// // 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 `) }