private static void validateParameters(AesSivParameters parameters)
      throws GeneralSecurityException {
    if (parameters.getKeySizeBytes() != KEY_SIZE_IN_BYTES) {
      throw new InvalidAlgorithmParameterException(
          "invalid key size: "
              + parameters.getKeySizeBytes()
              + ". Valid keys must have "
              + KEY_SIZE_IN_BYTES
              + " bytes.");
    }
  }
This key manager generates new {@code AesSivKey} keys and produces new instances of {@code
AesSiv}.
java_src/src/main/java/com/google/crypto/tink/daead/AesSivKeyManager.java