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

5 files changed, 1141 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());
+        }
+    }
+}
diff --git a/rand/src/prng/isaac.rs b/rand/src/prng/isaac.rs
new file mode 100644
index 0000000..cf5eb67
--- /dev/null
+++ b/rand/src/prng/isaac.rs
@@ -0,0 +1,328 @@
+// Copyright 2013 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 ISAAC random number generator.
+
+#![allow(non_camel_case_types)]
+
+use core::slice;
+use core::iter::repeat;
+use core::num::Wrapping as w;
+use core::fmt;
+
+use {Rng, SeedableRng, Rand};
+
+#[allow(bad_style)]
+type w32 = w<u32>;
+
+const RAND_SIZE_LEN: usize = 8;
+const RAND_SIZE: u32 = 1 << RAND_SIZE_LEN;
+const RAND_SIZE_USIZE: usize = 1 << RAND_SIZE_LEN;
+
+/// A random number generator that uses the ISAAC algorithm[1].
+///
+/// The ISAAC algorithm is generally accepted as suitable for
+/// cryptographic purposes, but this implementation has not be
+/// verified as such. Prefer a generator like `OsRng` that defers to
+/// the operating system for cases that need high security.
+///
+/// [1]: Bob Jenkins, [*ISAAC: A fast cryptographic random number
+/// generator*](http://www.burtleburtle.net/bob/rand/isaacafa.html)
+#[derive(Copy)]
+pub struct IsaacRng {
+    cnt: u32,
+    rsl: [w32; RAND_SIZE_USIZE],
+    mem: [w32; RAND_SIZE_USIZE],
+    a: w32,
+    b: w32,
+    c: w32,
+}
+
+static EMPTY: IsaacRng = IsaacRng {
+    cnt: 0,
+    rsl: [w(0); RAND_SIZE_USIZE],
+    mem: [w(0); RAND_SIZE_USIZE],
+    a: w(0), b: w(0), c: w(0),
+};
+
+impl IsaacRng {
+
+    /// Create an ISAAC random number generator using the default
+    /// fixed seed.
+    pub fn new_unseeded() -> IsaacRng {
+        let mut rng = EMPTY;
+        rng.init(false);
+        rng
+    }
+
+    /// Initialises `self`. If `use_rsl` is true, then use the current value
+    /// of `rsl` as a seed, otherwise construct one algorithmically (not
+    /// randomly).
+    fn init(&mut self, use_rsl: bool) {
+        let mut a = w(0x9e3779b9);
+        let mut b = a;
+        let mut c = a;
+        let mut d = a;
+        let mut e = a;
+        let mut f = a;
+        let mut g = a;
+        let mut h = a;
+
+        macro_rules! mix {
+            () => {{
+                a=a^(b<<11); d=d+a; b=b+c;
+                b=b^(c>>2);  e=e+b; c=c+d;
+                c=c^(d<<8);  f=f+c; d=d+e;
+                d=d^(e>>16); g=g+d; e=e+f;
+                e=e^(f<<10); h=h+e; f=f+g;
+                f=f^(g>>4);  a=a+f; g=g+h;
+                g=g^(h<<8);  b=b+g; h=h+a;
+                h=h^(a>>9);  c=c+h; a=a+b;
+            }}
+        }
+
+        for _ in 0..4 {
+            mix!();
+        }
+
+        if use_rsl {
+            macro_rules! memloop {
+                ($arr:expr) => {{
+                    for i in (0..RAND_SIZE_USIZE/8).map(|i| i * 8) {
+                        a=a+$arr[i  ]; b=b+$arr[i+1];
+                        c=c+$arr[i+2]; d=d+$arr[i+3];
+                        e=e+$arr[i+4]; f=f+$arr[i+5];
+                        g=g+$arr[i+6]; h=h+$arr[i+7];
+                        mix!();
+                        self.mem[i  ]=a; self.mem[i+1]=b;
+                        self.mem[i+2]=c; self.mem[i+3]=d;
+                        self.mem[i+4]=e; self.mem[i+5]=f;
+                        self.mem[i+6]=g; self.mem[i+7]=h;
+                    }
+                }}
+            }
+
+            memloop!(self.rsl);
+            memloop!(self.mem);
+        } else {
+            for i in (0..RAND_SIZE_USIZE/8).map(|i| i * 8) {
+                mix!();
+                self.mem[i  ]=a; self.mem[i+1]=b;
+                self.mem[i+2]=c; self.mem[i+3]=d;
+                self.mem[i+4]=e; self.mem[i+5]=f;
+                self.mem[i+6]=g; self.mem[i+7]=h;
+            }
+        }
+
+        self.isaac();
+    }
+
+    /// Refills the output buffer (`self.rsl`)
+    #[inline]
+    fn isaac(&mut self) {
+        self.c = self.c + w(1);
+        // abbreviations
+        let mut a = self.a;
+        let mut b = self.b + self.c;
+
+        const MIDPOINT: usize = RAND_SIZE_USIZE / 2;
+
+        macro_rules! ind {
+            ($x:expr) => ( self.mem[($x >> 2usize).0 as usize & (RAND_SIZE_USIZE - 1)] )
+        }
+
+        let r = [(0, MIDPOINT), (MIDPOINT, 0)];
+        for &(mr_offset, m2_offset) in r.iter() {
+
+            macro_rules! rngstepp {
+                ($j:expr, $shift:expr) => {{
+                    let base = $j;
+                    let mix = a << $shift;
+
+                    let x = self.mem[base  + mr_offset];
+                    a = (a ^ mix) + self.mem[base + m2_offset];
+                    let y = ind!(x) + a + b;
+                    self.mem[base + mr_offset] = y;
+
+                    b = ind!(y >> RAND_SIZE_LEN) + x;
+                    self.rsl[base + mr_offset] = b;
+                }}
+            }
+
+            macro_rules! rngstepn {
+                ($j:expr, $shift:expr) => {{
+                    let base = $j;
+                    let mix = a >> $shift;
+
+                    let x = self.mem[base  + mr_offset];
+                    a = (a ^ mix) + self.mem[base + m2_offset];
+                    let y = ind!(x) + a + b;
+                    self.mem[base + mr_offset] = y;
+
+                    b = ind!(y >> RAND_SIZE_LEN) + x;
+                    self.rsl[base + mr_offset] = b;
+                }}
+            }
+
+            for i in (0..MIDPOINT/4).map(|i| i * 4) {
+                rngstepp!(i + 0, 13);
+                rngstepn!(i + 1, 6);
+                rngstepp!(i + 2, 2);
+                rngstepn!(i + 3, 16);
+            }
+        }
+
+        self.a = a;
+        self.b = b;
+        self.cnt = RAND_SIZE;
+    }
+}
+
+// Cannot be derived because [u32; 256] does not implement Clone
+impl Clone for IsaacRng {
+    fn clone(&self) -> IsaacRng {
+        *self
+    }
+}
+
+impl Rng for IsaacRng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        if self.cnt == 0 {
+            // make some more numbers
+            self.isaac();
+        }
+        self.cnt -= 1;
+
+        // self.cnt is at most RAND_SIZE, but that is before the
+        // subtraction above. We want to index without bounds
+        // checking, but this could lead to incorrect code if someone
+        // misrefactors, so we check, sometimes.
+        //
+        // (Changes here should be reflected in Isaac64Rng.next_u64.)
+        debug_assert!(self.cnt < RAND_SIZE);
+
+        // (the % is cheaply telling the optimiser that we're always
+        // in bounds, without unsafe. NB. this is a power of two, so
+        // it optimises to a bitwise mask).
+        self.rsl[(self.cnt % RAND_SIZE) as usize].0
+    }
+}
+
+impl<'a> SeedableRng<&'a [u32]> for IsaacRng {
+    fn reseed(&mut self, seed: &'a [u32]) {
+        // make the seed into [seed[0], seed[1], ..., seed[seed.len()
+        // - 1], 0, 0, ...], to fill rng.rsl.
+        let seed_iter = seed.iter().map(|&x| x).chain(repeat(0u32));
+
+        for (rsl_elem, seed_elem) in self.rsl.iter_mut().zip(seed_iter) {
+            *rsl_elem = w(seed_elem);
+        }
+        self.cnt = 0;
+        self.a = w(0);
+        self.b = w(0);
+        self.c = w(0);
+
+        self.init(true);
+    }
+
+    /// Create an ISAAC random number generator with a seed. This can
+    /// be any length, although the maximum number of elements used is
+    /// 256 and any more will be silently ignored. A generator
+    /// constructed with a given seed will generate the same sequence
+    /// of values as all other generators constructed with that seed.
+    fn from_seed(seed: &'a [u32]) -> IsaacRng {
+        let mut rng = EMPTY;
+        rng.reseed(seed);
+        rng
+    }
+}
+
+impl Rand for IsaacRng {
+    fn rand<R: Rng>(other: &mut R) -> IsaacRng {
+        let mut ret = EMPTY;
+        unsafe {
+            let ptr = ret.rsl.as_mut_ptr() as *mut u8;
+
+            let slice = slice::from_raw_parts_mut(ptr, RAND_SIZE_USIZE * 4);
+            other.fill_bytes(slice);
+        }
+        ret.cnt = 0;
+        ret.a = w(0);
+        ret.b = w(0);
+        ret.c = w(0);
+
+        ret.init(true);
+        return ret;
+    }
+}
+
+impl fmt::Debug for IsaacRng {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "IsaacRng {{}}")
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use {Rng, SeedableRng};
+    use super::IsaacRng;
+
+    #[test]
+    fn test_rng_32_rand_seeded() {
+        let s = ::test::rng().gen_iter::<u32>().take(256).collect::<Vec<u32>>();
+        let mut ra: IsaacRng = SeedableRng::from_seed(&s[..]);
+        let mut rb: IsaacRng = SeedableRng::from_seed(&s[..]);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_32_seeded() {
+        let seed: &[_] = &[1, 23, 456, 7890, 12345];
+        let mut ra: IsaacRng = SeedableRng::from_seed(seed);
+        let mut rb: IsaacRng = SeedableRng::from_seed(seed);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_32_reseed() {
+        let s = ::test::rng().gen_iter::<u32>().take(256).collect::<Vec<u32>>();
+        let mut r: IsaacRng = 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_32_true_values() {
+        let seed: &[_] = &[1, 23, 456, 7890, 12345];
+        let mut ra: IsaacRng = SeedableRng::from_seed(seed);
+        // Regression test that isaac is actually using the above vector
+        let v = (0..10).map(|_| ra.next_u32()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(2558573138, 873787463, 263499565, 2103644246, 3595684709,
+                        4203127393, 264982119, 2765226902, 2737944514, 3900253796));
+
+        let seed: &[_] = &[12345, 67890, 54321, 9876];
+        let mut rb: IsaacRng = SeedableRng::from_seed(seed);
+        // skip forward to the 10000th number
+        for _ in 0..10000 { rb.next_u32(); }
+
+        let v = (0..10).map(|_| rb.next_u32()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(3676831399, 3183332890, 2834741178, 3854698763, 2717568474,
+                        1576568959, 3507990155, 179069555, 141456972, 2478885421));
+    }
+}
diff --git a/rand/src/prng/isaac64.rs b/rand/src/prng/isaac64.rs
new file mode 100644
index 0000000..b98e3fe
--- /dev/null
+++ b/rand/src/prng/isaac64.rs
@@ -0,0 +1,340 @@
+// Copyright 2013 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 ISAAC-64 random number generator.
+
+use core::slice;
+use core::iter::repeat;
+use core::num::Wrapping as w;
+use core::fmt;
+
+use {Rng, SeedableRng, Rand};
+
+#[allow(bad_style)]
+type w64 = w<u64>;
+
+const RAND_SIZE_64_LEN: usize = 8;
+const RAND_SIZE_64: usize = 1 << RAND_SIZE_64_LEN;
+
+/// A random number generator that uses ISAAC-64[1], the 64-bit
+/// variant of the ISAAC algorithm.
+///
+/// The ISAAC algorithm is generally accepted as suitable for
+/// cryptographic purposes, but this implementation has not be
+/// verified as such. Prefer a generator like `OsRng` that defers to
+/// the operating system for cases that need high security.
+///
+/// [1]: Bob Jenkins, [*ISAAC: A fast cryptographic random number
+/// generator*](http://www.burtleburtle.net/bob/rand/isaacafa.html)
+#[derive(Copy)]
+pub struct Isaac64Rng {
+    cnt: usize,
+    rsl: [w64; RAND_SIZE_64],
+    mem: [w64; RAND_SIZE_64],
+    a: w64,
+    b: w64,
+    c: w64,
+}
+
+static EMPTY_64: Isaac64Rng = Isaac64Rng {
+    cnt: 0,
+    rsl: [w(0); RAND_SIZE_64],
+    mem: [w(0); RAND_SIZE_64],
+    a: w(0), b: w(0), c: w(0),
+};
+
+impl Isaac64Rng {
+    /// Create a 64-bit ISAAC random number generator using the
+    /// default fixed seed.
+    pub fn new_unseeded() -> Isaac64Rng {
+        let mut rng = EMPTY_64;
+        rng.init(false);
+        rng
+    }
+
+    /// Initialises `self`. If `use_rsl` is true, then use the current value
+    /// of `rsl` as a seed, otherwise construct one algorithmically (not
+    /// randomly).
+    fn init(&mut self, use_rsl: bool) {
+        macro_rules! init {
+            ($var:ident) => (
+                let mut $var = w(0x9e3779b97f4a7c13);
+            )
+        }
+        init!(a); init!(b); init!(c); init!(d);
+        init!(e); init!(f); init!(g); init!(h);
+
+        macro_rules! mix {
+            () => {{
+                a=a-e; f=f^(h>>9);  h=h+a;
+                b=b-f; g=g^(a<<9);  a=a+b;
+                c=c-g; h=h^(b>>23); b=b+c;
+                d=d-h; a=a^(c<<15); c=c+d;
+                e=e-a; b=b^(d>>14); d=d+e;
+                f=f-b; c=c^(e<<20); e=e+f;
+                g=g-c; d=d^(f>>17); f=f+g;
+                h=h-d; e=e^(g<<14); g=g+h;
+            }}
+        }
+
+        for _ in 0..4 {
+            mix!();
+        }
+
+        if use_rsl {
+            macro_rules! memloop {
+                ($arr:expr) => {{
+                    for i in (0..RAND_SIZE_64 / 8).map(|i| i * 8) {
+                        a=a+$arr[i  ]; b=b+$arr[i+1];
+                        c=c+$arr[i+2]; d=d+$arr[i+3];
+                        e=e+$arr[i+4]; f=f+$arr[i+5];
+                        g=g+$arr[i+6]; h=h+$arr[i+7];
+                        mix!();
+                        self.mem[i  ]=a; self.mem[i+1]=b;
+                        self.mem[i+2]=c; self.mem[i+3]=d;
+                        self.mem[i+4]=e; self.mem[i+5]=f;
+                        self.mem[i+6]=g; self.mem[i+7]=h;
+                    }
+                }}
+            }
+
+            memloop!(self.rsl);
+            memloop!(self.mem);
+        } else {
+            for i in (0..RAND_SIZE_64 / 8).map(|i| i * 8) {
+                mix!();
+                self.mem[i  ]=a; self.mem[i+1]=b;
+                self.mem[i+2]=c; self.mem[i+3]=d;
+                self.mem[i+4]=e; self.mem[i+5]=f;
+                self.mem[i+6]=g; self.mem[i+7]=h;
+            }
+        }
+
+        self.isaac64();
+    }
+
+    /// Refills the output buffer (`self.rsl`)
+    fn isaac64(&mut self) {
+        self.c = self.c + w(1);
+        // abbreviations
+        let mut a = self.a;
+        let mut b = self.b + self.c;
+        const MIDPOINT: usize =  RAND_SIZE_64 / 2;
+        const MP_VEC: [(usize, usize); 2] = [(0,MIDPOINT), (MIDPOINT, 0)];
+        macro_rules! ind {
+            ($x:expr) => {
+                *self.mem.get_unchecked((($x >> 3usize).0 as usize) & (RAND_SIZE_64 - 1))
+            }
+        }
+
+        for &(mr_offset, m2_offset) in MP_VEC.iter() {
+            for base in (0..MIDPOINT / 4).map(|i| i * 4) {
+
+                macro_rules! rngstepp {
+                    ($j:expr, $shift:expr) => {{
+                        let base = base + $j;
+                        let mix = a ^ (a << $shift);
+                        let mix = if $j == 0 {!mix} else {mix};
+
+                        unsafe {
+                            let x = *self.mem.get_unchecked(base + mr_offset);
+                            a = mix + *self.mem.get_unchecked(base + m2_offset);
+                            let y = ind!(x) + a + b;
+                            *self.mem.get_unchecked_mut(base + mr_offset) = y;
+
+                            b = ind!(y >> RAND_SIZE_64_LEN) + x;
+                            *self.rsl.get_unchecked_mut(base + mr_offset) = b;
+                        }
+                    }}
+                }
+
+                macro_rules! rngstepn {
+                    ($j:expr, $shift:expr) => {{
+                        let base = base + $j;
+                        let mix = a ^ (a >> $shift);
+                        let mix = if $j == 0 {!mix} else {mix};
+
+                        unsafe {
+                            let x = *self.mem.get_unchecked(base + mr_offset);
+                            a = mix + *self.mem.get_unchecked(base + m2_offset);
+                            let y = ind!(x) + a + b;
+                            *self.mem.get_unchecked_mut(base + mr_offset) = y;
+
+                            b = ind!(y >> RAND_SIZE_64_LEN) + x;
+                            *self.rsl.get_unchecked_mut(base + mr_offset) = b;
+                        }
+                    }}
+                }
+
+                rngstepp!(0, 21);
+                rngstepn!(1, 5);
+                rngstepp!(2, 12);
+                rngstepn!(3, 33);
+            }
+        }
+
+        self.a = a;
+        self.b = b;
+        self.cnt = RAND_SIZE_64;
+    }
+}
+
+// Cannot be derived because [u32; 256] does not implement Clone
+impl Clone for Isaac64Rng {
+    fn clone(&self) -> Isaac64Rng {
+        *self
+    }
+}
+
+impl Rng for Isaac64Rng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        self.next_u64() as u32
+    }
+
+    #[inline]
+    fn next_u64(&mut self) -> u64 {
+        if self.cnt == 0 {
+            // make some more numbers
+            self.isaac64();
+        }
+        self.cnt -= 1;
+
+        // See corresponding location in IsaacRng.next_u32 for
+        // explanation.
+        debug_assert!(self.cnt < RAND_SIZE_64);
+        self.rsl[(self.cnt % RAND_SIZE_64) as usize].0
+    }
+}
+
+impl<'a> SeedableRng<&'a [u64]> for Isaac64Rng {
+    fn reseed(&mut self, seed: &'a [u64]) {
+        // make the seed into [seed[0], seed[1], ..., seed[seed.len()
+        // - 1], 0, 0, ...], to fill rng.rsl.
+        let seed_iter = seed.iter().map(|&x| x).chain(repeat(0u64));
+
+        for (rsl_elem, seed_elem) in self.rsl.iter_mut().zip(seed_iter) {
+            *rsl_elem = w(seed_elem);
+        }
+        self.cnt = 0;
+        self.a = w(0);
+        self.b = w(0);
+        self.c = w(0);
+
+        self.init(true);
+    }
+
+    /// Create an ISAAC random number generator with a seed. This can
+    /// be any length, although the maximum number of elements used is
+    /// 256 and any more will be silently ignored. A generator
+    /// constructed with a given seed will generate the same sequence
+    /// of values as all other generators constructed with that seed.
+    fn from_seed(seed: &'a [u64]) -> Isaac64Rng {
+        let mut rng = EMPTY_64;
+        rng.reseed(seed);
+        rng
+    }
+}
+
+impl Rand for Isaac64Rng {
+    fn rand<R: Rng>(other: &mut R) -> Isaac64Rng {
+        let mut ret = EMPTY_64;
+        unsafe {
+            let ptr = ret.rsl.as_mut_ptr() as *mut u8;
+
+            let slice = slice::from_raw_parts_mut(ptr, RAND_SIZE_64 * 8);
+            other.fill_bytes(slice);
+        }
+        ret.cnt = 0;
+        ret.a = w(0);
+        ret.b = w(0);
+        ret.c = w(0);
+
+        ret.init(true);
+        return ret;
+    }
+}
+
+impl fmt::Debug for Isaac64Rng {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Isaac64Rng {{}}")
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use {Rng, SeedableRng};
+    use super::Isaac64Rng;
+
+    #[test]
+    fn test_rng_64_rand_seeded() {
+        let s = ::test::rng().gen_iter::<u64>().take(256).collect::<Vec<u64>>();
+        let mut ra: Isaac64Rng = SeedableRng::from_seed(&s[..]);
+        let mut rb: Isaac64Rng = SeedableRng::from_seed(&s[..]);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_64_seeded() {
+        let seed: &[_] = &[1, 23, 456, 7890, 12345];
+        let mut ra: Isaac64Rng = SeedableRng::from_seed(seed);
+        let mut rb: Isaac64Rng = SeedableRng::from_seed(seed);
+        assert!(::test::iter_eq(ra.gen_ascii_chars().take(100),
+                                rb.gen_ascii_chars().take(100)));
+    }
+
+    #[test]
+    fn test_rng_64_reseed() {
+        let s = ::test::rng().gen_iter::<u64>().take(256).collect::<Vec<u64>>();
+        let mut r: Isaac64Rng = 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_64_true_values() {
+        let seed: &[_] = &[1, 23, 456, 7890, 12345];
+        let mut ra: Isaac64Rng = SeedableRng::from_seed(seed);
+        // Regression test that isaac is actually using the above vector
+        let v = (0..10).map(|_| ra.next_u64()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(547121783600835980, 14377643087320773276, 17351601304698403469,
+                        1238879483818134882, 11952566807690396487, 13970131091560099343,
+                        4469761996653280935, 15552757044682284409, 6860251611068737823,
+                        13722198873481261842));
+
+        let seed: &[_] = &[12345, 67890, 54321, 9876];
+        let mut rb: Isaac64Rng = SeedableRng::from_seed(seed);
+        // skip forward to the 10000th number
+        for _ in 0..10000 { rb.next_u64(); }
+
+        let v = (0..10).map(|_| rb.next_u64()).collect::<Vec<_>>();
+        assert_eq!(v,
+                   vec!(18143823860592706164, 8491801882678285927, 2699425367717515619,
+                        17196852593171130876, 2606123525235546165, 15790932315217671084,
+                        596345674630742204, 9947027391921273664, 11788097613744130851,
+                        10391409374914919106));
+    }
+
+    #[test]
+    fn test_rng_clone() {
+        let seed: &[_] = &[1, 23, 456, 7890, 12345];
+        let mut rng: Isaac64Rng = SeedableRng::from_seed(seed);
+        let mut clone = rng.clone();
+        for _ in 0..16 {
+            assert_eq!(rng.next_u64(), clone.next_u64());
+        }
+    }
+}
diff --git a/rand/src/prng/mod.rs b/rand/src/prng/mod.rs
new file mode 100644
index 0000000..ed3e018
--- /dev/null
+++ b/rand/src/prng/mod.rs
@@ -0,0 +1,51 @@
+// Copyright 2017 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.
+
+//! Pseudo random number generators are algorithms to produce *apparently
+//! random* numbers deterministically, and usually fairly quickly.
+//! 
+//! So long as the algorithm is computationally secure, is initialised with
+//! sufficient entropy (i.e. unknown by an attacker), and its internal state is
+//! also protected (unknown to an attacker), the output will also be
+//! *computationally secure*. Computationally Secure Pseudo Random Number
+//! Generators (CSPRNGs) are thus suitable sources of random numbers for
+//! cryptography. There are a couple of gotchas here, however. First, the seed
+//! used for initialisation must be unknown. Usually this should be provided by
+//! the operating system and should usually be secure, however this may not
+//! always be the case (especially soon after startup). Second, user-space
+//! memory may be vulnerable, for example when written to swap space, and after
+//! forking a child process should reinitialise any user-space PRNGs. For this
+//! reason it may be preferable to source random numbers directly from the OS
+//! for cryptographic applications.
+//! 
+//! PRNGs are also widely used for non-cryptographic uses: randomised
+//! algorithms, simulations, games. In these applications it is usually not
+//! important for numbers to be cryptographically *unguessable*, but even
+//! distribution and independence from other samples (from the point of view
+//! of someone unaware of the algorithm used, at least) may still be important.
+//! Good PRNGs should satisfy these properties, but do not take them for
+//! granted; Wikipedia's article on 
+//! [Pseudorandom number generators](https://en.wikipedia.org/wiki/Pseudorandom_number_generator)
+//! provides some background on this topic.
+//! 
+//! Care should be taken when seeding (initialising) PRNGs. Some PRNGs have
+//! short periods for some seeds. If one PRNG is seeded from another using the
+//! same algorithm, it is possible that both will yield the same sequence of
+//! values (with some lag).
+
+mod chacha;
+mod isaac;
+mod isaac64;
+mod xorshift;
+
+pub use self::chacha::ChaChaRng;
+pub use self::isaac::IsaacRng;
+pub use self::isaac64::Isaac64Rng;
+pub use self::xorshift::XorShiftRng;
diff --git a/rand/src/prng/xorshift.rs b/rand/src/prng/xorshift.rs
new file mode 100644
index 0000000..dd367e9
--- /dev/null
+++ b/rand/src/prng/xorshift.rs
@@ -0,0 +1,101 @@
+// Copyright 2017 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.
+
+//! Xorshift generators
+
+use core::num::Wrapping as w;
+use {Rng, SeedableRng, Rand};
+
+/// An Xorshift[1] random number
+/// generator.
+///
+/// The Xorshift algorithm is not suitable for cryptographic purposes
+/// but is very fast. If you do not know for sure that it fits your
+/// requirements, use a more secure one such as `IsaacRng` or `OsRng`.
+///
+/// [1]: Marsaglia, George (July 2003). ["Xorshift
+/// RNGs"](http://www.jstatsoft.org/v08/i14/paper). *Journal of
+/// Statistical Software*. Vol. 8 (Issue 14).
+#[allow(missing_copy_implementations)]
+#[derive(Clone, Debug)]
+pub struct XorShiftRng {
+    x: w<u32>,
+    y: w<u32>,
+    z: w<u32>,
+    w: w<u32>,
+}
+
+impl XorShiftRng {
+    /// Creates a new XorShiftRng instance which is not seeded.
+    ///
+    /// The initial values of this RNG are constants, so all generators created
+    /// by this function will yield the same stream of random numbers. It is
+    /// highly recommended that this is created through `SeedableRng` instead of
+    /// this function
+    pub fn new_unseeded() -> XorShiftRng {
+        XorShiftRng {
+            x: w(0x193a6754),
+            y: w(0xa8a7d469),
+            z: w(0x97830e05),
+            w: w(0x113ba7bb),
+        }
+    }
+}
+
+impl Rng for XorShiftRng {
+    #[inline]
+    fn next_u32(&mut self) -> u32 {
+        let x = self.x;
+        let t = x ^ (x << 11);
+        self.x = self.y;
+        self.y = self.z;
+        self.z = self.w;
+        let w_ = self.w;
+        self.w = w_ ^ (w_ >> 19) ^ (t ^ (t >> 8));
+        self.w.0
+    }
+}
+
+impl SeedableRng<[u32; 4]> for XorShiftRng {
+    /// Reseed an XorShiftRng. This will panic if `seed` is entirely 0.
+    fn reseed(&mut self, seed: [u32; 4]) {
+        assert!(!seed.iter().all(|&x| x == 0),
+                "XorShiftRng.reseed called with an all zero seed.");
+
+        self.x = w(seed[0]);
+        self.y = w(seed[1]);
+        self.z = w(seed[2]);
+        self.w = w(seed[3]);
+    }
+
+    /// Create a new XorShiftRng. This will panic if `seed` is entirely 0.
+    fn from_seed(seed: [u32; 4]) -> XorShiftRng {
+        assert!(!seed.iter().all(|&x| x == 0),
+                "XorShiftRng::from_seed called with an all zero seed.");
+
+        XorShiftRng {
+            x: w(seed[0]),
+            y: w(seed[1]),
+            z: w(seed[2]),
+            w: w(seed[3]),
+        }
+    }
+}
+
+impl Rand for XorShiftRng {
+    fn rand<R: Rng>(rng: &mut R) -> XorShiftRng {
+        let mut tuple: (u32, u32, u32, u32) = rng.gen();
+        while tuple == (0, 0, 0, 0) {
+            tuple = rng.gen();
+        }
+        let (x, y, z, w_) = tuple;
+        XorShiftRng { x: w(x), y: w(y), z: w(z), w: w(w_) }
+    }
+}