Setup now generates each voter's return-code card by collecting shares from all
four CCs over the bus (the GenEncLongCodeShares exchange) and distributes cards
and the mapping table over CONFIDENTIAL channels.
- codes.go: deriveReturnCodeKey is the SINGLE key-derivation function used by a
CC both when contributing to card assembly and (later) at vote-time extraction
— structurally preventing the setup/extraction derivation mismatch (F1). Each
CC computes its choice/confirm shares from its private return-code secret;
only the shares (validated as G_q members on decode) cross the bus.
- RunCards assembles cards, registers mapping-table entries, and delivers cards
to voters + the mapping table to the server via sendConfidential (X25519 ECDH
session key + AES-256-GCM, then Ed25519-signed) — exercising the secure
channel in the ceremony, not just in tests.
- returncodes: MappingTable Export/ImportMappingTable for transport.
Test confirms every voter receives its card confidentially with the right code
count and the server receives the full mapping table + public election keys.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
pkg/party models each endpoint of the system as a separate object holding only
its own private state, wired together through the transport bus.
- ceremony.go: NewCeremony bootstraps the Ed25519 root CA, enrolls all parties
(setup, 4 CCs, electoral board, voting server, verifier, N voters) with
CA-signed identity certs, registers each in the directory, and wires its
handler into the bus.
- parties.go: the six party types and a shared hello/ack handshake; Handshake()
proves the full sign -> route -> verify -> reply -> verify path for every
party before any election logic runs.
- state.go: per-party private state structs (nothing shared across parties).
- transcript.go: PublicTranscript, the append-only bulletin board a remote
verifier will consume (no secrets).
- phases.go: phase handlers reject unknown message types cleanly (the transport
boundary never panics on unexpected input) — filled in over the next commits.
Transport CA API simplified to own its serial counter (NewCA/Issue).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
