Artifact Content
Not logged in

Artifact 111ef93e4f82ec81c11ec293e8129d27c239bb3f:


//! `crypto_secretbox_xsalsa20poly1305`, a particular
//! combination of Salsa20 and Poly1305 specified in
//! [Cryptography in `NaCl`](http://nacl.cr.yp.to/valid.html).
//!
//! This function is conjectured to meet the standard notions of privacy and
//! authenticity.

use ffi;
use marshal::marshal;
use randombytes::randombytes_into;
#[cfg(feature = "rustc-serialize")]
use rustc_serialize;

/// Number of bytes in `Key`.
pub const KEYBYTES: usize = ffi::crypto_secretbox_xsalsa20poly1305_KEYBYTES;

/// Number of bytes in a `Nonce`.
pub const NONCEBYTES: usize = ffi::crypto_secretbox_xsalsa20poly1305_NONCEBYTES;

new_type! {
    /// `Key` for symmetric authenticated encryption
    ///
    /// When a `Key` goes out of scope its contents
    /// will be zeroed out
    secret Key(KEYBYTES);
}

new_type! {
    /// `Nonce` for symmetric authenticated encryption
    nonce Nonce(NONCEBYTES);
}

const ZEROBYTES: usize = 32;
const BOXZEROBYTES: usize = 16;

/// Number of bytes in the authenticator tag of an encrypted message
/// i.e. the number of bytes by which the ciphertext is larger than the
/// plaintext.
pub const MACBYTES: usize = ffi::crypto_secretbox_xsalsa20poly1305_MACBYTES;

/// `gen_key()` randomly generates a secret key
///
/// THREAD SAFETY: `gen_key()` is thread-safe provided that you have
/// called `rust_sodium::init()` once before using any other function
/// from `rust_sodium`.
pub fn gen_key() -> Key {
    let mut key = [0; KEYBYTES];
    randombytes_into(&mut key);
    Key(key)
}

/// `gen_nonce()` randomly generates a nonce
///
/// THREAD SAFETY: `gen_key()` is thread-safe provided that you have
/// called `rust_sodium::init()` once before using any other function
/// from `rust_sodium`.
pub fn gen_nonce() -> Nonce {
    let mut nonce = [0; NONCEBYTES];
    randombytes_into(&mut nonce);
    Nonce(nonce)
}

/// `seal()` encrypts and authenticates a message `m` using a secret key `k` and a
/// nonce `n`.  It returns a ciphertext `c`.
pub fn seal(m: &[u8], &Nonce(ref n): &Nonce, &Key(ref k): &Key) -> Vec<u8> {
    let (c, _) = marshal(m, ZEROBYTES, BOXZEROBYTES, |dst, src, len| unsafe {
        ffi::crypto_secretbox_xsalsa20poly1305(dst, src, len, n.as_ptr(), k.as_ptr())
    });
    c
}

/// `open()` verifies and decrypts a ciphertext `c` using a secret key `k` and a nonce `n`.
/// It returns a plaintext `Ok(m)`.
/// If the ciphertext fails verification, `open()` returns `Err(())`.
pub fn open(c: &[u8], &Nonce(ref n): &Nonce, &Key(ref k): &Key) -> Result<Vec<u8>, ()> {
    if c.len() < BOXZEROBYTES {
        return Err(());
    }
    let (m, ret) =
        marshal(c, BOXZEROBYTES, ZEROBYTES, |dst, src, len| unsafe {
            ffi::crypto_secretbox_xsalsa20poly1305_open(dst, src, len, n.as_ptr(), k.as_ptr())
        });
    if ret == 0 { Ok(m) } else { Err(()) }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_seal_open() {
        use randombytes::randombytes;
        assert!(::init());
        for i in 0..256usize {
            let k = gen_key();
            let m = randombytes(i);
            let n = gen_nonce();
            let c = seal(&m, &n, &k);
            let opened = open(&c, &n, &k);
            assert!(Ok(m) == opened);
        }
    }

    #[test]
    #[cfg_attr(feature="cargo-clippy", allow(needless_range_loop))]
    fn test_seal_open_tamper() {
        use randombytes::randombytes;
        assert!(::init());
        for i in 0..32usize {
            let k = gen_key();
            let m = randombytes(i);
            let n = gen_nonce();
            let mut c = seal(&m, &n, &k);
            for i in 0..c.len() {
                c[i] ^= 0x20;
                assert!(Err(()) == open(&c, &n, &k));
                c[i] ^= 0x20;
            }
        }
    }

    #[test]
    fn test_vector_1() {
        assert!(::init());
        let firstkey = Key([0x1b, 0x27, 0x55, 0x64, 0x73, 0xe9, 0x85, 0xd4, 0x62, 0xcd, 0x51,
                            0x19, 0x7a, 0x9a, 0x46, 0xc7, 0x60, 0x09, 0x54, 0x9e, 0xac, 0x64,
                            0x74, 0xf2, 0x06, 0xc4, 0xee, 0x08, 0x44, 0xf6, 0x83, 0x89]);
        let nonce = Nonce([0x69, 0x69, 0x6e, 0xe9, 0x55, 0xb6, 0x2b, 0x73, 0xcd, 0x62, 0xbd,
                           0xa8, 0x75, 0xfc, 0x73, 0xd6, 0x82, 0x19, 0xe0, 0x03, 0x6b, 0x7a,
                           0x0b, 0x37]);
        let m = vec![0xbe, 0x07, 0x5f, 0xc5, 0x3c, 0x81, 0xf2, 0xd5, 0xcf, 0x14, 0x13, 0x16, 0xeb,
                     0xeb, 0x0c, 0x7b, 0x52, 0x28, 0xc5, 0x2a, 0x4c, 0x62, 0xcb, 0xd4, 0x4b, 0x66,
                     0x84, 0x9b, 0x64, 0x24, 0x4f, 0xfc, 0xe5, 0xec, 0xba, 0xaf, 0x33, 0xbd, 0x75,
                     0x1a, 0x1a, 0xc7, 0x28, 0xd4, 0x5e, 0x6c, 0x61, 0x29, 0x6c, 0xdc, 0x3c, 0x01,
                     0x23, 0x35, 0x61, 0xf4, 0x1d, 0xb6, 0x6c, 0xce, 0x31, 0x4a, 0xdb, 0x31, 0x0e,
                     0x3b, 0xe8, 0x25, 0x0c, 0x46, 0xf0, 0x6d, 0xce, 0xea, 0x3a, 0x7f, 0xa1, 0x34,
                     0x80, 0x57, 0xe2, 0xf6, 0x55, 0x6a, 0xd6, 0xb1, 0x31, 0x8a, 0x02, 0x4a, 0x83,
                     0x8f, 0x21, 0xaf, 0x1f, 0xde, 0x04, 0x89, 0x77, 0xeb, 0x48, 0xf5, 0x9f, 0xfd,
                     0x49, 0x24, 0xca, 0x1c, 0x60, 0x90, 0x2e, 0x52, 0xf0, 0xa0, 0x89, 0xbc, 0x76,
                     0x89, 0x70, 0x40, 0xe0, 0x82, 0xf9, 0x37, 0x76, 0x38, 0x48, 0x64, 0x5e, 0x07,
                     0x05];

        let c_expected =
            vec![0xf3, 0xff, 0xc7, 0x70, 0x3f, 0x94, 0x00, 0xe5, 0x2a, 0x7d, 0xfb, 0x4b, 0x3d,
                 0x33, 0x05, 0xd9, 0x8e, 0x99, 0x3b, 0x9f, 0x48, 0x68, 0x12, 0x73, 0xc2, 0x96,
                 0x50, 0xba, 0x32, 0xfc, 0x76, 0xce, 0x48, 0x33, 0x2e, 0xa7, 0x16, 0x4d, 0x96,
                 0xa4, 0x47, 0x6f, 0xb8, 0xc5, 0x31, 0xa1, 0x18, 0x6a, 0xc0, 0xdf, 0xc1, 0x7c,
                 0x98, 0xdc, 0xe8, 0x7b, 0x4d, 0xa7, 0xf0, 0x11, 0xec, 0x48, 0xc9, 0x72, 0x71,
                 0xd2, 0xc2, 0x0f, 0x9b, 0x92, 0x8f, 0xe2, 0x27, 0x0d, 0x6f, 0xb8, 0x63, 0xd5,
                 0x17, 0x38, 0xb4, 0x8e, 0xee, 0xe3, 0x14, 0xa7, 0xcc, 0x8a, 0xb9, 0x32, 0x16,
                 0x45, 0x48, 0xe5, 0x26, 0xae, 0x90, 0x22, 0x43, 0x68, 0x51, 0x7a, 0xcf, 0xea,
                 0xbd, 0x6b, 0xb3, 0x73, 0x2b, 0xc0, 0xe9, 0xda, 0x99, 0x83, 0x2b, 0x61, 0xca,
                 0x01, 0xb6, 0xde, 0x56, 0x24, 0x4a, 0x9e, 0x88, 0xd5, 0xf9, 0xb3, 0x79, 0x73,
                 0xf6, 0x22, 0xa4, 0x3d, 0x14, 0xa6, 0x59, 0x9b, 0x1f, 0x65, 0x4c, 0xb4, 0x5a,
                 0x74, 0xe3, 0x55, 0xa5];
        let c = seal(&m, &nonce, &firstkey);
        assert!(c == c_expected);
        let m2 = open(&c, &nonce, &firstkey);
        assert!(Ok(m) == m2);
    }

    #[cfg(any(feature = "serde", feature = "rustc-serialize"))]
    #[test]
    fn test_serialisation() {
        use test_utils::round_trip;
        assert!(::init());
        for _ in 0..256usize {
            let k = gen_key();
            let n = gen_nonce();
            round_trip(k);
            round_trip(n);
        }
    }
}

#[cfg(feature = "benchmarks")]
#[cfg(test)]
mod bench {
    extern crate test;
    use super::*;
    use randombytes::randombytes;

    const BENCH_SIZES: [usize; 14] = [0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096];

    #[bench]
    fn bench_seal_open(b: &mut test::Bencher) {
        assert!(::init());
        let k = gen_key();
        let n = gen_nonce();
        let ms: Vec<Vec<u8>> = BENCH_SIZES.iter().map(|s| randombytes(*s)).collect();
        b.iter(|| for m in ms.iter() {
                   unwrap!(open(&seal(&m, &n, &k), &n, &k));
               });
    }
}