void verifySignature()

in DynamoDbEncryption/runtimes/java/src/main/sdkv1/com/amazonaws/services/dynamodbv2/datamodeling/encryption/DynamoDBSigner.java [92:142]

46 lines of code
7 McCabe index (conditional complexity)


  void verifySignature(
    Map<String, AttributeValue> itemAttributes,
    Map<String, Set<EncryptionFlags>> attributeActionsOnEncrypt,
    byte[] associatedData,
    Key verificationKey,
    ByteBuffer signature
  ) throws GeneralSecurityException {
    //    System.out.println("verifySignature");
    //    System.out.println(itemAttributes);
    //    System.out.println(attributeActionsOnEncrypt);
    //    System.out.println("==========");

    if (verificationKey instanceof DelegatedKey) {
      DelegatedKey dKey = (DelegatedKey) verificationKey;
      byte[] stringToSign = calculateStringToSign(
        itemAttributes,
        attributeActionsOnEncrypt,
        associatedData
      );
      if (
        !dKey.verify(stringToSign, toByteArray(signature), dKey.getAlgorithm())
      ) {
        throw new SignatureException("Bad signature");
      }
    } else if (verificationKey instanceof SecretKey) {
      byte[] calculatedSig = calculateSignature(
        itemAttributes,
        attributeActionsOnEncrypt,
        associatedData,
        (SecretKey) verificationKey
      );
      if (!safeEquals(signature, calculatedSig)) {
        throw new SignatureException("Bad signature");
      }
    } else if (verificationKey instanceof PublicKey) {
      PublicKey integrityKey = (PublicKey) verificationKey;
      byte[] stringToSign = calculateStringToSign(
        itemAttributes,
        attributeActionsOnEncrypt,
        associatedData
      );
      Signature sig = Signature.getInstance(getSigningAlgorithm());
      sig.initVerify(integrityKey);
      sig.update(stringToSign);
      if (!sig.verify(toByteArray(signature))) {
        throw new SignatureException("Bad signature");
      }
    } else {
      throw new IllegalArgumentException("No integrity key provided");
    }
  }