> For the complete documentation index, see [llms.txt](https://http3-explained.haxx.se/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://http3-explained.haxx.se/en/quic/quic-tls.md).

# Connections use TLS

Immediately after the initial packet setting up a connection, the initiator sends a crypto frame that starts setting up the secure layer handshake. The security layer uses TLS 1.3 security.

There is no way to opt-out or avoid using TLS for a QUIC connection. The protocol is designed to be hard for middle-boxes to tamper with, in order to help prevent ossification of the protocol.