unit tests

src/dghv.rs

@@ -37,3 +37,78 @@ pub fn generate_secret_key(eta: u32) -> Integer {
         .find(|p: &Integer| p.is_odd())
         .unwrap()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_secret_key_generation_properties() {
+        let eta = 64;
+        let key = generate_secret_key(eta);
+        assert!(key.significant_bits() <= eta);
+        assert!(key.significant_bits() >= eta - 1);
+        assert!(key.is_odd());
+    }
+
+    #[test]
+    fn test_encrypt_decrypt_bit() {
+        let eta = 64;
+        let key = generate_secret_key(eta);
+
+        let bit = 0;
+        let ciphertext = encrypt_bit(bit, &key);
+        let decrypted = decrypt_bit(&ciphertext, &key);
+        assert_eq!(decrypted, bit);
+
+        let bit = 1;
+        let ciphertext = encrypt_bit(bit, &key);
+        let decrypted = decrypt_bit(&ciphertext, &key);
+        assert_eq!(decrypted, bit);
+    }
+
+    #[test]
+    fn test_multiple_encryptions_are_different() {
+        let eta = 64;
+        let key = generate_secret_key(eta);
+
+        let bit = 1;
+        let c1 = encrypt_bit(bit, &key);
+        let c2 = encrypt_bit(bit, &key);
+
+        assert_ne!(c1, c2);
+        assert_eq!(decrypt_bit(&c1, &key), bit);
+        assert_eq!(decrypt_bit(&c2, &key), bit);
+    }
+
+    #[test]
+    fn test_is_homomorphic() {
+        let eta = 1024;
+        let key = generate_secret_key(eta);
+
+        for &(b1, b2) in &[(0, 0), (0, 1), (1, 0), (1, 1)] {
+            let c1 = encrypt_bit(b1, &key);
+            let c2 = encrypt_bit(b2, &key);
+
+            let sum: Integer = c1.clone() + &c2;
+            let product: Integer = c1 * c2;
+
+            let decrypted_sum = decrypt_bit(&sum, &key);
+            let decrypted_product = decrypt_bit(&product, &key);
+
+            let expected_xor = b1 ^ b2;
+            let expected_and = b1 & b2;
+
+            assert_eq!(
+                decrypted_sum, expected_xor,
+                "Failed XOR test for inputs: {}, {}",
+                b1, b2
+            );
+            assert_eq!(
+                decrypted_product, expected_and,
+                "Failed AND test for inputs: {}, {}",
+                b1, b2
+            );
+        }
+    }
+}