The differentiator. A single self-contained browser page (no libraries, offline)
renders each real cryptographic operation as typeset mathematics the instant it
runs, with the actual runtime values:
- E_1 = (γ, φ) = (g^r, pk^r·m), r ← Z_q (ElGamal ballot encryption)
- e = H((p,q,g), y, c, h_aux) mod q (Fiat-Shamir challenge)
- C' = { ReEnc_pk(C_π(i); ρ_i) } (Bayer-Groth verifiable shuffle)
- σ ← Ed25519.Sign_sk(SHA256(envelope)) (transport signature)
- s = a·B = b·A ∈ X25519, k = SHA256(…) (X25519 key agreement)
Math is rendered via a focused LaTeX→native-MathML converter written for exactly
the notation the instrumentation emits — so it works in any modern browser with
zero dependencies and nothing to ship. Unknown tokens fall back to literal text,
never crashing the view.
`evote cockpit` starts an HTTP server; on page connect it runs one full multi-
party ceremony, streaming every crypto event over SSE with configurable pacing
(--delay) so a human can follow along. A stakeholder sidebar highlights the
acting party; a phase timeline tracks setup→cards→voting→tally→verify; each op
shows its live values as expandable, copyable chips.
Verified in a real browser: all five operation kinds render correctly (96 sign,
36 challenge, 6 keyex, 2 encrypt, 5 shuffle in a 2-voter run), no console errors,
ceremony completes and verifies.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Correctness/security review of the whole PoC, with fixes and regression tests.
Cryptographic soundness:
- mixnet: enforce the multi-exponentiation c_{B_m}=commit(0;0) check that was
stubbed out with an empty if — without it a malicious mixer can prove a
non-permutation shuffle.
- zkp: derive all four Fiat-Shamir challenges via RecursiveHashToZq instead of
a biased `hash mod q` (which also capped the challenge space at 256 bits for
production-sized groups).
Verification honesty:
- protocol: VerifyTally now actually calls zkp.VerifySchnorrProof and returns
the true aggregate result instead of an unconditional true.
- protocol: persist the padded mix input (event.MixInput) so the verifier checks
shuffle 0 against the same padding the tally used (fixes false INVALID for N<2).
Other correctness:
- kdf: length-prefix BuildKDFInfo parts so the info encoding is injective.
- math: GqElementFromSquareRoot accepts the valid root q (off-by-one that could
panic in HashAndSquare); RandomGqElement samples the full canonical range.
- cmd: validate demo --voters/--options instead of panicking on degenerate values.
- protocol: use crypto/rand in the demo driver (drop the last math/rand import).
Transport security (new): pkg/transportsec exposes Ed25519 signatures and X25519
ECDH — implemented in Rust (rust/transportsec: ed25519-dalek, x25519-dalek),
linked into Go via cgo. No RSA. Cross-language conformance test proves the Rust
Ed25519 signatures interoperate with Go's crypto/ed25519. Makefile builds the
Rust static lib before the Go binary.
Tests: added unit/round-trip/tamper coverage for math, hash, elgamal, zkp,
mixnet, kdf, returncodes, protocol (end-to-end), and the Rust FFI bridge.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Proof-of-concept reimplementation of the Swiss Post e-voting
cryptographic protocol in Go. Single binary, 52 source files,
2 dependencies. Covers ElGamal encryption, Bayer-Groth verifiable
shuffles, zero-knowledge proofs, return codes, and a full
election ceremony demo.
