*
 *  * The server's handshake certificates must have a [held certificate][HeldCertificate] (a
 *    certificate and its private key). The certificate's subject alternative names must match the
 *    server's hostname. The server must also have is a (possibly-empty) chain of intermediate
 *    certificates to establish trust from a root certificate to the server's certificate. The root
 *    certificate is not included in this chain.

 * They specify that the call may be plaintext (`http`) or encrypted (`https`), but not which cryptographic algorithms should be used. Nor do they specify how to verify the peer's certificates (the [HostnameVerifier](https://developer.android.com/reference/javax/net/ssl/HostnameVerifier.html)) or which certificates can be trusted (the [SSLSocketFactory](https://developer.android.com/reference/org/apache/http/conn/ssl/SSLSocketFactory.html)).

 * certificate.
 *
 * Use of the chain cleaner is necessary to omit unexpected certificates that aren't relevant to
 * the TLS handshake and to extract the trusted CA certificate for the benefit of certificate
 * pinning.
 */
abstract class CertificateChainCleaner {
  @Throws(SSLPeerUnverifiedException::class)
  abstract fun clean(
    chain: List<Certificate>,

    val exception = IOException("Non-handshake exception")
    assertThat(retryTlsHandshake(exception)).isFalse()
  }

  @Test fun nonRetryableSSLHandshakeException() {
    val exception =
      SSLHandshakeException("Certificate handshake exception").apply {
        initCause(CertificateException())
      }
    assertThat(retryTlsHandshake(exception)).isFalse()
  }

  @Test fun retryableSSLHandshakeException() {

        .build()
    return@lazy HandshakeCertificates.Builder()
      .addPlatformTrustedCertificates()
      .heldCertificate(heldCertificate)
      .addTrustedCertificate(heldCertificate.certificate)
      .build()
  }

  @Before
  fun init() {
    assumeTrue("Supported on API 29+", Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q)

    client =
      OkHttpClient.Builder()

   * This is unexpected unless the trust root index in this class has a different trust manager than
   * what was used to establish [chain].
   */
  @Throws(SSLPeerUnverifiedException::class)
  override fun clean(
    chain: List<Certificate>,
    hostname: String,
  ): List<Certificate> {
    val queue: Deque<Certificate> = ArrayDeque(chain)

              "emyPxgcYxn/eR44/KJ4EBs+lVDR3veyJm+kXQ99b21/+jh5Xos1AnX5iItreGCc=\n" +
              "-----END CERTIFICATE-----";

      CertificateFactory cf = CertificateFactory.getInstance("X.509");
      Certificate isgCertificate = cf.generateCertificate(new ByteArrayInputStream(isgCert.getBytes("UTF-8")));

      HandshakeCertificates certificates = new HandshakeCertificates.Builder()
              .addTrustedCertificate((X509Certificate) isgCertificate)

    }

    // Should not be pinned:
    certificatePinner.check("uk", listOf(certB1.certificate))
    certificatePinner.check("co.uk", listOf(certB1.certificate))
    certificatePinner.check("anotherexample.co.uk", listOf(certB1.certificate))
    certificatePinner.check("foo.anotherexample.co.uk", listOf(certB1.certificate))
  }

  @Test
  fun testBadPin() {

 * [okhttp-stats](https://github.com/flipkart-incubator/okhttp-stats): Get stats like average network speed.
 * [okhttp-system-keystore](https://github.com/charleskorn/okhttp-system-keystore): Use trusted certificates from the operating system keystore (Keychain on macOS, Certificate Store on Windows).
 * ⬜️ [Okio](https://github.com/square/okio/): A modern I/O API for Java.

on-300-000-iranians-using-fake-google-certificate.html). It also assumes your HTTPS servers’ certificates are signed by a certificate authority.

Use [CertificatePinner](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-certificate-pinner/) to restrict which certificates and certificate authorities are trusted. Certificate pinning increases security, but limits your server team’s abilities to update their TLS certificates. **Do not use certificate pinning without the blessing of your server’s...