* @return a decryption cipher
     */
    protected Cipher pollDecryptoCipher() {
        Cipher cipher = decryptoQueue.poll();
        if (cipher == null) {
            try {
                final SecretKeySpec sksSpec = new SecretKeySpec(key.getBytes(charsetName), algorithm);
                cipher = Cipher.getInstance(algorithm);
                cipher.init(Cipher.DECRYPT_MODE, sksSpec);

---

<a name="tlsv13_only"></a>
#### ¹ TLSv1.3 Only

Cipher suites that are only available with TLSv1.3.

<a name="http2_naughty"></a>
#### ² HTTP/2 Cipher Suite Denylist

Cipher suites that are [discouraged for use][http2_denylist] with HTTP/2. OkHttp includes them because better suites are not commonly available. For example, none of the better cipher suites listed above shipped with Android 4.4 or Java 7.

        return new HMACT64(key);
    }

    /**
     * Get an RC4 cipher instance initialized with the specified key.
     * @param key the encryption key
     * @return RC4 cipher in encryption mode
     */
    public static Cipher getArcfour(final byte[] key) {
        try {
            final Cipher c = Cipher.getInstance("RC4");
            c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "RC4"));
            return c;

            final Cipher cipher = Cipher.getInstance(transformation);
            final GCMParameterSpec gcmSpec = new GCMParameterSpec(getAuthTagLength() * 8, nonce);

            cipher.init(encrypt ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE, keySpec, gcmSpec);
            return cipher;
        } finally {
            // Guaranteed cleanup of all key material
            if (key != null) {

    assertThat(forJavaName(java.lang.String(cs.javaName) as String))
      .isSameAs(cs)
  }

  @Test
  fun equals() {
    assertThat(forJavaName("cipher")).isEqualTo(forJavaName("cipher"))
    assertThat(forJavaName("cipherB")).isNotEqualTo(forJavaName("cipherA"))
    assertThat(CipherSuite.TLS_RSA_EXPORT_WITH_RC4_40_MD5)
      .isEqualTo(forJavaName("SSL_RSA_EXPORT_WITH_RC4_40_MD5"))

        cipher.setKey("mySecretKey");

        final String original = "";
        final String encrypted = cipher.encryptText(original);
        final String decrypted = cipher.decryptText(encrypted);

        assertThat(decrypted, is(original));
    }

    @Test
    public void testLongText() {
        final CachedCipher cipher = new CachedCipher();
        cipher.setKey("mySecretKey");

        final int start = dstIndex;
        SMBUtil.writeInt2(this.ciphers != null ? this.ciphers.length : 0, dst, dstIndex);
        dstIndex += 2;

        if (this.ciphers != null) {
            for (final int cipher : this.ciphers) {
                SMBUtil.writeInt2(cipher, dst, dstIndex);
                dstIndex += 2;
            }
        }
        return dstIndex - start;

        byte[] keybytes = key.getEncoded();
        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keybytes, "AES"), new IvParameterSpec(ZERO_IV, 0, ZERO_IV.length));
        if (constant.length != cipher.getBlockSize()) {
            constant = expandNFold(constant, cipher.getBlockSize());
        }
        byte[] enc = constant;

        final PrimaryCipher cipher = ComponentUtil.getPrimaryCipher();
        ParameterUtil.parse(value).entrySet().stream().map(e -> {
            final String k = e.getKey();
            final String v = e.getValue();
            if (properyPattern.matcher(k).matches() && !v.startsWith(CIPHER_PREFIX)) {
                return new Pair<>(k, CIPHER_PREFIX + cipher.encrypt(v));
            }

        SecretKeySpec dataKey = new SecretKeySpec(dataHmac, KerberosConstants.RC4_ALGORITHM);

        cipher = Cipher.getInstance(KerberosConstants.RC4_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, dataKey);

        int plainDataLength = data.length - KerberosConstants.CHECKSUM_SIZE;
        byte[] plainData = cipher.doFinal(data, KerberosConstants.CHECKSUM_SIZE, plainDataLength);