@Test
public void testPrfUniformity() throws GeneralSecurityException {

  for (MacTestVector t : HMAC_TEST_VECTORS) {
    Prf prf = new PrfHmacJce(t.algName, new SecretKeySpec(t.key, "HMAC"));
    // We need a string of bytes identical in size to the tag output size for the given algorithm
    // so we can test cross correlation. We're not actually validating the output contents of the
    // HMAC in this function. Therefore - just feed the test tag into the HMAC.
    byte[] prBytes = prf.compute(t.tag, t.tag.length);
    TestUtil.ztestUniformString(prBytes);
    TestUtil.ztestAutocorrelationUniformString(prBytes);
    TestUtil.ztestCrossCorrelationUniformStrings(prBytes, t.tag);
  }
}