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mrambossekandClaude Opus 5 3520eabd21 app: scaffold echolot-app + core-protocol — client spine verified live vs fmr
Multi-module Android app, built bottom-up from a verifiable core.
core-protocol is pure Kotlin/JVM (no Android SDK): SPKI-pinned control
plane (enroll/profile/session over HttpsURLConnection — API-1 compatible,
hostname verification off, trust is the pin), HKDF-SHA256 session keys,
ELT1 UDP data plane (HMAC gate, ECHO+observation, MTU probe) —
byte-compatible with the Go server.

Unit tests incl. the RFC 5869 HKDF vector (key derivation provably matches
the server). LiveServerTest + scripts/test-fmr.sh prove the client
end-to-end against the deployed fmr server: profile (8 caps), session,
ECHO rtt~11ms with the observation block returning our observed NAT port,
MTU 1400->1400, observations. Live test self-skips without ECHOLOT_LIVE_*.

Two client bugs caught live: java.net.http hostname verification (→
HttpsURLConnection, also the Android-minSdk-26 choice) and ECHO padding
needed for the observation to survive anti-amplification.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-07-31 21:16:41 +02:00

43 KiB