public static KeyData createAesSivKeyData(int keySize) throws Exception {
    AesSivKey keyProto =
        AesSivKey.newBuilder().setKeyValue(ByteString.copyFrom(Random.randBytes(keySize))).build();
    return TestUtil.createKeyData(
        keyProto, DeterministicAeadConfig.AES_SIV_TYPE_URL, KeyData.KeyMaterialType.SYMMETRIC);
  }
@return a {@code KeyData} containing a {@code AesSivKey}.
java_src/src/main/java/com/google/crypto/tink/testing/TestUtil.java