//! `HMAC-SHA-512-256`, i.e., the first 256 bits of
//! `HMAC-SHA-512`.  `HMAC-SHA-512-256` is conjectured to meet the standard notion
//! of unforgeability.
use ffi::{crypto_auth_hmacsha512256,
          crypto_auth_hmacsha512256_verify,
          crypto_auth_hmacsha512256_state,
          crypto_auth_hmacsha512256_init,
          crypto_auth_hmacsha512256_update,
          crypto_auth_hmacsha512256_final,
          crypto_auth_hmacsha512256_KEYBYTES,
          crypto_auth_hmacsha512256_BYTES
};

auth_module!(crypto_auth_hmacsha512256,
             crypto_auth_hmacsha512256_verify,
             crypto_auth_hmacsha512256_KEYBYTES,
             crypto_auth_hmacsha512256_BYTES);

auth_state!(crypto_auth_hmacsha512256_state,
            crypto_auth_hmacsha512256_init,
            crypto_auth_hmacsha512256_update,
            crypto_auth_hmacsha512256_final,
            crypto_auth_hmacsha512256_BYTES);

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

    #[test]
    fn test_vector_1() {
        // corresponding to tests/auth.c from NaCl
        // "Test Case 2" from RFC 4231
        let key = Key([74, 101, 102, 101, 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]);
        let c = [0x77, 0x68, 0x61, 0x74, 0x20, 0x64, 0x6f, 0x20
                ,0x79, 0x61, 0x20, 0x77, 0x61, 0x6e, 0x74, 0x20
                ,0x66, 0x6f, 0x72, 0x20, 0x6e, 0x6f, 0x74, 0x68
                ,0x69, 0x6e, 0x67, 0x3f];

        let a_expected = [0x16,0x4b,0x7a,0x7b,0xfc,0xf8,0x19,0xe2
                         ,0xe3,0x95,0xfb,0xe7,0x3b,0x56,0xe0,0xa3
                         ,0x87,0xbd,0x64,0x22,0x2e,0x83,0x1f,0xd6
                         ,0x10,0x27,0x0c,0xd7,0xea,0x25,0x05,0x54];

        let Tag(a) = authenticate(&c, &key);
        assert!(a == a_expected);
    }

    #[test]
    fn test_vector_state_1() {
        // corresponding to tests/auth.c from NaCl
        // "Test Case 2" from RFC 4231
        let key = [74, 101, 102, 101, 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];
        let c = [0x77, 0x68, 0x61, 0x74, 0x20, 0x64, 0x6f, 0x20
                ,0x79, 0x61, 0x20, 0x77, 0x61, 0x6e, 0x74, 0x20
                ,0x66, 0x6f, 0x72, 0x20, 0x6e, 0x6f, 0x74, 0x68
                ,0x69, 0x6e, 0x67, 0x3f];

        let a_expected = [0x16,0x4b,0x7a,0x7b,0xfc,0xf8,0x19,0xe2
                         ,0xe3,0x95,0xfb,0xe7,0x3b,0x56,0xe0,0xa3
                         ,0x87,0xbd,0x64,0x22,0x2e,0x83,0x1f,0xd6
                         ,0x10,0x27,0x0c,0xd7,0xea,0x25,0x05,0x54];

        let mut state = State::init(&key);
        state.update(&c);
        let Tag(a) = state.finalize();
        assert!(a == a_expected);
    }
}
