Automatic Key Exchange: faster, post-quantum secure origin handshakes for 45 billion daily connections (and counting)

What happened

Every time Cloudflare opens a new TLS 1.3 connection to an origin server, we have to make a guess: the protocol requires us to commit to a key agreement algorithm in the very first packet we send, before the origin has told us anything about itself or what it can support. If we guess right, the handshake completes in one round trip. Guess wrong, and the origin replies with a HelloRetryRequest , we start over, and th…

Summary assembled by rule from the sources below

Sources