// Add a bad intermediate CA and have that issue a rogue certificate for localhost. Prepare
    // an SSL context for an attacking webserver. It includes both these rogue certificates plus the
    // trusted good certificate above. The attack is that by including the good certificate in the
    // chain, we may trick the certificate pinner into accepting the rouge certificate.
    val compromisedIntermediateCa =
      HeldCertificate

to generate a trusted root certificate, an intermediate certificate, and a server certificate.
We use `certificateAuthority(int)` to create certificates that can sign other certificates. The
int specifies how many intermediate certificates are allowed beneath it in the chain.

```java
HeldCertificate rootCertificate = new HeldCertificate.Builder()
    .certificateAuthority(1)
    .build();

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

1. [Install MinIO Server](#install-minio-server)
2. [Use an Existing Key and Certificate with MinIO](#use-an-existing-key-and-certificate-with-minio)
3. [Generate and use Self-signed Keys and Certificates with MinIO](#generate-use-self-signed-keys-certificates)
4. [Install Certificates from Third-party CAs](#install-certificates-from-third-party-cas)

The domains are securely verified and the certificates are generated automatically. This also allows automating the renewal of these certificates.

	// configured expiry and the duration until the certificate itself
	// expires.
	// We must not issue credentials that out-live the certificate.
	if validUntil := time.Until(certificate.NotAfter); validUntil < expiry {
		expiry = validUntil
	}

	// Associate any service accounts to the certificate CN
	parentUser := "tls" + getKeySeparator() + certificate.Subject.CommonName

credentials via the STS API. It can authenticate via a client certificate and obtain a access/secret key pair as well as a session token. These credentials are associated to an S3 policy at the MinIO server.

In case of certificate-based authentication, MinIO has to map the client-provided certificate to an S3 policy. MinIO does this via the subject common name field of the X.509 certificate. So, MinIO will associate a certificate with a subject `CN = foobar` to a S3 policy named `foobar`....

    val certificate: X509Certificate = heldCertificate.certificate
    val certificatePinner: CertificatePinner = CertificatePinner.Builder().build()
    val certificates: List<Certificate> = listOf()
    certificatePinner.check("", listOf(certificate))
    certificatePinner.check("", arrayOf<Certificate>(certificate, certificate).toList())
    val pin: String = CertificatePinner.pin(certificate)

	}

	cert, ok := clientKey.(*ssh.Certificate)
	if !ok {
		return errSftpPublicKeyWithoutCert
	}

	// ssh.CheckCert called by ssh.Authenticate accepts certificates
	// with empty principles list so we block those in here.
	if len(cert.ValidPrincipals) == 0 {
		return errSftpCertWithoutPrincipals
	}

	// Verify that certificate provided by user is issued by trusted CA,

  /** Can still coalesce when pinning is used if pins match.  */
  @Test
  fun coalescesWhenCertificatePinsMatch() {
    val pinner =
      CertificatePinner
        .Builder()
        .add("san.com", pin(certificate.certificate))
        .build()
    client = client.newBuilder().certificatePinner(pinner).build()
    server.enqueue(MockResponse())
    server.enqueue(MockResponse())