* C'est une couche en dessous de HTTP.
    * Donc, le certificat et le traitement du cryptage sont faits avant HTTP.
* TCP ne connaît pas les "domaines", seulement les adresses IP.
    * L'information sur le domaine spécifique demandé se trouve dans les données HTTP.
* Les certificats HTTPS "certifient" un certain domaine, mais le protocole et le cryptage se font au niveau TCP, avant de savoir quel domaine est traité.

Der TLS-Terminierungsproxy hätte Zugriff auf ein oder mehrere **TLS-Zertifikate** (HTTPS-Zertifikate).

Mithilfe der oben beschriebenen **SNI-Erweiterung** würde der TLS-Terminierungsproxy herausfinden, welches der verfügbaren TLS-Zertifikate (HTTPS) er für diese Verbindung verwenden muss, und zwar das, welches mit der vom Client erwarteten Domain übereinstimmt.

In diesem Fall würde er das Zertifikat für `someapp.example.com` verwenden.

* O TCP não sabe sobre "domínios". Apenas sobre endereços IP.
    * As informações sobre o domínio solicitado vão nos dados HTTP.
* Os certificados HTTPS “certificam” um determinado domínio, mas o protocolo e a encriptação acontecem ao nível do TCP, antes de sabermos de que domínio se trata.
* Por padrão, isso significa que você só pode ter um certificado HTTPS por endereço IP.

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...

In this case, it would use the certificate for `someapp.example.com`.

<img src="/img/deployment/https/https03.svg">

The client already **trusts** the entity that generated that TLS certificate (in this case Let's Encrypt, but we'll see about that later), so it can **verify** that the certificate is valid.

要从用户的视角**了解 HTTPS 的基础知识**，请查看 <a href="https://howhttps.works/" class="external-link" target="_blank">https://howhttps.works/</a>。

现在，从**开发人员的视角**，在了解 HTTPS 时需要记住以下几点：

* 要使用 HTTPS，**服务器**需要拥有由**第三方**生成的**"证书(certificate)"**。
     * 这些证书实际上是从第三方**获取**的，而不是“生成”的。
* 证书有**生命周期**。
     * 它们会**过期**。
     * 然后它们需要**更新**，**再次从第三方获取**。
* 连接的加密发生在 **TCP 层**。
     * 这是 HTTP 协议**下面的一层**。
     * 因此，**证书和加密**处理是在 **HTTP之前**完成的。