Os domínios são verificados com segurança e os certificados são gerados automaticamente. Isso também permite automatizar a renovação desses certificados.

* Traefik (que también puede manejar la renovación de certificados)
* Caddy (que también puede manejar la renovación de certificados)
* Nginx
* HAProxy

## Let's Encrypt { #lets-encrypt }

Antes de Let's Encrypt, estos **certificados HTTPS** eran vendidos por terceros.

El proceso para adquirir uno de estos certificados solía ser complicado, requerir bastante papeleo y los certificados eran bastante costosos.

    val data = CertificateAdapters.certificate.toDer(this)
    try {
      val certificateFactory = CertificateFactory.getInstance("X.509")
      val certificates = certificateFactory.generateCertificates(Buffer().write(data).inputStream())
      return certificates.single() as X509Certificate
    } catch (e: NoSuchElementException) {
      throw IllegalArgumentException("failed to decode certificate", e)
    } catch (e: IllegalArgumentException) {

Maintenant, du point de vue d'un développeur, voici plusieurs choses à avoir en tête en pensant au HTTPS :

* Pour le HTTPS, le serveur a besoin de "certificats" générés par une tierce partie.
    * Ces certificats sont en fait acquis auprès de la tierce partie, et non "générés".
* Les certificats ont une durée de vie.
    * Ils expirent.
    * Puis ils doivent être renouvelés et acquis à nouveau auprès de la tierce partie.

 * ```
 *
 * In this example the HTTP client already knows and trusts the last certificate, "Entrust Root
 * Certification Authority - G2". That certificate is used to verify the signature of the
 * intermediate certificate, "Entrust Certification Authority - L1M". The intermediate certificate
 * is used to verify the signature of the "www.squareup.com" certificate.
 *

        .serialNumber(1L)
        .build()
    val rootB =
      HeldCertificate
        .Builder()
        .serialNumber(2L)
        .build()
    assertThat(get(rootB.certificate, rootA.certificate))
      .isEqualTo(get(rootA.certificate, rootB.certificate))
  }

  @Test
  fun equalsFromTrustManager() {
    val handshakeCertificates = HandshakeCertificates.Builder().build()

    }

    // 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() {

    .heldCertificate(serverCertificate, intermediateCertificate.certificate())
    .build();
```

The client only needs to know the trusted root certificate. It checks the server's certificate by
validating the signatures within the chain.

```java
HandshakeCertificates clientCertificates = new HandshakeCertificates.Builder()
    .addTrustedCertificate(rootCertificate.certificate())
    .build();

```

### 3.2 Use OpenSSL to Generate a Certificate

Use one of the following methods to generate a certificate using `openssl`:

* 3.2.1 [Generate a private key with ECDSA](#generate-private-key-with-ecdsa)
* 3.2.2 [Generate a private key with RSA](#generate-private-key-with-rsa)
* 3.2.3 [Generate a self-signed certificate](#generate-a-self-signed-certificate)

#### 3.2.1 Generate a private key with ECDSA

 *
 *  * 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.