## Version 4.2.0

_2019-09-10_

 *  New: API to decode a certificate and private key to create a `HeldCertificate`. This accepts a
    string containing both a certificate and PKCS #8-encoded private key.

    ```kotlin
    val heldCertificate = HeldCertificate.decode("""
        |-----BEGIN CERTIFICATE-----
        |MIIBYTCCAQegAwIBAgIBKjAKBggqhkjOPQQDAjApMRQwEgYDVQQLEwtlbmdpbmVl

              "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()

import okhttp3.mockwebserver.MockResponse;
import okhttp3.mockwebserver.MockWebServer;
import okhttp3.tls.HandshakeCertificates;
import okhttp3.tls.HeldCertificate;

/**
 * Create an HTTPS server with a self-signed certificate that OkHttp trusts.
 */
public class HttpsServer {
  public void run() throws Exception {
    HeldCertificate localhostCertificate = new HeldCertificate.Builder()
        .addSubjectAlternativeName("localhost")

    /**
     * Returns the SHA-256 of `certificate`'s public key.
     *
     * In OkHttp 3.1.2 and earlier, this returned a SHA-1 hash of the public key. Both types are
     * supported, but SHA-256 is preferred.
     */
    @JvmStatic
    fun pin(certificate: Certificate): String {
      require(certificate is X509Certificate) { "Certificate pinning requires X509 certificates" }

import okhttp3.Request
import okhttp3.tls.HandshakeCertificates
import okhttp3.tls.decodeCertificatePem
import org.junit.jupiter.api.Tag
import org.junit.jupiter.api.Test

/**
 * Test for new Let's Encrypt Root Certificate.
 */
@Tag("Remote")
class LetsEncryptClientTest {
  @Test fun get() {
    // These tests wont actually run before Android 8.0 as per
    // https://github.com/mannodermaus/android-junit5

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...

  @get:JvmName("localCertificates") val localCertificates: List<Certificate>,
  // Delayed provider of peerCertificates, to allow lazy cleaning.
  peerCertificatesFn: () -> List<Certificate>,
) {
  /** Returns a possibly-empty list of certificates that identify the remote peer. */
  @get:JvmName("peerCertificates")
  val peerCertificates: List<Certificate> by lazy {
    try {
      peerCertificatesFn()

    assertTrue(pin.matchesCertificate(certA1.certificate))
    assertFalse(pin.matchesCertificate(certB1.certificate))
  }

  @Test fun testMatchesSha1() {
    val pin = Pin("example.com", certC1Sha1Pin)
    assertTrue(pin.matchesCertificate(certC1.certificate))
    assertFalse(pin.matchesCertificate(certB1.certificate))
  }

  @Test fun pinList() {
    val builder =

        try (InputStream in = new FileInputStream(filename)) {
            Certificate certificate = CertificateFactory.getInstance("X.509").generateCertificate(in);

            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keyStore.load(null, null);
            keyStore.setCertificateEntry("server", certificate);

     * a line containing the cipher suite. Next is the length of the peer certificate chain. These
     * certificates are base64-encoded and appear each on their own line. The next line contains the
     * length of the local certificate chain. These certificates are also base64-encoded and appear
     * each on their own line. A length of -1 is used to encode a null array. The last line is