Replay

TLS 1.3 Early Data Trades One Round Trip for Replay Exposure

A resumed TLS 1.3 connection can carry application bytes before the server finishes the new handshake. That latency reduction changes a security boundary: early data is protected in transit, yet the protocol does not give it the same replay property as ordinary post-handshake application data. The distinction matters when an endpoint maps one request to a state-changing operation. A captured early-data flight can be presented again under conditions in which a server accepts it, so confidentiality and integrity on the wire do not imply single execution.