Diffie-Hellman implementation

crypto/src/asymmetric/dh/mod.rs

@@ -0,0 +1,112 @@
+use bigint::{BigUint, RandBigInt};
+use num::FromPrimitive;
+use num::{One,Zero};
+
+use rand;
+
+use asymmetric::utils::modular::Power;
+
+// From rfc 2409 (https://tools.ietf.org/html/rfc2409).
+pub const RFC2409_PRIME_768: [u8; 96] = [
+        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,
+        0x21,0x68,0xC2,0x34,0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,
+        0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,0x02,0x0B,0xBE,0xA6,
+        0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+        0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,
+        0xF2,0x5F,0x14,0x37,0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,
+        0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,0xF4,0x4C,0x42,0xE9,
+        0xA6,0x3A,0x36,0x20,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    ];
+
+pub const RFC2409_GENERATOR_768: u64 = 2;
+
+pub const RFC2409_PRIME_1024: [u8; 128] = [
+        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,
+        0x21,0x68,0xC2,0x34,0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,
+        0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,0x02,0x0B,0xBE,0xA6,
+        0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+        0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,
+        0xF2,0x5F,0x14,0x37,0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,
+        0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,0xF4,0x4C,0x42,0xE9,
+        0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+        0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,
+        0x7C,0x4B,0x1F,0xE6,0x49,0x28,0x66,0x51,0xEC,0xE6,0x53,0x81,
+        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    ];
+
+pub const RFC2409_GENERATOR_1024: u64 = 2;
+
+
+pub struct DHPublicKey {
+    pub_key: BigUint,
+}
+
+pub struct DHPrivateKey<'a> {
+    params: &'a DHParameters,
+    priv_key: BigUint,
+}
+
+impl DHPublicKey {
+    pub fn new(pub_key: BigUint) -> DHPublicKey {
+        DHPublicKey {
+            pub_key: pub_key
+        }
+    }
+
+    pub fn key(&self) -> BigUint {
+        self.pub_key.clone()
+    }
+}
+
+impl<'a> DHPrivateKey<'a> {
+    pub fn key(&self) -> BigUint {
+        self.priv_key.clone()
+    }
+
+    pub fn public_key(&self) -> DHPublicKey {
+        let pub_key = (&self.params.g).pow_mod(&self.priv_key, &self.params.p);
+
+        DHPublicKey {
+            pub_key: pub_key
+        }
+    }
+
+    pub fn exchange(&self, pub_key: &DHPublicKey) -> BigUint {
+        (&pub_key.pub_key).pow_mod(&self.priv_key, &self.params.p)
+    }
+}
+
+pub struct DHParameters {
+    p: BigUint,
+    g: BigUint,
+}
+
+impl DHParameters {
+    pub fn new(p: &[u8], g: u64) -> DHParameters {
+        DHParameters {
+            p: BigUint::from_bytes_be(p),
+            g: BigUint::from_u64(g).expect("Could not convert g")
+        }
+    }
+
+    pub fn key_length(&self) -> usize {
+        self.p.bits()
+    }
+
+    pub fn private_key(&self) -> DHPrivateKey {
+        let mut rng = match rand::OsRng::new() {
+            Ok(g) => g,
+            Err(e) => panic!("Could not load the OS' RNG! Error: {}", e)
+        };
+
+        let mut priv_key = rng.gen_biguint(self.key_length());
+        while (priv_key == BigUint::one()) || (priv_key == BigUint::zero()) {
+            priv_key = rng.gen_biguint(self.key_length());
+        }
+
+        DHPrivateKey {
+            params: self,
+            priv_key: priv_key
+        }
+    }
+}

crypto/src/asymmetric/mod.rs

@@ -2,4 +2,6 @@
 
 pub mod rsa;
 
+pub mod dh;
+
 mod utils;

crypto/tests/asymmetric/dh/mod.rs

@@ -0,0 +1,20 @@
+use crypto::asymmetric::dh::{DHParameters, RFC2409_PRIME_768, RFC2409_GENERATOR_768,
+        RFC2409_PRIME_1024, RFC2409_GENERATOR_1024};
+
+
+fn test_exhange_with_params(params: &DHParameters) {
+    let priv_key1 = params.private_key();
+    let priv_key2 = params.private_key();
+    let pub_key1 = priv_key1.public_key();
+    let pub_key2 = priv_key2.public_key();
+    let shared_key1 = priv_key2.exchange(&pub_key1);
+    let shared_key2 = priv_key1.exchange(&pub_key2);
+    assert!(shared_key1 == shared_key2);
+}
+
+#[test]
+fn test_exchange() {
+    test_exhange_with_params(&DHParameters::new(&[0x17], 5));
+    test_exhange_with_params(&DHParameters::new(&RFC2409_PRIME_768, RFC2409_GENERATOR_768));
+    test_exhange_with_params(&DHParameters::new(&RFC2409_PRIME_1024, RFC2409_GENERATOR_1024));
+}

crypto/tests/asymmetric/mod.rs

@@ -0,0 +1 @@
+mod dh;

crypto/tests/lib.rs

@@ -2,3 +2,4 @@ extern crate octavo_crypto as crypto;
 
 mod block;
 mod stream;
+mod asymmetric;