Glossary · Protocols & authentication
TLS / SSL
The encryption that protects HTTPS traffic, which a proxy tunnels through untouched rather than reading.
TLS, the successor to SSL, is the encryption behind the padlock in a browser. It secures the connection between you and a website so no one in between can read or alter it. Almost all web traffic now runs over it, which shapes what a proxy can and cannot do.
Because TLS is end-to-end between you and the destination, an HTTP proxy cannot read inside an HTTPS request; it opens a tunnel with the CONNECT method and passes the encrypted stream through blind. This is a feature, not a limit: it means the proxy relays your secure traffic without being able to see your data.
TLS also leaves a fingerprint, the specific way a client negotiates the encryption, which detection systems increasingly use. That is a separate topic from the encryption's protective job, and the one that makes the TLS handshake interesting to anyone thinking about how proxied traffic is identified.
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