Foundation for the 0-RTT path that follows. Two additive pieces:
- TlsKeySchedule.clientEarlyTrafficSecret + deriveEarlyTraffic
(transcriptAfterClientHello). RFC 8446 §7.1:
client_early_traffic_secret = Derive-Secret(early_secret,
"c e traffic", H(ClientHello)). Driven by the QUIC layer right after
the resumption ClientHello is appended to the transcript so the
early-data keys are available for the writer to install before
ServerHello arrives.
- encodeEarlyDataEmpty for the ClientHello-side early_data extension
body (empty per RFC 8446 §4.2.10 — its mere presence signals "I'm
about to send 0-RTT"). NewSessionTicket carries a uint32
max_early_data_size variant which is parsed but not yet acted on;
the resumption path doesn't require it.
Wire build, packet protection, and pre-handshake stream creation
follow.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Vitor Pamplona
ff8398c693