptr(),
-                time_window,
-                raw_data.mode == OtpMode::EightDigits,
-                raw_data.use_enter,
-                raw_data.use_token_id,
-                raw_data.token_id.as_ptr(),
-                self.temp_password_ptr(),
-            )
-        })
-    }
-
-    fn erase_hotp_slot(&mut self, slot: u8) -> Result<(), Error> {
-        get_command_result(unsafe {
-            nitrokey_sys::NK_erase_hotp_slot(slot, self.temp_password_ptr())
-        })
-    }
-
-    fn erase_totp_slot(&mut self, slot: u8) -> Result<(), Error> {
-        get_command_result(unsafe {
-            nitrokey_sys::NK_erase_totp_slot(slot, self.temp_password_ptr())
-        })
-    }
-}
-
-impl<'a, T: Device<'a>> AuthenticatedDevice<T> for Admin<'a, T> {
-    fn new(device: T, temp_password: Vec<u8>) -> Self {
-        Admin {
-            device,
-            temp_password,
-            marker: marker::PhantomData,
-        }
-    }
-
-    fn temp_password_ptr(&self) -> *const c_char {
-        self.temp_password.as_ptr() as *const c_char
-    }
-}
-
-impl<'a> Authenticate<'a> for DeviceWrapper<'a> {
-    fn authenticate_user(self, password: &str) -> Result<User<'a, Self>, (Self, Error)> {
-        match self {
-            DeviceWrapper::Storage(storage) => {
-                authenticate_user_wrapper(storage, DeviceWrapper::Storage, password)
-            }
-            DeviceWrapper::Pro(pro) => authenticate_user_wrapper(pro, DeviceWrapper::Pro, password),
-        }
-    }
-
-    fn authenticate_admin(self, password: &str) -> Result<Admin<'a, Self>, (Self, Error)> {
-        match self {
-            DeviceWrapper::Storage(storage) => {
-                authenticate_admin_wrapper(storage, DeviceWrapper::Storage, password)
-            }
-            DeviceWrapper::Pro(pro) => {
-                authenticate_admin_wrapper(pro, DeviceWrapper::Pro, password)
-            }
-        }
-    }
-}
-
-impl<'a> Authenticate<'a> for Pro<'a> {
-    fn authenticate_user(self, password: &str) -> Result<User<'a, Self>, (Self, Error)> {
-        authenticate(self, password, |password_ptr, temp_password_ptr| unsafe {
-            nitrokey_sys::NK_user_authenticate(password_ptr, temp_password_ptr)
-        })
-    }
-
-    fn authenticate_admin(self, password: &str) -> Result<Admin<'a, Self>, (Self, Error)> {
-        authenticate(self, password, |password_ptr, temp_password_ptr| unsafe {
-            nitrokey_sys::NK_first_authenticate(password_ptr, temp_password_ptr)
-        })
-    }
-}
-
-impl<'a> Authenticate<'a> for Storage<'a> {
-    fn authenticate_user(self, password: &str) -> Result<User<'a, Self>, (Self, Error)> {
-        authenticate(self, password, |password_ptr, temp_password_ptr| unsafe {
-            nitrokey_sys::NK_user_authenticate(password_ptr, temp_password_ptr)
-        })
-    }
-
-    fn authenticate_admin(self, password: &str) -> Result<Admin<'a, Self>, (Self, Error)> {
-        authenticate(self, password, |password_ptr, temp_password_ptr| unsafe {
-            nitrokey_sys::NK_first_authenticate(password_ptr, temp_password_ptr)
-        })
-    }
-}
diff --git a/nitrokey/src/config.rs b/nitrokey/src/config.rs
deleted file mode 100644
index cb678d7..0000000
--- a/nitrokey/src/config.rs
+++ /dev/null
@@ -1,106 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::convert;
-
-use crate::error::{Error, LibraryError};
-
-/// The configuration for a Nitrokey.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub struct Config {
-    /// If set, the stick will generate a code from the HOTP slot with the given number if numlock
-    /// is pressed.  The slot number must be 0, 1 or 2.
-    pub numlock: Option<u8>,
-    /// If set, the stick will generate a code from the HOTP slot with the given number if capslock
-    /// is pressed.  The slot number must be 0, 1 or 2.
-    pub capslock: Option<u8>,
-    /// If set, the stick will generate a code from the HOTP slot with the given number if
-    /// scrollock is pressed.  The slot number must be 0, 1 or 2.
-    pub scrollock: Option<u8>,
-    /// If set, OTP generation using [`get_hotp_code`][] or [`get_totp_code`][] requires user
-    /// authentication.  Otherwise, OTPs can be generated without authentication.
-    ///
-    /// [`get_hotp_code`]: trait.ProvideOtp.html#method.get_hotp_code
-    /// [`get_totp_code`]: trait.ProvideOtp.html#method.get_totp_code
-    pub user_password: bool,
-}
-
-#[derive(Debug)]
-pub struct RawConfig {
-    pub numlock: u8,
-    pub capslock: u8,
-    pub scrollock: u8,
-    pub user_password: bool,
-}
-
-fn config_otp_slot_to_option(value: u8) -> Option<u8> {
-    if value < 3 {
-        Some(value)
-    } else {
-        None
-    }
-}
-
-fn option_to_config_otp_slot(value: Option<u8>) -> Result<u8, Error> {
-    if let Some(value) = value {
-        if value < 3 {
-            Ok(value)
-        } else {
-            Err(LibraryError::InvalidSlot.into())
-        }
-    } else {
-        Ok(255)
-    }
-}
-
-impl Config {
-    /// Constructs a new instance of this struct.
-    pub fn new(
-        numlock: Option<u8>,
-        capslock: Option<u8>,
-        scrollock: Option<u8>,
-        user_password: bool,
-    ) -> Config {
-        Config {
-            numlock,
-            capslock,
-            scrollock,
-            user_password,
-        }
-    }
-}
-
-impl convert::TryFrom<Config> for RawConfig {
-    type Error = Error;
-
-    fn try_from(config: Config) -> Result<RawConfig, Error> {
-        Ok(RawConfig {
-            numlock: option_to_config_otp_slot(config.numlock)?,
-            capslock: option_to_config_otp_slot(config.capslock)?,
-            scrollock: option_to_config_otp_slot(config.scrollock)?,
-            user_password: config.user_password,
-        })
-    }
-}
-
-impl From<[u8; 5]> for RawConfig {
-    fn from(data: [u8; 5]) -> Self {
-        RawConfig {
-            numlock: data[0],
-            capslock: data[1],
-            scrollock: data[2],
-            user_password: data[3] != 0,
-        }
-    }
-}
-
-impl Into<Config> for RawConfig {
-    fn into(self) -> Config {
-        Config {
-            numlock: config_otp_slot_to_option(self.numlock),
-            capslock: config_otp_slot_to_option(self.capslock),
-            scrollock: config_otp_slot_to_option(self.scrollock),
-            user_password: self.user_password,
-        }
-    }
-}
diff --git a/nitrokey/src/device/mod.rs b/nitrokey/src/device/mod.rs
deleted file mode 100644
index 5e15f08..0000000
--- a/nitrokey/src/device/mod.rs
+++ /dev/null
@@ -1,464 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-mod pro;
-mod storage;
-mod wrapper;
-
-use std::fmt;
-
-use libc;
-use nitrokey_sys;
-
-use crate::auth::Authenticate;
-use crate::config::{Config, RawConfig};
-use crate::error::{CommunicationError, Error};
-use crate::otp::GenerateOtp;
-use crate::pws::GetPasswordSafe;
-use crate::util::{
-    get_command_result, get_cstring, get_last_error, result_from_string, result_or_error,
-};
-
-pub use pro::Pro;
-pub use storage::{
-    SdCardData, Storage, StorageProductionInfo, StorageStatus, VolumeMode, VolumeStatus,
-};
-pub use wrapper::DeviceWrapper;
-
-/// Available Nitrokey models.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum Model {
-    /// The Nitrokey Storage.
-    Storage,
-    /// The Nitrokey Pro.
-    Pro,
-}
-
-impl fmt::Display for Model {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(match *self {
-            Model::Pro => "Pro",
-            Model::Storage => "Storage",
-        })
-    }
-}
-
-/// A firmware version for a Nitrokey device.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub struct FirmwareVersion {
-    /// The major firmware version, e. g. 0 in v0.40.
-    pub major: u8,
-    /// The minor firmware version, e. g. 40 in v0.40.
-    pub minor: u8,
-}
-
-impl fmt::Display for FirmwareVersion {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "v{}.{}", self.major, self.minor)
-    }
-}
-
-/// A Nitrokey device.
-///
-/// This trait provides the commands that can be executed without authentication and that are
-/// present on all supported Nitrokey devices.
-pub trait Device<'a>: Authenticate<'a> + GetPasswordSafe<'a> + GenerateOtp + fmt::Debug {
-    /// Returns the [`Manager`][] instance that has been used to connect to this device.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::{Device, DeviceWrapper};
-    ///
-    /// fn do_something(device: DeviceWrapper) {
-    ///     // reconnect to any device
-    ///     let manager = device.into_manager();
-    ///     let device = manager.connect();
-    ///     // do something with the device
-    ///     // ...
-    /// }
-    ///
-    /// match nitrokey::take()?.connect() {
-    ///     Ok(device) => do_something(device),
-    ///     Err(err) => println!("Could not connect to a Nitrokey: {}", err),
-    /// }
-    /// # Ok::<(), nitrokey::Error>(())
-    /// ```
-    fn into_manager(self) -> &'a mut crate::Manager;
-
-    /// Returns the model of the connected Nitrokey device.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// println!("Connected to a Nitrokey {}", device.get_model());
-    /// #    Ok(())
-    /// # }
-    fn get_model(&self) -> Model;
-
-    /// Returns the serial number of the Nitrokey device.  The serial number is the string
-    /// representation of a hex number.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.get_serial_number() {
-    ///     Ok(number) => println!("serial no: {}", number),
-    ///     Err(err) => eprintln!("Could not get serial number: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn get_serial_number(&self) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_device_serial_number() })
-    }
-
-    /// Returns the number of remaining authentication attempts for the user.  The total number of
-    /// available attempts is three.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let count = device.get_user_retry_count();
-    /// match device.get_user_retry_count() {
-    ///     Ok(count) => println!("{} remaining authentication attempts (user)", count),
-    ///     Err(err) => eprintln!("Could not get user retry count: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn get_user_retry_count(&self) -> Result<u8, Error> {
-        result_or_error(unsafe { nitrokey_sys::NK_get_user_retry_count() })
-    }
-
-    /// Returns the number of remaining authentication attempts for the admin.  The total number of
-    /// available attempts is three.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let count = device.get_admin_retry_count();
-    /// match device.get_admin_retry_count() {
-    ///     Ok(count) => println!("{} remaining authentication attempts (admin)", count),
-    ///     Err(err) => eprintln!("Could not get admin retry count: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn get_admin_retry_count(&self) -> Result<u8, Error> {
-        result_or_error(unsafe { nitrokey_sys::NK_get_admin_retry_count() })
-    }
-
-    /// Returns the firmware version.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.get_firmware_version() {
-    ///     Ok(version) => println!("Firmware version: {}", version),
-    ///     Err(err) => eprintln!("Could not access firmware version: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn get_firmware_version(&self) -> Result<FirmwareVersion, Error> {
-        let major = result_or_error(unsafe { nitrokey_sys::NK_get_major_firmware_version() })?;
-        let minor = result_or_error(unsafe { nitrokey_sys::NK_get_minor_firmware_version() })?;
-        Ok(FirmwareVersion { major, minor })
-    }
-
-    /// Returns the current configuration of the Nitrokey device.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let config = device.get_config()?;
-    /// println!("numlock binding:          {:?}", config.numlock);
-    /// println!("capslock binding:         {:?}", config.capslock);
-    /// println!("scrollock binding:        {:?}", config.scrollock);
-    /// println!("require password for OTP: {:?}", config.user_password);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn get_config(&self) -> Result<Config, Error> {
-        let config_ptr = unsafe { nitrokey_sys::NK_read_config() };
-        if config_ptr.is_null() {
-            return Err(get_last_error());
-        }
-        let config_array_ptr = config_ptr as *const [u8; 5];
-        let raw_config = unsafe { RawConfig::from(*config_array_ptr) };
-        unsafe { libc::free(config_ptr as *mut libc::c_void) };
-        Ok(raw_config.into())
-    }
-
-    /// Changes the administrator PIN.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the current admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.change_admin_pin("12345678", "12345679") {
-    ///     Ok(()) => println!("Updated admin PIN."),
-    ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn change_admin_pin(&mut self, current: &str, new: &str) -> Result<(), Error> {
-        let current_string = get_cstring(current)?;
-        let new_string = get_cstring(new)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_change_admin_PIN(current_string.as_ptr(), new_string.as_ptr())
-        })
-    }
-
-    /// Changes the user PIN.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the current user password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.change_user_pin("123456", "123457") {
-    ///     Ok(()) => println!("Updated admin PIN."),
-    ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn change_user_pin(&mut self, current: &str, new: &str) -> Result<(), Error> {
-        let current_string = get_cstring(current)?;
-        let new_string = get_cstring(new)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_change_user_PIN(current_string.as_ptr(), new_string.as_ptr())
-        })
-    }
-
-    /// Unlocks the user PIN after three failed login attempts and sets it to the given value.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.unlock_user_pin("12345678", "123456") {
-    ///     Ok(()) => println!("Unlocked user PIN."),
-    ///     Err(err) => eprintln!("Failed to unlock user PIN: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn unlock_user_pin(&mut self, admin_pin: &str, user_pin: &str) -> Result<(), Error> {
-        let admin_pin_string = get_cstring(admin_pin)?;
-        let user_pin_string = get_cstring(user_pin)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_unlock_user_password(
-                admin_pin_string.as_ptr(),
-                user_pin_string.as_ptr(),
-            )
-        })
-    }
-
-    /// Locks the Nitrokey device.
-    ///
-    /// This disables the password store if it has been unlocked.  On the Nitrokey Storage, this
-    /// also disables the volumes if they have been enabled.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.lock() {
-    ///     Ok(()) => println!("Locked the Nitrokey device."),
-    ///     Err(err) => eprintln!("Could not lock the Nitrokey device: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    fn lock(&mut self) -> Result<(), Error> {
-        get_command_result(unsafe { nitrokey_sys::NK_lock_device() })
-    }
-
-    /// Performs a factory reset on the Nitrokey device.
-    ///
-    /// This commands performs a factory reset on the smart card (like the factory reset via `gpg
-    /// --card-edit`) and then clears the flash memory (password safe, one-time passwords etc.).
-    /// After a factory reset, [`build_aes_key`][] has to be called before the password safe or the
-    /// encrypted volume can be used.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.factory_reset("12345678") {
-    ///     Ok(()) => println!("Performed a factory reset."),
-    ///     Err(err) => eprintln!("Could not perform a factory reset: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`build_aes_key`]: #method.build_aes_key
-    fn factory_reset(&mut self, admin_pin: &str) -> Result<(), Error> {
-        let admin_pin_string = get_cstring(admin_pin)?;
-        get_command_result(unsafe { nitrokey_sys::NK_factory_reset(admin_pin_string.as_ptr()) })
-    }
-
-    /// Builds a new AES key on the Nitrokey.
-    ///
-    /// The AES key is used to encrypt the password safe and the encrypted volume.  You may need
-    /// to call this method after a factory reset, either using [`factory_reset`][] or using `gpg
-    /// --card-edit`.  You can also use it to destroy the data stored in the password safe or on
-    /// the encrypted volume.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::Device;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.build_aes_key("12345678") {
-    ///     Ok(()) => println!("New AES keys have been built."),
-    ///     Err(err) => eprintln!("Could not build new AES keys: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`factory_reset`]: #method.factory_reset
-    fn build_aes_key(&mut self, admin_pin: &str) -> Result<(), Error> {
-        let admin_pin_string = get_cstring(admin_pin)?;
-        get_command_result(unsafe { nitrokey_sys::NK_build_aes_key(admin_pin_string.as_ptr()) })
-    }
-}
-
-fn get_connected_model() -> Option<Model> {
-    match unsafe { nitrokey_sys::NK_get_device_model() } {
-        nitrokey_sys::NK_device_model_NK_PRO => Some(Model::Pro),
-        nitrokey_sys::NK_device_model_NK_STORAGE => Some(Model::Storage),
-        _ => None,
-    }
-}
-
-pub(crate) fn create_device_wrapper(
-    manager: &mut crate::Manager,
-    model: Model,
-) -> DeviceWrapper<'_> {
-    match model {
-        Model::Pro => Pro::new(manager).into(),
-        Model::Storage => Storage::new(manager).into(),
-    }
-}
-
-pub(crate) fn get_connected_device(
-    manager: &mut crate::Manager,
-) -> Result<DeviceWrapper<'_>, Error> {
-    match get_connected_model() {
-        Some(model) => Ok(create_device_wrapper(manager, model)),
-        None => Err(CommunicationError::NotConnected.into()),
-    }
-}
-
-pub(crate) fn connect_enum(model: Model) -> bool {
-    let model = match model {
-        Model::Storage => nitrokey_sys::NK_device_model_NK_STORAGE,
-        Model::Pro => nitrokey_sys::NK_device_model_NK_PRO,
-    };
-    unsafe { nitrokey_sys::NK_login_enum(model) == 1 }
-}
diff --git a/nitrokey/src/device/pro.rs b/nitrokey/src/device/pro.rs
deleted file mode 100644
index a65345e..0000000
--- a/nitrokey/src/device/pro.rs
+++ /dev/null
@@ -1,79 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use nitrokey_sys;
-
-use crate::device::{Device, Model};
-use crate::otp::GenerateOtp;
-
-/// A Nitrokey Pro device without user or admin authentication.
-///
-/// Use the [`connect`][] method to obtain an instance wrapper or the [`connect_pro`] method to
-/// directly obtain an instance.  If you want to execute a command that requires user or admin
-/// authentication, use [`authenticate_admin`][] or [`authenticate_user`][].
-///
-/// # Examples
-///
-/// Authentication with error handling:
-///
-/// ```no_run
-/// use nitrokey::{Authenticate, User, Pro};
-/// # use nitrokey::Error;
-///
-/// fn perform_user_task<'a>(device: &User<'a, Pro<'a>>) {}
-/// fn perform_other_task(device: &Pro) {}
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect_pro()?;
-/// let device = match device.authenticate_user("123456") {
-///     Ok(user) => {
-///         perform_user_task(&user);
-///         user.device()
-///     },
-///     Err((device, err)) => {
-///         eprintln!("Could not authenticate as user: {}", err);
-///         device
-///     },
-/// };
-/// perform_other_task(&device);
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
-/// [`authenticate_user`]: trait.Authenticate.html#method.authenticate_user
-/// [`connect`]: struct.Manager.html#method.connect
-/// [`connect_pro`]: struct.Manager.html#method.connect_pro
-#[derive(Debug)]
-pub struct Pro<'a> {
-    manager: Option<&'a mut crate::Manager>,
-}
-
-impl<'a> Pro<'a> {
-    pub(crate) fn new(manager: &'a mut crate::Manager) -> Pro<'a> {
-        Pro {
-            manager: Some(manager),
-        }
-    }
-}
-
-impl<'a> Drop for Pro<'a> {
-    fn drop(&mut self) {
-        unsafe {
-            nitrokey_sys::NK_logout();
-        }
-    }
-}
-
-impl<'a> Device<'a> for Pro<'a> {
-    fn into_manager(mut self) -> &'a mut crate::Manager {
-        self.manager.take().unwrap()
-    }
-
-    fn get_model(&self) -> Model {
-        Model::Pro
-    }
-}
-
-impl<'a> GenerateOtp for Pro<'a> {}
diff --git a/nitrokey/src/device/storage.rs b/nitrokey/src/device/storage.rs
deleted file mode 100644
index 370ce36..0000000
--- a/nitrokey/src/device/storage.rs
+++ /dev/null
@@ -1,735 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::fmt;
-
-use nitrokey_sys;
-
-use crate::device::{Device, FirmwareVersion, Model};
-use crate::error::Error;
-use crate::otp::GenerateOtp;
-use crate::util::{get_command_result, get_cstring};
-
-/// A Nitrokey Storage device without user or admin authentication.
-///
-/// Use the [`connect`][] method to obtain an instance wrapper or the [`connect_storage`] method to
-/// directly obtain an instance.  If you want to execute a command that requires user or admin
-/// authentication, use [`authenticate_admin`][] or [`authenticate_user`][].
-///
-/// # Examples
-///
-/// Authentication with error handling:
-///
-/// ```no_run
-/// use nitrokey::{Authenticate, User, Storage};
-/// # use nitrokey::Error;
-///
-/// fn perform_user_task<'a>(device: &User<'a, Storage<'a>>) {}
-/// fn perform_other_task(device: &Storage) {}
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect_storage()?;
-/// let device = match device.authenticate_user("123456") {
-///     Ok(user) => {
-///         perform_user_task(&user);
-///         user.device()
-///     },
-///     Err((device, err)) => {
-///         eprintln!("Could not authenticate as user: {}", err);
-///         device
-///     },
-/// };
-/// perform_other_task(&device);
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
-/// [`authenticate_user`]: trait.Authenticate.html#method.authenticate_user
-/// [`connect`]: struct.Manager.html#method.connect
-/// [`connect_storage`]: struct.Manager.html#method.connect_storage
-#[derive(Debug)]
-pub struct Storage<'a> {
-    manager: Option<&'a mut crate::Manager>,
-}
-
-/// The access mode of a volume on the Nitrokey Storage.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum VolumeMode {
-    /// A read-only volume.
-    ReadOnly,
-    /// A read-write volume.
-    ReadWrite,
-}
-
-impl fmt::Display for VolumeMode {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(match *self {
-            VolumeMode::ReadOnly => "read-only",
-            VolumeMode::ReadWrite => "read-write",
-        })
-    }
-}
-
-/// The status of a volume on a Nitrokey Storage device.
-#[derive(Debug)]
-pub struct VolumeStatus {
-    /// Indicates whether the volume is read-only.
-    pub read_only: bool,
-    /// Indicates whether the volume is active.
-    pub active: bool,
-}
-
-/// Information about the SD card in a Storage device.
-#[derive(Debug)]
-pub struct SdCardData {
-    /// The serial number of the SD card.
-    pub serial_number: u32,
-    /// The size of the SD card in GB.
-    pub size: u8,
-    /// The year the card was manufactured, e. g. 17 for 2017.
-    pub manufacturing_year: u8,
-    /// The month the card was manufactured.
-    pub manufacturing_month: u8,
-    /// The OEM ID.
-    pub oem: u16,
-    /// The manufacturer ID.
-    pub manufacturer: u8,
-}
-
-/// Production information for a Storage device.
-#[derive(Debug)]
-pub struct StorageProductionInfo {
-    /// The firmware version.
-    pub firmware_version: FirmwareVersion,
-    /// The internal firmware version.
-    pub firmware_version_internal: u8,
-    /// The serial number of the CPU.
-    pub serial_number_cpu: u32,
-    /// Information about the SD card.
-    pub sd_card: SdCardData,
-}
-
-/// The status of a Nitrokey Storage device.
-#[derive(Debug)]
-pub struct StorageStatus {
-    /// The status of the unencrypted volume.
-    pub unencrypted_volume: VolumeStatus,
-    /// The status of the encrypted volume.
-    pub encrypted_volume: VolumeStatus,
-    /// The status of the hidden volume.
-    pub hidden_volume: VolumeStatus,
-    /// The firmware version.
-    pub firmware_version: FirmwareVersion,
-    /// Indicates whether the firmware is locked.
-    pub firmware_locked: bool,
-    /// The serial number of the SD card in the Storage stick.
-    pub serial_number_sd_card: u32,
-    /// The serial number of the smart card in the Storage stick.
-    pub serial_number_smart_card: u32,
-    /// The number of remaining login attempts for the user PIN.
-    pub user_retry_count: u8,
-    /// The number of remaining login attempts for the admin PIN.
-    pub admin_retry_count: u8,
-    /// Indicates whether a new SD card was found.
-    pub new_sd_card_found: bool,
-    /// Indicates whether the SD card is filled with random characters.
-    pub filled_with_random: bool,
-    /// Indicates whether the stick has been initialized by generating
-    /// the AES keys.
-    pub stick_initialized: bool,
-}
-
-impl<'a> Storage<'a> {
-    pub(crate) fn new(manager: &'a mut crate::Manager) -> Storage<'a> {
-        Storage {
-            manager: Some(manager),
-        }
-    }
-
-    /// Changes the update PIN.
-    ///
-    /// The update PIN is used to enable firmware updates.  Unlike the user and the admin PIN, the
-    /// update PIN is not managed by the OpenPGP smart card but by the Nitrokey firmware.  There is
-    /// no retry counter as with the other PIN types.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the current update password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.change_update_pin("12345678", "87654321") {
-    ///     Ok(()) => println!("Updated update PIN."),
-    ///     Err(err) => eprintln!("Failed to update update PIN: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn change_update_pin(&mut self, current: &str, new: &str) -> Result<(), Error> {
-        let current_string = get_cstring(current)?;
-        let new_string = get_cstring(new)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_change_update_password(current_string.as_ptr(), new_string.as_ptr())
-        })
-    }
-
-    /// Enables the firmware update mode.
-    ///
-    /// During firmware update mode, the Nitrokey can no longer be accessed using HID commands.
-    /// To resume normal operation, run `dfu-programmer at32uc3a3256s launch`.  In order to enter
-    /// the firmware update mode, you need the update password that can be changed using the
-    /// [`change_update_pin`][] method.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the current update password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.enable_firmware_update("12345678") {
-    ///     Ok(()) => println!("Nitrokey entered update mode."),
-    ///     Err(err) => eprintln!("Could not enter update mode: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn enable_firmware_update(&mut self, update_pin: &str) -> Result<(), Error> {
-        let update_pin_string = get_cstring(update_pin)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_enable_firmware_update(update_pin_string.as_ptr())
-        })
-    }
-
-    /// Enables the encrypted storage volume.
-    ///
-    /// Once the encrypted volume is enabled, it is presented to the operating system as a block
-    /// device.  The API does not provide any information on the name or path of this block device.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the provided user password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.enable_encrypted_volume("123456") {
-    ///     Ok(()) => println!("Enabled the encrypted volume."),
-    ///     Err(err) => eprintln!("Could not enable the encrypted volume: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn enable_encrypted_volume(&mut self, user_pin: &str) -> Result<(), Error> {
-        let user_pin = get_cstring(user_pin)?;
-        get_command_result(unsafe { nitrokey_sys::NK_unlock_encrypted_volume(user_pin.as_ptr()) })
-    }
-
-    /// Disables the encrypted storage volume.
-    ///
-    /// Once the volume is disabled, it can be no longer accessed as a block device.  If the
-    /// encrypted volume has not been enabled, this method still returns a success.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// fn use_volume() {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.enable_encrypted_volume("123456") {
-    ///     Ok(()) => {
-    ///         println!("Enabled the encrypted volume.");
-    ///         use_volume();
-    ///         match device.disable_encrypted_volume() {
-    ///             Ok(()) => println!("Disabled the encrypted volume."),
-    ///             Err(err) => {
-    ///                 eprintln!("Could not disable the encrypted volume: {}", err);
-    ///             },
-    ///         };
-    ///     },
-    ///     Err(err) => eprintln!("Could not enable the encrypted volume: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    pub fn disable_encrypted_volume(&mut self) -> Result<(), Error> {
-        get_command_result(unsafe { nitrokey_sys::NK_lock_encrypted_volume() })
-    }
-
-    /// Enables a hidden storage volume.
-    ///
-    /// This function will only succeed if the encrypted storage ([`enable_encrypted_volume`][]) or
-    /// another hidden volume has been enabled previously.  Once the hidden volume is enabled, it
-    /// is presented to the operating system as a block device and any previously opened encrypted
-    /// or hidden volumes are closed.  The API does not provide any information on the name or path
-    /// of this block device.
-    ///
-    /// Note that the encrypted and the hidden volumes operate on the same storage area, so using
-    /// both at the same time might lead to data loss.
-    ///
-    /// The hidden volume to unlock is selected based on the provided password.
-    ///
-    /// # Errors
-    ///
-    /// - [`AesDecryptionFailed`][] if the encrypted storage has not been opened before calling
-    ///   this method or the AES key has not been built
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// device.enable_encrypted_volume("123445")?;
-    /// match device.enable_hidden_volume("hidden-pw") {
-    ///     Ok(()) => println!("Enabled a hidden volume."),
-    ///     Err(err) => eprintln!("Could not enable the hidden volume: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`enable_encrypted_volume`]: #method.enable_encrypted_volume
-    /// [`AesDecryptionFailed`]: enum.CommandError.html#variant.AesDecryptionFailed
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    pub fn enable_hidden_volume(&mut self, volume_password: &str) -> Result<(), Error> {
-        let volume_password = get_cstring(volume_password)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_unlock_hidden_volume(volume_password.as_ptr())
-        })
-    }
-
-    /// Disables a hidden storage volume.
-    ///
-    /// Once the volume is disabled, it can be no longer accessed as a block device.  If no hidden
-    /// volume has been enabled, this method still returns a success.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// fn use_volume() {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// device.enable_encrypted_volume("123445")?;
-    /// match device.enable_hidden_volume("hidden-pw") {
-    ///     Ok(()) => {
-    ///         println!("Enabled the hidden volume.");
-    ///         use_volume();
-    ///         match device.disable_hidden_volume() {
-    ///             Ok(()) => println!("Disabled the hidden volume."),
-    ///             Err(err) => {
-    ///                 eprintln!("Could not disable the hidden volume: {}", err);
-    ///             },
-    ///         };
-    ///     },
-    ///     Err(err) => eprintln!("Could not enable the hidden volume: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    pub fn disable_hidden_volume(&mut self) -> Result<(), Error> {
-        get_command_result(unsafe { nitrokey_sys::NK_lock_hidden_volume() })
-    }
-
-    /// Creates a hidden volume.
-    ///
-    /// The volume is crated in the given slot and in the given range of the available memory,
-    /// where `start` is the start position as a percentage of the available memory, and `end` is
-    /// the end position as a percentage of the available memory.  The volume will be protected by
-    /// the given password.
-    ///
-    /// Note that the encrypted and the hidden volumes operate on the same storage area, so using
-    /// both at the same time might lead to data loss.
-    ///
-    /// According to the libnitrokey documentation, this function only works if the encrypted
-    /// storage has been opened.
-    ///
-    /// # Errors
-    ///
-    /// - [`AesDecryptionFailed`][] if the encrypted storage has not been opened before calling
-    ///   this method or the AES key has not been built
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// device.enable_encrypted_volume("123445")?;
-    /// device.create_hidden_volume(0, 0, 100, "hidden-pw")?;
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`AesDecryptionFailed`]: enum.CommandError.html#variant.AesDecryptionFailed
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    pub fn create_hidden_volume(
-        &mut self,
-        slot: u8,
-        start: u8,
-        end: u8,
-        password: &str,
-    ) -> Result<(), Error> {
-        let password = get_cstring(password)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_create_hidden_volume(slot, start, end, password.as_ptr())
-        })
-    }
-
-    /// Sets the access mode of the unencrypted volume.
-    ///
-    /// This command will reconnect the unencrypted volume so buffers should be flushed before
-    /// calling it.  Since firmware version v0.51, this command requires the admin PIN.  Older
-    /// firmware versions are not supported.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the provided admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    /// use nitrokey::VolumeMode;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.set_unencrypted_volume_mode("12345678", VolumeMode::ReadWrite) {
-    ///     Ok(()) => println!("Set the unencrypted volume to read-write mode."),
-    ///     Err(err) => eprintln!("Could not set the unencrypted volume to read-write mode: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn set_unencrypted_volume_mode(
-        &mut self,
-        admin_pin: &str,
-        mode: VolumeMode,
-    ) -> Result<(), Error> {
-        let admin_pin = get_cstring(admin_pin)?;
-        let result = match mode {
-            VolumeMode::ReadOnly => unsafe {
-                nitrokey_sys::NK_set_unencrypted_read_only_admin(admin_pin.as_ptr())
-            },
-            VolumeMode::ReadWrite => unsafe {
-                nitrokey_sys::NK_set_unencrypted_read_write_admin(admin_pin.as_ptr())
-            },
-        };
-        get_command_result(result)
-    }
-
-    /// Sets the access mode of the encrypted volume.
-    ///
-    /// This command will reconnect the encrypted volume so buffers should be flushed before
-    /// calling it.  It is only available in firmware version 0.49.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the provided admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    /// use nitrokey::VolumeMode;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.set_encrypted_volume_mode("12345678", VolumeMode::ReadWrite) {
-    ///     Ok(()) => println!("Set the encrypted volume to read-write mode."),
-    ///     Err(err) => eprintln!("Could not set the encrypted volume to read-write mode: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn set_encrypted_volume_mode(
-        &mut self,
-        admin_pin: &str,
-        mode: VolumeMode,
-    ) -> Result<(), Error> {
-        let admin_pin = get_cstring(admin_pin)?;
-        let result = match mode {
-            VolumeMode::ReadOnly => unsafe {
-                nitrokey_sys::NK_set_encrypted_read_only(admin_pin.as_ptr())
-            },
-            VolumeMode::ReadWrite => unsafe {
-                nitrokey_sys::NK_set_encrypted_read_write(admin_pin.as_ptr())
-            },
-        };
-        get_command_result(result)
-    }
-
-    /// Returns the status of the connected storage device.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// fn use_volume() {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect_storage()?;
-    /// match device.get_status() {
-    ///     Ok(status) => {
-    ///         println!("SD card ID: {:#x}", status.serial_number_sd_card);
-    ///     },
-    ///     Err(err) => eprintln!("Could not get Storage status: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    pub fn get_status(&self) -> Result<StorageStatus, Error> {
-        let mut raw_status = nitrokey_sys::NK_storage_status {
-            unencrypted_volume_read_only: false,
-            unencrypted_volume_active: false,
-            encrypted_volume_read_only: false,
-            encrypted_volume_active: false,
-            hidden_volume_read_only: false,
-            hidden_volume_active: false,
-            firmware_version_major: 0,
-            firmware_version_minor: 0,
-            firmware_locked: false,
-            serial_number_sd_card: 0,
-            serial_number_smart_card: 0,
-            user_retry_count: 0,
-            admin_retry_count: 0,
-            new_sd_card_found: false,
-            filled_with_random: false,
-            stick_initialized: false,
-        };
-        let raw_result = unsafe { nitrokey_sys::NK_get_status_storage(&mut raw_status) };
-        get_command_result(raw_result).map(|_| StorageStatus::from(raw_status))
-    }
-
-    /// Returns the production information for the connected storage device.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// fn use_volume() {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect_storage()?;
-    /// match device.get_production_info() {
-    ///     Ok(data) => {
-    ///         println!("SD card ID:   {:#x}", data.sd_card.serial_number);
-    ///         println!("SD card size: {} GB", data.sd_card.size);
-    ///     },
-    ///     Err(err) => eprintln!("Could not get Storage production info: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    pub fn get_production_info(&self) -> Result<StorageProductionInfo, Error> {
-        let mut raw_data = nitrokey_sys::NK_storage_ProductionTest {
-            FirmwareVersion_au8: [0, 2],
-            FirmwareVersionInternal_u8: 0,
-            SD_Card_Size_u8: 0,
-            CPU_CardID_u32: 0,
-            SmartCardID_u32: 0,
-            SD_CardID_u32: 0,
-            SC_UserPwRetryCount: 0,
-            SC_AdminPwRetryCount: 0,
-            SD_Card_ManufacturingYear_u8: 0,
-            SD_Card_ManufacturingMonth_u8: 0,
-            SD_Card_OEM_u16: 0,
-            SD_WriteSpeed_u16: 0,
-            SD_Card_Manufacturer_u8: 0,
-        };
-        let raw_result = unsafe { nitrokey_sys::NK_get_storage_production_info(&mut raw_data) };
-        get_command_result(raw_result).map(|_| StorageProductionInfo::from(raw_data))
-    }
-
-    /// Clears the warning for a new SD card.
-    ///
-    /// The Storage status contains a field for a new SD card warning.  After a factory reset, the
-    /// field is set to true.  After filling the SD card with random data, it is set to false.
-    /// This method can be used to set it to false without filling the SD card with random data.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if the provided password contains a null byte
-    /// - [`WrongPassword`][] if the provided admin password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect_storage()?;
-    /// match device.clear_new_sd_card_warning("12345678") {
-    ///     Ok(()) => println!("Cleared the new SD card warning."),
-    ///     Err(err) => eprintln!("Could not set the clear the new SD card warning: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn clear_new_sd_card_warning(&mut self, admin_pin: &str) -> Result<(), Error> {
-        let admin_pin = get_cstring(admin_pin)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_clear_new_sd_card_warning(admin_pin.as_ptr())
-        })
-    }
-
-    /// Blinks the red and green LED alternatively and infinitely until the device is reconnected.
-    pub fn wink(&mut self) -> Result<(), Error> {
-        get_command_result(unsafe { nitrokey_sys::NK_wink() })
-    }
-
-    /// Exports the firmware to the unencrypted volume.
-    ///
-    /// This command requires the admin PIN.  The unencrypted volume must be in read-write mode
-    /// when this command is executed.  Otherwise, it will still return `Ok` but not write the
-    /// firmware.
-    ///
-    /// This command unmounts the unencrypted volume if it has been mounted, so all buffers should
-    /// be flushed.  The firmware is written to the `firmware.bin` file on the unencrypted volume.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`WrongPassword`][] if the admin password is wrong
-    ///
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    pub fn export_firmware(&mut self, admin_pin: &str) -> Result<(), Error> {
-        let admin_pin_string = get_cstring(admin_pin)?;
-        get_command_result(unsafe { nitrokey_sys::NK_export_firmware(admin_pin_string.as_ptr()) })
-    }
-}
-
-impl<'a> Drop for Storage<'a> {
-    fn drop(&mut self) {
-        unsafe {
-            nitrokey_sys::NK_logout();
-        }
-    }
-}
-
-impl<'a> Device<'a> for Storage<'a> {
-    fn into_manager(mut self) -> &'a mut crate::Manager {
-        self.manager.take().unwrap()
-    }
-
-    fn get_model(&self) -> Model {
-        Model::Storage
-    }
-}
-
-impl<'a> GenerateOtp for Storage<'a> {}
-
-impl From<nitrokey_sys::NK_storage_ProductionTest> for StorageProductionInfo {
-    fn from(data: nitrokey_sys::NK_storage_ProductionTest) -> Self {
-        Self {
-            firmware_version: FirmwareVersion {
-                major: data.FirmwareVersion_au8[0],
-                minor: data.FirmwareVersion_au8[1],
-            },
-            firmware_version_internal: data.FirmwareVersionInternal_u8,
-            serial_number_cpu: data.CPU_CardID_u32,
-            sd_card: SdCardData {
-                serial_number: data.SD_CardID_u32,
-                size: data.SD_Card_Size_u8,
-                manufacturing_year: data.SD_Card_ManufacturingYear_u8,
-                manufacturing_month: data.SD_Card_ManufacturingMonth_u8,
-                oem: data.SD_Card_OEM_u16,
-                manufacturer: data.SD_Card_Manufacturer_u8,
-            },
-        }
-    }
-}
-
-impl From<nitrokey_sys::NK_storage_status> for StorageStatus {
-    fn from(status: nitrokey_sys::NK_storage_status) -> Self {
-        StorageStatus {
-            unencrypted_volume: VolumeStatus {
-                read_only: status.unencrypted_volume_read_only,
-                active: status.unencrypted_volume_active,
-            },
-            encrypted_volume: VolumeStatus {
-                read_only: status.encrypted_volume_read_only,
-                active: status.encrypted_volume_active,
-            },
-            hidden_volume: VolumeStatus {
-                read_only: status.hidden_volume_read_only,
-                active: status.hidden_volume_active,
-            },
-            firmware_version: FirmwareVersion {
-                major: status.firmware_version_major,
-                minor: status.firmware_version_minor,
-            },
-            firmware_locked: status.firmware_locked,
-            serial_number_sd_card: status.serial_number_sd_card,
-            serial_number_smart_card: status.serial_number_smart_card,
-            user_retry_count: status.user_retry_count,
-            admin_retry_count: status.admin_retry_count,
-            new_sd_card_found: status.new_sd_card_found,
-            filled_with_random: status.filled_with_random,
-            stick_initialized: status.stick_initialized,
-        }
-    }
-}
diff --git a/nitrokey/src/device/wrapper.rs b/nitrokey/src/device/wrapper.rs
deleted file mode 100644
index a3a18f9..0000000
--- a/nitrokey/src/device/wrapper.rs
+++ /dev/null
@@ -1,134 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use crate::device::{Device, Model, Pro, Storage};
-use crate::error::Error;
-use crate::otp::GenerateOtp;
-
-/// A wrapper for a Nitrokey device of unknown type.
-///
-/// Use the [`connect`][] method to obtain a wrapped instance.  The wrapper implements all traits
-/// that are shared between all Nitrokey devices so that the shared functionality can be used
-/// without knowing the type of the underlying device.  If you want to use functionality that is
-/// not available for all devices, you have to extract the device.
-///
-/// # Examples
-///
-/// Authentication with error handling:
-///
-/// ```no_run
-/// use nitrokey::{Authenticate, DeviceWrapper, User};
-/// # use nitrokey::Error;
-///
-/// fn perform_user_task<'a>(device: &User<'a, DeviceWrapper<'a>>) {}
-/// fn perform_other_task(device: &DeviceWrapper) {}
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect()?;
-/// let device = match device.authenticate_user("123456") {
-///     Ok(user) => {
-///         perform_user_task(&user);
-///         user.device()
-///     },
-///     Err((device, err)) => {
-///         eprintln!("Could not authenticate as user: {}", err);
-///         device
-///     },
-/// };
-/// perform_other_task(&device);
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// Device-specific commands:
-///
-/// ```no_run
-/// use nitrokey::{DeviceWrapper, Storage};
-/// # use nitrokey::Error;
-///
-/// fn perform_common_task(device: &DeviceWrapper) {}
-/// fn perform_storage_task(device: &Storage) {}
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect()?;
-/// perform_common_task(&device);
-/// match device {
-///     DeviceWrapper::Storage(storage) => perform_storage_task(&storage),
-///     _ => (),
-/// };
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// [`connect`]: struct.Manager.html#method.connect
-#[derive(Debug)]
-pub enum DeviceWrapper<'a> {
-    /// A Nitrokey Storage device.
-    Storage(Storage<'a>),
-    /// A Nitrokey Pro device.
-    Pro(Pro<'a>),
-}
-
-impl<'a> DeviceWrapper<'a> {
-    fn device(&self) -> &dyn Device<'a> {
-        match *self {
-            DeviceWrapper::Storage(ref storage) => storage,
-            DeviceWrapper::Pro(ref pro) => pro,
-        }
-    }
-
-    fn device_mut(&mut self) -> &mut dyn Device<'a> {
-        match *self {
-            DeviceWrapper::Storage(ref mut storage) => storage,
-            DeviceWrapper::Pro(ref mut pro) => pro,
-        }
-    }
-}
-
-impl<'a> From<Pro<'a>> for DeviceWrapper<'a> {
-    fn from(device: Pro<'a>) -> Self {
-        DeviceWrapper::Pro(device)
-    }
-}
-
-impl<'a> From<Storage<'a>> for DeviceWrapper<'a> {
-    fn from(device: Storage<'a>) -> Self {
-        DeviceWrapper::Storage(device)
-    }
-}
-
-impl<'a> GenerateOtp for DeviceWrapper<'a> {
-    fn get_hotp_slot_name(&self, slot: u8) -> Result<String, Error> {
-        self.device().get_hotp_slot_name(slot)
-    }
-
-    fn get_totp_slot_name(&self, slot: u8) -> Result<String, Error> {
-        self.device().get_totp_slot_name(slot)
-    }
-
-    fn get_hotp_code(&mut self, slot: u8) -> Result<String, Error> {
-        self.device_mut().get_hotp_code(slot)
-    }
-
-    fn get_totp_code(&self, slot: u8) -> Result<String, Error> {
-        self.device().get_totp_code(slot)
-    }
-}
-
-impl<'a> Device<'a> for DeviceWrapper<'a> {
-    fn into_manager(self) -> &'a mut crate::Manager {
-        match self {
-            DeviceWrapper::Pro(dev) => dev.into_manager(),
-            DeviceWrapper::Storage(dev) => dev.into_manager(),
-        }
-    }
-
-    fn get_model(&self) -> Model {
-        match *self {
-            DeviceWrapper::Pro(_) => Model::Pro,
-            DeviceWrapper::Storage(_) => Model::Storage,
-        }
-    }
-}
diff --git a/nitrokey/src/error.rs b/nitrokey/src/error.rs
deleted file mode 100644
index 9e6adc0..0000000
--- a/nitrokey/src/error.rs
+++ /dev/null
@@ -1,269 +0,0 @@
-// Copyright (C) 2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::error;
-use std::fmt;
-use std::os::raw;
-use std::str;
-use std::sync;
-
-use crate::device;
-
-/// An error returned by the nitrokey crate.
-#[derive(Debug)]
-pub enum Error {
-    /// An error reported by the Nitrokey device in the response packet.
-    CommandError(CommandError),
-    /// A device communication error.
-    CommunicationError(CommunicationError),
-    /// An error occurred due to concurrent access to the Nitrokey device.
-    ConcurrentAccessError,
-    /// A library usage error.
-    LibraryError(LibraryError),
-    /// An error that occurred due to a poisoned lock.
-    PoisonError(sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>),
-    /// An error that occurred during random number generation.
-    RandError(Box<dyn error::Error>),
-    /// An error that is caused by an unexpected value returned by libnitrokey.
-    UnexpectedError,
-    /// An unknown error returned by libnitrokey.
-    UnknownError(i64),
-    /// An error occurred when interpreting a UTF-8 string.
-    Utf8Error(str::Utf8Error),
-}
-
-impl From<raw::c_int> for Error {
-    fn from(code: raw::c_int) -> Self {
-        if let Some(err) = CommandError::try_from(code) {
-            Error::CommandError(err)
-        } else if let Some(err) = CommunicationError::try_from(256 - code) {
-            Error::CommunicationError(err)
-        } else if let Some(err) = LibraryError::try_from(code) {
-            Error::LibraryError(err)
-        } else {
-            Error::UnknownError(code.into())
-        }
-    }
-}
-
-impl From<CommandError> for Error {
-    fn from(err: CommandError) -> Self {
-        Error::CommandError(err)
-    }
-}
-
-impl From<CommunicationError> for Error {
-    fn from(err: CommunicationError) -> Self {
-        Error::CommunicationError(err)
-    }
-}
-
-impl From<LibraryError> for Error {
-    fn from(err: LibraryError) -> Self {
-        Error::LibraryError(err)
-    }
-}
-
-impl From<str::Utf8Error> for Error {
-    fn from(error: str::Utf8Error) -> Self {
-        Error::Utf8Error(error)
-    }
-}
-
-impl From<sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>> for Error {
-    fn from(error: sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>) -> Self {
-        Error::PoisonError(error)
-    }
-}
-
-impl From<sync::TryLockError<sync::MutexGuard<'static, crate::Manager>>> for Error {
-    fn from(error: sync::TryLockError<sync::MutexGuard<'static, crate::Manager>>) -> Self {
-        match error {
-            sync::TryLockError::Poisoned(err) => err.into(),
-            sync::TryLockError::WouldBlock => Error::ConcurrentAccessError,
-        }
-    }
-}
-
-impl<'a, T: device::Device<'a>> From<(T, Error)> for Error {
-    fn from((_, err): (T, Error)) -> Self {
-        err
-    }
-}
-
-impl error::Error for Error {
-    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-        match *self {
-            Error::CommandError(ref err) => Some(err),
-            Error::CommunicationError(ref err) => Some(err),
-            Error::ConcurrentAccessError => None,
-            Error::LibraryError(ref err) => Some(err),
-            Error::PoisonError(ref err) => Some(err),
-            Error::RandError(ref err) => Some(err.as_ref()),
-            Error::UnexpectedError => None,
-            Error::UnknownError(_) => None,
-            Error::Utf8Error(ref err) => Some(err),
-        }
-    }
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match *self {
-            Error::CommandError(ref err) => write!(f, "Command error: {}", err),
-            Error::CommunicationError(ref err) => write!(f, "Communication error: {}", err),
-            Error::ConcurrentAccessError => write!(f, "Internal error: concurrent access"),
-            Error::LibraryError(ref err) => write!(f, "Library error: {}", err),
-            Error::PoisonError(_) => write!(f, "Internal error: poisoned lock"),
-            Error::RandError(ref err) => write!(f, "RNG error: {}", err),
-            Error::UnexpectedError => write!(f, "An unexpected error occurred"),
-            Error::UnknownError(ref err) => write!(f, "Unknown error: {}", err),
-            Error::Utf8Error(ref err) => write!(f, "UTF-8 error: {}", err),
-        }
-    }
-}
-
-/// An error reported by the Nitrokey device in the response packet.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum CommandError {
-    /// A packet with a wrong checksum has been sent or received.
-    WrongCrc,
-    /// A command tried to access an OTP slot that does not exist.
-    WrongSlot,
-    /// A command tried to generate an OTP on a slot that is not configured.
-    SlotNotProgrammed,
-    /// The provided password is wrong.
-    WrongPassword,
-    /// You are not authorized for this command or provided a wrong temporary
-    /// password.
-    NotAuthorized,
-    /// An error occurred when getting or setting the time.
-    Timestamp,
-    /// You did not provide a name for the OTP slot.
-    NoName,
-    /// This command is not supported by this device.
-    NotSupported,
-    /// This command is unknown.
-    UnknownCommand,
-    /// AES decryption failed.
-    AesDecryptionFailed,
-}
-
-impl CommandError {
-    fn try_from(value: raw::c_int) -> Option<Self> {
-        match value {
-            1 => Some(CommandError::WrongCrc),
-            2 => Some(CommandError::WrongSlot),
-            3 => Some(CommandError::SlotNotProgrammed),
-            4 => Some(CommandError::WrongPassword),
-            5 => Some(CommandError::NotAuthorized),
-            6 => Some(CommandError::Timestamp),
-            7 => Some(CommandError::NoName),
-            8 => Some(CommandError::NotSupported),
-            9 => Some(CommandError::UnknownCommand),
-            10 => Some(CommandError::AesDecryptionFailed),
-            _ => None,
-        }
-    }
-}
-
-impl error::Error for CommandError {}
-
-impl fmt::Display for CommandError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(match *self {
-            CommandError::WrongCrc => "A packet with a wrong checksum has been sent or received",
-            CommandError::WrongSlot => "The given slot does not exist",
-            CommandError::SlotNotProgrammed => "The given slot is not programmed",
-            CommandError::WrongPassword => "The given password is wrong",
-            CommandError::NotAuthorized => {
-                "You are not authorized for this command or provided a wrong temporary \
-                 password"
-            }
-            CommandError::Timestamp => "An error occurred when getting or setting the time",
-            CommandError::NoName => "You did not provide a name for the slot",
-            CommandError::NotSupported => "This command is not supported by this device",
-            CommandError::UnknownCommand => "This command is unknown",
-            CommandError::AesDecryptionFailed => "AES decryption failed",
-        })
-    }
-}
-
-/// A device communication error.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum CommunicationError {
-    /// Could not connect to a Nitrokey device.
-    NotConnected,
-    /// Sending a packet failed.
-    SendingFailure,
-    /// Receiving a packet failed.
-    ReceivingFailure,
-    /// A packet with a wrong checksum was received.
-    InvalidCrc,
-}
-
-impl CommunicationError {
-    fn try_from(value: raw::c_int) -> Option<Self> {
-        match value {
-            2 => Some(CommunicationError::NotConnected),
-            3 => Some(CommunicationError::SendingFailure),
-            4 => Some(CommunicationError::ReceivingFailure),
-            5 => Some(CommunicationError::InvalidCrc),
-            _ => None,
-        }
-    }
-}
-
-impl error::Error for CommunicationError {}
-
-impl fmt::Display for CommunicationError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(match *self {
-            CommunicationError::NotConnected => "Could not connect to a Nitrokey device",
-            CommunicationError::SendingFailure => "Sending a packet failed",
-            CommunicationError::ReceivingFailure => "Receiving a packet failed",
-            CommunicationError::InvalidCrc => "A packet with a wrong checksum was received",
-        })
-    }
-}
-
-/// A library usage error.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum LibraryError {
-    /// A supplied string exceeded a length limit.
-    StringTooLong,
-    /// You passed an invalid slot.
-    InvalidSlot,
-    /// The supplied string was not in hexadecimal format.
-    InvalidHexString,
-    /// The target buffer was smaller than the source.
-    TargetBufferTooSmall,
-    /// You passed a string containing a null byte.
-    InvalidString,
-}
-
-impl LibraryError {
-    fn try_from(value: raw::c_int) -> Option<Self> {
-        match value {
-            200 => Some(LibraryError::StringTooLong),
-            201 => Some(LibraryError::InvalidSlot),
-            202 => Some(LibraryError::InvalidHexString),
-            203 => Some(LibraryError::TargetBufferTooSmall),
-            _ => None,
-        }
-    }
-}
-
-impl error::Error for LibraryError {}
-
-impl fmt::Display for LibraryError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(match *self {
-            LibraryError::StringTooLong => "The supplied string is too long",
-            LibraryError::InvalidSlot => "The given slot is invalid",
-            LibraryError::InvalidHexString => "The supplied string is not in hexadecimal format",
-            LibraryError::TargetBufferTooSmall => "The target buffer is too small",
-            LibraryError::InvalidString => "You passed a string containing a null byte",
-        })
-    }
-}
diff --git a/nitrokey/src/lib.rs b/nitrokey/src/lib.rs
deleted file mode 100644
index 059792d..0000000
--- a/nitrokey/src/lib.rs
+++ /dev/null
@@ -1,465 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-//! Provides access to a Nitrokey device using the native libnitrokey API.
-//!
-//! # Usage
-//!
-//! Operations on the Nitrokey require different authentication levels.  Some operations can be
-//! performed without authentication, some require user access, and some require admin access.
-//! This is modelled using the types [`User`][] and [`Admin`][].
-//!
-//! You can only connect to one Nitrokey at a time.  Use the global [`take`][] function to obtain
-//! an reference to the [`Manager`][] singleton that keeps track of the connections.  Then use the
-//! [`connect`][] method to connect to any Nitrokey device.  The method will return a
-//! [`DeviceWrapper`][] that abstracts over the supported Nitrokey devices.  You can also use
-//! [`connect_model`][], [`connect_pro`][] or [`connect_storage`][] to connect to a specific
-//! device.
-//!
-//! You can call [`authenticate_user`][] or [`authenticate_admin`][] to get an authenticated device
-//! that can perform operations that require authentication.  You can use [`device`][] to go back
-//! to the unauthenticated device.
-//!
-//! This makes sure that you can only execute a command if you have the required access rights.
-//! Otherwise, your code will not compile.  The only exception are the methods to generate one-time
-//! passwords – [`get_hotp_code`][] and [`get_totp_code`][].  Depending on the stick configuration,
-//! these operations are available without authentication or with user authentication.
-//!
-//! # Examples
-//!
-//! Connect to any Nitrokey and print its serial number:
-//!
-//! ```no_run
-//! use nitrokey::Device;
-//! # use nitrokey::Error;
-//!
-//! # fn try_main() -> Result<(), Error> {
-//! let mut manager = nitrokey::take()?;
-//! let device = manager.connect()?;
-//! println!("{}", device.get_serial_number()?);
-//! #     Ok(())
-//! # }
-//! ```
-//!
-//! Configure an HOTP slot:
-//!
-//! ```no_run
-//! use nitrokey::{Authenticate, ConfigureOtp, OtpMode, OtpSlotData};
-//! # use nitrokey::Error;
-//!
-//! # fn try_main() -> Result<(), Error> {
-//! let mut manager = nitrokey::take()?;
-//! let device = manager.connect()?;
-//! let slot_data = OtpSlotData::new(1, "test", "01234567890123456689", OtpMode::SixDigits);
-//! match device.authenticate_admin("12345678") {
-//!     Ok(mut admin) => {
-//!         match admin.write_hotp_slot(slot_data, 0) {
-//!             Ok(()) => println!("Successfully wrote slot."),
-//!             Err(err) => eprintln!("Could not write slot: {}", err),
-//!         }
-//!     },
-//!     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-//! }
-//! #     Ok(())
-//! # }
-//! ```
-//!
-//! Generate an HOTP one-time password:
-//!
-//! ```no_run
-//! use nitrokey::{Device, GenerateOtp};
-//! # use nitrokey::Error;
-//!
-//! # fn try_main() -> Result<(), Error> {
-//! let mut manager = nitrokey::take()?;
-//! let mut device = manager.connect()?;
-//! match device.get_hotp_code(1) {
-//!     Ok(code) => println!("Generated HOTP code: {}", code),
-//!     Err(err) => eprintln!("Could not generate HOTP code: {}", err),
-//! }
-//! #     Ok(())
-//! # }
-//! ```
-//!
-//! [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
-//! [`authenticate_user`]: trait.Authenticate.html#method.authenticate_user
-//! [`take`]: fn.take.html
-//! [`connect`]: struct.Manager.html#method.connect
-//! [`connect_model`]: struct.Manager.html#method.connect_model
-//! [`connect_pro`]: struct.Manager.html#method.connect_pro
-//! [`connect_storage`]: struct.Manager.html#method.connect_storage
-//! [`manager`]: trait.Device.html#method.manager
-//! [`device`]: struct.User.html#method.device
-//! [`get_hotp_code`]: trait.GenerateOtp.html#method.get_hotp_code
-//! [`get_totp_code`]: trait.GenerateOtp.html#method.get_totp_code
-//! [`Admin`]: struct.Admin.html
-//! [`DeviceWrapper`]: enum.DeviceWrapper.html
-//! [`User`]: struct.User.html
-
-#![warn(missing_docs, rust_2018_compatibility, rust_2018_idioms, unused)]
-
-#[macro_use(lazy_static)]
-extern crate lazy_static;
-
-mod auth;
-mod config;
-mod device;
-mod error;
-mod otp;
-mod pws;
-mod util;
-
-use std::fmt;
-use std::marker;
-use std::sync;
-
-use nitrokey_sys;
-
-pub use crate::auth::{Admin, Authenticate, User};
-pub use crate::config::Config;
-pub use crate::device::{
-    Device, DeviceWrapper, Model, Pro, SdCardData, Storage, StorageProductionInfo, StorageStatus,
-    VolumeMode, VolumeStatus,
-};
-pub use crate::error::{CommandError, CommunicationError, Error, LibraryError};
-pub use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData};
-pub use crate::pws::{GetPasswordSafe, PasswordSafe, SLOT_COUNT};
-pub use crate::util::LogLevel;
-
-/// The default admin PIN for all Nitrokey devices.
-pub const DEFAULT_ADMIN_PIN: &str = "12345678";
-/// The default user PIN for all Nitrokey devices.
-pub const DEFAULT_USER_PIN: &str = "123456";
-
-lazy_static! {
-    static ref MANAGER: sync::Mutex<Manager> = sync::Mutex::new(Manager::new());
-}
-
-/// A version of the libnitrokey library.
-///
-/// Use the [`get_library_version`](fn.get_library_version.html) function to query the library
-/// version.
-#[derive(Clone, Debug, PartialEq)]
-pub struct Version {
-    /// The Git library version as a string.
-    ///
-    /// The library version is the output of `git describe --always` at compile time, for example
-    /// `v3.3` or `v3.4.1`.  If the library has not been built from a release, the version string
-    /// contains the number of commits since the last release and the hash of the current commit, for
-    /// example `v3.3-19-gaee920b`.  If the library has not been built from a Git checkout, this
-    /// string may be empty.
-    pub git: String,
-    /// The major library version.
-    pub major: u32,
-    /// The minor library version.
-    pub minor: u32,
-}
-
-impl fmt::Display for Version {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        if self.git.is_empty() {
-            write!(f, "v{}.{}", self.major, self.minor)
-        } else {
-            f.write_str(&self.git)
-        }
-    }
-}
-
-/// A manager for connections to Nitrokey devices.
-///
-/// Currently, libnitrokey only provides access to one Nitrokey device at the same time.  This
-/// manager struct makes sure that `nitrokey-rs` does not try to connect to two devices at the same
-/// time.
-///
-/// To obtain a reference to an instance of this manager, use the [`take`][] function.  Use one of
-/// the connect methods – [`connect`][], [`connect_model`][], [`connect_pro`][] or
-/// [`connect_storage`][] – to retrieve a [`Device`][] instance.
-///
-/// # Examples
-///
-/// Connect to a single device:
-///
-/// ```no_run
-/// use nitrokey::Device;
-/// # use nitrokey::Error;
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect()?;
-/// println!("{}", device.get_serial_number()?);
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// Connect to a Pro and a Storage device:
-///
-/// ```no_run
-/// use nitrokey::{Device, Model};
-/// # use nitrokey::Error;
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let device = manager.connect_model(Model::Pro)?;
-/// println!("Pro: {}", device.get_serial_number()?);
-/// drop(device);
-/// let device = manager.connect_model(Model::Storage)?;
-/// println!("Storage: {}", device.get_serial_number()?);
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// [`connect`]: #method.connect
-/// [`connect_model`]: #method.connect_model
-/// [`connect_pro`]: #method.connect_pro
-/// [`connect_storage`]: #method.connect_storage
-/// [`manager`]: trait.Device.html#method.manager
-/// [`take`]: fn.take.html
-/// [`Device`]: trait.Device.html
-#[derive(Debug)]
-pub struct Manager {
-    marker: marker::PhantomData<()>,
-}
-
-impl Manager {
-    fn new() -> Self {
-        Manager {
-            marker: marker::PhantomData,
-        }
-    }
-
-    /// Connects to a Nitrokey device.
-    ///
-    /// This method can be used to connect to any connected device, both a Nitrokey Pro and a
-    /// Nitrokey Storage.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::DeviceWrapper;
-    ///
-    /// fn do_something(device: DeviceWrapper) {}
-    ///
-    /// let mut manager = nitrokey::take()?;
-    /// match manager.connect() {
-    ///     Ok(device) => do_something(device),
-    ///     Err(err) => println!("Could not connect to a Nitrokey: {}", err),
-    /// }
-    /// # Ok::<(), nitrokey::Error>(())
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect(&mut self) -> Result<DeviceWrapper<'_>, Error> {
-        if unsafe { nitrokey_sys::NK_login_auto() } == 1 {
-            device::get_connected_device(self)
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-
-    /// Connects to a Nitrokey device of the given model.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::DeviceWrapper;
-    /// use nitrokey::Model;
-    ///
-    /// fn do_something(device: DeviceWrapper) {}
-    ///
-    /// match nitrokey::take()?.connect_model(Model::Pro) {
-    ///     Ok(device) => do_something(device),
-    ///     Err(err) => println!("Could not connect to a Nitrokey Pro: {}", err),
-    /// }
-    /// # Ok::<(), nitrokey::Error>(())
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect_model(&mut self, model: Model) -> Result<DeviceWrapper<'_>, Error> {
-        if device::connect_enum(model) {
-            Ok(device::create_device_wrapper(self, model))
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-
-    /// Connects to a Nitrokey Pro.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::Pro;
-    ///
-    /// fn use_pro(device: Pro) {}
-    ///
-    /// match nitrokey::take()?.connect_pro() {
-    ///     Ok(device) => use_pro(device),
-    ///     Err(err) => println!("Could not connect to the Nitrokey Pro: {}", err),
-    /// }
-    /// # Ok::<(), nitrokey::Error>(())
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect_pro(&mut self) -> Result<Pro<'_>, Error> {
-        if device::connect_enum(device::Model::Pro) {
-            Ok(device::Pro::new(self))
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-
-    /// Connects to a Nitrokey Storage.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::Storage;
-    ///
-    /// fn use_storage(device: Storage) {}
-    ///
-    /// match nitrokey::take()?.connect_storage() {
-    ///     Ok(device) => use_storage(device),
-    ///     Err(err) => println!("Could not connect to the Nitrokey Storage: {}", err),
-    /// }
-    /// # Ok::<(), nitrokey::Error>(())
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect_storage(&mut self) -> Result<Storage<'_>, Error> {
-        if device::connect_enum(Model::Storage) {
-            Ok(Storage::new(self))
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-}
-
-/// Take an instance of the connection manager, blocking until an instance is available.
-///
-/// There may only be one [`Manager`][] instance at the same time.  If there already is an
-/// instance, this method blocks.  If you want a non-blocking version, use [`take`][].
-///
-/// # Errors
-///
-/// - [`PoisonError`][] if the lock is poisoned
-///
-/// [`take`]: fn.take.html
-/// [`PoisonError`]: struct.Error.html#variant.PoisonError
-/// [`Manager`]: struct.Manager.html
-pub fn take_blocking() -> Result<sync::MutexGuard<'static, Manager>, Error> {
-    MANAGER.lock().map_err(Into::into)
-}
-
-/// Try to take an instance of the connection manager.
-///
-/// There may only be one [`Manager`][] instance at the same time.  If there already is an
-/// instance, a [`ConcurrentAccessError`][] is returned.  If you want a blocking version, use
-/// [`take_blocking`][].  If you want to access the manager instance even if the cache is poisoned,
-/// use [`force_take`][].
-///
-/// # Errors
-///
-/// - [`ConcurrentAccessError`][] if the token for the `Manager` instance cannot be locked
-/// - [`PoisonError`][] if the lock is poisoned
-///
-/// [`take_blocking`]: fn.take_blocking.html
-/// [`force_take`]: fn.force_take.html
-/// [`ConcurrentAccessError`]: struct.Error.html#variant.ConcurrentAccessError
-/// [`PoisonError`]: struct.Error.html#variant.PoisonError
-/// [`Manager`]: struct.Manager.html
-pub fn take() -> Result<sync::MutexGuard<'static, Manager>, Error> {
-    MANAGER.try_lock().map_err(Into::into)
-}
-
-/// Try to take an instance of the connection manager, ignoring a poisoned cache.
-///
-/// There may only be one [`Manager`][] instance at the same time.  If there already is an
-/// instance, a [`ConcurrentAccessError`][] is returned.  If you want a blocking version, use
-/// [`take_blocking`][].
-///
-/// If a thread has previously panicked while accessing the manager instance, the cache is
-/// poisoned.  The default implementation, [`take`][], returns a [`PoisonError`][] on subsequent
-/// calls.  This implementation ignores the poisoned cache and returns the manager instance.
-///
-/// # Errors
-///
-/// - [`ConcurrentAccessError`][] if the token for the `Manager` instance cannot be locked
-///
-/// [`take`]: fn.take.html
-/// [`take_blocking`]: fn.take_blocking.html
-/// [`ConcurrentAccessError`]: struct.Error.html#variant.ConcurrentAccessError
-/// [`Manager`]: struct.Manager.html
-pub fn force_take() -> Result<sync::MutexGuard<'static, Manager>, Error> {
-    match take() {
-        Ok(guard) => Ok(guard),
-        Err(err) => match err {
-            Error::PoisonError(err) => Ok(err.into_inner()),
-            err => Err(err),
-        },
-    }
-}
-
-/// Enables or disables debug output.  Calling this method with `true` is equivalent to setting the
-/// log level to `Debug`; calling it with `false` is equivalent to the log level `Error` (see
-/// [`set_log_level`][]).
-///
-/// If debug output is enabled, detailed information about the communication with the Nitrokey
-/// device is printed to the standard output.
-///
-/// [`set_log_level`]: fn.set_log_level.html
-pub fn set_debug(state: bool) {
-    unsafe {
-        nitrokey_sys::NK_set_debug(state);
-    }
-}
-
-/// Sets the log level for libnitrokey.  All log messages are written to the standard error stream.
-/// Setting the log level enables all log messages on the same or on a higher log level.
-pub fn set_log_level(level: LogLevel) {
-    unsafe {
-        nitrokey_sys::NK_set_debug_level(level.into());
-    }
-}
-
-/// Returns the libnitrokey library version.
-///
-/// # Errors
-///
-/// - [`Utf8Error`][] if libnitrokey returned an invalid UTF-8 string
-///
-/// # Example
-///
-/// ```
-/// let version = nitrokey::get_library_version()?;
-/// println!("Using libnitrokey {}", version.git);
-/// # Ok::<(), nitrokey::Error>(())
-/// ```
-///
-/// [`Utf8Error`]: enum.Error.html#variant.Utf8Error
-pub fn get_library_version() -> Result<Version, Error> {
-    // NK_get_library_version returns a static string, so we don’t have to free the pointer.
-    let git = unsafe { nitrokey_sys::NK_get_library_version() };
-    let git = if git.is_null() {
-        String::new()
-    } else {
-        util::owned_str_from_ptr(git)?
-    };
-    let major = unsafe { nitrokey_sys::NK_get_major_library_version() };
-    let minor = unsafe { nitrokey_sys::NK_get_minor_library_version() };
-    Ok(Version { git, major, minor })
-}
diff --git a/nitrokey/src/otp.rs b/nitrokey/src/otp.rs
deleted file mode 100644
index 4667aff..0000000
--- a/nitrokey/src/otp.rs
+++ /dev/null
@@ -1,423 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::ffi::CString;
-
-use nitrokey_sys;
-
-use crate::error::Error;
-use crate::util::{get_command_result, get_cstring, result_from_string};
-
-/// Modes for one-time password generation.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum OtpMode {
-    /// Generate one-time passwords with six digits.
-    SixDigits,
-    /// Generate one-time passwords with eight digits.
-    EightDigits,
-}
-
-/// Provides methods to configure and erase OTP slots on a Nitrokey device.
-pub trait ConfigureOtp {
-    /// Configure an HOTP slot with the given data and set the HOTP counter to the given value
-    /// (default 0).
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`InvalidString`][] if the provided token ID contains a null byte
-    /// - [`NoName`][] if the provided name is empty
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, ConfigureOtp, OtpMode, OtpSlotData};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let slot_data = OtpSlotData::new(1, "test", "01234567890123456689", OtpMode::SixDigits);
-    /// match device.authenticate_admin("12345678") {
-    ///     Ok(mut admin) => {
-    ///         match admin.write_hotp_slot(slot_data, 0) {
-    ///             Ok(()) => println!("Successfully wrote slot."),
-    ///             Err(err) => eprintln!("Could not write slot: {}", err),
-    ///         }
-    ///     },
-    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`NoName`]: enum.CommandError.html#variant.NoName
-    fn write_hotp_slot(&mut self, data: OtpSlotData, counter: u64) -> Result<(), Error>;
-
-    /// Configure a TOTP slot with the given data and set the TOTP time window to the given value
-    /// (default 30).
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`InvalidString`][] if the provided token ID contains a null byte
-    /// - [`NoName`][] if the provided name is empty
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, ConfigureOtp, OtpMode, OtpSlotData};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// let slot_data = OtpSlotData::new(1, "test", "01234567890123456689", OtpMode::EightDigits);
-    /// match device.authenticate_admin("12345678") {
-    ///     Ok(mut admin) => {
-    ///         match admin.write_totp_slot(slot_data, 30) {
-    ///             Ok(()) => println!("Successfully wrote slot."),
-    ///             Err(err) => eprintln!("Could not write slot: {}", err),
-    ///         }
-    ///     },
-    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`NoName`]: enum.CommandError.html#variant.NoName
-    fn write_totp_slot(&mut self, data: OtpSlotData, time_window: u16) -> Result<(), Error>;
-
-    /// Erases an HOTP slot.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, ConfigureOtp};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.authenticate_admin("12345678") {
-    ///     Ok(mut admin) => {
-    ///         match admin.erase_hotp_slot(1) {
-    ///             Ok(()) => println!("Successfully erased slot."),
-    ///             Err(err) => eprintln!("Could not erase slot: {}", err),
-    ///         }
-    ///     },
-    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    fn erase_hotp_slot(&mut self, slot: u8) -> Result<(), Error>;
-
-    /// Erases a TOTP slot.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Authenticate, ConfigureOtp};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.authenticate_admin("12345678") {
-    ///     Ok(mut admin) => {
-    ///         match admin.erase_totp_slot(1) {
-    ///             Ok(()) => println!("Successfully erased slot."),
-    ///             Err(err) => eprintln!("Could not erase slot: {}", err),
-    ///         }
-    ///     },
-    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    fn erase_totp_slot(&mut self, slot: u8) -> Result<(), Error>;
-}
-
-/// Provides methods to generate OTP codes and to query OTP slots on a Nitrokey
-/// device.
-pub trait GenerateOtp {
-    /// Sets the time on the Nitrokey.
-    ///
-    /// `time` is the number of seconds since January 1st, 1970 (Unix timestamp).  Unless `force`
-    /// is set to `true`, this command fails if the timestamp on the device is larger than the
-    /// given timestamp or if it is zero.
-    ///
-    /// The time is used for TOTP generation (see [`get_totp_code`][]).
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use std::time;
-    /// use nitrokey::GenerateOtp;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let time = time::SystemTime::now().duration_since(time::UNIX_EPOCH);
-    /// match time {
-    ///     Ok(time) => device.set_time(time.as_secs(), false)?,
-    ///     Err(_) => eprintln!("The system time is before the Unix epoch!"),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// # Errors
-    ///
-    /// - [`Timestamp`][] if the time could not be set
-    ///
-    /// [`get_totp_code`]: #method.get_totp_code
-    /// [`Timestamp`]: enum.CommandError.html#variant.Timestamp
-    fn set_time(&mut self, time: u64, force: bool) -> Result<(), Error> {
-        let result = if force {
-            unsafe { nitrokey_sys::NK_totp_set_time(time) }
-        } else {
-            unsafe { nitrokey_sys::NK_totp_set_time_soft(time) }
-        };
-        get_command_result(result)
-    }
-
-    /// Returns the name of the given HOTP slot.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`SlotNotProgrammed`][] if the given slot is not configured
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{CommandError, Error, GenerateOtp};
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.get_hotp_slot_name(1) {
-    ///     Ok(name) => println!("HOTP slot 1: {}", name),
-    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => eprintln!("HOTP slot 1 not programmed"),
-    ///     Err(err) => eprintln!("Could not get slot name: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    fn get_hotp_slot_name(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_hotp_slot_name(slot) })
-    }
-
-    /// Returns the name of the given TOTP slot.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`SlotNotProgrammed`][] if the given slot is not configured
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{CommandError, Error, GenerateOtp};
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let device = manager.connect()?;
-    /// match device.get_totp_slot_name(1) {
-    ///     Ok(name) => println!("TOTP slot 1: {}", name),
-    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => eprintln!("TOTP slot 1 not programmed"),
-    ///     Err(err) => eprintln!("Could not get slot name: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    fn get_totp_slot_name(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_totp_slot_name(slot) })
-    }
-
-    /// Generates an HOTP code on the given slot.  This operation may require user authorization,
-    /// depending on the device configuration (see [`get_config`][]).
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`NotAuthorized`][] if OTP generation requires user authentication
-    /// - [`SlotNotProgrammed`][] if the given slot is not configured
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GenerateOtp;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let code = device.get_hotp_code(1)?;
-    /// println!("Generated HOTP code on slot 1: {}", code);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`get_config`]: trait.Device.html#method.get_config
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`NotAuthorized`]: enum.CommandError.html#variant.NotAuthorized
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    fn get_hotp_code(&mut self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_hotp_code(slot) })
-    }
-
-    /// Generates a TOTP code on the given slot.  This operation may require user authorization,
-    /// depending on the device configuration (see [`get_config`][]).
-    ///
-    /// To make sure that the Nitrokey’s time is in sync, consider calling [`set_time`][] before
-    /// calling this method.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if there is no slot with the given number
-    /// - [`NotAuthorized`][] if OTP generation requires user authentication
-    /// - [`SlotNotProgrammed`][] if the given slot is not configured
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use std::time;
-    /// use nitrokey::GenerateOtp;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let time = time::SystemTime::now().duration_since(time::UNIX_EPOCH);
-    /// match time {
-    ///     Ok(time) => {
-    ///         device.set_time(time.as_secs(), false)?;
-    ///         let code = device.get_totp_code(1)?;
-    ///         println!("Generated TOTP code on slot 1: {}", code);
-    ///     },
-    ///     Err(_) => eprintln!("Timestamps before 1970-01-01 are not supported!"),
-    /// }
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`set_time`]: #method.set_time
-    /// [`get_config`]: trait.Device.html#method.get_config
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`NotAuthorized`]: enum.CommandError.html#variant.NotAuthorized
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    fn get_totp_code(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_totp_code(slot, 0, 0, 0) })
-    }
-}
-
-/// The configuration for an OTP slot.
-#[derive(Debug)]
-pub struct OtpSlotData {
-    /// The number of the slot – must be less than three for HOTP and less than 15 for TOTP.
-    pub number: u8,
-    /// The name of the slot – must not be empty.
-    pub name: String,
-    /// The secret for the slot.
-    pub secret: String,
-    /// The OTP generation mode.
-    pub mode: OtpMode,
-    /// If true, press the enter key after sending an OTP code using double-pressed
-    /// numlock, capslock or scrolllock.
-    pub use_enter: bool,
-    /// Set the token ID, see [OATH Token Identifier Specification][tokspec], section “Class A”.
-    ///
-    /// [tokspec]: https://openauthentication.org/token-specs/
-    pub token_id: Option<String>,
-}
-
-#[derive(Debug)]
-pub struct RawOtpSlotData {
-    pub number: u8,
-    pub name: CString,
-    pub secret: CString,
-    pub mode: OtpMode,
-    pub use_enter: bool,
-    pub use_token_id: bool,
-    pub token_id: CString,
-}
-
-impl OtpSlotData {
-    /// Constructs a new instance of this struct.
-    pub fn new<S: Into<String>, T: Into<String>>(
-        number: u8,
-        name: S,
-        secret: T,
-        mode: OtpMode,
-    ) -> OtpSlotData {
-        OtpSlotData {
-            number,
-            name: name.into(),
-            secret: secret.into(),
-            mode,
-            use_enter: false,
-            token_id: None,
-        }
-    }
-
-    /// Enables pressing the enter key after sending an OTP code using double-pressed numlock,
-    /// capslock or scrollock.
-    pub fn use_enter(mut self) -> OtpSlotData {
-        self.use_enter = true;
-        self
-    }
-
-    /// Sets the token ID, see [OATH Token Identifier Specification][tokspec], section “Class A”.
-    ///
-    /// [tokspec]: https://openauthentication.org/token-specs/
-    pub fn token_id<S: Into<String>>(mut self, id: S) -> OtpSlotData {
-        self.token_id = Some(id.into());
-        self
-    }
-}
-
-impl RawOtpSlotData {
-    pub fn new(data: OtpSlotData) -> Result<RawOtpSlotData, Error> {
-        let name = get_cstring(data.name)?;
-        let secret = get_cstring(data.secret)?;
-        let use_token_id = data.token_id.is_some();
-        let token_id = get_cstring(data.token_id.unwrap_or_else(String::new))?;
-
-        Ok(RawOtpSlotData {
-            number: data.number,
-            name,
-            secret,
-            mode: data.mode,
-            use_enter: data.use_enter,
-            use_token_id,
-            token_id,
-        })
-    }
-}
diff --git a/nitrokey/src/pws.rs b/nitrokey/src/pws.rs
deleted file mode 100644
index 3398deb..0000000
--- a/nitrokey/src/pws.rs
+++ /dev/null
@@ -1,391 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use libc;
-use nitrokey_sys;
-
-use crate::device::{Device, DeviceWrapper, Pro, Storage};
-use crate::error::{CommandError, Error};
-use crate::util::{get_command_result, get_cstring, get_last_error, result_from_string};
-
-/// The number of slots in a [`PasswordSafe`][].
-///
-/// [`PasswordSafe`]: struct.PasswordSafe.html
-pub const SLOT_COUNT: u8 = 16;
-
-/// A password safe on a Nitrokey device.
-///
-/// The password safe stores a tuple consisting of a name, a login and a password on a slot.  The
-/// number of available slots is [`SLOT_COUNT`][].  The slots are addressed starting with zero.  To
-/// retrieve a password safe from a Nitrokey device, use the [`get_password_safe`][] method from
-/// the [`GetPasswordSafe`][] trait.  Note that the device must live at least as long as the
-/// password safe.
-///
-/// Once the password safe has been unlocked, it can be accessed without a password.  Therefore it
-/// is mandatory to call [`lock`][] on the corresponding device after the password store is used.
-/// As this command may have side effects on the Nitrokey Storage, it cannot be called
-/// automatically once the password safe is destroyed.
-///
-/// # Examples
-///
-/// Open a password safe and access a password:
-///
-/// ```no_run
-/// use nitrokey::{Device, GetPasswordSafe, PasswordSafe};
-/// # use nitrokey::Error;
-///
-/// fn use_password_safe(pws: &PasswordSafe) -> Result<(), Error> {
-///     let name = pws.get_slot_name(0)?;
-///     let login = pws.get_slot_login(0)?;
-///     let password = pws.get_slot_login(0)?;
-///     println!("Credentials for {}: login {}, password {}", name, login, password);
-///     Ok(())
-/// }
-///
-/// # fn try_main() -> Result<(), Error> {
-/// let mut manager = nitrokey::take()?;
-/// let mut device = manager.connect()?;
-/// let pws = device.get_password_safe("123456")?;
-/// use_password_safe(&pws);
-/// drop(pws);
-/// device.lock()?;
-/// #     Ok(())
-/// # }
-/// ```
-///
-/// [`SLOT_COUNT`]: constant.SLOT_COUNT.html
-/// [`get_password_safe`]: trait.GetPasswordSafe.html#method.get_password_safe
-/// [`lock`]: trait.Device.html#method.lock
-/// [`GetPasswordSafe`]: trait.GetPasswordSafe.html
-#[derive(Debug)]
-pub struct PasswordSafe<'a, 'b> {
-    _device: &'a dyn Device<'b>,
-}
-
-/// Provides access to a [`PasswordSafe`][].
-///
-/// The device that implements this trait must always live at least as long as a password safe
-/// retrieved from it.
-///
-/// [`PasswordSafe`]: struct.PasswordSafe.html
-pub trait GetPasswordSafe<'a> {
-    /// Enables and returns the password safe.
-    ///
-    /// The underlying device must always live at least as long as a password safe retrieved from
-    /// it.  It is mandatory to lock the underlying device using [`lock`][] after the password safe
-    /// has been used.  Otherwise, other applications can access the password store without
-    /// authentication.
-    ///
-    /// If this method returns an `AesDecryptionFailed` (Nitrokey Pro) or `Unknown` (Nitrokey
-    /// Storage) error, the AES data object on the smart card could not be accessed.  This problem
-    /// occurs after a factory reset using `gpg --card-edit` and can be fixed using the
-    /// [`Device::build_aes_key`][] command.
-    ///
-    /// # Errors
-    ///
-    /// - [`AesDecryptionFailed`][] if the secret for the password safe could not be decrypted
-    ///   (Nitrokey Pro only)
-    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
-    /// - [`Unknown`][] if the secret for the password safe could not be decrypted (Nitrokey
-    ///   Storage only)
-    /// - [`WrongPassword`][] if the current user password is wrong
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{Device, GetPasswordSafe, PasswordSafe};
-    /// # use nitrokey::Error;
-    ///
-    /// fn use_password_safe(pws: &PasswordSafe) {}
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.get_password_safe("123456") {
-    ///     Ok(pws) => {
-    ///         use_password_safe(&pws);
-    ///     },
-    ///     Err(err) => eprintln!("Could not open the password safe: {}", err),
-    /// };
-    /// device.lock()?;
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`device`]: struct.PasswordSafe.html#method.device
-    /// [`lock`]: trait.Device.html#method.lock
-    /// [`AesDecryptionFailed`]: enum.CommandError.html#variant.AesDecryptionFailed
-    /// [`Device::build_aes_key`]: trait.Device.html#method.build_aes_key
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    /// [`Unknown`]: enum.CommandError.html#variant.Unknown
-    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
-    fn get_password_safe(&mut self, user_pin: &str) -> Result<PasswordSafe<'_, 'a>, Error>;
-}
-
-fn get_password_safe<'a, 'b>(
-    device: &'a dyn Device<'b>,
-    user_pin: &str,
-) -> Result<PasswordSafe<'a, 'b>, Error> {
-    let user_pin_string = get_cstring(user_pin)?;
-    get_command_result(unsafe { nitrokey_sys::NK_enable_password_safe(user_pin_string.as_ptr()) })
-        .map(|_| PasswordSafe { _device: device })
-}
-
-fn get_pws_result(s: String) -> Result<String, Error> {
-    if s.is_empty() {
-        Err(CommandError::SlotNotProgrammed.into())
-    } else {
-        Ok(s)
-    }
-}
-
-impl<'a, 'b> PasswordSafe<'a, 'b> {
-    /// Returns the status of all password slots.
-    ///
-    /// The status indicates whether a slot is programmed or not.
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::{GetPasswordSafe, SLOT_COUNT};
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let pws = device.get_password_safe("123456")?;
-    /// pws.get_slot_status()?.iter().enumerate().for_each(|(slot, programmed)| {
-    ///     let status = match *programmed {
-    ///         true => "programmed",
-    ///         false => "not programmed",
-    ///     };
-    ///     println!("Slot {}: {}", slot, status);
-    /// });
-    /// #     Ok(())
-    /// # }
-    /// ```
-    pub fn get_slot_status(&self) -> Result<[bool; SLOT_COUNT as usize], Error> {
-        let status_ptr = unsafe { nitrokey_sys::NK_get_password_safe_slot_status() };
-        if status_ptr.is_null() {
-            return Err(get_last_error());
-        }
-        let status_array_ptr = status_ptr as *const [u8; SLOT_COUNT as usize];
-        let status_array = unsafe { *status_array_ptr };
-        let mut result = [false; SLOT_COUNT as usize];
-        for i in 0..SLOT_COUNT {
-            result[i as usize] = status_array[i as usize] == 1;
-        }
-        unsafe {
-            libc::free(status_ptr as *mut libc::c_void);
-        }
-        Ok(result)
-    }
-
-    /// Returns the name of the given slot (if it is programmed).
-    ///
-    /// This method also returns a `SlotNotProgrammed` error if the name is empty.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the given slot is out of range
-    /// - [`SlotNotProgrammed`][] if the slot is not programmed
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GetPasswordSafe;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// match device.get_password_safe("123456") {
-    ///     Ok(pws) => {
-    ///         let name = pws.get_slot_name(0)?;
-    ///         let login = pws.get_slot_login(0)?;
-    ///         let password = pws.get_slot_login(0)?;
-    ///         println!("Credentials for {}: login {}, password {}", name, login, password);
-    ///     },
-    ///     Err(err) => eprintln!("Could not open the password safe: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    pub fn get_slot_name(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_password_safe_slot_name(slot) })
-            .and_then(get_pws_result)
-    }
-
-    /// Returns the login for the given slot (if it is programmed).
-    ///
-    /// This method also returns a `SlotNotProgrammed` error if the login is empty.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the given slot is out of range
-    /// - [`SlotNotProgrammed`][] if the slot is not programmed
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GetPasswordSafe;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let pws = device.get_password_safe("123456")?;
-    /// let name = pws.get_slot_name(0)?;
-    /// let login = pws.get_slot_login(0)?;
-    /// let password = pws.get_slot_login(0)?;
-    /// println!("Credentials for {}: login {}, password {}", name, login, password);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    pub fn get_slot_login(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_password_safe_slot_login(slot) })
-            .and_then(get_pws_result)
-    }
-
-    /// Returns the password for the given slot (if it is programmed).
-    ///
-    /// This method also returns a `SlotNotProgrammed` error if the password is empty.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the given slot is out of range
-    /// - [`SlotNotProgrammed`][] if the slot is not programmed
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GetPasswordSafe;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let pws = device.get_password_safe("123456")?;
-    /// let name = pws.get_slot_name(0)?;
-    /// let login = pws.get_slot_login(0)?;
-    /// let password = pws.get_slot_login(0)?;
-    /// println!("Credentials for {}: login {}, password {}", name, login, password);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`SlotNotProgrammed`]: enum.CommandError.html#variant.SlotNotProgrammed
-    pub fn get_slot_password(&self, slot: u8) -> Result<String, Error> {
-        result_from_string(unsafe { nitrokey_sys::NK_get_password_safe_slot_password(slot) })
-            .and_then(get_pws_result)
-    }
-
-    /// Writes the given slot with the given name, login and password.
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the given slot is out of range
-    /// - [`InvalidString`][] if the provided token ID contains a null byte
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GetPasswordSafe;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let pws = device.get_password_safe("123456")?;
-    /// let name = pws.get_slot_name(0)?;
-    /// let login = pws.get_slot_login(0)?;
-    /// let password = pws.get_slot_login(0)?;
-    /// println!("Credentials for {}: login {}, password {}", name, login, password);
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
-    pub fn write_slot(
-        &mut self,
-        slot: u8,
-        name: &str,
-        login: &str,
-        password: &str,
-    ) -> Result<(), Error> {
-        let name_string = get_cstring(name)?;
-        let login_string = get_cstring(login)?;
-        let password_string = get_cstring(password)?;
-        get_command_result(unsafe {
-            nitrokey_sys::NK_write_password_safe_slot(
-                slot,
-                name_string.as_ptr(),
-                login_string.as_ptr(),
-                password_string.as_ptr(),
-            )
-        })
-    }
-
-    /// Erases the given slot.  Erasing clears the stored name, login and password (if the slot was
-    /// programmed).
-    ///
-    /// # Errors
-    ///
-    /// - [`InvalidSlot`][] if the given slot is out of range
-    ///
-    /// # Example
-    ///
-    /// ```no_run
-    /// use nitrokey::GetPasswordSafe;
-    /// # use nitrokey::Error;
-    ///
-    /// # fn try_main() -> Result<(), Error> {
-    /// let mut manager = nitrokey::take()?;
-    /// let mut device = manager.connect()?;
-    /// let mut pws = device.get_password_safe("123456")?;
-    /// match pws.erase_slot(0) {
-    ///     Ok(()) => println!("Erased slot 0."),
-    ///     Err(err) => eprintln!("Could not erase slot 0: {}", err),
-    /// };
-    /// #     Ok(())
-    /// # }
-    /// ```
-    ///
-    /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    pub fn erase_slot(&mut self, slot: u8) -> Result<(), Error> {
-        get_command_result(unsafe { nitrokey_sys::NK_erase_password_safe_slot(slot) })
-    }
-}
-
-impl<'a, 'b> Drop for PasswordSafe<'a, 'b> {
-    fn drop(&mut self) {
-        // TODO: disable the password safe -- NK_lock_device has side effects on the Nitrokey
-        // Storage, see https://github.com/Nitrokey/nitrokey-storage-firmware/issues/65
-    }
-}
-
-impl<'a> GetPasswordSafe<'a> for Pro<'a> {
-    fn get_password_safe(&mut self, user_pin: &str) -> Result<PasswordSafe<'_, 'a>, Error> {
-        get_password_safe(self, user_pin)
-    }
-}
-
-impl<'a> GetPasswordSafe<'a> for Storage<'a> {
-    fn get_password_safe(&mut self, user_pin: &str) -> Result<PasswordSafe<'_, 'a>, Error> {
-        get_password_safe(self, user_pin)
-    }
-}
-
-impl<'a> GetPasswordSafe<'a> for DeviceWrapper<'a> {
-    fn get_password_safe(&mut self, user_pin: &str) -> Result<PasswordSafe<'_, 'a>, Error> {
-        get_password_safe(self, user_pin)
-    }
-}
diff --git a/nitrokey/src/util.rs b/nitrokey/src/util.rs
deleted file mode 100644
index 5a56c55..0000000
--- a/nitrokey/src/util.rs
+++ /dev/null
@@ -1,99 +0,0 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
-// SPDX-License-Identifier: MIT
-
-use std::ffi::{CStr, CString};
-use std::os::raw::{c_char, c_int};
-
-use libc::{c_void, free};
-use rand_core::{OsRng, RngCore};
-
-use crate::error::{Error, LibraryError};
-
-/// Log level for libnitrokey.
-///
-/// Setting the log level to a lower level enables all output from higher levels too.  Currently,
-/// only the log levels `Warning`, `DebugL1`, `Debug` and `DebugL2` are actually used.
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub enum LogLevel {
-    /// Error messages.  Currently not used.
-    Error,
-    /// Warning messages.
-    Warning,
-    /// Informational messages.  Currently not used.
-    Info,
-    /// Basic debug messages, especially basic information on the sent and received packets.
-    DebugL1,
-    /// Detailed debug messages, especially detailed information on the sent and received packets.
-    Debug,
-    /// Very detailed debug messages, especially detailed information about the control flow for
-    /// device communication (for example function entries and exits).
-    DebugL2,
-}
-
-pub fn owned_str_from_ptr(ptr: *const c_char) -> Result<String, Error> {
-    unsafe { CStr::from_ptr(ptr) }
-        .to_str()
-        .map(String::from)
-        .map_err(Error::from)
-}
-
-pub fn result_from_string(ptr: *const c_char) -> Result<String, Error> {
-    if ptr.is_null() {
-        return Err(Error::UnexpectedError);
-    }
-    let s = owned_str_from_ptr(ptr)?;
-    unsafe { free(ptr as *mut c_void) };
-    // An empty string can both indicate an error or be a valid return value.  In this case, we
-    // have to check the last command status to decide what to return.
-    if s.is_empty() {
-        get_last_result().map(|_| s)
-    } else {
-        Ok(s)
-    }
-}
-
-pub fn result_or_error<T>(value: T) -> Result<T, Error> {
-    get_last_result().and(Ok(value))
-}
-
-pub fn get_command_result(value: c_int) -> Result<(), Error> {
-    if value == 0 {
-        Ok(())
-    } else {
-        Err(Error::from(value))
-    }
-}
-
-pub fn get_last_result() -> Result<(), Error> {
-    get_command_result(unsafe { nitrokey_sys::NK_get_last_command_status() }.into())
-}
-
-pub fn get_last_error() -> Error {
-    match get_last_result() {
-        Ok(()) => Error::UnexpectedError,
-        Err(err) => err,
-    }
-}
-
-pub fn generate_password(length: usize) -> Result<Vec<u8>, Error> {
-    let mut data = vec![0u8; length];
-    OsRng.fill_bytes(&mut data[..]);
-    Ok(data)
-}
-
-pub fn get_cstring<T: Into<Vec<u8>>>(s: T) -> Result<CString, Error> {
-    CString::new(s).or_else(|_| Err(LibraryError::InvalidString.into()))
-}
-
-impl Into<i32> for LogLevel {
-    fn into(self) -> i32 {
-        match self {
-            LogLevel::Error => 0,
-            LogLevel::Warning => 1,
-            LogLevel::Info => 2,
-            LogLevel::DebugL1 => 3,
-            LogLevel::Debug => 4,
-            LogLevel::DebugL2 => 5,
-        }
-    }
-}