DSA support!

src/dsa/mod.rs

@@ -0,0 +1,67 @@
+mod errors;
+mod params;
+mod private;
+mod public;
+mod rfc6979;
+#[cfg(test)]
+mod tests;
+
+pub use self::params::*;
+pub use self::private::*;
+pub use self::public::*;
+
+use cryptonum::unsigned::*;
+use rand::Rng;
+use rand::distributions::Standard;
+
+pub struct DSAKeyPair<P,L,N>
+{
+    pub private: DSAPrivKey<P,N>,
+    pub public: DSAPubKey<P,L>
+}
+
+pub trait DSAKeyGeneration<P>
+{
+    fn generate<G: Rng>(params: &P, rng: &mut G) -> Self;
+}
+
+macro_rules! generate_dsa_pair {
+    ($ptype: ident, $ltype: ident, $ntype: ident, $nbig: ident) => {
+        impl DSAKeyGeneration<$ptype> for DSAKeyPair<$ptype,$ltype,$ntype>
+          where
+           DSAPrivKey<$ptype,$ntype>: DSAPrivateKey<$ptype,$ltype,$ntype>,
+        {
+            fn generate<G: Rng>(params: &$ptype, rng: &mut G) -> Self
+            {
+                // 1. N = len(q); L = len(p);
+                let n = $ptype::n_size();
+                // 2. If the (L,N) pair is invalid, then return an ERROR indicator,
+                //    Invalid_x, and Invalid_y.
+                // 3. requested_security_strength = the security strength associated
+                //    with the (L, N) pair; see SP 800-57.
+                // 4. Obtain a string of N+64 returned_bits from an RBG with a security
+                //    strength of requested_security_strength or more. If an ERROR
+                //    indication is returned, then return an ERROR indication,
+                //    Invalid_x, and Invalid_y.
+                let returned_bits: Vec<u8> = rng.sample_iter(&Standard).take(n + 8).collect();
+                // 5. Convert returned_bits to the (non-negative) integer c.
+                let c = $nbig::from_bytes(&returned_bits);
+                // 6. x = (c mod (q-1)) + 1.
+                let one = $nbig::from(1 as u64);
+                let qbig = $nbig::from(&params.q);
+                let x = $ntype::from( (&c % (&qbig - &one)) + &one );
+                // 7. y = g^x mod p
+                let y = params.g.modexp(&$ltype::from(&x), &params.p);
+                // 8. Return SUCCESS, x, and y.
+                let private = DSAPrivKey::new(params.clone(), x);
+                let public  = DSAPubKey::new(params.clone(), y);
+                DSAKeyPair { private, public }
+            }
+        }
+    };
+}
+
+generate_dsa_pair!(L1024N160, U1024, U192, U256);
+generate_dsa_pair!(L2048N224, U2048, U256, U384);
+generate_dsa_pair!(L2048N256, U2048, U256, U384);
+generate_dsa_pair!(L3072N256, U3072, U256, U384);