@Test
public void deriveKey_returnstheExpectedKey() {

  final String knownRandomNumber = "7034522dc85138530e44b38d0569ca67";
  final String knownGeneratedKey = "09cafa70264eaa47dcf0678dfd03aa73d24044df47b0381c17ebe0ed4e2f3d91";
  final byte[] salt = Hex.decode(knownRandomNumber); // gen'dp originally from SecureRandom..
  final Key derivedKey = subject.deriveKey(Collections.unmodifiableList(asList(ArrayUtils.toObject(salt))));
  final String hexOutput = Hex.toHexString(derivedKey.getEncoded());
  assertThat(hexOutput, equalTo(knownGeneratedKey));
  assertThat(derivedKey.getEncoded().length, equalTo(32));
}