* specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash
   * functions together: {@code Hashing.concatenating(Hashing.sha512(), Hashing.sha512())}.
   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {

   * specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash
   * functions together: {@code Hashing.concatenating(Hashing.sha512(), Hashing.sha512())}.
   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {

/**
 * Static methods for implementing hash-based collections.
 *
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
@GwtCompatible
final class Hashing {
  private Hashing() {}

  /*
   * These should be ints, but we need to use longs to force GWT to do the multiplications with
   * enough precision.
   */
  private static final long C1 = 0xcc9e2d51;

        Hashing.md5().bits() + Hashing.md5().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.md5()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.murmur3_32()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits() + Hashing.murmur3_128().bits(),

        Hashing.md5().bits() + Hashing.md5().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.md5()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.murmur3_32()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits() + Hashing.murmur3_128().bits(),

@NullUnmarked
enum HashFunctionEnum {
  ADLER32(Hashing.adler32()),
  CRC32(Hashing.crc32()),
  GOOD_FAST_HASH_32(Hashing.goodFastHash(32)),
  GOOD_FAST_HASH_64(Hashing.goodFastHash(64)),
  GOOD_FAST_HASH_128(Hashing.goodFastHash(128)),
  GOOD_FAST_HASH_256(Hashing.goodFastHash(256)),
  MD5(Hashing.md5()),
  MURMUR3_128(Hashing.murmur3_128()),
  MURMUR3_32(Hashing.murmur3_32()),
  MURMUR3_32_FIXED(Hashing.murmur3_32_fixed()),
  SHA1(Hashing.sha1()),

    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(MD5_KEY).toString());
    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(keyData).toString());

    assertEquals(
        "Hashing.hmacSha1(Key[algorithm=HmacSHA1, format=RAW])",
        Hashing.hmacSha1(SHA1_KEY).toString());
    assertEquals(

# OAuth2 com Senha (e hashing), Bearer com tokens JWT

Agora que temos todo o fluxo de segurança, vamos tornar a aplicação realmente segura, usando tokens <abbr title="JSON Web Tokens">JWT</abbr> e hashing de senhas seguras.

Este código é algo que você pode realmente usar na sua aplicação, salvar os hashes das senhas no seu banco de dados, etc.

Vamos começar de onde paramos no capítulo anterior e incrementá-lo.

## Sobre o JWT

    verifyNoMoreInteractions(hashFunction, hasher);
  }

  public void testHash_hashesCorrectly() throws Exception {
    HashCode expectedHash = Hashing.md5().hashBytes(testBytes);
    HashingInputStream in = new HashingInputStream(Hashing.md5(), buffer);

    byte[] buf = new byte[4];
    int numOfByteRead = in.read(buf, 0, buf.length);
    assertEquals(4, numOfByteRead);

    verifyNoMoreInteractions(hashFunction, hasher);
  }

  public void testHash_hashesCorrectly() throws Exception {
    HashCode expectedHash = Hashing.md5().hashBytes(testBytes);
    HashingInputStream in = new HashingInputStream(Hashing.md5(), buffer);

    byte[] buf = new byte[4];
    int numOfByteRead = in.read(buf, 0, buf.length);
    assertEquals(4, numOfByteRead);