key[i] = (byte) i;
      int seed = 256 - i;
      byte[] hash = hashFunction.hash(Arrays.copyOf(key, i), seed);
      System.arraycopy(hash, 0, hashes, i * hashBytes, hash.length);
    }

    // Then hash the result array
    byte[] result = hashFunction.hash(hashes, 0);

    // interpreted in little-endian order.
    int verification = Integer.reverseBytes(Ints.fromByteArray(result));

    if (expected != verification) {

          this.hashAlgorithm = "sha1"
          this.hash = pin.substring("sha1/".length).decodeBase64() ?: throw IllegalArgumentException("Invalid pin hash: $pin")
        }
        pin.startsWith("sha256/") -> {
          this.hashAlgorithm = "sha256"
          this.hash = pin.substring("sha256/".length).decodeBase64() ?: throw IllegalArgumentException("Invalid pin hash: $pin")
        }

        // Verify hash is not null
        byte[] hash = transport.getPreauthIntegrityHash();
        assertNotNull(hash);

        // Verify hash is a copy, not the original
        byte[] hash2 = transport.getPreauthIntegrityHash();
        assertNotSame(hash, hash2);
        assertArrayEquals(hash, hash2);
    }

    /**
     * Test that pre-auth hash is reset on error
     */
    @Test

    assertThrows(IllegalStateException.class, () -> hasher.putInt(42));
  }

  public void testHashTwice() {
    Hasher hasher = Hashing.hmacMd5(MD5_KEY).newHasher();

    assertEquals(
        "9753980fe94daa8ecaa82216519393a9",
        hasher.putString("The quick brown fox jumps over the lazy dog", UTF_8).hash().toString());

    return (bits + 31) & ~31;
  }

  /**
   * Returns a hash function which computes its hash code by concatenating the hash codes of the
   * underlying hash functions together. This can be useful if you need to generate hash codes of a
   * specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash

        byte[] expectedHash = preauthService.getCurrentPreauthHash(sessionId);

        // Validation should pass with correct hash
        assertTrue(preauthService.validatePreauthIntegrity(sessionId, expectedHash));

        // Validation should fail with incorrect hash
        byte[] incorrectHash = new byte[expectedHash.length];
        secureRandom.nextBytes(incorrectHash);

   * size of the input (in bytes). This is only important for non-streaming hash functions (hash
   * functions that need to buffer their whole input before processing any of it).
   */
  Hasher newHasher(int expectedInputSize);

  /**
   * Shortcut for {@code newHasher().putInt(input).hash()}; returns the hash code for the given

   * size of the input (in bytes). This is only important for non-streaming hash functions (hash
   * functions that need to buffer their whole input before processing any of it).
   */
  Hasher newHasher(int expectedInputSize);

  /**
   * Shortcut for {@code newHasher().putInt(input).hash()}; returns the hash code for the given

            assertEquals(context.size(), encodedSize);
            assertEquals(1, buffer[0]); // hash algo count (little endian)
            assertEquals(0, buffer[1]);
            assertEquals(8, buffer[2]); // salt length (little endian)
            assertEquals(0, buffer[3]);
            assertEquals(1, buffer[4]); // SHA512 hash algo (little endian)
            assertEquals(0, buffer[5]);

  // }
  //
  // The imaginary `hash` and `next` values are combined into a single `int` value in the `entries`
  // array. The top bits of this value are the remaining bits of the hash value that were not used
  // in the short hash. We saw that a mask of 0x7f would keep the 7-bit value 0x6f from a full
  // hashcode of 0x89abcdef. The imaginary `hash` value would then be the remaining top 25 bits,