@Test
public void createKey_multipleTimes() throws Exception {

  AesCmacKeyManager manager = new AesCmacKeyManager();
  AesCmacKeyFormat keyFormat = makeAesCmacKeyFormat(32, 16);
  assertThat(manager.keyFactory().createKey(keyFormat).getKeyValue())
      .isNotEqualTo(manager.keyFactory().createKey(keyFormat).getKeyValue());
}