ceremonyclient/nekryptology/test/frost_dkg/ed25519/main.go

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2023-07-05 05:32:28 +00:00
//
// Copyright Coinbase, Inc. All Rights Reserved.
//
// SPDX-License-Identifier: Apache-2.0
//
package main
import (
"crypto/sha512"
"flag"
"fmt"
"filippo.io/edwards25519"
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/core/curves"
dkg "source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/dkg/frost"
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/sharing"
"source.quilibrium.com/quilibrium/monorepo/nekryptology/pkg/ted25519/frost"
)
const LIMIT = 4
const THRESHOLD = 2
const Ctx = "string to prevent replay attack"
func main() {
var threshold int
var limit int
var help bool
flag.IntVar(&threshold, "t", THRESHOLD, "the minimum number of participants to sign")
flag.IntVar(&threshold, "threshold", THRESHOLD, "the minimum number of participants to sign")
flag.IntVar(&limit, "n", LIMIT, "the total number of participants")
flag.IntVar(&limit, "limit", LIMIT, "the total number of participants")
flag.BoolVar(&help, "h", false, "Print this menu")
flag.BoolVar(&help, "help", false, "Print this menu")
flag.Parse()
if help {
printHelp()
return
}
fmt.Printf("Threshold is %d\n", threshold)
fmt.Printf("Total participants is %d\n", limit)
// DEMO doing FROST DKG and that signers can compute a signature
participants := createDkgParticipants(threshold, limit)
// DKG Round 1
rnd1Bcast, rnd1P2p := round1(participants)
// DKG Round 2
verificationKey, signingShares := round2(participants, rnd1Bcast, rnd1P2p)
// Signing common setup for all participants
msg := []byte("All my bitcoin is stored here")
curve := curves.ED25519()
scheme, _ := sharing.NewShamir(uint32(threshold), uint32(limit), curve)
shares := make([]*sharing.ShamirShare, 0, threshold)
cnt := 0
for _, share := range signingShares {
if cnt == threshold {
break
}
cnt++
shares = append(shares, share)
}
sk, err := scheme.Combine(shares...)
if err != nil {
panic(err)
}
vk := curve.ScalarBaseMult(sk)
if !vk.Equal(verificationKey) {
panic("verification keys are not equal")
}
skC := sk.(*curves.ScalarEd25519).GetEdwardsScalar()
r, s := sign(skC, vk.ToAffineCompressed(), []byte("no nonce"), msg)
ok := verify(vk.ToAffineCompressed(), msg, r, s)
fmt.Printf("Signature verification - %v\n", ok)
// Test threshold signing
lCoeffs, err := scheme.LagrangeCoeffs([]uint32{signingShares[1].Id, signingShares[2].Id})
if err != nil {
panic(err)
}
signers := make(map[uint32]*frost.Signer, 2)
signers[1], err = frost.NewSigner(participants[1], 1, uint32(threshold), lCoeffs, []uint32{1, 2}, &frost.Ed25519ChallengeDeriver{})
if err != nil {
panic(err)
}
signers[2], err = frost.NewSigner(participants[2], 2, uint32(threshold), lCoeffs, []uint32{1, 2}, &frost.Ed25519ChallengeDeriver{})
if err != nil {
panic(err)
}
sigRnd1Bcast := make(map[uint32]*frost.Round1Bcast, 2)
sigRnd1Bcast[1], err = signers[1].SignRound1()
if err != nil {
panic(err)
}
sigRnd1Bcast[2], err = signers[2].SignRound1()
if err != nil {
panic(err)
}
sigRng2BCast := make(map[uint32]*frost.Round2Bcast, 2)
sigRng2BCast[1], err = signers[1].SignRound2(msg, sigRnd1Bcast)
if err != nil {
panic(err)
}
sigRng2BCast[2], err = signers[2].SignRound2(msg, sigRnd1Bcast)
if err != nil {
panic(err)
}
sigRng3BCast, err := signers[1].SignRound3(sigRng2BCast)
if err != nil {
panic(err)
}
sigR := sigRng3BCast.R.(*curves.PointEd25519).GetEdwardsPoint()
sigS := sigRng3BCast.Z.(*curves.ScalarEd25519).GetEdwardsScalar()
ok = verify(vk.ToAffineCompressed(), msg, sigR, sigS)
fmt.Printf("Threshold Signature verification - %v\n", ok)
}
func sign(skC *edwards25519.Scalar, pubKey, nonce, msg []byte) (*edwards25519.Point, *edwards25519.Scalar) {
h := sha512.New()
_, _ = h.Write(nonce)
_, _ = h.Write(msg)
digest := h.Sum(nil)
digestReduced, err := edwards25519.NewScalar().SetUniformBytes(digest)
if err != nil {
panic(err)
}
r := edwards25519.NewGeneratorPoint().ScalarBaseMult(digestReduced)
encodedR := r.Bytes()
h.Reset()
_, _ = h.Write(encodedR)
_, _ = h.Write(pubKey)
_, _ = h.Write(msg)
k, err := edwards25519.NewScalar().SetUniformBytes(h.Sum(nil))
if err != nil {
panic(err)
}
s := edwards25519.NewScalar().MultiplyAdd(k, skC, digestReduced)
return r, s
}
func verify(pk, msg []byte, r *edwards25519.Point, s *edwards25519.Scalar) bool {
h := sha512.New()
_, _ = h.Write(r.Bytes())
_, _ = h.Write(pk)
_, _ = h.Write(msg)
k, err := edwards25519.NewScalar().SetUniformBytes(h.Sum(nil))
if err != nil {
panic(err)
}
minusA, _ := edwards25519.NewIdentityPoint().SetBytes(pk)
minusA.Negate(minusA)
lhs := edwards25519.NewIdentityPoint().VarTimeDoubleScalarBaseMult(k, minusA, s)
return lhs.Equal(r) == 1
}
func round1(participants map[uint32]*dkg.DkgParticipant) (map[uint32]*dkg.Round1Bcast, map[uint32]dkg.Round1P2PSend) {
// DKG Round 1
rnd1Bcast := make(map[uint32]*dkg.Round1Bcast, len(participants))
rnd1P2p := make(map[uint32]dkg.Round1P2PSend, len(participants))
for id, p := range participants {
fmt.Printf("Computing DKG Round 1 for participant %d\n", id)
bcast, p2psend, err := p.Round1(nil)
if err != nil {
panic(err)
}
rnd1Bcast[id] = bcast
rnd1P2p[id] = p2psend
}
return rnd1Bcast, rnd1P2p
}
func round2(participants map[uint32]*dkg.DkgParticipant,
rnd1Bcast map[uint32]*dkg.Round1Bcast,
rnd1P2p map[uint32]dkg.Round1P2PSend,
) (curves.Point, map[uint32]*sharing.ShamirShare) {
signingShares := make(map[uint32]*sharing.ShamirShare, len(participants))
var verificationKey curves.Point
for id := range rnd1Bcast {
fmt.Printf("Computing DKG Round 2 for participant %d\n", id)
rnd1P2pForP := make(map[uint32]*sharing.ShamirShare)
for jid := range rnd1P2p {
if jid == id {
continue
}
rnd1P2pForP[jid] = rnd1P2p[jid][id]
}
rnd2Out, err := participants[id].Round2(rnd1Bcast, rnd1P2pForP)
if err != nil {
panic(err)
}
verificationKey = rnd2Out.VerificationKey
share := &sharing.ShamirShare{
Id: id,
Value: participants[id].SkShare.Bytes(),
}
signingShares[id] = share
}
return verificationKey, signingShares
}
func createDkgParticipants(thresh, limit int) map[uint32]*dkg.DkgParticipant {
curve := curves.ED25519()
participants := make(map[uint32]*dkg.DkgParticipant, limit)
for i := 1; i <= limit; i++ {
otherIds := make([]uint32, limit-1)
idx := 0
for j := 1; j <= limit; j++ {
if i == j {
continue
}
otherIds[idx] = uint32(j)
idx++
}
p, err := dkg.NewDkgParticipant(uint32(i), uint32(thresh), Ctx, curve, otherIds...)
if err != nil {
panic(err)
}
participants[uint32(i)] = p
}
return participants
}
func printHelp() {
fmt.Printf(`
ed25519 INPUT
Simulate a DKG using Ed25519 keys
FLAGS:
-h, --help Show this help message and exit
-n, --limit The total number of participants
-t, --treshold The minimum number of participants needed to sign
`)
}