nettle 3.0.0

Rust bindings for the Nettle cryptographic library
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use nettle_sys::{
    __gmpz_init,
    __gmpz_clear,
    __gmpz_init_set,
    mpz_t,
    nettle_dsa_generate_keypair,
};
use std::mem::zeroed;
use super::Params;
use helper::{
    convert_buffer_to_gmpz,
    convert_gmpz_to_buffer
};
use Random;

/// Public DSA key.
pub struct PublicKey {
    pub(crate) public: mpz_t,
}

impl PublicKey {
    /// Creates a new public key.
    pub fn new(y: &[u8]) -> PublicKey {
        PublicKey{
            public: [convert_buffer_to_gmpz(y)],
        }
    }

    /// Returns the public key `y` as big endian number.
    pub fn as_bytes(&self) -> Box<[u8]> {
        convert_gmpz_to_buffer(self.public[0])
    }
}

impl Clone for PublicKey {
    fn clone(&self) -> Self {
        unsafe {
            let mut ret: mpz_t = zeroed();

            __gmpz_init_set(&mut ret[0], &self.public[0]);
            PublicKey{ public: ret }
        }
    }
}

impl Drop for PublicKey {
    fn drop(&mut self) {
        unsafe {
            __gmpz_clear(&mut self.public[0] as *mut _);
        }
    }
}

/// Private DSA key.
pub struct PrivateKey {
    pub(crate) private: mpz_t,
}

impl PrivateKey {
    /// Creates a new private key sructure. The secret exponent `x` must be a big endian integer.
    pub fn new(x: &[u8]) -> PrivateKey {
        PrivateKey{
            private: [convert_buffer_to_gmpz(x)],
        }
    }

    /// Returns the secret exponent `x` as bit endian integer.
    pub fn as_bytes(&self) -> Box<[u8]> {
        convert_gmpz_to_buffer(self.private[0])
    }
}

impl Clone for PrivateKey {
    fn clone(&self) -> Self {
        unsafe {
            let mut ret: mpz_t = zeroed();

            __gmpz_init_set(&mut ret[0], &self.private[0]);
            PrivateKey{ private: ret }
        }
    }
}

impl Drop for PrivateKey {
    fn drop(&mut self) {
        unsafe {
            __gmpz_clear(&mut self.private[0] as *mut _);
        }
    }
}

/// Generates a fresh DSA key pair.
///
/// Generator and primes must be supplied via `params`. Entrophy is
/// gathered using `random`.
pub fn generate_keypair<R: Random>(params: &Params, random: &mut R) -> (PublicKey,PrivateKey) {
    unsafe {
        let mut public: mpz_t = zeroed();
        let mut private: mpz_t = zeroed();

        __gmpz_init(&mut public[0] as *mut _);
        __gmpz_init(&mut private[0] as *mut _);

        nettle_dsa_generate_keypair(&params.params, &mut public[0], &mut private[0], random.context(), Some(R::random));

        let ret_pub = PublicKey{ public: public };
        let ret_key = PrivateKey{ private: private };

        (ret_pub,ret_key)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use Yarrow;
    use dsa::{sign,verify,Params};

    #[test]
    fn generate_key() {
        let mut rand = Yarrow::default();
        let params = Params::generate(&mut rand,1024,160).unwrap();

        for _ in 0..3 {
            let _ = generate_keypair(&params,&mut rand);
        }
    }

    #[test]
    fn clone() {
        let mut rand = Yarrow::default();
        let params = Params::generate(&mut rand,1024,160).unwrap();
        let (public,private) = generate_keypair(&params,&mut rand);

        let public = public.clone();
        let private = private.clone();
        let params = params.clone();
        let mut msg = [0u8; 160];

        rand.random(&mut msg);
        let sig = sign(&params, &private, &msg, &mut rand).unwrap();
        let sig = sig.clone();

        assert!(verify(&params, &public, &msg, &sig));
    }
}