//! `crypto_stream_xsalsa20`, a particular cipher specified in
//! [Cryptography in NaCl](http://nacl.cr.yp.to/valid.html), Section 7.
//! This cipher is conjectured to meet the standard notion of
//! unpredictability.
use ffi::{crypto_stream_xsalsa20,
          crypto_stream_xsalsa20_xor,
          crypto_stream_xsalsa20_xor_ic,
          crypto_stream_xsalsa20_KEYBYTES,
          crypto_stream_xsalsa20_NONCEBYTES};

stream_module!(crypto_stream_xsalsa20,
               crypto_stream_xsalsa20_xor,
               crypto_stream_xsalsa20_xor_ic,
               crypto_stream_xsalsa20_KEYBYTES,
               crypto_stream_xsalsa20_NONCEBYTES);

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

    #[test]
    fn test_vector_1() {
        // corresponding to tests/stream.c and tests/stream5.cpp from NaCl
        use crypto::hash::sha256::{hash, Digest};
        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 output = stream(4194304, &nonce, &firstkey);
        let digest_expected = [0x66, 0x2b, 0x9d, 0x0e, 0x34, 0x63, 0x02, 0x91,
                               0x56, 0x06, 0x9b, 0x12, 0xf9, 0x18, 0x69, 0x1a,
                               0x98, 0xf7, 0xdf, 0xb2, 0xca, 0x03, 0x93, 0xc9,
                               0x6b, 0xbf, 0xc6, 0xb1, 0xfb, 0xd6, 0x30, 0xa2];
        let Digest(digest) = hash(&output);
        assert!(digest == digest_expected);

    }

    #[test]
    fn test_vector_2() {
        // corresponding to tests/stream3.c and tests/stream7.cpp from NaCl
        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 rs = stream(32, &nonce, &firstkey);
        let rs_expected = vec![0xee,0xa6,0xa7,0x25,0x1c,0x1e,0x72,0x91
                              ,0x6d,0x11,0xc2,0xcb,0x21,0x4d,0x3c,0x25
                              ,0x25,0x39,0x12,0x1d,0x8e,0x23,0x4e,0x65
                              ,0x2d,0x65,0x1f,0xa4,0xc8,0xcf,0xf8,0x80];
        assert!(rs == rs_expected);
    }

    #[test]
    fn test_vector_3() {
        // corresponding to tests/stream4.c and tests/stream8.cpp from NaCl
        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 = &[    0,   0,   0,   0,   0,   0,   0,   0
                 ,    0,   0,   0,   0,   0,   0,   0,   0
                 ,    0,   0,   0,   0,   0,   0,   0,   0
                 ,    0,   0,   0,   0,   0,   0,   0,   0
                 , 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 = stream_xor(m, &nonce, &firstkey);
        let c_expected = [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];
        assert!(&c[32..] == &c_expected[..]);
    }
}
