Add nitrokey as a dependency to nitrocli

The nitrokey crate provides a simple interface to the Nitrokey Storage
and the Nitrokey Pro based on the libnitrokey library developed by
Nitrokey UG.  The low-level bindings to this library are available in
the nitrokey-sys crate.

This patch adds version v0.2.1 of the nitrokey crate as a dependency
for nitrocli.  It includes the indirect dependencies nitrokey-sys
(version 3.4.1) and rand (version 0.4.3).

Import subrepo nitrokey/:nitrokey at 2eccc96ceec2282b868891befe9cda7f941fbe7b
Import subrepo nitrokey-sys/:nitrokey-sys at f1a11ebf72610fb9cf80ac7f9f147b4ba1a5336f
Import subrepo rand/:rand at d7d5da49daf7ceb3e5940072940d495cced3a1b3

1 files changed, 321 insertions, 0 deletions

diff --git a/rand/src/prng/chacha.rs b/rand/src/prng/chacha.rs
new file mode 100644
index 0000000..a73e8e7
--- /dev/null
+++ b/rand/src/prng/chacha.rs
@@ -0,0 +1,321 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The ChaCha random number generator.
+
+use core::num::Wrapping as w;
+use {Rng, SeedableRng, Rand};
+
+#[allow(bad_style)]
+type w32 = w<u32>;
+
+const KEY_WORDS    : usize =  8; // 8 words for the 256-bit key
+const STATE_WORDS  : usize = 16;
+const CHACHA_ROUNDS: u32 = 20; // Cryptographically secure from 8 upwards as of this writing
+
+/// A random number generator that uses the ChaCha20 algorithm [1].
+///
+/// The ChaCha algorithm is widely accepted as suitable for
+/// cryptographic purposes, but this implementation has not been
+/// verified as such. Prefer a generator like `OsRng` that defers to
+/// the operating system for cases that need high security.
+///
+/// [1]: D. J. Bernstein, [*ChaCha, a variant of
+/// Salsa20*](http://cr.yp.to/chacha.html)
+#[derive(Copy, Clone, Debug)]
+pub struct ChaChaRng {
+    buffer:  [w32; STATE_WORDS], // Internal buffer of output
+    state:   [w32; STATE_WORDS], // Initial state
+    index:   usize,                 // Index into state
+}
+
+static EMPTY: ChaChaRng = ChaChaRng {
+    buffer:  [w(0); STATE_WORDS],
+    state:   [w(0); STATE_WORDS],
+    index:   STATE_WORDS
+};
+
+
+macro_rules! quarter_round{
+    ($a: expr, $b: expr, $c: expr, $d: expr) => {{
+        $a = $a + $b; $d = $d ^ $a; $d = w($d.0.rotate_left(16));
+        $c = $c + $d; $b = $b ^ $c; $b = w($b.0.rotate_left(12));
+        $a = $a + $b; $d = $d ^ $a; $d = w($d.0.rotate_left( 8));
+        $c = $c + $d; $b = $b ^ $c; $b = w($b.0.rotate_left( 7));
+    }}
+}
+
+macro_rules! double_round{
+    ($x: expr) => {{
+        // Column round
+        quarter_round!($x[ 0], $x[ 4], $x[ 8], $x[12]);
+        quarter_round!($x[ 1], $x[ 5], $x[ 9], $x[13]);
+        quarter_round!($x[ 2], $x[ 6], $x[10], $x[14]);
+        quarter_round!($x[ 3], $x[ 7], $x[11], $x[15]);
+        // Diagonal round
+        quarter_round!($x[ 0], $x[ 5], $x[10], $x[15]);
+        quarter_round!($x[ 1], $x[ 6], $x[11], $x[12]);
+        quarter_round!($x[ 2], $x[ 7], $x[ 8], $x[13]);
+        quarter_round!($x[ 3], $x[ 4], $x[ 9], $x[14]);
+    }}
+}
+
+#[inline]
+fn core(output: &mut [w32; STATE_WORDS], input: &[w32; STATE_WORDS]) {
+    *output = *input;
+
+    for _ in 0..CHACHA_ROUNDS / 2 {
+        double_round!(output);
+    }
+
+    for i in 0..STATE_WORDS {
+        output[i] = output[i] + input[i];
+    }
+}
+
+impl ChaChaRng {
+
+    /// Create an ChaCha random number generator using the default
+    /// fixed key of 8 zero words.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use rand::{Rng, ChaChaRng};
+    ///
+    /// let mut ra = ChaChaRng::new_unseeded();
+    /// println!("{:?}", ra.next_u32());
+    /// println!("{:?}", ra.next_u32());
+    /// ```
+    ///
+    /// Since this equivalent to a RNG with a fixed seed, repeated executions
+    /// of an unseeded RNG will produce the same result. This code sample will
+    /// consistently produce:
+    ///
+    /// - 2917185654
+    /// - 2419978656
+    pub fn new_unseeded() -> ChaChaRng {
+        let mut rng = EMPTY;
+        rng.init(&[0; KEY_WORDS]);
+        rng
+    }
+
+    /// Sets the internal 128-bit ChaCha counter to
+    /// a user-provided value. This permits jumping
+    /// arbitrarily ahead (or backwards) in the pseudorandom stream.
+    ///
+    /// Since the nonce words are used to extend the counter to 128 bits,
+    /// users wishing to obtain the conventional ChaCha pseudorandom stream
+    /// associated with a particular nonce can call this function with
+    /// arguments `0, desired_nonce`.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use rand::{Rng, ChaChaRng};
+    ///
+    /// let mut ra = ChaChaRng::new_unseeded();
+    /// ra.set_counter(0u64, 1234567890u64);
+    /// println!("{:?}", ra.next_u32());
+    /// println!("{:?}", ra.next_u32());
+    /// ```
+    pub fn set_counter(&mut self, counter_low: u64, counter_high: u64) {
+        self.state[12] = w((counter_low >>  0) as u32);
+        self.state[13] = w((counter_low >> 32) as u32);
+        self.state[14] = w((counter_high >>  0) as u32);
+        self.state[15] = w((counter_high >> 32) as u32);
+        self.index = STATE_WORDS; // force recomputation
+    }
+
+    /// Initializes `self.state` with the appropriate key and constants
+    ///
+    /// We deviate slightly from the ChaCha specification regarding
+    /// the nonce, which is used to extend the counter to 128 bits.
+    /// This is provably as strong as the original cipher, though,
+    /// since any distinguishing attack on our variant also works
+    /// against ChaCha with a chosen-nonce. See the XSalsa20 [1]
+    /// security proof for a more involved example of this.
+    ///
+    /// The modified word layout is:
+    /// ```text
+    /// constant constant constant constant
+    /// key      key      key      key
+    /// key      key      key      key
+    /// counter  counter  counter  counter
+    /// ```
+    /// [1]: Daniel J. Bernstein. [*Extending the Salsa20
+    /// nonce.*](http://cr.yp.to/papers.html#xsalsa)
+    fn init(&mut self, key: &[u32; KEY_WORDS]) {
+        self.state[0] = w(0x61707865);
+        self.state[1] = w(0x3320646E);
+        self.state[2] = w(0x79622D32);
+        self.state[3] = w(0x6B206574);
+
+        for i in 0..KEY_WORDS {
+            self.state[4+i] = w(key[i]);
+        }
+
+        self.state[12] = w(0);
+        self.state[13] = w(0);
+        self.state[14] = w(0);
+        self.state[15] = w(0);
+
+        self.index = STATE_WORDS;
+    }
+
+    /// Refill the internal output buffer (`self.buffer`)
+    fn update(&mut self) {
+        core(&mut self.buffer, &self.state);
+        self.index = 0;
+        // update 128-bit counter
+        self.state[12] = self.state[12] + w(1);
+        if self.state[12] != w(0) { return };
+        self.state[13] = self.state[13] + w(1);
+        if self.state[13] != w(0) { return };
+        self.state[14] = self.state[14] + w(1);
+        if self.state[14] != w(0) { return };
+        self.state[15] = self.state[15] + w(1);
+    }
+}
+
+impl Rng for ChaChaRng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        if self.index == STATE_WORDS {
+            self.update();
+        }
+
+        let value = self.buffer[self.index % STATE_WORDS];
+        self.index += 1;
+        value.0
+    }
+}
+
+impl<'a> SeedableRng<&'a [u32]> for ChaChaRng {
+
+    fn reseed(&mut self, seed: &'a [u32]) {
+        // reset state
+        self.init(&[0u32; KEY_WORDS]);
+        // set key in place
+        let key = &mut self.state[4 .. 4+KEY_WORDS];
+        for (k, s) in key.iter_mut().zip(seed.iter()) {
+            *k = w(*s);
+        }
+    }
+
+    /// Create a ChaCha generator from a seed,
+    /// obtained from a variable-length u32 array.
+    /// Only up to 8 words are used; if less than 8
+    /// words are used, the remaining are set to zero.
+    fn from_seed(seed: &'a [u32]) -> ChaChaRng {
+        let mut rng = EMPTY;
+        rng.reseed(seed);
+        rng
+    }
+}
+
+impl Rand for ChaChaRng {
+    fn rand<R: Rng>(other: &mut R) -> ChaChaRng {
+        let mut key : [u32; KEY_WORDS] = [0; KEY_WORDS];
+        for word in key.iter_mut() {
+            *word = other.gen();
+        }
+        SeedableRng::from_seed(&key[..])
+    }
+}
+
+
+#[cfg(test)]
+mod test {
+    use {Rng, SeedableRng};
+    use super::ChaChaRng;
+
+    #[test]
+    fn test_rng_rand_seeded() {
+        let s = ::test::rng().gen_iter::<u32>().take(8).collect::<Vec<u32>>();
+        let mut ra: ChaChaRng = SeedableRng::from_seed(&s[..]);
+        let mut rb: ChaChaRng = SeedableRng::from_seed(&s[..]);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_seeded() {
+        let seed : &[_] = &[0,1,2,3,4,5,6,7];
+        let mut ra: ChaChaRng = SeedableRng::from_seed(seed);
+        let mut rb: ChaChaRng = SeedableRng::from_seed(seed);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_reseed() {
+        let s = ::test::rng().gen_iter::<u32>().take(8).collect::<Vec<u32>>();
+        let mut r: ChaChaRng = SeedableRng::from_seed(&s[..]);
+        let string1: String = r.gen_ascii_chars().take(100).collect();
+
+        r.reseed(&s);
+
+        let string2: String = r.gen_ascii_chars().take(100).collect();
+        assert_eq!(string1, string2);
+    }
+
+    #[test]
+    fn test_rng_true_values() {
+        // Test vectors 1 and 2 from
+        // http://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
+        let seed : &[_] = &[0u32; 8];
+        let mut ra: ChaChaRng = SeedableRng::from_seed(seed);
+
+        let v = (0..16).map(|_| ra.next_u32()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(0xade0b876, 0x903df1a0, 0xe56a5d40, 0x28bd8653,
+                        0xb819d2bd, 0x1aed8da0, 0xccef36a8, 0xc70d778b,
+                        0x7c5941da, 0x8d485751, 0x3fe02477, 0x374ad8b8,
+                        0xf4b8436a, 0x1ca11815, 0x69b687c3, 0x8665eeb2));
+
+        let v = (0..16).map(|_| ra.next_u32()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(0xbee7079f, 0x7a385155, 0x7c97ba98, 0x0d082d73,
+                        0xa0290fcb, 0x6965e348, 0x3e53c612, 0xed7aee32,
+                        0x7621b729, 0x434ee69c, 0xb03371d5, 0xd539d874,
+                        0x281fed31, 0x45fb0a51, 0x1f0ae1ac, 0x6f4d794b));
+
+
+        let seed : &[_] = &[0,1,2,3,4,5,6,7];
+        let mut ra: ChaChaRng = SeedableRng::from_seed(seed);
+
+        // Store the 17*i-th 32-bit word,
+        // i.e., the i-th word of the i-th 16-word block
+        let mut v : Vec<u32> = Vec::new();
+        for _ in 0..16 {
+            v.push(ra.next_u32());
+            for _ in 0..16 {
+                ra.next_u32();
+            }
+        }
+
+        assert_eq!(v,
+                   vec!(0xf225c81a, 0x6ab1be57, 0x04d42951, 0x70858036,
+                        0x49884684, 0x64efec72, 0x4be2d186, 0x3615b384,
+                        0x11cfa18e, 0xd3c50049, 0x75c775f6, 0x434c6530,
+                        0x2c5bad8f, 0x898881dc, 0x5f1c86d9, 0xc1f8e7f4));
+    }
+
+    #[test]
+    fn test_rng_clone() {
+        let seed : &[_] = &[0u32; 8];
+        let mut rng: ChaChaRng = SeedableRng::from_seed(seed);
+        let mut clone = rng.clone();
+        for _ in 0..16 {
+            assert_eq!(rng.next_u64(), clone.next_u64());
+        }
+    }
+}