* [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.

    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() {

 * **Handshake**: cipherSuite, localCertificates, localPrincipal, peerCertificates, peerPrincipal,
   tlsVersion
 * **HandshakeCertificates**: keyManager, trustManager
 * **Headers**: size
 * **HeldCertificate**: certificate, keyPair
 * **HttpLoggingInterceptor**: level
 * **HttpUrl**: encodedFragment, encodedPassword, encodedPath, encodedPathSegments, encodedQuery,
   encodedUsername, fragment, host, password, pathSegments, pathSize, port, query,

set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j2.disable.jmx=true
set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j2.formatMsgNoLookups=true
set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j.skipJansi=true

REM SSL truststore for certificate validation over https
REM FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djavax.net.ssl.trustStore=/tech/elastic/config/truststore.jks
REM FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djavax.net.ssl.trustStorePassword=changeit

import java.util.Map;

import javax.security.auth.kerberos.KerberosKey;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.util.Hexdump;

/**
 * Privilege Attribute Certificate (PAC) decoder for Kerberos tickets.
 * Parses and validates PAC data structures containing user authorization information
 * from Active Directory Kerberos tickets.
 */
public class Pac {

- Added two client certificate metrics for exec auth:
    - `rest_client_certificate_expiration_seconds` a gauge reporting the lifetime of the current client certificate. Reports the time of expiry in seconds since January 1, 1970 UTC.

  /**
   * Returns true if the host and port are unchanged from when this was created. This is used to
   * detect if followups need to do a full connection-finding process including DNS resolution, and
   * certificate pin checks.
   */
  fun sameHostAndPort(url: HttpUrl): Boolean

  /**
   * A plan holds either an immediately-usable connection, or one that must be connected first.

import java.io.IOException
import java.net.InetAddress
import java.net.UnknownHostException
import java.security.KeyStore
import java.security.SecureRandom
import java.security.Security
import java.security.cert.Certificate
import java.security.cert.CertificateException
import java.security.cert.X509Certificate
import java.util.concurrent.atomic.AtomicInteger
import java.util.logging.Handler
import java.util.logging.Level

    // 3. This connection's server certificates must cover the new host.
    if (address.hostnameVerifier !== OkHostnameVerifier) return false
    if (!supportsUrl(address.url)) return false

    // 4. Certificate pinning must match the host.
    try {
      address.certificatePinner!!.check(address.url.host, handshake()!!.peerCertificates)
    } catch (_: SSLPeerUnverifiedException) {
      return false
    }

    server.enqueue(MockResponse())

    // Make a first request without certificate pinning. Use it to collect certificates to pin.
    val request1 = Request.Builder().url(server.url("/")).build()
    val response1 = client.newCall(request1).execute()
    val certificatePinnerBuilder = CertificatePinner.Builder()
    for (certificate in response1.handshake!!.peerCertificates) {
      certificatePinnerBuilder.add(