Issue #33 fix different algorithms matching (#35)

* Fix bug in verification of presentation with key binding that uses different algorithm. Resolves #33

Signed-off-by: Aziz Mukhtorjonov <[email protected]>
Co-authored-by: Abdulbois <[email protected]>

Author: AzizMukhtorjonov

src/verifier.rs

@@ -73,6 +73,12 @@ impl SDJWTVerifier {
         verifier.verified_claims = verifier.extract_sd_claims()?;
 
         if let (Some(expected_aud), Some(expected_nonce)) = (&expected_aud, &expected_nonce) {
+            let sign_alg = verifier.sd_jwt_engine.unverified_input_key_binding_jwt
+                .as_ref()
+                .and_then(|value| {
+                    SDJWTCommon::decode_header_and_get_sign_algorithm(&value)
+                });
+
             verifier.verify_key_binding_jwt(
                 expected_aud.to_owned(),
                 expected_nonce.to_owned(),
@@ -391,6 +397,17 @@ mod tests {
     const PRIVATE_ISSUER_ED25519_PEM: &str = "-----BEGIN PRIVATE KEY-----\nMFECAQEwBQYDK2VwBCIEIF93k6rxZ8W38cm0rOwfGdH+YY3k10hP+7gd0falPLg0\ngSEAdW31QyWzfed4EPcw1rYuUa1QU+fXEL0HhdAfYZRkihc=\n-----END PRIVATE KEY-----\n";
     const PUBLIC_ISSUER_ED25519_PEM: &str = "-----BEGIN PUBLIC KEY-----\nMCowBQYDK2VwAyEAdW31QyWzfed4EPcw1rYuUa1QU+fXEL0HhdAfYZRkihc=\n-----END PUBLIC KEY-----\n";
 
+    // EdDSA (Ed25519)
+    const HOLDER_KEY_ED25519: &str = "-----BEGIN PRIVATE KEY-----\nMC4CAQAwBQYDK2VwBCIEIOeIDnHHMoPCUTiq206gR+FdCdNtc31SzF1nKX31hvhd\n-----END PRIVATE KEY-----";
+
+    const HOLDER_JWK_KEY_ED25519: &str = r#"{
+        "alg": "EdDSA",
+        "crv": "Ed25519",
+        "kid": "52128f2e-900e-414e-81c3-0b5f86f0f7b3",
+        "kty": "OKP",
+        "x": "24QLWXJ18wtbg3k_MDGhGM17Xh39UftuxbwJZzRLzkA"
+    }"#;
+
     #[test]
     fn verify_full_presentation() {
         let user_claims = json!({
@@ -728,4 +745,75 @@ mod tests {
             .verified_claims;
         assert_eq!(user_claims, verified_claims);
     }
+    #[test]
+    fn verify_presentation_when_sd_jwt_uses_es256_and_key_binding_uses_eddsa() {
+
+        let user_claims = json!({
+            "address": {
+                "street_address": "Schulstr. 12",
+                "locality": "Schulpforta",
+                "region": "Sachsen-Anhalt",
+                "country": "DE"
+            },
+            "exp": 1883000000,
+            "iat": 1683000000,
+            "iss": "https://example.com/issuer",
+            "sub": "6c5c0a49-b589-431d-bae7-219122a9ec2c",
+
+        });
+
+        let private_issuer_bytes = PRIVATE_ISSUER_PEM.as_bytes();
+        let issuer_key = EncodingKey::from_ec_pem(private_issuer_bytes).unwrap();
+
+        let mut issuer = SDJWTIssuer::new(issuer_key, Some("ES256".to_string()));
+
+        let sd_jwt = issuer.issue_sd_jwt(
+            user_claims.clone(),
+            ClaimsForSelectiveDisclosureStrategy::AllLevels,
+            Some(serde_json::from_str(HOLDER_JWK_KEY_ED25519).unwrap()),
+            false,
+            SDJWTSerializationFormat::JSON, // Changed to Json format
+        ).unwrap();
+
+        let private_holder_bytes = HOLDER_KEY_ED25519.as_bytes();
+        let holder_key = EncodingKey::from_ed_pem(private_holder_bytes).unwrap();
+
+        let nonce = Some(String::from("testNonce"));
+        let aud = Some(String::from("testAud"));
+
+        let mut holder = SDJWTHolder::new(sd_jwt.clone(), SDJWTSerializationFormat::JSON).unwrap(); // Changed to Json format
+        let presentation = holder.create_presentation(
+                user_claims.as_object().unwrap().clone(),
+                nonce.clone(),
+                aud.clone(),
+                Some(holder_key),
+                Some("EdDSA".to_string())
+            )
+            .unwrap();
+        let verified_claims = SDJWTVerifier::new(
+            presentation,
+            Box::new(|_, _| {
+                let public_issuer_bytes = PUBLIC_ISSUER_PEM.as_bytes();
+                DecodingKey::from_ec_pem(public_issuer_bytes).unwrap()
+            }),
+            aud.clone(),
+            nonce.clone(),
+            SDJWTSerializationFormat::JSON, // Changed to Json format
+        )
+            .unwrap()
+            .verified_claims;
+
+        let claims_to_check = json!({
+            "iss": user_claims["iss"].clone(),
+            "iat": user_claims["iat"].clone(),
+            "exp": user_claims["exp"].clone(),
+            "cnf": {
+                "jwk": serde_json::from_str::<Value>(HOLDER_JWK_KEY_ED25519).unwrap(),
+            },
+            "sub": user_claims["sub"].clone(),
+            "address": user_claims["address"].clone(),
+        });
+
+        assert_eq!(claims_to_check, verified_claims);
+    }
 }