public static boolean arrayEquals(byte[] a, byte[] b) {
    if (a.length != b.length) {
      return false;
    }
    byte res = 0;
    for (int i = 0; i < a.length; i++) {
      res |= (byte) (a[i] ^ b[i]);
    }
    return res == 0;
  }
@return true iff two arrays are equal.
java_src/src/main/java/com/google/crypto/tink/testing/TestUtil.java