swisspost-evoting-go-poc/pkg/protocol/actors.go

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Go
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package protocol
import (
"fmt"
Due-diligence hardening + Rust transport-security layer 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>
2026-07-06 12:42:34 +00:00
"math/big"
emath "github.com/user/evote/pkg/math"
)
Due-diligence hardening + Rust transport-security layer 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>
2026-07-06 12:42:34 +00:00
func bigIntN(n int) *big.Int { return big.NewInt(int64(n)) }
// RunDemoElection runs a complete election ceremony with the given parameters.
func RunDemoElection(numVoters, numOptions int) {
fmt.Println("========================================")
fmt.Println(" Swiss Post E-Voting Protocol PoC (Go)")
fmt.Println("========================================")
fmt.Printf(" Voters: %d, Options: %d, CCs: 4\n", numVoters, numOptions)
fmt.Println()
// Phase 1: Setup
fmt.Println("--- SETUP PHASE ---")
cfg := DefaultConfig(numVoters, numOptions)
fmt.Printf(" Group: %d-bit safe prime\n", cfg.Group.Q().BitLen())
event := Setup(cfg)
fmt.Printf(" Generated %d voting cards\n", numVoters)
fmt.Printf(" Mapping table: %d entries\n", event.MappingTable.Size())
fmt.Println(" Setup complete.")
// Phase 2: Voting
fmt.Println("\n--- VOTING PHASE ---")
for v := 0; v < numVoters; v++ {
Due-diligence hardening + Rust transport-security layer 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>
2026-07-06 12:42:34 +00:00
// Randomly select 1 option for each voter (CSPRNG; simulation only).
selected := []int{int(emath.RandomBigInt(bigIntN(numOptions)).Int64())}
CastVote(event, v, selected)
}
fmt.Printf(" All %d votes cast.\n", numVoters)
// Phase 3: Tally
Tally(event)
// Phase 4: Verify
VerifyTally(event)
}