Core: Support for ECDSA JOSE signatures (#614)

include/PowerAuth/PublicTypes.h

@@ -386,24 +386,53 @@ namespace powerAuth
             HMAC_Activation = 3
         };
 
+        enum SignatureFormat
+        {
+            /**
+             If default signature is used, then `ECDSA_DER` is used for ECDSA signature.
+             The raw bytes are always used for HMAC signatures.
+             */
+            Default = 0,
+            /**
+             ECDSA signature in DER format is expected at input, or produced at output:
+             ```
+             ASN.1 notation:
+             ECDSASignature ::= SEQUENCE {
+                 r   INTEGER,
+                 s   INTEGER
+             }
+             ```
+             */
+            ECDSA_DER = 1,
+            /**
+             ECDSA signature in JOSE format is epxpected at input, or produced at output.
+             */
+            ECDSA_JOSE = 2,
+        };
+
         /**
          A key type used for signature calculation.
          */
         SigningKey signingKey;
         /**
-         An arbitrary data
+         Format of signature expected at input, or produced at output.
+         */
+        SignatureFormat signatureFormat;
+        /**
+         An arbitrary data.
          */
         cc7::ByteArray data;
         /**
-         A signagure calculated for data
+         A signagure calculated for data.
          */
         cc7::ByteArray signature;
 
         /**
-         Default constructor
+         Default constructor.
          */
-        SignedData(SigningKey signingKey = ECDSA_MasterServerKey) :
-            signingKey(signingKey)
+        SignedData(SigningKey signingKey = ECDSA_MasterServerKey, SignatureFormat signatureFormat = Default) :
+            signingKey(signingKey),
+            signatureFormat(signatureFormat)
         {
         }
 

include/PowerAuth/Session.h

@@ -429,7 +429,8 @@ namespace powerAuth
                  EC_WrongParam, if some required parameter is missing
          */
         ErrorCode signDataWithDevicePrivateKey(const std::string & c_vault_key, const SignatureUnlockKeys & keys,
-                                               const cc7::ByteRange & data, cc7::ByteArray & out_signature);
+                                               const cc7::ByteRange & data, SignedData::SignatureFormat out_format,
+                                               cc7::ByteArray & out_signature);
 
     private:
 

proj-android/PowerAuthLibrary/src/main/java/io/getlime/security/powerauth/core/Session.java

@@ -477,10 +477,11 @@ public byte[] prepareKeyValueDictionaryForDataSigning(Map<String, String> keyVal
      * @param cVaultKey encrypted vault key
      * @param unlockKeys unlock keys object with required possession factor
      * @param data data to be signed
+     * @param signatureFormat Format of produced signature.
      *
      * @return array of bytes with calculated signature or null in case of failure.
      */
-    public native byte[] signDataWithDevicePrivateKey(String cVaultKey, SignatureUnlockKeys unlockKeys, byte[] data);
+    public native byte[] signDataWithDevicePrivateKey(String cVaultKey, SignatureUnlockKeys unlockKeys, byte[] data, @SignatureFormat int signatureFormat);
 
     //
     // External encryption key

proj-android/PowerAuthLibrary/src/main/java/io/getlime/security/powerauth/core/SignatureFormat.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2024 Wultra s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.getlime.security.powerauth.core;
+
+import androidx.annotation.IntDef;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import static io.getlime.security.powerauth.core.SignatureFormat.DEFAULT;
+import static io.getlime.security.powerauth.core.SignatureFormat.ECDSA_DER;
+import static io.getlime.security.powerauth.core.SignatureFormat.ECDSA_JOSE;
+
+/**
+ * The {@code SignatureFormat} enumeration defines signature type expected at input, or produced at output.
+ */
+@Retention(RetentionPolicy.SOURCE)
+@IntDef({DEFAULT, ECDSA_DER, ECDSA_JOSE})
+public @interface SignatureFormat {
+    /**
+     * If default signature is used, then `ECDSA_DER` is used for ECDSA signature. The raw bytes are always used for
+     * HMAC signatures.
+     */
+    int DEFAULT = 0;
+    /**
+     * ECDSA signature in DER format is expected at input, or produced at output:
+     *  <pre>
+     *  ASN.1 notation:
+     *  ECDSASignature ::= SEQUENCE {
+     *     r   INTEGER,
+     *     s   INTEGER
+     * }
+     * </pre>
+     */
+    int ECDSA_DER = 1;
+    /**
+     * ECDSA signature in JOSE format is epxpected at input, or produced at output.
+     */
+    int ECDSA_JOSE = 2;
+}

proj-android/PowerAuthLibrary/src/main/java/io/getlime/security/powerauth/core/SignedData.java

@@ -34,15 +34,22 @@ public class SignedData {
      */
     @SigningDataKey
     public final int signingKey;
+    /**
+     * Format of signature expected at input, or produced at output.
+     */
+    @SignatureFormat
+    public final int signatureFormat;
 
     /**
      * @param data data protected with signature
      * @param signature signature calculated for data
      * @param signingKey Key used to sign data, or will be used for the signature calculation.
+     * @param signatureFormat Format of signature expected at input, or produced at output.
      */
-    public SignedData(byte[] data, byte[] signature, @SigningDataKey int signingKey) {
+    public SignedData(byte[] data, byte[] signature, @SigningDataKey int signingKey, @SignatureFormat int signatureFormat) {
         this.data = data;
         this.signature = signature;
         this.signingKey = signingKey;
+        this.signatureFormat = signatureFormat;
     }
 }

proj-android/PowerAuthLibrary/src/main/java/io/getlime/security/powerauth/sdk/PowerAuthSDK.java

@@ -29,7 +29,6 @@
 import com.google.gson.reflect.TypeToken;
 
 import java.nio.charset.StandardCharsets;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.locks.ReentrantLock;
@@ -1791,7 +1790,7 @@ public boolean verifyServerSignedData(byte[] data, byte[] signature, boolean use
 
         // Verify signature
         final int signingKey = useMasterKey ? SigningDataKey.ECDSA_MASTER_SERVER_KEY : SigningDataKey.ECDSA_PERSONALIZED_KEY;
-        final SignedData signedData = new SignedData(data, signature, signingKey);
+        final SignedData signedData = new SignedData(data, signature, signingKey, SignatureFormat.ECDSA_DER);
         return mSession.verifyServerSignedData(signedData) == ErrorCode.OK;
     }
 
@@ -1805,15 +1804,28 @@ public boolean verifyServerSignedData(byte[] data, byte[] signature, boolean use
      */
     public @Nullable
     ICancelable signDataWithDevicePrivateKey(@NonNull final Context context, @NonNull PowerAuthAuthentication authentication, @NonNull final byte[] data, @NonNull final IDataSignatureListener listener) {
+        return signDataWithDevicePrivateKeyImpl(context, authentication, data, SignatureFormat.ECDSA_DER, listener);
+    }
 
+    /**
+     * Sign provided data with a private key that is stored in secure vault.
+     * @param context Context.
+     * @param authentication Authentication object for vault unlock request.
+     * @param data Data to be signed.
+     * @param signatureFormat Format of output signature.
+     * @param listener Listener with callbacks to signature status.
+     * @return Async task associated with vault unlock request.
+     */
+    private @Nullable
+    ICancelable signDataWithDevicePrivateKeyImpl(@NonNull final Context context, @NonNull PowerAuthAuthentication authentication, @NonNull final byte[] data, @SignatureFormat int signatureFormat, @NonNull final IDataSignatureListener listener) {
         // Fetch vault encryption key using vault unlock request.
         return this.fetchEncryptedVaultUnlockKey(context, authentication, VaultUnlockReason.SIGN_WITH_DEVICE_PRIVATE_KEY, new IFetchEncryptedVaultUnlockKeyListener() {
             @Override
             public void onFetchEncryptedVaultUnlockKeySucceed(String encryptedEncryptionKey) {
                 if (encryptedEncryptionKey != null) {
                     // Let's sign the data
                     SignatureUnlockKeys keys = new SignatureUnlockKeys(deviceRelatedKey(context), null, null);
-                    byte[] signature = mSession.signDataWithDevicePrivateKey(encryptedEncryptionKey, keys, data);
+                    byte[] signature = mSession.signDataWithDevicePrivateKey(encryptedEncryptionKey, keys, data, signatureFormat);
                     // Propagate error
                     if (signature != null) {
                         listener.onDataSignedSucceed(signature);
@@ -1830,8 +1842,10 @@ public void onFetchEncryptedVaultUnlockKeyFailed(Throwable t) {
                 listener.onDataSignedFailed(t);
             }
         });
+
     }
 
+
     /**
      * Change the password using local re-encryption, do not validate old password by calling any endpoint.
      *
@@ -2535,7 +2549,7 @@ public ICancelable signJwtWithDevicePrivateKey(@NonNull Context context, @NonNul
         final String jwtHeader = "eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9"; // {"alg":"ES256","typ":"JWT"}
         final String jwtClaims = serialization.serializeJwtObject(claims);
         final String jwtHeaderAndClaims = jwtHeader + "." + jwtClaims;
-        return signDataWithDevicePrivateKey(context, authentication, jwtHeaderAndClaims.getBytes(StandardCharsets.US_ASCII), new IDataSignatureListener() {
+        return signDataWithDevicePrivateKeyImpl(context, authentication, jwtHeaderAndClaims.getBytes(StandardCharsets.US_ASCII), SignatureFormat.ECDSA_JOSE, new IDataSignatureListener() {
             @Override
             public void onDataSignedSucceed(@NonNull byte[] signature) {
                 // Encoded signature

proj-xcode/PowerAuthCore/PowerAuthCoreSession.h

@@ -457,7 +457,8 @@
  */
 - (nullable NSData*) signDataWithDevicePrivateKey:(nonnull NSString*)cVaultKey
                                              keys:(nonnull PowerAuthCoreSignatureUnlockKeys*)unlockKeys
-                                             data:(nonnull NSData*)data;
+                                             data:(nonnull NSData*)data
+                                           format:(PowerAuthCoreSignatureFormat)format;
 
 #pragma mark - External Encryption Key
 

proj-xcode/PowerAuthCore/PowerAuthCoreSession.mm

@@ -380,15 +380,17 @@ - (nullable NSData*) deriveCryptographicKeyFromVaultKey:(nonnull NSString*)cVaul
 - (nullable NSData*) signDataWithDevicePrivateKey:(nonnull NSString*)cVaultKey
                                              keys:(nonnull PowerAuthCoreSignatureUnlockKeys*)unlockKeys
                                              data:(nonnull NSData*)data
+                                           format:(PowerAuthCoreSignatureFormat)format
 {
     REQUIRE_READ_ACCESS();
     std::string cpp_c_vault_key = cc7::objc::CopyFromNSString(cVaultKey);
     cc7::ByteArray cpp_data     = cc7::objc::CopyFromNSData(data);
+    auto cpp_format             = static_cast<SignedData::SignatureFormat>(format);
     SignatureUnlockKeys cpp_keys;
     PowerAuthCoreSignatureUnlockKeysToStruct(unlockKeys, cpp_keys);
 
     cc7::ByteArray cpp_signature;
-    auto error = _session->signDataWithDevicePrivateKey(cpp_c_vault_key, cpp_keys, cpp_data, cpp_signature);
+    auto error = _session->signDataWithDevicePrivateKey(cpp_c_vault_key, cpp_keys, cpp_data, cpp_format, cpp_signature);
     if (error == EC_Ok) {
         return cc7::objc::CopyToNSData(cpp_signature);
     }

proj-xcode/PowerAuthCore/PowerAuthCoreTypes.h

@@ -318,12 +318,45 @@ typedef NS_ENUM(int, PowerAuthCoreSigningDataKey) {
     PowerAuthCoreSigningDataKey_HMAC_Activation = 3
 };
 
+/**
+ The `PowerAuthCoreSignatureFormat` enumeration defines signature type expected at input, or produced
+ at output.
+ */
+typedef NS_ENUM(int, PowerAuthCoreSignatureFormat) {
+    /**
+     If used, then `PowerAuthCoreSignatureFormat_ECDSA_DER` is used for ECDSA signature.
+     For the HMAC signature, the raw bytes is always used.
+     */
+    PowerAuthCoreSignatureFormat_Default = 0,
+    /**
+     ECDSA signature in DER format is expected at input, or produced at output:
+     ```
+     // ASN.1 notation:
+     ECDSASignature ::= SEQUENCE {
+         r   INTEGER,
+         s   INTEGER
+     }
+     ```
+     */
+    PowerAuthCoreSignatureFormat_ECDSA_DER = 1,
+    /**
+     ECDSA signature in JOSE format is epxpected at input, or produced at output.
+     */
+    PowerAuthCoreSignatureFormat_ECDSA_JOSE = 2
+};
+
 /**
  The PowerAuthCoreSignedData object contains data and signature calculated from data.
  */
 @interface PowerAuthCoreSignedData : NSObject
-
+/**
+ A signign key to use.
+ */
 @property (nonatomic, assign) PowerAuthCoreSigningDataKey signingDataKey;
+/**
+ A format of signature expected at input or produced at output.
+ */
+@property (nonatomic, assign) PowerAuthCoreSignatureFormat signatureFormat;
 /**
  A data protected with signature
  */

proj-xcode/PowerAuthCore/PowerAuthCoreTypes.mm

@@ -156,6 +156,17 @@ - (void) setSigningDataKey:(PowerAuthCoreSigningDataKey)signingDataKey
     _signedData.signingKey = static_cast<SignedData::SigningKey>(signingDataKey);
 }
 
+// Signature type
+
+- (PowerAuthCoreSignatureFormat) signatureFormat
+{
+    return static_cast<PowerAuthCoreSignatureFormat>(_signedData.signatureFormat);
+}
+
+- (void) setSignatureFormat:(PowerAuthCoreSignatureFormat)signatureType
+{
+    _signedData.signatureFormat = static_cast<SignedData::SignatureFormat>(signatureType);
+}
 
 // Bytes setters and getters
 
@@ -204,7 +215,7 @@ - (void) setSignatureBase64:(NSString *)signatureBase64
 #ifdef DEBUG
 - (NSString*) description
 {
-    return [NSString stringWithFormat:@"<PowerAuthCoreSignedData data=%@, signature=%@>", self.dataBase64, self.signatureBase64];
+    return [NSString stringWithFormat:@"<PowerAuthCoreSignedData key=%d, data=%@, signature=%@>", _signedData.signingKey, self.dataBase64, self.signatureBase64];
 }
 #endif
 

src/PowerAuth/Session.cpp

@@ -706,7 +706,13 @@ namespace powerAuth
         }
         if (nullptr != ec_public_key) {
             // validate signature
-            success = crypto::ECDSA_ValidateSignature(data.data, data.signature, ec_public_key);
+            if (data.signatureFormat == SignedData::ECDSA_JOSE) {
+                // Convert signature from JOSE to DER first.
+                success = crypto::ECDSA_ValidateSignature(data.data, crypto::ECDSA_JOSEtoDER(data.signature), ec_public_key);
+            } else {
+                // No signature conversion required.
+                success = crypto::ECDSA_ValidateSignature(data.data, data.signature, ec_public_key);
+            }
             //
         } else {
             CC7_LOG("Session %p: ServerSig: %s public key is invalid.", this, use_master_server_key ? "Master server" : "Server");
@@ -735,7 +741,7 @@ namespace powerAuth
         }
         cc7::ByteArray signing_key;
         if (app_scope) {
-            signing_key = cc7::MakeRange(_setup.applicationSecret);
+            signing_key.readFromBase64String(_setup.applicationSecret);
         } else {
             // Unlock transport key
             protocol::SignatureKeys plain;
@@ -904,7 +910,8 @@ namespace powerAuth
     }
 
     ErrorCode Session::signDataWithDevicePrivateKey(const std::string & c_vault_key, const SignatureUnlockKeys & keys,
-                                                    const cc7::ByteRange & in_data, cc7::ByteArray & out_signature)
+                                                    const cc7::ByteRange & in_data, SignedData::SignatureFormat out_format,
+                                                    cc7::ByteArray & out_signature)
     {
         LOCK_GUARD();
         cc7::ByteArray vault_key;
@@ -932,6 +939,13 @@ namespace powerAuth
                 // Signature calculation failed.
                 break;
             }
+            if (out_format == SignedData::ECDSA_JOSE) {
+                out_signature = crypto::ECDSA_DERtoJOSE(out_signature);
+                if (out_signature.empty()) {
+                    // Conversion to JOSE format failed.
+                    break;
+                }
+            }
             code = EC_Ok;
         } while (false);