Support ECDSA key generation.

src/ecdsa/mod.rs

@@ -2,3 +2,52 @@ pub mod curve;
 pub mod point;
 pub mod private;
 pub mod public;
+
+use cryptonum::signed::{I192,I256,I384,I576};
+use cryptonum::unsigned::{CryptoNum,Decoder};
+use cryptonum::unsigned::{U192,U256,U384,U576};
+use rand::Rng;
+use rand::distributions::Standard;
+use self::curve::{EllipticCurve,P192,P224,P256,P384,P521};
+use self::point::{ECCPoint,Point};
+pub use self::private::{ECCPrivateKey,ECCPrivate};
+pub use self::public::{ECCPublicKey,ECCPublic};
+
+pub trait ECDSAKeyPair<Public,Private> {
+    fn generate<G: Rng>(g: &mut G) -> (Public, Private);
+}
+
+macro_rules! generate_impl {
+    ($curve: ident, $un: ident, $si: ident) => {
+        impl ECDSAKeyPair<ECCPublic<$curve>,ECCPrivate<$curve>> for $curve {
+            fn generate<G: Rng>(rng: &mut G) -> (ECCPublic<$curve>, ECCPrivate<$curve>)
+            {
+                loop {
+                    let size = ($curve::size() + 7) / 8;
+                    let random_bytes: Vec<u8> = rng.sample_iter(&Standard).take(size).collect();
+                    let proposed_d = $un::from_bytes(&random_bytes);
+
+                    if proposed_d.is_zero() {
+                        continue;
+                    }
+
+                    if proposed_d >= $curve::n() {
+                        continue;
+                    }
+
+                    let d = $si::from(&proposed_d);
+                    let public_point = Point::<$curve>::default().scale(&d);
+                    let public = ECCPublic::<$curve>::new(public_point);
+                    let private = ECCPrivate::<$curve>::new(proposed_d);
+                    return (public, private);
+                }
+            }
+        }
+    };
+}
+
+generate_impl!(P192, U192, I192);
+generate_impl!(P224, U256, I256);
+generate_impl!(P256, U256, I256);
+generate_impl!(P384, U384, I384);
+generate_impl!(P521, U576, I576);