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Remove duplicate CL libraries, add signing logic to VAA

This commit is contained in:
Hendrik Hofstadt 2020-08-05 10:48:43 +02:00
parent 90e75b3d22
commit a1ba223361
21 changed files with 153 additions and 2464 deletions
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304
bridge/pkg/signatures/ethdss/ethdss.go
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@ -1,304 +0,0 @@
// Package ethdss implements the Distributed Schnorr Signature protocol from the
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// paper "Provably Secure Distributed Schnorr Signatures and a (t, n)
// Threshold Scheme for Implicit Certificates".
// https://dl.acm.org/citation.cfm?id=678297
// To generate a distributed signature from a group of participants, the group
// must first generate one longterm distributed secret with the share/dkg
// package, and then one random secret to be used only once.
// Each participant then creates a DSS struct, that can issue partial signatures
// with `dss.PartialSignature()`. These partial signatures can be broadcasted to
// the whole group or to a trusted combiner. Once one has collected enough
// partial signatures, it is possible to compute the distributed signature with
// the `Signature` method.
//
// This is mostly copied from the sign/dss package, with minor adjustments for
// use with ethschnorr.
package ethdss
import (
"bytes"
"errors"
"math/big"
"github.com/certusone/wormhole/bridge/pkg/signatures/ethschnorr"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/share"
)
// Suite represents the functionalities needed by the dss package
type Suite interface {
kyber.Group
kyber.HashFactory
kyber.Random
}
var secp256k1Suite = secp256k1.NewBlakeKeccackSecp256k1()
var secp256k1Group kyber.Group = secp256k1Suite
// DistKeyShare is an abstraction to allow one to use distributed key share
// from different schemes easily into this distributed threshold Schnorr
// signature framework.
type DistKeyShare interface {
PriShare() *share.PriShare
Commitments() []kyber.Point
}
// DSS holds the information used to issue partial signatures as well as to
// compute the distributed schnorr signature.
type DSS struct {
// Keypair for this participant in the signing process (i.e., the one where
// this struct is stored.) This is not the keypair for full signing key; that
// would defeat the point.
secret kyber.Scalar
public kyber.Point
// Index value of this participant in the signing process. The index is shared
// across participants.
index int
// Public keys of potential participants in the signing process
participants []kyber.Point
// Number of participants needed to construct a signature
T int
// Shares of the distributed long-term signing keypair
long DistKeyShare
// Shares of the distributed ephemeral nonce keypair
random DistKeyShare
// Pedersen commitments to the coefficients of the polynomial implicitly used
// to share the long-term signing public/private keypair.
longPoly *share.PubPoly
// Pedersen commitments to the coefficients of the polynomial implicitly used
// to share the ephemeral nonce keypair.
randomPoly *share.PubPoly
// Message to be signed
msg *big.Int
// The partial signatures collected so far.
partials []*share.PriShare
// Indices for the participants who have provided their partial signatures to
// this participant.
partialsIdx map[int]bool
// True iff the partial signature for this dss has been signed by its owner.
signed bool
// String which uniquely identifies this signature, shared by all
// participants.
sessionID []byte
}
// DSSArgs is the arguments to NewDSS, as a struct. See NewDSS for details.
type DSSArgs = struct {
secret kyber.Scalar
participants []kyber.Point
long DistKeyShare
random DistKeyShare
msg *big.Int
T int
}
// PartialSig is partial representation of the final distributed signature. It
// must be sent to each of the other participants.
type PartialSig struct {
Partial *share.PriShare
SessionID []byte
Signature ethschnorr.Signature
}
// NewDSS returns a DSS struct out of the suite, the longterm secret of this
// node, the list of participants, the longterm and random distributed key
// (generated by the dkg package), the message to sign and finally the T
// threshold. It returns an error if the public key of the secret can't be found
// in the list of participants.
func NewDSS(args DSSArgs) (*DSS, error) {
public := secp256k1Group.Point().Mul(args.secret, nil)
var i int
var found bool
for j, p := range args.participants {
if p.Equal(public) {
found = true
i = j
break
}
}
if !found {
return nil, errors.New("dss: public key not found in list of participants")
}
return &DSS{
secret: args.secret,
public: public,
index: i,
participants: args.participants,
long: args.long,
longPoly: share.NewPubPoly(secp256k1Suite,
secp256k1Group.Point().Base(), args.long.Commitments()),
random: args.random,
randomPoly: share.NewPubPoly(secp256k1Suite,
secp256k1Group.Point().Base(), args.random.Commitments()),
msg: args.msg,
T: args.T,
partialsIdx: make(map[int]bool),
sessionID: sessionID(secp256k1Suite, args.long, args.random),
}, nil
}
// PartialSig generates the partial signature related to this DSS. This
// PartialSig can be broadcasted to every other participant or only to a
// trusted combiner as described in the paper.
// The signature format is compatible with EdDSA verification implementations.
//
// Corresponds to section 4.2, step 2 the Stinson 2001 paper.
func (d *DSS) PartialSig() (*PartialSig, error) {
secretPartialLongTermKey := d.long.PriShare().V // ɑᵢ, in the paper
secretPartialCommitmentKey := d.random.PriShare().V // βᵢ, in the paper
fullChallenge := d.hashSig() // h(m‖V), in the paper
secretChallengeMultiple := secp256k1Suite.Scalar().Mul(
fullChallenge, secretPartialLongTermKey) // ɑᵢh(m‖V)G, in the paper
// Corresponds to ɣᵢG=βᵢG+ɑᵢh(m‖V)G in the paper, but NB, in its notation, we
// use ɣᵢG=βᵢG-ɑᵢh(m‖V)G. (Subtract instead of add.)
partialSignature := secp256k1Group.Scalar().Sub(
secretPartialCommitmentKey, secretChallengeMultiple)
ps := &PartialSig{
Partial: &share.PriShare{V: partialSignature, I: d.index},
SessionID: d.sessionID,
}
var err error
ps.Signature, err = ethschnorr.Sign(d.secret, ps.Hash()) // sign share
if !d.signed {
d.partialsIdx[d.index] = true
d.partials = append(d.partials, ps.Partial)
d.signed = true
}
return ps, err
}
// ProcessPartialSig takes a PartialSig from another participant and stores it
// for generating the distributed signature. It returns an error if the index is
// wrong, or the signature is invalid or if a partial signature has already been
// received by the same peer. To know whether the distributed signature can be
// computed after this call, one can use the `EnoughPartialSigs` method.
//
// Corresponds to section 4.3, step 3 of the paper
func (d *DSS) ProcessPartialSig(ps *PartialSig) error {
var err error
public, ok := findPub(d.participants, ps.Partial.I)
if !ok {
err = errors.New("dss: partial signature with invalid index")
}
// nothing secret here
if err == nil && !bytes.Equal(ps.SessionID, d.sessionID) {
err = errors.New("dss: session id do not match")
}
if err == nil {
if vrr := ethschnorr.Verify(public, ps.Hash(), ps.Signature); vrr != nil {
err = vrr
}
}
if err == nil {
if _, ok := d.partialsIdx[ps.Partial.I]; ok {
err = errors.New("dss: partial signature already received from peer")
}
}
if err != nil {
return err
}
hash := d.hashSig() // h(m‖V), in the paper's notation
idx := ps.Partial.I
// βᵢG=sum(cₖi^kG), in the paper, defined as sᵢ in step 2 of section 2.4
randShare := d.randomPoly.Eval(idx)
// ɑᵢG=sum(bₖi^kG), defined as sᵢ in step 2 of section 2.4
longShare := d.longPoly.Eval(idx)
// h(m‖V)(Y+...) term from equation (3) of the paper. AKA h(m‖V)ɑᵢG
challengeSummand := secp256k1Group.Point().Mul(hash, longShare.V)
// RHS of equation (3), except we subtract the second term instead of adding.
// AKA (βᵢ-ɑᵢh(m‖V))G, which should equal ɣᵢG, according to equation (3)
maybePartialSigCommitment := secp256k1Group.Point().Sub(randShare.V,
challengeSummand)
// Check that equation (3) holds (ɣᵢ is represented as ps.Partial.V, here.)
partialSigCommitment := secp256k1Group.Point().Mul(ps.Partial.V, nil)
if !partialSigCommitment.Equal(maybePartialSigCommitment) {
return errors.New("dss: partial signature not valid")
}
d.partialsIdx[ps.Partial.I] = true
d.partials = append(d.partials, ps.Partial)
return nil
}
// EnoughPartialSig returns true if there are enough partial signature to compute
// the distributed signature. It returns false otherwise. If there are enough
// partial signatures, one can issue the signature with `Signature()`.
func (d *DSS) EnoughPartialSig() bool {
return len(d.partials) >= d.T
}
// Signature computes the distributed signature from the list of partial
// signatures received. It returns an error if there are not enough partial
// signatures.
//
// Corresponds to section 4.2, step 4 of Stinson, 2001 paper
func (d *DSS) Signature() (ethschnorr.Signature, error) {
if !d.EnoughPartialSig() {
return nil, errors.New("dkg: not enough partial signatures to sign")
}
// signature corresponds to σ in step 4 of section 4.2
signature, err := share.RecoverSecret(secp256k1Suite, d.partials, d.T,
len(d.participants))
if err != nil {
return nil, err
}
rv := ethschnorr.NewSignature()
rv.Signature = secp256k1.ToInt(signature)
// commitmentPublicKey corresponds to V in step 4 of section 4.2
commitmentPublicKey := d.random.Commitments()[0]
rv.CommitmentPublicAddress = secp256k1.EthereumAddress(commitmentPublicKey)
return rv, nil
}
// hashSig returns, in the paper's notation, h(m‖V). It is the challenge hash
// for the signature. (Actually, the hash also includes the public key, but that
// has no effect on the correctness or robustness arguments from the paper.)
func (d *DSS) hashSig() kyber.Scalar {
v := d.random.Commitments()[0] // Public-key commitment, in signature from d
vAddress := secp256k1.EthereumAddress(v)
publicKey := d.long.Commitments()[0]
rv, err := ethschnorr.ChallengeHash(publicKey, vAddress, d.msg)
if err != nil {
panic(err)
}
return rv
}
// Verify takes a public key, a message and a signature and returns an error if
// the signature is invalid.
func Verify(public kyber.Point, msg *big.Int, sig ethschnorr.Signature) error {
return ethschnorr.Verify(public, msg, sig)
}
// Hash returns the hash representation of this PartialSig to be used in a
// signature.
func (ps *PartialSig) Hash() *big.Int {
h := secp256k1Suite.Hash()
_, _ = h.Write(ps.Partial.Hash(secp256k1Suite))
_, _ = h.Write(ps.SessionID)
return (&big.Int{}).SetBytes(h.Sum(nil))
}
func findPub(list []kyber.Point, i int) (kyber.Point, bool) {
if i >= len(list) {
return nil, false
}
return list[i], true
}
func sessionID(s Suite, a, b DistKeyShare) []byte {
h := s.Hash()
for _, p := range a.Commitments() {
_, _ = p.MarshalTo(h)
}
for _, p := range b.Commitments() {
_, _ = p.MarshalTo(h)
}
return h.Sum(nil)
}

290
bridge/pkg/signatures/ethdss/ethdss_test.go
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@ -1,290 +0,0 @@
package ethdss
import (
"crypto/rand"
"fmt"
"math/big"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
"github.com/certusone/wormhole/bridge/pkg/signatures/ethschnorr"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
"go.dedis.ch/kyber/v3"
dkg "go.dedis.ch/kyber/v3/share/dkg/rabin"
)
var suite = secp256k1.NewBlakeKeccackSecp256k1()
var nbParticipants = 7
var t = nbParticipants/2 + 1
var partPubs []kyber.Point
var partSec []kyber.Scalar
var longterms []*dkg.DistKeyShare
var randoms []*dkg.DistKeyShare
var msg *big.Int
var randomStream = cryptotest.NewStream(&testing.T{}, 0)
func init() {
partPubs = make([]kyber.Point, nbParticipants)
partSec = make([]kyber.Scalar, nbParticipants)
for i := 0; i < nbParticipants; i++ {
kp := secp256k1.Generate(randomStream)
partPubs[i] = kp.Public
partSec[i] = kp.Private
}
// Corresponds to section 4.2, step 1 of Stinson, 2001 paper
longterms = genDistSecret(true) // Keep trying until valid public key
randoms = genDistSecret(false)
var err error
msg, err = rand.Int(rand.Reader, big.NewInt(0).Lsh(big.NewInt(1), 256))
if err != nil {
panic(err)
}
}
func TestDSSNew(t *testing.T) {
dssArgs := DSSArgs{secret: partSec[0], participants: partPubs,
long: longterms[0], random: randoms[0], msg: msg, T: 4}
dss, err := NewDSS(dssArgs)
assert.NotNil(t, dss)
assert.Nil(t, err)
dssArgs.secret = suite.Scalar().Zero()
dss, err = NewDSS(dssArgs)
assert.Nil(t, dss)
assert.Error(t, err)
}
func TestDSSPartialSigs(t *testing.T) {
dss0 := getDSS(0)
dss1 := getDSS(1)
ps0, err := dss0.PartialSig()
assert.Nil(t, err)
assert.NotNil(t, ps0)
assert.Len(t, dss0.partials, 1)
// second time should not affect list
ps0, err = dss0.PartialSig()
assert.Nil(t, err)
assert.NotNil(t, ps0)
assert.Len(t, dss0.partials, 1)
// wrong index
goodI := ps0.Partial.I
ps0.Partial.I = 100
err = dss1.ProcessPartialSig(ps0)
assert.Error(t, err)
assert.Contains(t, err.Error(), "invalid index")
ps0.Partial.I = goodI
// wrong sessionID
goodSessionID := ps0.SessionID
ps0.SessionID = []byte("ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh")
err = dss1.ProcessPartialSig(ps0)
assert.Error(t, err)
assert.Contains(t, err.Error(), "dss: session id")
ps0.SessionID = goodSessionID
// wrong Signature
goodSig := ps0.Signature
ps0.Signature = ethschnorr.NewSignature()
copy(ps0.Signature.CommitmentPublicAddress[:], randomBytes(20))
badSig := secp256k1.ToInt(suite.Scalar().Pick(randomStream))
ps0.Signature.Signature.Set(badSig)
assert.Error(t, dss1.ProcessPartialSig(ps0))
ps0.Signature = goodSig
// invalid partial sig
goodV := ps0.Partial.V
ps0.Partial.V = suite.Scalar().Zero()
ps0.Signature, err = ethschnorr.Sign(dss0.secret, ps0.Hash())
require.Nil(t, err)
err = dss1.ProcessPartialSig(ps0)
assert.Error(t, err)
assert.Contains(t, err.Error(), "not valid")
ps0.Partial.V = goodV
ps0.Signature = goodSig
// fine
err = dss1.ProcessPartialSig(ps0)
assert.Nil(t, err)
// already received
assert.Error(t, dss1.ProcessPartialSig(ps0))
// if not enough partial signatures, can't generate signature
sig, err := dss1.Signature()
assert.Nil(t, sig) // XXX: Should also check err is nil?
assert.Error(t, err)
assert.Contains(t, err.Error(), "not enough")
// enough partial sigs ?
for i := 2; i < nbParticipants; i++ {
dss := getDSS(i)
ps, e := dss.PartialSig()
require.Nil(t, e)
require.Nil(t, dss1.ProcessPartialSig(ps))
}
assert.True(t, dss1.EnoughPartialSig())
sig, err = dss1.Signature()
assert.NoError(t, err)
assert.NoError(t, Verify(dss1.long.Commitments()[0], msg, sig))
}
var printTests = false
func printTest(t *testing.T, msg *big.Int, public kyber.Point,
signature ethschnorr.Signature) {
pX, pY := secp256k1.Coordinates(public)
fmt.Printf(" ['%064x',\n '%064x',\n '%064x',\n '%064x',\n '%040x'],\n",
msg, pX, pY, signature.Signature,
signature.CommitmentPublicAddress)
}
func TestDSSSignature(t *testing.T) {
dsss := make([]*DSS, nbParticipants)
pss := make([]*PartialSig, nbParticipants)
for i := 0; i < nbParticipants; i++ {
dsss[i] = getDSS(i)
ps, err := dsss[i].PartialSig()
require.Nil(t, err)
require.NotNil(t, ps)
pss[i] = ps
}
for i, dss := range dsss {
for j, ps := range pss {
if i == j {
continue
}
require.Nil(t, dss.ProcessPartialSig(ps))
}
}
// issue and verify signature
dss0 := dsss[0]
sig, err := dss0.Signature()
assert.NotNil(t, sig)
assert.Nil(t, err)
assert.NoError(t, ethschnorr.Verify(longterms[0].Public(), dss0.msg, sig))
// Original contains this second check. Unclear why.
assert.NoError(t, ethschnorr.Verify(longterms[0].Public(), dss0.msg, sig))
if printTests {
printTest(t, dss0.msg, dss0.long.Commitments()[0], sig)
}
}
func TestPartialSig_Hash(t *testing.T) {
observedHashes := make(map[*big.Int]bool)
for i := 0; i < nbParticipants; i++ {
psig, err := getDSS(i).PartialSig()
require.NoError(t, err)
hash := psig.Hash()
require.False(t, observedHashes[hash])
observedHashes[hash] = true
}
}
func getDSS(i int) *DSS {
dss, err := NewDSS(DSSArgs{secret: partSec[i], participants: partPubs,
long: longterms[i], random: randoms[i], msg: msg, T: t})
if dss == nil || err != nil {
panic("nil dss")
}
return dss
}
func _genDistSecret() []*dkg.DistKeyShare {
dkgs := make([]*dkg.DistKeyGenerator, nbParticipants)
for i := 0; i < nbParticipants; i++ {
dkg, err := dkg.NewDistKeyGenerator(suite, partSec[i], partPubs, nbParticipants/2+1)
if err != nil {
panic(err)
}
dkgs[i] = dkg
}
// full secret sharing exchange
// 1. broadcast deals
resps := make([]*dkg.Response, 0, nbParticipants*nbParticipants)
for _, dkg := range dkgs {
deals, err := dkg.Deals()
if err != nil {
panic(err)
}
for i, d := range deals {
resp, err := dkgs[i].ProcessDeal(d)
if err != nil {
panic(err)
}
if !resp.Response.Approved {
panic("wrong approval")
}
resps = append(resps, resp)
}
}
// 2. Broadcast responses
for _, resp := range resps {
for h, dkg := range dkgs {
// ignore all messages from ourself
if resp.Response.Index == uint32(h) {
continue
}
j, err := dkg.ProcessResponse(resp)
if err != nil || j != nil {
panic("wrongProcessResponse")
}
}
}
// 4. Broadcast secret commitment
for i, dkg := range dkgs {
scs, err := dkg.SecretCommits()
if err != nil {
panic("wrong SecretCommits")
}
for j, dkg2 := range dkgs {
if i == j {
continue
}
cc, err := dkg2.ProcessSecretCommits(scs)
if err != nil || cc != nil {
panic("wrong ProcessSecretCommits")
}
}
}
// 5. reveal shares
dkss := make([]*dkg.DistKeyShare, len(dkgs))
for i, dkg := range dkgs {
dks, err := dkg.DistKeyShare()
if err != nil {
panic(err)
}
dkss[i] = dks
}
return dkss
}
func genDistSecret(checkValidPublicKey bool) []*dkg.DistKeyShare {
rv := _genDistSecret()
if checkValidPublicKey {
// Because of the trick we're using to verify the signatures on-chain, we
// need to make sure that the ordinate of this distributed public key is
// in the lower half of {0,...,}
for !secp256k1.ValidPublicKey(rv[0].Public()) {
rv = _genDistSecret() // Keep trying until valid distributed public key.
}
}
return rv
}
func randomBytes(n int) []byte {
var buff = make([]byte, n)
_, _ = rand.Read(buff[:])
return buff
}

154
bridge/pkg/signatures/ethschnorr/ethschnorr.go
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@ -1,154 +0,0 @@
// Package ethschnorr implements a version of the Schnorr signature which is
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// cheap to verify on-chain.
//
// See https://en.wikipedia.org/wiki/Schnorr_signature For vanilla Schnorr.
//
// Since we are targeting ethereum specifically, there is no need to abstract
// away the group operations, as original kyber Schnorr code does. Thus, these
// functions only work with secp256k1 objects, even though they are expressed in
// terms of the abstract kyber Group interfaces.
//
// This code is largely based on EPFL-DEDIS's go.dedis.ch/kyber/sign/schnorr
package ethschnorr
import (
"bytes"
"fmt"
"go.dedis.ch/kyber/v3"
"math/big"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
)
var secp256k1Suite = secp256k1.NewBlakeKeccackSecp256k1()
var secp256k1Group kyber.Group = secp256k1Suite
type signature = struct {
CommitmentPublicAddress [20]byte
R string
Signature *big.Int
}
// Signature is a representation of the Schnorr signature generated and verified
// by this library.
type Signature = *signature
func i() *big.Int { return big.NewInt(0) }
var one = big.NewInt(1)
var u256Cardinality = i().Lsh(one, 256)
var maxUint256 = i().Sub(u256Cardinality, one)
// NewSignature allocates space for a Signature, and returns it
func NewSignature() Signature { return &signature{Signature: i()} }
var zero = i()
// ValidSignature(s) is true iff s.Signature represents an element of secp256k1
func ValidSignature(s Signature) bool {
return s.Signature.Cmp(secp256k1.GroupOrder) == -1 &&
s.Signature.Cmp(zero) != -1
}
// ChallengeHash returns the value the signer must use to demonstrate knowledge
// of the secret key
//
// NB: for parity with the on-chain hash, it's important that public and r
// marshall to the big-endian x ordinate, followed by a byte which is 0 if the y
// ordinate is even, 1 if it's odd. See evm/contracts/SchnorrSECP256K1.sol and
// evm/test/schnorr_test.js
func ChallengeHash(public kyber.Point, rAddress [20]byte, msg *big.Int) (
kyber.Scalar, error) {
var err error
h := secp256k1Suite.Hash()
if _, herr := public.MarshalTo(h); herr != nil {
err = fmt.Errorf("failed to hash public key for signature: %s", herr)
}
if err != nil && (msg.BitLen() > 256 || msg.Cmp(zero) == -1) {
err = fmt.Errorf("msg must be a uint256")
}
if err == nil {
if _, herr := h.Write(msg.Bytes()); herr != nil {
err = fmt.Errorf("failed to hash message for signature: %s", herr)
}
}
if err == nil {
if _, herr := h.Write(rAddress[:]); herr != nil {
err = fmt.Errorf("failed to hash r for signature: %s", herr)
}
}
if err != nil {
return nil, err
}
return secp256k1Suite.Scalar().SetBytes(h.Sum(nil)), nil
}
// Sign creates a signature from a msg and a private key. Verify with the
// function Verify, or on-chain with SchnorrSECP256K1.sol.
func Sign(private kyber.Scalar, msg *big.Int) (Signature, error) {
if !secp256k1.IsSecp256k1Scalar(private) {
return nil, fmt.Errorf("private key is not a secp256k1 scalar")
}
// create random secret and public commitment to it
commitmentSecretKey := secp256k1Group.Scalar().Pick(
secp256k1Suite.RandomStream())
commitmentPublicKey := secp256k1Group.Point().Mul(commitmentSecretKey, nil)
commitmentPublicAddress := secp256k1.EthereumAddress(commitmentPublicKey)
public := secp256k1Group.Point().Mul(private, nil)
challenge, err := ChallengeHash(public, commitmentPublicAddress, msg)
if err != nil {
return nil, err
}
// commitmentSecretKey-private*challenge
s := secp256k1Group.Scalar().Sub(commitmentSecretKey,
secp256k1Group.Scalar().Mul(private, challenge))
rv := signature{commitmentPublicAddress, commitmentPublicKey.String(), secp256k1.ToInt(s)}
return &rv, nil
}
// Verify verifies the given Schnorr signature. It returns true iff the
// signature is valid.
func Verify(public kyber.Point, msg *big.Int, s Signature) error {
var err error
if !ValidSignature(s) {
err = fmt.Errorf("s is not a valid signature")
}
if err == nil && !secp256k1.IsSecp256k1Point(public) {
err = fmt.Errorf("public key is not a secp256k1 point")
}
if err == nil && !secp256k1.ValidPublicKey(public) {
err = fmt.Errorf("`public` is not a valid public key")
}
if err == nil && (msg.Cmp(zero) == -1 || msg.Cmp(maxUint256) == 1) {
err = fmt.Errorf("msg is not a uint256")
}
var challenge kyber.Scalar
var herr error
if err == nil {
challenge, herr = ChallengeHash(public, s.CommitmentPublicAddress, msg)
if herr != nil {
err = herr
}
println("hash", challenge.String())
}
if err != nil {
return err
}
sigScalar := secp256k1.IntToScalar(s.Signature)
// s*g + challenge*public = s*g + challenge*(secretKey*g) =
// commitmentSecretKey*g = commitmentPublicKey
maybeCommitmentPublicKey := secp256k1Group.Point().Add(
secp256k1Group.Point().Mul(sigScalar, nil),
secp256k1Group.Point().Mul(challenge, public))
println("commpoint", maybeCommitmentPublicKey.String())
maybeCommitmentPublicAddress := secp256k1.EthereumAddress(maybeCommitmentPublicKey)
if !bytes.Equal(s.CommitmentPublicAddress[:],
maybeCommitmentPublicAddress[:]) {
return fmt.Errorf("signature mismatch")
}
return nil
}

119
bridge/pkg/signatures/ethschnorr/ethschnorr_test.go
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@ -1,119 +0,0 @@
package ethschnorr
// This code is largely based on go.dedis.ch/kyber/sign/schnorr_test from
// EPFL's DEDIS
import (
crand "crypto/rand"
"encoding/hex"
"fmt"
"math/big"
mrand "math/rand"
"testing"
"github.com/stretchr/testify/require"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/group/curve25519"
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
)
var numSignatures = 5
var randomStream = cryptotest.NewStream(&testing.T{}, 0)
var printTests = false
func printTest(t *testing.T, msg *big.Int, private kyber.Scalar,
public kyber.Point, signature Signature) {
privateBytes, err := private.MarshalBinary()
require.Nil(t, err)
pX, pY := secp256k1.Coordinates(public)
fmt.Printf(" ['%064x',\n '%064x',\n '%064x',\n '%064x',\n "+
"'%064x',\n '%040x'],\n",
msg, privateBytes, pX, pY, signature.Signature,
signature.CommitmentPublicAddress)
}
func TestShortSchnorr_SignAndVerify(t *testing.T) {
if printTests {
fmt.Printf("tests = [\n")
}
for i := 0; i < numSignatures; i++ {
rand := mrand.New(mrand.NewSource(2))
msg, err := crand.Int(rand, maxUint256)
require.NoError(t, err)
kp := secp256k1.Generate(randomStream)
sig, err := Sign(kp.Private, msg)
require.NoError(t, err, "failed to sign message")
println("msg", hex.EncodeToString(msg.Bytes()))
println("sig", hex.EncodeToString(sig.Signature.Bytes()))
println("addr", hex.EncodeToString(sig.CommitmentPublicAddress[:]))
println("pub", kp.Public.String())
require.NoError(t, Verify(kp.Public, msg, sig),
"failed to validate own signature")
require.Error(t, Verify(kp.Public, u256Cardinality, sig),
"failed to abort on too large a message")
require.Error(t, Verify(kp.Public, big.NewInt(0).Neg(big.NewInt(1)), sig),
"failed to abort on negative message")
if printTests {
printTest(t, msg, kp.Private, kp.Public, sig)
}
wrongMsg := big.NewInt(0).Add(msg, big.NewInt(1))
require.Error(t, Verify(kp.Public, wrongMsg, sig),
"failed to reject signature with bad message")
wrongPublic := secp256k1Group.Point().Add(kp.Public, kp.Public)
require.Error(t, Verify(wrongPublic, msg, sig),
"failed to reject signature with bad public key")
wrongSignature := &signature{
CommitmentPublicAddress: sig.CommitmentPublicAddress,
Signature: big.NewInt(0).Add(sig.Signature, one),
}
require.Error(t, Verify(kp.Public, msg, wrongSignature),
"failed to reject bad signature")
badPublicCommitmentAddress := &signature{Signature: sig.Signature}
copy(badPublicCommitmentAddress.CommitmentPublicAddress[:],
sig.CommitmentPublicAddress[:])
badPublicCommitmentAddress.CommitmentPublicAddress[0] ^= 1 // Corrupt it
require.Error(t, Verify(kp.Public, msg, badPublicCommitmentAddress),
"failed to reject signature with bad public commitment")
}
if printTests {
fmt.Println("]")
}
// Check other validations
edSuite := curve25519.NewBlakeSHA256Curve25519(false)
badScalar := edSuite.Scalar()
_, err := Sign(badScalar, i())
require.Error(t, err)
require.Contains(t, err.Error(), "not a secp256k1 scalar")
err = Verify(edSuite.Point(), i(), NewSignature())
require.Error(t, err)
require.Contains(t, err.Error(), "not a secp256k1 point")
err = Verify(secp256k1Suite.Point(), i(), &signature{Signature: big.NewInt(-1)})
require.Error(t, err)
require.Contains(t, err.Error(), "not a valid signature")
err = Verify(secp256k1Suite.Point(), i(), &signature{Signature: u256Cardinality})
require.Error(t, err)
require.Contains(t, err.Error(), "not a valid signature")
}
func TestShortSchnorr_NewSignature(t *testing.T) {
s := NewSignature()
require.Equal(t, s.Signature, big.NewInt(0))
}
func TestShortSchnorr_ChallengeHash(t *testing.T) {
point := secp256k1Group.Point()
var hash [20]byte
h, err := ChallengeHash(point, hash, big.NewInt(-1))
require.Nil(t, h)
require.Error(t, err)
require.Contains(t, err.Error(), "msg must be a uint256")
h, err = ChallengeHash(point, hash, u256Cardinality)
require.Nil(t, h)
require.Error(t, err)
require.Contains(t, err.Error(), "msg must be a uint256")
}

44
bridge/pkg/signatures/secp256k1/curve.go
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@ -1,44 +0,0 @@
// Package secp256k1 is an implementation of the kyber.{Group,Point,Scalar}
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// interfaces, based on btcd/btcec and kyber/group/mod
//
// XXX: NOT CONSTANT TIME!
package secp256k1
import (
"math/big"
secp256k1BTCD "github.com/btcsuite/btcd/btcec"
"go.dedis.ch/kyber/v3"
)
// Secp256k1 represents the secp256k1 group.
// There are no parameters and no initialization is required
// because it supports only this one specific curve.
type Secp256k1 struct{}
// s256 is the btcec representation of secp256k1.
var s256 *secp256k1BTCD.KoblitzCurve = secp256k1BTCD.S256()
// String returns the name of the curve
func (*Secp256k1) String() string { return "Secp256k1" }
var egScalar kyber.Scalar = newScalar(big.NewInt(0))
var egPoint kyber.Point = &Secp256k1Point{newFieldZero(), newFieldZero()}
// ScalarLen returns the length of a marshalled Scalar
func (*Secp256k1) ScalarLen() int { return egScalar.MarshalSize() }
// Scalar creates a new Scalar for the prime-order group on the secp256k1 curve
func (*Secp256k1) Scalar() kyber.Scalar { return newScalar(big.NewInt(0)) }
// PointLen returns the length of a marshalled Point
func (*Secp256k1) PointLen() int { return egPoint.MarshalSize() }
// Point returns a new secp256k1 point
func (*Secp256k1) Point() kyber.Point {
return &Secp256k1Point{newFieldZero(), newFieldZero()}
}

20
bridge/pkg/signatures/secp256k1/curve_test.go
View File

@ -1,20 +0,0 @@
package secp256k1
import (
"testing"
"github.com/stretchr/testify/require"
)
var group = &Secp256k1{}
func TestSecp256k1_String(t *testing.T) {
require.Equal(t, group.String(), "Secp256k1")
}
func TestSecp256k1_Constructors(t *testing.T) {
require.Equal(t, group.ScalarLen(), 32)
require.Equal(t, ToInt(group.Scalar()), bigZero)
require.Equal(t, group.PointLen(), 33)
require.Equal(t, group.Point(), &Secp256k1Point{fieldZero, fieldZero})
}

170
bridge/pkg/signatures/secp256k1/field.go
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@ -1,170 +0,0 @@
// Package secp256k1 is an implementation of the kyber.{Group,Point,Scalar}
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// interfaces, based on btcd/btcec and kyber/group/mod
//
// XXX: NOT CONSTANT TIME!
package secp256k1
// Arithmetic operations in the base field of secp256k1, i.e. ℤ/qℤ, where q is
// the base field characteristic.
import (
"crypto/cipher"
"fmt"
"math/big"
"go.dedis.ch/kyber/v3/util/random"
)
// q is the field characteristic (cardinality) of the secp256k1 base field. All
// arithmetic operations on the field are modulo this.
var q = s256.P
var halfQ = new(big.Int).Div(q, big.NewInt(2))
type fieldElt big.Int
// newFieldZero returns a newly allocated field element.
func newFieldZero() *fieldElt { return (*fieldElt)(big.NewInt(0)) }
// Int returns f as a big.Int
func (f *fieldElt) Int() *big.Int { return (*big.Int)(f) }
// modQ reduces f's underlying big.Int modulo q, and returns it
func (f *fieldElt) modQ() *fieldElt {
if f.Int().Cmp(q) != -1 || f.Int().Cmp(bigZero) == -1 {
// f ∉ {0, ..., q-1}. Find the representative of f+qℤ in that set.
//
// Per Mod docstring, "Mod implements Euclidean modulus", meaning that after
// this, f will be the smallest non-negative representative of its
// equivalence class in ℤ/qℤ. TODO(alx): Make this faster
f.Int().Mod(f.Int(), q)
}
return f
}
// This differs from SetInt below, in that it does not take a copy of v.
func fieldEltFromBigInt(v *big.Int) *fieldElt { return (*fieldElt)(v).modQ() }
func fieldEltFromInt(v int64) *fieldElt {
return fieldEltFromBigInt(big.NewInt(int64(v))).modQ()
}
var fieldZero = fieldEltFromInt(0)
var bigZero = big.NewInt(0)
// String returns the string representation of f
func (f *fieldElt) String() string {
return fmt.Sprintf("fieldElt{%x}", f.Int())
}
// Equal returns true iff f=g, i.e. the backing big.Ints satisfy f ≡ g mod q
func (f *fieldElt) Equal(g *fieldElt) bool {
if f == (*fieldElt)(nil) && g == (*fieldElt)(nil) {
return true
}
if f == (*fieldElt)(nil) { // f is nil, g is not
return false
}
if g == (*fieldElt)(nil) { // g is nil, f is not
return false
}
return bigZero.Cmp(newFieldZero().Sub(f, g).modQ().Int()) == 0
}
// Add sets f to the sum of a and b modulo q, and returns it.
func (f *fieldElt) Add(a, b *fieldElt) *fieldElt {
f.Int().Add(a.Int(), b.Int())
return f.modQ()
}
// Sub sets f to a-b mod q, and returns it.
func (f *fieldElt) Sub(a, b *fieldElt) *fieldElt {
f.Int().Sub(a.Int(), b.Int())
return f.modQ()
}
// Set sets f's value to v, and returns f.
func (f *fieldElt) Set(v *fieldElt) *fieldElt {
f.Int().Set(v.Int())
return f.modQ()
}
// SetInt sets f's value to v mod q, and returns f.
func (f *fieldElt) SetInt(v *big.Int) *fieldElt {
f.Int().Set(v)
return f.modQ()
}
// Pick samples uniformly from {0, ..., q-1}, assigns sample to f, and returns f
func (f *fieldElt) Pick(rand cipher.Stream) *fieldElt {
return f.SetInt(random.Int(q, rand)) // random.Int safe because q≅2²⁵⁶, q<2²⁵⁶
}
// Neg sets f to the negation of g modulo q, and returns it
func (f *fieldElt) Neg(g *fieldElt) *fieldElt {
f.Int().Neg(g.Int())
return f.modQ()
}
// Clone returns a new fieldElt, backed by a clone of f
func (f *fieldElt) Clone() *fieldElt { return newFieldZero().Set(f.modQ()) }
// SetBytes sets f to the 32-byte big-endian value represented by buf, reduces
// it, and returns it.
func (f *fieldElt) SetBytes(buf [32]byte) *fieldElt {
f.Int().SetBytes(buf[:])
return f.modQ()
}
// Bytes returns the 32-byte big-endian representation of f
func (f *fieldElt) Bytes() [32]byte {
bytes := f.modQ().Int().Bytes()
if len(bytes) > 32 {
panic("field element longer than 256 bits")
}
var rv [32]byte
copy(rv[32-len(bytes):], bytes) // leftpad w zeros
return rv
}
var two = big.NewInt(2)
// square returns y² mod q
func fieldSquare(y *fieldElt) *fieldElt {
return fieldEltFromBigInt(newFieldZero().Int().Exp(y.Int(), two, q))
}
// sqrtPower is s.t. n^sqrtPower≡sqrt(n) mod q, if n has a root at all. See
// https://math.stackexchange.com/a/1816280, for instance
//
// What I'm calling sqrtPower is called q on the s256 struct. (See
// btcec.initS256), which is confusing because the "Q" in "QPlus1Div4" refers to
// the field characteristic
var sqrtPower = s256.QPlus1Div4()
// maybeSqrtInField returns a square root of v, if it has any, else nil
func maybeSqrtInField(v *fieldElt) *fieldElt {
s := newFieldZero()
s.Int().Exp(v.Int(), sqrtPower, q)
if !fieldSquare(s).Equal(v) {
return nil
}
return s
}
var three = big.NewInt(3)
var seven = fieldEltFromInt(7)
// rightHandSide returns the RHS of the secp256k1 equation, x³+7 mod q, given x
func rightHandSide(x *fieldElt) *fieldElt {
xCubed := newFieldZero()
xCubed.Int().Exp(x.Int(), three, q)
return xCubed.Add(xCubed, seven)
}
// isEven returns true if f is even, false otherwise
func (f *fieldElt) isEven() bool {
return big.NewInt(0).Mod(f.Int(), two).Cmp(big.NewInt(0)) == 0
}

159
bridge/pkg/signatures/secp256k1/field_test.go
View File

@ -1,159 +0,0 @@
package secp256k1
import (
"encoding/hex"
"math/big"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
)
var numFieldSamples = 10
var observedFieldElts map[string]bool
func init() {
observedFieldElts = make(map[string]bool)
}
// observedFieldElt ensures that novel scalars are being picked.
func observedFieldElt(t *testing.T, s *fieldElt) {
elt := s.Bytes()
data := hex.Dump(elt[:])
require.False(t, observedFieldElts[data])
observedFieldElts[data] = true
}
var randomStream = cryptotest.NewStream(&testing.T{}, 0)
func TestField_SetIntAndEqual(t *testing.T) {
tests := []int64{5, 67108864, 67108865, 4294967295}
g := newFieldZero()
for _, test := range tests {
f := fieldEltFromInt(test)
i := big.NewInt(test)
g.SetInt(i)
assert.Equal(t, f, g,
"different values obtained for same input, using "+
"SetInt vs fieldEltFromInt")
i.Add(i, big.NewInt(1))
assert.Equal(t, f, g,
"SetInt should take a copy of the backing big.Int")
}
}
func TestField_String(t *testing.T) {
require.Equal(t, fieldZero.String(), "fieldElt{0}")
}
func TestField_Equal(t *testing.T) {
require.True(t, (*fieldElt)(nil).Equal((*fieldElt)(nil)))
require.False(t, (*fieldElt)(nil).Equal(fieldZero))
require.False(t, fieldZero.Equal((*fieldElt)(nil)))
}
func TestField_Set(t *testing.T) {
f := fieldEltFromInt(1)
g := newFieldZero()
g.Set(f)
g.Add(g, fieldEltFromInt(1))
assert.Equal(t, f, fieldEltFromInt(1),
"Set takes a copy of the backing big.Int")
}
func TestFieldEltFromInt(t *testing.T) {
assert.Equal(t, fieldEltFromInt(1), // Also tests fieldElt.modQ
fieldEltFromBigInt(new(big.Int).Add(q, big.NewInt(1))),
"only one representation of a ℤ/qℤ element should be used")
}
func TestField_SmokeTestPick(t *testing.T) {
f := newFieldZero()
f.Pick(randomStream)
observedFieldElt(t, f)
assert.True(t, f.Int().Cmp(big.NewInt(1000000000)) == 1,
"should be greater than 1000000000, with very high probability")
}
func TestField_Neg(t *testing.T) {
f := newFieldZero()
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStream)
observedFieldElt(t, f)
g := f.Clone()
g.Neg(g)
require.True(t, g.Add(f, g).Equal(fieldZero),
"adding something to its negative should give zero: "+
"failed with %s", f)
}
}
func TestField_Sub(t *testing.T) {
f := newFieldZero()
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStream)
observedFieldElt(t, f)
require.True(t, f.Sub(f, f).Equal(fieldZero),
"subtracting something from itself should give zero: "+
"failed with %s", f)
}
}
func TestField_Clone(t *testing.T) {
f := fieldEltFromInt(1)
g := f.Clone()
h := f.Clone()
assert.Equal(t, f, g, "clone output does not equal original")
g.Add(f, f)
assert.Equal(t, f, h, "clone does not make a copy")
}
func TestField_SetBytesAndBytes(t *testing.T) {
f := newFieldZero()
g := newFieldZero()
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStream)
observedFieldElt(t, f)
g.SetBytes(f.Bytes())
require.True(t, g.Equal(f),
"roundtrip through serialization should give same "+
"result back: failed with %s", f)
}
}
func TestField_MaybeSquareRootInField(t *testing.T) {
f := newFieldZero()
minusOne := fieldEltFromInt(-1)
assert.Nil(t, maybeSqrtInField(minusOne), "-1 is not a square, in this field")
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStream)
observedFieldElt(t, f)
require.True(t, f.Int().Cmp(q) == -1, "picked larger value than q: %s", f)
require.True(t, f.Int().Cmp(big.NewInt(-1)) != -1,
"backing Int must be non-negative")
s := fieldSquare(f)
g := maybeSqrtInField(s)
require.NotEqual(t, g, (*fieldElt)(nil))
ng := newFieldZero().Neg(g)
require.True(t, f.Equal(g) || f.Equal(ng), "squaring something and "+
"taking the square root should give ± the original: failed with %s", f)
bigIntSqrt := newFieldZero() // Cross-check against big.ModSqrt
rv := bigIntSqrt.Int().ModSqrt(s.Int(), q)
require.NotNil(t, rv)
require.True(t, bigIntSqrt.Equal(g) || bigIntSqrt.Equal(ng))
nonSquare := newFieldZero().Neg(s)
rv = bigIntSqrt.Int().ModSqrt(nonSquare.Int(), q)
require.Nil(t, rv, "ModSqrt indicates nonSquare is square")
require.Nil(t, maybeSqrtInField(nonSquare), "the negative of square "+
"should not be a square")
}
}
func TestField_RightHandSide(t *testing.T) {
assert.Equal(t, rightHandSide(fieldEltFromInt(1)), fieldEltFromInt(8))
assert.Equal(t, rightHandSide(fieldEltFromInt(2)), fieldEltFromInt(15))
}

386
bridge/pkg/signatures/secp256k1/point.go
View File

@ -1,386 +0,0 @@
// Package secp256k1 is an implementation of the kyber.{Group,Point,Scalar}
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// interfaces, based on btcd/btcec and kyber/group/mod
//
// XXX: NOT CONSTANT TIME!
package secp256k1
// Implementation of kyber.Point interface for elliptic-curve arithmetic
// operations on secpk256k1.
//
// This is mostly a wrapper of the functionality provided by btcec
import (
"crypto/cipher"
"fmt"
"io"
"math/big"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/util/key"
"golang.org/x/crypto/sha3"
)
// btcec's public interface uses this affine representation for points on the
// curve. This does not naturally accommodate the point at infinity. btcec
// represents it as (0, 0), which is not a point on {y²=x³+7}.
type Secp256k1Point struct {
X *fieldElt
Y *fieldElt
}
func NewPoint() *Secp256k1Point {
return &Secp256k1Point{newFieldZero(), newFieldZero()}
}
// String returns a string representation of P
func (P *Secp256k1Point) String() string {
return fmt.Sprintf("Secp256k1{X: %s, Y: %s}", P.X, P.Y)
}
// Equal returns true if p and pPrime represent the same point, false otherwise.
func (P *Secp256k1Point) Equal(pPrime kyber.Point) bool {
return P.X.Equal(pPrime.(*Secp256k1Point).X) &&
P.Y.Equal(pPrime.(*Secp256k1Point).Y)
}
// Null sets p to the group-identity value, and returns it.
func (P *Secp256k1Point) Null() kyber.Point {
P.X = fieldEltFromInt(0) // btcec representation of null point is (0,0)
P.Y = fieldEltFromInt(0)
return P
}
// Base sets p to a copy of the standard group generator, and returns it.
func (P *Secp256k1Point) Base() kyber.Point {
P.X.SetInt(s256.Gx)
P.Y.SetInt(s256.Gy)
return P
}
// Pick sets P to a random point sampled from rand, and returns it.
func (P *Secp256k1Point) Pick(rand cipher.Stream) kyber.Point {
for { // Keep trying X's until one fits the curve (~50% probability of
// success each iteration
P.X.Set(newFieldZero().Pick(rand))
maybeRHS := rightHandSide(P.X)
if maybeY := maybeSqrtInField(maybeRHS); maybeY != (*fieldElt)(nil) {
P.Y.Set(maybeY)
// Take the negative with 50% probability
b := make([]byte, 1)
rand.XORKeyStream(b[:], b[:])
if b[0]&1 == 0 {
P.Y.Neg(P.Y)
}
return P
}
}
}
// Set sets P to copies of pPrime's values, and returns it.
func (P *Secp256k1Point) Set(pPrime kyber.Point) kyber.Point {
P.X.Set(pPrime.(*Secp256k1Point).X)
P.Y.Set(pPrime.(*Secp256k1Point).Y)
return P
}
// Clone returns a copy of P.
func (P *Secp256k1Point) Clone() kyber.Point {
return &Secp256k1Point{X: P.X.Clone(), Y: P.Y.Clone()}
}
// EmbedLen returns the number of bytes of data which can be embedded in a point.
func (*Secp256k1Point) EmbedLen() int {
// Reserve the most-significant 8 bits for pseudo-randomness.
// Reserve the least-significant 8 bits for embedded data length.
return (255 - 8 - 8) / 8
}
// Embed encodes a limited amount of specified data in the Point, using r as a
// source of cryptographically secure random data. Implementations only embed
// the first EmbedLen bytes of the given data.
func (P *Secp256k1Point) Embed(data []byte, r cipher.Stream) kyber.Point {
numEmbedBytes := P.EmbedLen()
if len(data) > numEmbedBytes {
panic("too much data to embed in a point")
}
numEmbedBytes = len(data)
var x [32]byte
randStart := 1 // First byte to fill with random data
if data != nil {
x[0] = byte(numEmbedBytes) // Encode length in low 8 bits
copy(x[1:1+numEmbedBytes], data) // Copy in data to embed
randStart = 1 + numEmbedBytes
}
maxAttempts := 10000
// Try random x ordinates satisfying the constraints, until one provides
// a point on secp256k1
for numAttempts := 0; numAttempts < maxAttempts; numAttempts++ {
// Fill the rest of the x ordinate with random data
r.XORKeyStream(x[randStart:], x[randStart:])
xOrdinate := newFieldZero().SetBytes(x)
// RHS of secp256k1 equation is x³+7 mod p. Success if square.
// We optimistically don't use btcec.IsOnCurve, here, because we
// hope to assign the intermediate result maybeY to P.Y
secp256k1RHS := rightHandSide(xOrdinate)
if maybeY := maybeSqrtInField(secp256k1RHS); maybeY != (*fieldElt)(nil) {
P.X = xOrdinate // success: found (x,y) s.t. y²=x³+7
P.Y = maybeY
return P
}
}
// Probability 2^{-maxAttempts}, under correct operation.
panic("failed to find point satisfying all constraints")
}
// Data returns data embedded in P, or an error if inconsistent with encoding
func (P *Secp256k1Point) Data() ([]byte, error) {
b := P.X.Bytes()
dataLength := int(b[0])
if dataLength > P.EmbedLen() {
return nil, fmt.Errorf("point specifies too much data")
}
return b[1 : dataLength+1], nil
}
// Add sets P to a+b (secp256k1 group operation) and returns it.
func (P *Secp256k1Point) Add(a, b kyber.Point) kyber.Point {
X, Y := s256.Add(
a.(*Secp256k1Point).X.Int(), a.(*Secp256k1Point).Y.Int(),
b.(*Secp256k1Point).X.Int(), b.(*Secp256k1Point).Y.Int())
P.X.SetInt(X)
P.Y.SetInt(Y)
return P
}
// Add sets P to a-b (secp256k1 group operation), and returns it.
func (P *Secp256k1Point) Sub(a, b kyber.Point) kyber.Point {
X, Y := s256.Add(
a.(*Secp256k1Point).X.Int(), a.(*Secp256k1Point).Y.Int(),
b.(*Secp256k1Point).X.Int(),
newFieldZero().Neg(b.(*Secp256k1Point).Y).Int()) // -b_y
P.X.SetInt(X)
P.Y.SetInt(Y)
return P
}
// Neg sets P to -a (in the secp256k1 group), and returns it.
func (P *Secp256k1Point) Neg(a kyber.Point) kyber.Point {
P.X = a.(*Secp256k1Point).X.Clone()
P.Y = newFieldZero().Neg(a.(*Secp256k1Point).Y)
return P
}
// Mul sets P to s*a (in the secp256k1 group, i.e. adding a to itself s times),
// and returns it. If a is nil, it is replaced by the secp256k1 generator.
func (P *Secp256k1Point) Mul(s kyber.Scalar, a kyber.Point) kyber.Point {
sBytes, err := s.(*secp256k1Scalar).MarshalBinary()
if err != nil {
panic(fmt.Errorf("failure while marshaling multiplier: %s",
err))
}
var X, Y *big.Int
if a == (*Secp256k1Point)(nil) || a == nil {
X, Y = s256.ScalarBaseMult(sBytes)
} else {
X, Y = s256.ScalarMult(a.(*Secp256k1Point).X.Int(),
a.(*Secp256k1Point).Y.Int(), sBytes)
}
P.X.SetInt(X)
P.Y.SetInt(Y)
return P
}
// MarshalBinary returns the concatenated big-endian representation of the X
// ordinate and a byte which is 0 if Y is even, 1 if it's odd. Or it returns an
// error on failure.
func (P *Secp256k1Point) MarshalBinary() ([]byte, error) {
maybeSqrt := maybeSqrtInField(rightHandSide(P.X))
if maybeSqrt == (*fieldElt)(nil) {
return nil, fmt.Errorf("x³+7 not a square")
}
minusMaybeSqrt := newFieldZero().Neg(maybeSqrt)
if !P.Y.Equal(maybeSqrt) && !P.Y.Equal(minusMaybeSqrt) {
return nil, fmt.Errorf(
"y ≠ ±maybeSqrt(x³+7), so not a point on the curve")
}
rv := make([]byte, P.MarshalSize())
signByte := P.MarshalSize() - 1 // Last byte contains sign of Y.
xordinate := P.X.Bytes()
copyLen := copy(rv[:signByte], xordinate[:])
if copyLen != P.MarshalSize()-1 {
return []byte{}, fmt.Errorf("marshal of x ordinate too short")
}
if P.Y.isEven() {
rv[signByte] = 0
} else {
rv[signByte] = 1
}
return rv, nil
}
// MarshalSize returns the length of the byte representation of P
func (P *Secp256k1Point) MarshalSize() int { return 33 }
// MarshalID returns the ID for a secp256k1 point
func (P *Secp256k1Point) MarshalID() [8]byte {
return [8]byte{'s', 'p', '2', '5', '6', '.', 'p', 'o'}
}
// UnmarshalBinary sets P to the point represented by contents of buf, or
// returns an non-nil error
func (P *Secp256k1Point) UnmarshalBinary(buf []byte) error {
var err error
if len(buf) != P.MarshalSize() {
err = fmt.Errorf("wrong length for marshaled point")
}
if err == nil && !(buf[32] == 0 || buf[32] == 1) {
err = fmt.Errorf("bad sign byte (the last one)")
}
if err != nil {
return err
}
var xordinate [32]byte
copy(xordinate[:], buf[:32])
P.X = newFieldZero().SetBytes(xordinate)
secp256k1RHS := rightHandSide(P.X)
maybeY := maybeSqrtInField(secp256k1RHS)
if maybeY == (*fieldElt)(nil) {
return fmt.Errorf("x ordinate does not correspond to a curve point")
}
isEven := maybeY.isEven()
P.Y.Set(maybeY)
if (buf[32] == 0 && !isEven) || (buf[32] == 1 && isEven) {
P.Y.Neg(P.Y)
} else {
if buf[32] != 0 && buf[32] != 1 {
return fmt.Errorf("parity byte must be 0 or 1")
}
}
return nil
}
// MarshalTo writes the serialized P to w, and returns the number of bytes
// written, or an error on failure.
func (P *Secp256k1Point) MarshalTo(w io.Writer) (int, error) {
buf, err := P.MarshalBinary()
if err != nil {
return 0, err
}
return w.Write(buf)
}
// UnmarshalFrom sets P to the secp256k1 point represented by bytes read from r,
// and returns the number of bytes read, or an error on failure.
func (P *Secp256k1Point) UnmarshalFrom(r io.Reader) (int, error) {
buf := make([]byte, P.MarshalSize())
n, err := io.ReadFull(r, buf)
if err != nil {
return 0, err
}
return n, P.UnmarshalBinary(buf)
}
// EthereumAddress returns the 160-bit address corresponding to p as public key.
func EthereumAddress(p kyber.Point) (rv [20]byte) {
// The Ethereum address of P is the bottom 160 bits of keccak256(P.X‖P.Y),
// where P.X and P.Y are represented in 32 bytes as big-endian. See equations
// (277, 284) of Ethereum Yellow Paper version 3e36772, or go-ethereum's
// crypto.PubkeyToAddress.
h := sha3.NewLegacyKeccak256()
if _, err := h.Write(LongMarshal(p)); err != nil {
panic(err)
}
copy(rv[:], h.Sum(nil)[12:])
return rv
}
// IsSecp256k1Point returns true if p is a Secp256k1Point
func IsSecp256k1Point(p kyber.Point) bool {
switch p.(type) {
case *Secp256k1Point:
return true
default:
return false
}
}
// Coordinates returns the coordinates of p
func Coordinates(p kyber.Point) (*big.Int, *big.Int) {
return p.(*Secp256k1Point).X.Int(), p.(*Secp256k1Point).Y.Int()
}
// ValidPublicKey returns true iff p can be used in the optimized on-chain
// Schnorr-signature verification. See SchnorrSECP256K1.sol for details.
func ValidPublicKey(p kyber.Point) bool {
if p == (*Secp256k1Point)(nil) || p == nil {
return false
}
P, ok := p.(*Secp256k1Point)
if !ok {
return false
}
// Verify that X < HALF_Q so it can be used for optimized on-chain verification
if P.X.Int().Cmp(halfQ) == 1 {
return false
}
// Verify that the pub key is a valid curve point
maybeY := maybeSqrtInField(rightHandSide(P.X))
return maybeY != nil && (P.Y.Equal(maybeY) || P.Y.Equal(maybeY.Neg(maybeY)))
}
// Generate generates a public/private key pair, which can be verified cheaply
// on-chain
func Generate(random cipher.Stream) *key.Pair {
p := key.Pair{}
for !ValidPublicKey(p.Public) {
p.Private = (&Secp256k1{}).Scalar().Pick(random)
p.Public = (&Secp256k1{}).Point().Mul(p.Private, nil)
}
return &p
}
// LongMarshal returns the concatenated coordinates serialized as uint256's
func LongMarshal(p kyber.Point) []byte {
xMarshal := p.(*Secp256k1Point).X.Bytes()
yMarshal := p.(*Secp256k1Point).Y.Bytes()
return append(xMarshal[:], yMarshal[:]...)
}
// LongUnmarshal returns the secp256k1 point represented by m, as a concatenated
// pair of uint256's
func LongUnmarshal(m []byte) (kyber.Point, error) {
if len(m) != 64 {
return nil, fmt.Errorf(
"0x%x does not represent an uncompressed Secp256k1Point. Should be length 64, but is length %d",
m, len(m))
}
p := NewPoint()
p.X.SetInt(big.NewInt(0).SetBytes(m[:32]))
p.Y.SetInt(big.NewInt(0).SetBytes(m[32:]))
if !ValidPublicKey(p) {
return nil, fmt.Errorf("%s is not a valid secp256k1 point", p)
}
return p, nil
}
// ScalarToPublicPoint returns the public secp256k1 point associated to s
func ScalarToPublicPoint(s kyber.Scalar) kyber.Point {
publicPoint := (&Secp256k1{}).Point()
return publicPoint.Mul(s, nil)
}
// SetCoordinates returns the point (x,y), or panics if an invalid Secp256k1Point
func SetCoordinates(x, y *big.Int) kyber.Point {
rv := NewPoint()
rv.X.SetInt(x)
rv.Y.SetInt(y)
if !ValidPublicKey(rv) {
panic("point requested from invalid coordinates")
}
return rv
}

232
bridge/pkg/signatures/secp256k1/point_test.go
View File

@ -1,232 +0,0 @@
package secp256k1
import (
"bytes"
"crypto/rand"
"fmt"
"math/big"
"testing"
"go.dedis.ch/kyber/v3/group/curve25519"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
)
var numPointSamples = 10
var randomStreamPoint = cryptotest.NewStream(&testing.T{}, 0)
func TestPoint_String(t *testing.T) {
require.Equal(t, NewPoint().String(),
"Secp256k1{X: fieldElt{0}, Y: fieldElt{0}}")
}
func TestPoint_CloneAndEqual(t *testing.T) {
f := NewPoint()
for i := 0; i < numPointSamples; i++ {
g := f.Clone()
f.Pick(randomStreamPoint)
assert.NotEqual(t, f, g,
"modifying original shouldn't change clone")
g, h := f.Clone(), f.Clone()
assert.Equal(t, f, g, "clones should be equal")
g.Add(g, f)
assert.Equal(t, h, f,
"modifying a clone shouldn't change originial")
}
}
func TestPoint_NullAndAdd(t *testing.T) {
f, g := NewPoint(), NewPoint()
for i := 0; i < numPointSamples; i++ {
g.Null()
f.Pick(randomStreamPoint)
g.Add(f, g)
assert.Equal(t, f, g, "adding zero should have no effect")
}
}
func TestPoint_Set(t *testing.T) {
p := NewPoint()
base := NewPoint().Base()
assert.NotEqual(t, p, base, "generator should not be zero")
p.Set(base)
assert.Equal(t, p, base, "setting to generator should yield generator")
}
func TestPoint_Embed(t *testing.T) {
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
data := make([]byte, p.EmbedLen())
_, err := rand.Read(data)
require.Nil(t, err)
p.Embed(data, randomStreamPoint)
require.True(t, s256.IsOnCurve(p.X.Int(), p.Y.Int()),
"should embed to a secp256k1 point")
output, err := p.Data()
require.NoError(t, err)
require.True(t, bytes.Equal(data, output),
"should get same value back after round-trip "+
"embedding, got %v, then %v", data, output)
}
var uint256Bytes [32]byte
uint256Bytes[0] = 30
p.X.SetBytes(uint256Bytes)
_, err := p.Data()
require.Error(t, err)
require.Contains(t, err.Error(), "specifies too much data")
var b bytes.Buffer
p.Pick(randomStreamPoint)
_, err = p.MarshalTo(&b)
require.NoError(t, err)
_, err = p.UnmarshalFrom(&b)
require.NoError(t, err)
data := make([]byte, p.EmbedLen()+1) // Check length validation. This test
defer func() { // comes last, because it triggers panic
r := recover()
require.NotNil(t, r, "calling embed with too much data should panic")
require.Contains(t, r, "too much data to embed in a point")
}()
p.Embed(data, randomStreamPoint)
}
func TestPoint_AddSubAndNeg(t *testing.T) {
zero := NewPoint().Null()
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
p.Pick(randomStreamPoint)
q := p.Clone()
p.Sub(p, q)
require.True(t, p.Equal(zero),
"subtracting a point from itself should give zero, "+
"got %v - %v = %v ≠ %v", q, q, p, zero)
p.Neg(q)
r := NewPoint().Add(p, q)
require.True(t, r.Equal(zero),
"adding a point to its negative should give zero"+
" got %v+%v=%v≠%v", q, p, r, zero)
r.Neg(q)
p.Sub(q, r)
s := NewPoint().Add(q, q)
require.True(t, p.Equal(s), "q-(-q)=q+q?"+
" got %v-%v=%v≠%v", q, r, p, s)
}
}
func TestPoint_Mul(t *testing.T) {
zero := NewPoint().Null()
multiplier := newScalar(bigZero)
one := newScalar(big.NewInt(int64(1)))
var p *Secp256k1Point
for i := 0; i < numPointSamples/5; i++ {
if i%20 == 0 {
p = nil // Test default to generator point
} else {
p = NewPoint()
p.Pick(randomStreamPoint)
}
multiplier.Pick(randomStreamPoint)
q := NewPoint().Mul(one, p)
comparee := NewPoint()
if p == (*Secp256k1Point)(nil) {
comparee.Base()
} else {
comparee = p.Clone().(*Secp256k1Point)
}
require.True(t, comparee.Equal(q), "1*p=p? %v * %v ≠ %v", one,
comparee, q)
q.Mul(multiplier, p)
negMultiplier := newScalar(bigZero).Neg(multiplier)
r := NewPoint().Mul(negMultiplier, p)
s := NewPoint().Add(q, r)
require.True(t, s.Equal(zero), "s*p+(-s)*p=0? got "+
"%v*%v + %v*%v = %v + %v = %v ≠ %v", multiplier, p,
)
}
}
func TestPoint_Marshal(t *testing.T) {
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
p.Pick(randomStreamPoint)
serialized, err := p.MarshalBinary()
require.Nil(t, err)
q := NewPoint()
err = q.UnmarshalBinary(serialized)
require.Nil(t, err)
require.True(t, p.Equal(q), "%v marshalled to %x, which "+
"unmarshalled to %v", p, serialized, q)
}
p.X.SetInt(big.NewInt(0)) // 0³+7 is not a square in the base field.
_, err := p.MarshalBinary()
require.Error(t, err)
require.Contains(t, err.Error(), "not a square")
p.X.SetInt(big.NewInt(1))
_, err = p.MarshalBinary()
require.Error(t, err)
require.Contains(t, err.Error(), "not a point on the curve")
id := p.MarshalID()
require.Equal(t, string(id[:]), "sp256.po")
data := make([]byte, 34)
err = p.UnmarshalBinary(data)
require.Error(t, err)
require.Contains(t, err.Error(), "wrong length for marshaled point")
require.Contains(t, p.UnmarshalBinary(data[:32]).Error(),
"wrong length for marshaled point")
data[32] = 2
require.Contains(t, p.UnmarshalBinary(data[:33]).Error(),
"bad sign byte")
data[32] = 0
data[31] = 5 // I.e., x-ordinate is now 5
require.Contains(t, p.UnmarshalBinary(data[:33]).Error(),
"does not correspond to a curve point")
}
func TestPoint_BaseTakesCopy(t *testing.T) {
p := NewPoint().Base()
p.Add(p, p)
q := NewPoint().Base()
assert.False(t, p.Equal(q),
"modifying output from Base changes S256.G{x,y}")
}
func TestPoint_EthereumAddress(t *testing.T) {
// Example taken from
// https://theethereum.wiki/w/index.php/Accounts,_Addresses,_Public_And_Private_Keys,_And_Tokens
pString := "3a1076bf45ab87712ad64ccb3b10217737f7faacbf2872e88fdd9a537d8fe266"
pInt, ok := big.NewInt(0).SetString(pString, 16)
require.True(t, ok, "failed to parse private key")
private := newScalar(pInt)
public := NewPoint().Mul(private, nil)
address := EthereumAddress(public)
assert.Equal(t, fmt.Sprintf("%x", address),
"c2d7cf95645d33006175b78989035c7c9061d3f9")
}
func TestIsSecp256k1Point(t *testing.T) {
p := curve25519.NewBlakeSHA256Curve25519(false).Point()
require.False(t, IsSecp256k1Point(p))
require.True(t, IsSecp256k1Point(NewPoint()))
}
func TestCoordinates(t *testing.T) {
x, y := Coordinates(NewPoint())
require.Equal(t, x, bigZero)
require.Equal(t, y, bigZero)
}
func TestValidPublicKey(t *testing.T) {
require.False(t, ValidPublicKey(NewPoint()), "zero is not a valid key")
require.True(t, ValidPublicKey(NewPoint().Base()))
}
func TestGenerate(t *testing.T) {
for {
if ValidPublicKey(Generate(randomStreamPoint).Public) {
break
}
}
}

228
bridge/pkg/signatures/secp256k1/scalar.go
View File

@ -1,228 +0,0 @@
// Package secp256k1 is an implementation of the kyber.{Group,Point,Scalcar}
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// interfaces, based on btcd/btcec and kyber/group/mod
//
// XXX: NOT CONSTANT TIME!
package secp256k1
// Implementation of kyber.Scalar interface for arithmetic operations mod the
// order of the secpk256k1 group (i.e. hex value
// 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141.)
import (
"crypto/cipher"
"fmt"
"io"
"math/big"
secp256k1BTCD "github.com/btcsuite/btcd/btcec"
"github.com/ethereum/go-ethereum/common"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/util/random"
)
var GroupOrder = secp256k1BTCD.S256().N
type secp256k1Scalar big.Int
// AllowVarTime, if passed true indicates that variable-time operations may be
// used on s.
func (s *secp256k1Scalar) AllowVarTime(varTimeAllowed bool) {
// Since constant-time operations are unimplemented for secp256k1, a
// value of false panics.
if !varTimeAllowed {
panic("implementation is not constant-time!")
}
}
// newScalar returns a secpk256k1 scalar, with value v modulo GroupOrder.
func newScalar(v *big.Int) kyber.Scalar {
return (*secp256k1Scalar)(zero().Mod(v, GroupOrder))
}
func zero() *big.Int { return big.NewInt(0) }
func ToInt(s kyber.Scalar) *big.Int { return (*big.Int)(s.(*secp256k1Scalar)) }
func (s *secp256k1Scalar) int() *big.Int { return (*big.Int)(s) }
func (s *secp256k1Scalar) modG() kyber.Scalar {
// TODO(alx): Make this faster
s.int().Mod(s.int(), GroupOrder)
return s
}
func (s *secp256k1Scalar) String() string {
return fmt.Sprintf("scalar{%x}", (*big.Int)(s))
}
var scalarZero = zero()
// Equal returns true if s and sPrime represent the same value modulo the group
// order, false otherwise
func (s *secp256k1Scalar) Equal(sPrime kyber.Scalar) bool {
difference := zero().Sub(s.int(), ToInt(sPrime))
return scalarZero.Cmp(difference.Mod(difference, GroupOrder)) == 0
}
// Set copies sPrime's value (modulo GroupOrder) to s, and returns it
func (s *secp256k1Scalar) Set(sPrime kyber.Scalar) kyber.Scalar {
return (*secp256k1Scalar)(s.int().Mod(ToInt(sPrime), GroupOrder))
}
// Clone returns a copy of s mod GroupOrder
func (s *secp256k1Scalar) Clone() kyber.Scalar {
return (*secp256k1Scalar)(zero().Mod(s.int(), GroupOrder))
}
// SetInt64 returns s with value set to v modulo GroupOrder
func (s *secp256k1Scalar) SetInt64(v int64) kyber.Scalar {
return (*secp256k1Scalar)(s.int().SetInt64(v)).modG()
}
// Zero sets s to 0 mod GroupOrder, and returns it
func (s *secp256k1Scalar) Zero() kyber.Scalar {
return s.SetInt64(0)
}
// Add sets s to a+b mod GroupOrder, and returns it
func (s *secp256k1Scalar) Add(a, b kyber.Scalar) kyber.Scalar {
s.int().Add(ToInt(a), ToInt(b))
return s.modG()
}
// Sub sets s to a-b mod GroupOrder, and returns it
func (s *secp256k1Scalar) Sub(a, b kyber.Scalar) kyber.Scalar {
s.int().Sub(ToInt(a), ToInt(b))
return s.modG()
}
// Neg sets s to -a mod GroupOrder, and returns it
func (s *secp256k1Scalar) Neg(a kyber.Scalar) kyber.Scalar {
s.int().Neg(ToInt(a))
return s.modG()
}
// One sets s to 1 mod GroupOrder, and returns it
func (s *secp256k1Scalar) One() kyber.Scalar {
return s.SetInt64(1)
}
// Mul sets s to a*b mod GroupOrder, and returns it
func (s *secp256k1Scalar) Mul(a, b kyber.Scalar) kyber.Scalar {
// TODO(alx): Make this faster
s.int().Mul(ToInt(a), ToInt(b))
return s.modG()
}
// Div sets s to a*b⁻¹ mod GroupOrder, and returns it
func (s *secp256k1Scalar) Div(a, b kyber.Scalar) kyber.Scalar {
if ToInt(b).Cmp(scalarZero) == 0 {
panic("attempt to divide by zero")
}
// TODO(alx): Make this faster
s.int().Mul(ToInt(a), zero().ModInverse(ToInt(b), GroupOrder))
return s.modG()
}
// Inv sets s to s⁻¹ mod GroupOrder, and returns it
func (s *secp256k1Scalar) Inv(a kyber.Scalar) kyber.Scalar {
if ToInt(a).Cmp(scalarZero) == 0 {
panic("attempt to divide by zero")
}
s.int().ModInverse(ToInt(a), GroupOrder)
return s
}
// Pick sets s to a random value mod GroupOrder sampled from rand, and returns
// it
func (s *secp256k1Scalar) Pick(rand cipher.Stream) kyber.Scalar {
return s.Set((*secp256k1Scalar)(random.Int(GroupOrder, rand)))
}
// MarshalBinary returns the big-endian byte representation of s, or an error on
// failure
func (s *secp256k1Scalar) MarshalBinary() ([]byte, error) {
b := ToInt(s.modG()).Bytes()
// leftpad with zeros
rv := append(make([]byte, s.MarshalSize()-len(b)), b...)
if len(rv) != s.MarshalSize() {
return nil, fmt.Errorf("marshalled scalar to wrong length")
}
return rv, nil
}
// MarshalSize returns the length of the byte representation of s
func (s *secp256k1Scalar) MarshalSize() int { return 32 }
// MarshalID returns the ID for a secp256k1 scalar
func (s *secp256k1Scalar) MarshalID() [8]byte {
return [8]byte{'s', 'p', '2', '5', '6', '.', 's', 'c'}
}
// UnmarshalBinary sets s to the scalar represented by the contents of buf,
// returning error on failure.
func (s *secp256k1Scalar) UnmarshalBinary(buf []byte) error {
if len(buf) != s.MarshalSize() {
return fmt.Errorf("cannot unmarshal to scalar: wrong length")
}
s.int().Mod(s.int().SetBytes(buf), GroupOrder)
return nil
}
// MarshalTo writes the serialized s to w, and returns the number of bytes
// written, or an error on failure.
func (s *secp256k1Scalar) MarshalTo(w io.Writer) (int, error) {
buf, err := s.MarshalBinary()
if err != nil {
return 0, fmt.Errorf("cannot marshal binary: %s", err)
}
return w.Write(buf)
}
// UnmarshalFrom sets s to the scalar represented by bytes read from r, and
// returns the number of bytes read, or an error on failure.
func (s *secp256k1Scalar) UnmarshalFrom(r io.Reader) (int, error) {
buf := make([]byte, s.MarshalSize())
n, err := io.ReadFull(r, buf)
if err != nil {
return n, err
}
return n, s.UnmarshalBinary(buf)
}
// SetBytes sets s to the number with big-endian representation a mod
// GroupOrder, and returns it
func (s *secp256k1Scalar) SetBytes(a []byte) kyber.Scalar {
return ((*secp256k1Scalar)(s.int().SetBytes(a))).modG()
}
// IsSecp256k1Scalar returns true if p is a secp256k1Scalar
func IsSecp256k1Scalar(s kyber.Scalar) bool {
switch s := s.(type) {
case *secp256k1Scalar:
s.modG()
return true
default:
return false
}
}
// IntToScalar returns i wrapped as a big.Int.
//
// May modify i to reduce mod GroupOrder
func IntToScalar(i *big.Int) kyber.Scalar {
return ((*secp256k1Scalar)(i)).modG()
}
func ScalarToHash(s kyber.Scalar) common.Hash {
return common.BigToHash(ToInt(s.(*secp256k1Scalar)))
}
// RepresentsScalar returns true iff i is in the right range to be a scalar
func RepresentsScalar(i *big.Int) bool {
return i.Cmp(GroupOrder) == -1
}

189
bridge/pkg/signatures/secp256k1/scalar_test.go
View File

@ -1,189 +0,0 @@
package secp256k1
import (
"bytes"
"encoding/hex"
"math/big"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/group/curve25519"
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
)
var numScalarSamples = 10
var observedScalars map[string]bool
func init() {
observedScalars = make(map[string]bool)
}
// observedScalar ensures that novel scalars are being picked.
func observedScalar(t *testing.T, s kyber.Scalar) {
data, err := s.(*secp256k1Scalar).modG().MarshalBinary()
require.NoError(t, err)
scalar := hex.Dump(data)
require.False(t, observedScalars[scalar])
observedScalars[scalar] = true
}
var randomStreamScalar = cryptotest.NewStream(&testing.T{}, 0)
func TestScalar_SetAndEqual(t *testing.T) {
tests := []int64{5, 67108864, 67108865, 4294967295}
g := newScalar(scalarZero)
for _, test := range tests {
f := newScalar(big.NewInt(test))
g.Set(f)
assert.Equal(t, f, g,
"the method Set should give the same value to receiver")
f.Add(f, newScalar(big.NewInt(1)))
assert.NotEqual(t, f, g,
"SetInt should take a copy of the backing big.Int")
}
}
func TestNewScalar(t *testing.T) {
one := newScalar(big.NewInt(1))
assert.Equal(t, ToInt(one),
ToInt(newScalar(big.NewInt(0).Add(ToInt(one), GroupOrder))),
"equivalence classes mod GroupOrder not equal")
}
func TestScalar_SmokeTestPick(t *testing.T) {
f := newScalar(scalarZero).Clone()
for i := 0; i < numScalarSamples; i++ {
f.Pick(randomStreamScalar)
observedScalar(t, f)
require.True(t, ToInt(f).Cmp(big.NewInt(1000000000)) == 1,
"implausibly low value returned from Pick: %v", f)
}
}
func TestScalar_Neg(t *testing.T) {
f := newScalar(scalarZero).Clone()
for i := 0; i < numScalarSamples; i++ {
f.Pick(randomStreamScalar)
observedScalar(t, f)
g := f.Clone()
g.Neg(g)
require.True(t, g.Add(f, g).Equal(newScalar(scalarZero)))
}
}
func TestScalar_Sub(t *testing.T) {
f := newScalar(scalarZero).Clone()
for i := 0; i < numScalarSamples; i++ {
f.Pick(randomStreamScalar)
observedScalar(t, f)
require.True(t, f.Sub(f, f).Equal(newScalar(scalarZero)),
"subtracting something from itself should give zero")
}
}
func TestScalar_Clone(t *testing.T) {
f := newScalar(big.NewInt(1))
g := f.Clone()
h := f.Clone()
assert.Equal(t, f, g, "clone output does not equal input")
g.Add(f, f)
assert.Equal(t, f, h, "clone does not make a copy")
}
func TestScalar_Marshal(t *testing.T) {
f := newScalar(scalarZero)
g := newScalar(scalarZero)
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStreamScalar)
observedScalar(t, f)
data, err := f.MarshalBinary()
require.Nil(t, err)
err = g.UnmarshalBinary(data)
require.Nil(t, err)
require.True(t, g.Equal(f),
"roundtrip through serialization should give same "+
"result back: failed with %s", f)
}
marshalID := f.(*secp256k1Scalar).MarshalID()
require.Equal(t, string(marshalID[:]), "sp256.sc")
data := make([]byte, 33)
require.Contains(t, f.UnmarshalBinary(data).Error(), "wrong length")
var buf bytes.Buffer
_, err := f.MarshalTo(&buf)
require.NoError(t, err)
_, err = f.UnmarshalFrom(&buf)
require.NoError(t, err)
}
func TestScalar_MulDivInv(t *testing.T) {
f := newScalar(scalarZero)
g := newScalar(scalarZero)
h := newScalar(scalarZero)
j := newScalar(scalarZero)
k := newScalar(scalarZero)
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStreamScalar)
observedScalar(t, f)
g.Inv(f)
h.Mul(f, g)
require.True(t, h.Equal(newScalar(big.NewInt(1))))
h.Div(f, f)
require.True(t, h.Equal(newScalar(big.NewInt(1))))
h.Div(newScalar(big.NewInt(1)), f)
require.True(t, h.Equal(g))
h.Pick(randomStreamScalar)
observedScalar(t, h)
j.Neg(j.Mul(h, f))
k.Mul(h, k.Neg(f))
require.True(t, j.Equal(k), "-(h*f) != h*(-f)")
}
}
func TestScalar_AllowVarTime(t *testing.T) {
defer func() { require.Contains(t, recover(), "not constant-time!") }()
newScalar(bigZero).(*secp256k1Scalar).AllowVarTime(false)
}
func TestScalar_String(t *testing.T) {
require.Equal(t, newScalar(bigZero).String(), "scalar{0}")
}
func TestScalar_SetInt64(t *testing.T) {
require.Equal(t, newScalar(bigZero).SetInt64(1), newScalar(big.NewInt(1)))
require.True(t, newScalar(big.NewInt(1)).Zero().Equal(newScalar(bigZero)))
require.Equal(t, newScalar(bigZero).One(), newScalar(big.NewInt(1)))
}
func TestScalar_DivPanicsOnZeroDivisor(t *testing.T) {
defer func() { require.Contains(t, recover(), "divide by zero") }()
newScalar(bigZero).Div(newScalar(bigZero).One(), newScalar(bigZero))
}
func TestScalar_InvPanicsOnZero(t *testing.T) {
defer func() { require.Contains(t, recover(), "divide by zero") }()
newScalar(bigZero).Inv(newScalar(bigZero))
}
func TestScalar_SetBytes(t *testing.T) {
u256Cardinality := zero().Lsh(big.NewInt(1), 256)
newScalar(bigZero).(*secp256k1Scalar).int().Cmp(
zero().Sub(u256Cardinality, GroupOrder))
}
func TestScalar_IsSecp256k1Scalar(t *testing.T) {
c := curve25519.NewBlakeSHA256Curve25519(true)
require.False(t, IsSecp256k1Scalar(c.Scalar()))
require.True(t, IsSecp256k1Scalar(newScalar(bigZero)))
}
func TestScalar_IntToScalar(t *testing.T) {
u256Cardinality := zero().Lsh(big.NewInt(1), 256)
IntToScalar(u256Cardinality)
require.Equal(t, u256Cardinality, zero().Sub(zero().Lsh(big.NewInt(1), 256),
GroupOrder))
}

89
bridge/pkg/signatures/secp256k1/suite.go
View File

@ -1,89 +0,0 @@
// Package secp256k1 is an implementation of the kyber.{Group,Point,Scalar}
////////////////////////////////////////////////////////////////////////////////
// XXX: Do not use in production until this code has been audited.
////////////////////////////////////////////////////////////////////////////////
// interfaces, based on btcd/btcec and kyber/group/mod
//
// XXX: NOT CONSTANT TIME!
package secp256k1
import (
"crypto/cipher"
"hash"
"io"
"reflect"
"golang.org/x/crypto/sha3"
"go.dedis.ch/fixbuf"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/util/random"
"go.dedis.ch/kyber/v3/xof/blake2xb"
)
// SuiteSecp256k1 implements some basic functionalities such as Group, HashFactory,
// and XOFFactory.
type SuiteSecp256k1 struct {
Secp256k1
r cipher.Stream
}
// Hash returns a newly instantiated keccak hash function.
func (s *SuiteSecp256k1) Hash() hash.Hash {
return sha3.NewLegacyKeccak256()
}
// XOF returns an XOR function, implemented via the Blake2b hash.
//
// This should only be used for generating secrets, so there is no need to make
// it cheap to compute on-chain.
func (s *SuiteSecp256k1) XOF(key []byte) kyber.XOF {
return blake2xb.New(key)
}
// Read implements the Encoding interface function, and reads a series of objs from r
// The objs must all be pointers
func (s *SuiteSecp256k1) Read(r io.Reader, objs ...interface{}) error {
return fixbuf.Read(r, s, objs...)
}
// Write implements the Encoding interface, and writes the objs to r using their
// built-in binary serializations. Supports Points, Scalars, fixed-length data
// types supported by encoding/binary/Write(), and structs, arrays, and slices
// containing these types.
func (s *SuiteSecp256k1) Write(w io.Writer, objs ...interface{}) error {
return fixbuf.Write(w, objs)
}
var aScalar kyber.Scalar
var tScalar = reflect.TypeOf(aScalar)
var aPoint kyber.Point
var tPoint = reflect.TypeOf(aPoint)
// New implements the kyber.Encoding interface, and returns a new element of
// type t, which can be a Point or a Scalar
func (s *SuiteSecp256k1) New(t reflect.Type) interface{} {
switch t {
case tScalar:
return s.Scalar()
case tPoint:
return s.Point()
}
return nil
}
// RandomStream returns a cipher.Stream that returns a key stream
// from crypto/rand.
func (s *SuiteSecp256k1) RandomStream() cipher.Stream {
if s.r != nil {
return s.r
}
return random.New()
}
// NewBlakeKeccackSecp256k1 returns a cipher suite based on package
// go.dedis.ch/kyber/xof/blake2xb, SHA-256, and the secp256k1 curve. It
// produces cryptographically secure random numbers via package crypto/rand.
func NewBlakeKeccackSecp256k1() *SuiteSecp256k1 {
return new(SuiteSecp256k1)
}

16
bridge/pkg/signatures/secp256k1/suite_test.go
View File

@ -1,16 +0,0 @@
package secp256k1
import (
"encoding/hex"
"testing"
"github.com/stretchr/testify/require"
)
func TestSuite(t *testing.T) {
s := NewBlakeKeccackSecp256k1()
emptyHashAsHex := hex.EncodeToString(s.Hash().Sum(nil))
require.Equal(t, emptyHashAsHex,
"c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470")
_ = s.RandomStream()
}

64
bridge/pkg/vaa/structs.go
View File

@ -4,9 +4,12 @@ import (
"bytes"
"encoding/binary"
"fmt"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
"github.com/certusone/wormhole/bridge/third_party/chainlink/ethschnorr"
"github.com/certusone/wormhole/bridge/third_party/chainlink/secp256k1"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"go.dedis.ch/kyber/v3"
"go.dedis.ch/kyber/v3/util/key"
"io"
"math"
"math/big"
@ -150,11 +153,66 @@ func ParseVAA(data []byte) (*VAA, error) {
return v, nil
}
// SigningBody returns the binary representation of the data that is relevant for signing and verifying the VAA
func (v *VAA) SigningBody() ([]byte, error) {
// signingBody returns the binary representation of the data that is relevant for signing and verifying the VAA
func (v *VAA) signingBody() ([]byte, error) {
return v.serializeBody()
}
// SigningMsg returns the hash of the signing body. This is used for signature generation and verification
func (v *VAA) SigningMsg() (*big.Int, error) {
body, err := v.signingBody()
if err != nil {
// Should never happen on a successfully parsed VAA
return nil, fmt.Errorf("failed to serialize signing body: %w", err)
}
hash := crypto.Keccak256Hash(body)
return hash.Big(), nil
}
// VerifySignature verifies the signature of the VAA given a public key
func (v *VAA) VerifySignature(pubKey kyber.Point) bool {
if v.Signature == nil {
return false
}
msg, err := v.SigningMsg()
if err != nil {
return false
}
sig := ethschnorr.NewSignature()
sig.Signature = new(big.Int).SetBytes(v.Signature.Sig[:])
sig.CommitmentPublicAddress = v.Signature.Address
err = ethschnorr.Verify(pubKey, msg, sig)
return err == nil
}
// Sign signs the VAA, setting it's signature field
func (v *VAA) Sign(key *key.Pair) error {
if v.Signature != nil {
return fmt.Errorf("VAA has already been signed")
}
hash, err := v.SigningMsg()
if err != nil {
return fmt.Errorf("failed to get signing message: %w", err)
}
sig, err := ethschnorr.Sign(key.Private, hash)
if err != nil {
return fmt.Errorf("failed to sign: %w", err)
}
// Set fields
v.Signature = &Signature{}
copy(v.Signature.Sig[:], common.LeftPadBytes(sig.Signature.Bytes(), 32))
v.Signature.Address = sig.CommitmentPublicAddress
return nil
}
// Serialize returns the binary representation of the VAA
func (v *VAA) Serialize() ([]byte, error) {
buf := new(bytes.Buffer)

27
bridge/pkg/vaa/types_test.go
View File

@ -1,8 +1,8 @@
package vaa
import (
"github.com/certusone/wormhole/bridge/pkg/signatures/cryptotest"
"github.com/certusone/wormhole/bridge/pkg/signatures/secp256k1"
"github.com/certusone/wormhole/bridge/third_party/chainlink/cryptotest"
"github.com/certusone/wormhole/bridge/third_party/chainlink/secp256k1"
"github.com/ethereum/go-ethereum/common"
"github.com/stretchr/testify/require"
"math/big"
@ -69,3 +69,26 @@ func TestSerializeDeserialize(t *testing.T) {
})
}
}
func TestVerifySignature(t *testing.T) {
key := secp256k1.Generate(randomStream)
v := &VAA{
Version: 8,
GuardianSetIndex: 9,
Timestamp: time.Unix(2837, 0),
Payload: &BodyTransfer{
SourceChain: 2,
TargetChain: 1,
TargetAddress: Address{2, 1, 3},
Asset: &AssetMeta{
Chain: 9,
Address: Address{9, 2, 4},
},
Amount: big.NewInt(29),
},
}
require.NoError(t, v.Sign(key))
require.True(t, v.VerifySignature(key.Public))
}

0
bridge/pkg/signatures/cryptotest/cryptotest.go → bridge/third_party/chainlink/cryptotest/cryptotest.go vendored
View File

33
bridge/third_party/chainlink/secp256k1/field.go vendored
View File

@ -21,6 +21,7 @@ import (
// q is the field characteristic (cardinality) of the secp256k1 base field. All
// arithmetic operations on the field are modulo this.
var q = s256.P
var halfQ = new(big.Int).Div(q, big.NewInt(2))
type fieldElt big.Int
@ -28,17 +29,17 @@ type fieldElt big.Int
func newFieldZero() *fieldElt { return (*fieldElt)(big.NewInt(0)) }
// Int returns f as a big.Int
func (f *fieldElt) int() *big.Int { return (*big.Int)(f) }
func (f *fieldElt) Int() *big.Int { return (*big.Int)(f) }
// modQ reduces f's underlying big.Int modulo q, and returns it
func (f *fieldElt) modQ() *fieldElt {
if f.int().Cmp(q) != -1 || f.int().Cmp(bigZero) == -1 {
if f.Int().Cmp(q) != -1 || f.Int().Cmp(bigZero) == -1 {
// f ∉ {0, ..., q-1}. Find the representative of f+qℤ in that set.
//
// Per Mod docstring, "Mod implements Euclidean modulus", meaning that after
// this, f will be the smallest non-negative representative of its
// equivalence class in ℤ/qℤ. TODO(alx): Make this faster
f.int().Mod(f.int(), q)
f.Int().Mod(f.Int(), q)
}
return f
}
@ -55,7 +56,7 @@ var bigZero = big.NewInt(0)
// String returns the string representation of f
func (f *fieldElt) String() string {
return fmt.Sprintf("fieldElt{%x}", f.int())
return fmt.Sprintf("fieldElt{%x}", f.Int())
}
// Equal returns true iff f=g, i.e. the backing big.Ints satisfy f ≡ g mod q
@ -69,30 +70,30 @@ func (f *fieldElt) Equal(g *fieldElt) bool {
if g == (*fieldElt)(nil) { // g is nil, f is not
return false
}
return bigZero.Cmp(newFieldZero().Sub(f, g).modQ().int()) == 0
return bigZero.Cmp(newFieldZero().Sub(f, g).modQ().Int()) == 0
}
// Add sets f to the sum of a and b modulo q, and returns it.
func (f *fieldElt) Add(a, b *fieldElt) *fieldElt {
f.int().Add(a.int(), b.int())
f.Int().Add(a.Int(), b.Int())
return f.modQ()
}
// Sub sets f to a-b mod q, and returns it.
func (f *fieldElt) Sub(a, b *fieldElt) *fieldElt {
f.int().Sub(a.int(), b.int())
f.Int().Sub(a.Int(), b.Int())
return f.modQ()
}
// Set sets f's value to v, and returns f.
func (f *fieldElt) Set(v *fieldElt) *fieldElt {
f.int().Set(v.int())
f.Int().Set(v.Int())
return f.modQ()
}
// SetInt sets f's value to v mod q, and returns f.
func (f *fieldElt) SetInt(v *big.Int) *fieldElt {
f.int().Set(v)
f.Int().Set(v)
return f.modQ()
}
@ -103,7 +104,7 @@ func (f *fieldElt) Pick(rand cipher.Stream) *fieldElt {
// Neg sets f to the negation of g modulo q, and returns it
func (f *fieldElt) Neg(g *fieldElt) *fieldElt {
f.int().Neg(g.int())
f.Int().Neg(g.Int())
return f.modQ()
}
@ -113,13 +114,13 @@ func (f *fieldElt) Clone() *fieldElt { return newFieldZero().Set(f.modQ()) }
// SetBytes sets f to the 32-byte big-endian value represented by buf, reduces
// it, and returns it.
func (f *fieldElt) SetBytes(buf [32]byte) *fieldElt {
f.int().SetBytes(buf[:])
f.Int().SetBytes(buf[:])
return f.modQ()
}
// Bytes returns the 32-byte big-endian representation of f
func (f *fieldElt) Bytes() [32]byte {
bytes := f.modQ().int().Bytes()
bytes := f.modQ().Int().Bytes()
if len(bytes) > 32 {
panic("field element longer than 256 bits")
}
@ -132,7 +133,7 @@ var two = big.NewInt(2)
// square returns y² mod q
func fieldSquare(y *fieldElt) *fieldElt {
return fieldEltFromBigInt(newFieldZero().int().Exp(y.int(), two, q))
return fieldEltFromBigInt(newFieldZero().Int().Exp(y.Int(), two, q))
}
// sqrtPower is s.t. n^sqrtPower≡sqrt(n) mod q, if n has a root at all. See
@ -146,7 +147,7 @@ var sqrtPower = s256.QPlus1Div4()
// maybeSqrtInField returns a square root of v, if it has any, else nil
func maybeSqrtInField(v *fieldElt) *fieldElt {
s := newFieldZero()
s.int().Exp(v.int(), sqrtPower, q)
s.Int().Exp(v.Int(), sqrtPower, q)
if !fieldSquare(s).Equal(v) {
return nil
}
@ -159,11 +160,11 @@ var seven = fieldEltFromInt(7)
// rightHandSide returns the RHS of the secp256k1 equation, x³+7 mod q, given x
func rightHandSide(x *fieldElt) *fieldElt {
xCubed := newFieldZero()
xCubed.int().Exp(x.int(), three, q)
xCubed.Int().Exp(x.Int(), three, q)
return xCubed.Add(xCubed, seven)
}
// isEven returns true if f is even, false otherwise
func (f *fieldElt) isEven() bool {
return big.NewInt(0).Mod(f.int(), two).Cmp(big.NewInt(0)) == 0
return big.NewInt(0).Mod(f.Int(), two).Cmp(big.NewInt(0)) == 0
}

12
bridge/third_party/chainlink/secp256k1/field_test.go vendored
View File

@ -74,7 +74,7 @@ func TestField_SmokeTestPick(t *testing.T) {
f := newFieldZero()
f.Pick(randomStream)
observedFieldElt(t, f)
assert.True(t, f.int().Cmp(big.NewInt(1000000000)) == 1,
assert.True(t, f.Int().Cmp(big.NewInt(1000000000)) == 1,
"should be greater than 1000000000, with very high probability")
}
@ -132,9 +132,9 @@ func TestField_MaybeSquareRootInField(t *testing.T) {
for i := 0; i < numFieldSamples; i++ {
f.Pick(randomStream)
observedFieldElt(t, f)
require.True(t, f.int().Cmp(q) == -1, "picked larger value than q: %s", f)
require.True(t, f.int().Cmp(big.NewInt(-1)) != -1,
"backing int must be non-negative")
require.True(t, f.Int().Cmp(q) == -1, "picked larger value than q: %s", f)
require.True(t, f.Int().Cmp(big.NewInt(-1)) != -1,
"backing Int must be non-negative")
s := fieldSquare(f)
g := maybeSqrtInField(s)
require.NotEqual(t, g, (*fieldElt)(nil))
@ -142,11 +142,11 @@ func TestField_MaybeSquareRootInField(t *testing.T) {
require.True(t, f.Equal(g) || f.Equal(ng), "squaring something and "+
"taking the square root should give ± the original: failed with %s", f)
bigIntSqrt := newFieldZero() // Cross-check against big.ModSqrt
rv := bigIntSqrt.int().ModSqrt(s.int(), q)
rv := bigIntSqrt.Int().ModSqrt(s.Int(), q)
require.NotNil(t, rv)
require.True(t, bigIntSqrt.Equal(g) || bigIntSqrt.Equal(ng))
nonSquare := newFieldZero().Neg(s)
rv = bigIntSqrt.int().ModSqrt(nonSquare.int(), q)
rv = bigIntSqrt.Int().ModSqrt(nonSquare.Int(), q)
require.Nil(t, rv, "ModSqrt indicates nonSquare is square")
require.Nil(t, maybeSqrtInField(nonSquare), "the negative of square "+
"should not be a square")

29
bridge/third_party/chainlink/secp256k1/point.go vendored
View File

@ -31,7 +31,7 @@ type secp256k1Point struct {
Y *fieldElt
}
func newPoint() *secp256k1Point {
func NewPoint() *secp256k1Point {
return &secp256k1Point{newFieldZero(), newFieldZero()}
}
@ -148,8 +148,8 @@ func (P *secp256k1Point) Data() ([]byte, error) {
// Add sets P to a+b (secp256k1 group operation) and returns it.
func (P *secp256k1Point) Add(a, b kyber.Point) kyber.Point {
X, Y := s256.Add(
a.(*secp256k1Point).X.int(), a.(*secp256k1Point).Y.int(),
b.(*secp256k1Point).X.int(), b.(*secp256k1Point).Y.int())
a.(*secp256k1Point).X.Int(), a.(*secp256k1Point).Y.Int(),
b.(*secp256k1Point).X.Int(), b.(*secp256k1Point).Y.Int())
P.X.SetInt(X)
P.Y.SetInt(Y)
return P
@ -158,9 +158,9 @@ func (P *secp256k1Point) Add(a, b kyber.Point) kyber.Point {
// Add sets P to a-b (secp256k1 group operation), and returns it.
func (P *secp256k1Point) Sub(a, b kyber.Point) kyber.Point {
X, Y := s256.Add(
a.(*secp256k1Point).X.int(), a.(*secp256k1Point).Y.int(),
b.(*secp256k1Point).X.int(),
newFieldZero().Neg(b.(*secp256k1Point).Y).int()) // -b_y
a.(*secp256k1Point).X.Int(), a.(*secp256k1Point).Y.Int(),
b.(*secp256k1Point).X.Int(),
newFieldZero().Neg(b.(*secp256k1Point).Y).Int()) // -b_y
P.X.SetInt(X)
P.Y.SetInt(Y)
return P
@ -185,8 +185,8 @@ func (P *secp256k1Point) Mul(s kyber.Scalar, a kyber.Point) kyber.Point {
if a == (*secp256k1Point)(nil) || a == nil {
X, Y = s256.ScalarBaseMult(sBytes)
} else {
X, Y = s256.ScalarMult(a.(*secp256k1Point).X.int(),
a.(*secp256k1Point).Y.int(), sBytes)
X, Y = s256.ScalarMult(a.(*secp256k1Point).X.Int(),
a.(*secp256k1Point).Y.Int(), sBytes)
}
P.X.SetInt(X)
P.Y.SetInt(Y)
@ -309,7 +309,7 @@ func IsSecp256k1Point(p kyber.Point) bool {
// Coordinates returns the coordinates of p
func Coordinates(p kyber.Point) (*big.Int, *big.Int) {
return p.(*secp256k1Point).X.int(), p.(*secp256k1Point).Y.int()
return p.(*secp256k1Point).X.Int(), p.(*secp256k1Point).Y.Int()
}
// ValidPublicKey returns true iff p can be used in the optimized on-chain
@ -322,6 +322,13 @@ func ValidPublicKey(p kyber.Point) bool {
if !ok {
return false
}
// Verify that X < HALF_Q so it can be used for optimized on-chain verification
if P.X.Int().Cmp(halfQ) == 1 {
return false
}
// Verify that the pub key is a valid curve point
maybeY := maybeSqrtInField(rightHandSide(P.X))
return maybeY != nil && (P.Y.Equal(maybeY) || P.Y.Equal(maybeY.Neg(maybeY)))
}
@ -352,7 +359,7 @@ func LongUnmarshal(m []byte) (kyber.Point, error) {
"0x%x does not represent an uncompressed secp256k1Point. Should be length 64, but is length %d",
m, len(m))
}
p := newPoint()
p := NewPoint()
p.X.SetInt(big.NewInt(0).SetBytes(m[:32]))
p.Y.SetInt(big.NewInt(0).SetBytes(m[32:]))
if !ValidPublicKey(p) {
@ -369,7 +376,7 @@ func ScalarToPublicPoint(s kyber.Scalar) kyber.Point {
// SetCoordinates returns the point (x,y), or panics if an invalid secp256k1Point
func SetCoordinates(x, y *big.Int) kyber.Point {
rv := newPoint()
rv := NewPoint()
rv.X.SetInt(x)
rv.Y.SetInt(y)
if !ValidPublicKey(rv) {

52
bridge/third_party/chainlink/secp256k1/point_test.go vendored
View File

@ -20,12 +20,12 @@ var numPointSamples = 10
var randomStreamPoint = cryptotest.NewStream(&testing.T{}, 0)
func TestPoint_String(t *testing.T) {
require.Equal(t, newPoint().String(),
require.Equal(t, NewPoint().String(),
"Secp256k1{X: fieldElt{0}, Y: fieldElt{0}}")
}
func TestPoint_CloneAndEqual(t *testing.T) {
f := newPoint()
f := NewPoint()
for i := 0; i < numPointSamples; i++ {
g := f.Clone()
f.Pick(randomStreamPoint)
@ -40,7 +40,7 @@ func TestPoint_CloneAndEqual(t *testing.T) {
}
func TestPoint_NullAndAdd(t *testing.T) {
f, g := newPoint(), newPoint()
f, g := NewPoint(), NewPoint()
for i := 0; i < numPointSamples; i++ {
g.Null()
f.Pick(randomStreamPoint)
@ -50,21 +50,21 @@ func TestPoint_NullAndAdd(t *testing.T) {
}
func TestPoint_Set(t *testing.T) {
p := newPoint()
base := newPoint().Base()
p := NewPoint()
base := NewPoint().Base()
assert.NotEqual(t, p, base, "generator should not be zero")
p.Set(base)
assert.Equal(t, p, base, "setting to generator should yield generator")
}
func TestPoint_Embed(t *testing.T) {
p := newPoint()
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
data := make([]byte, p.EmbedLen())
_, err := rand.Read(data)
require.Nil(t, err)
p.Embed(data, randomStreamPoint)
require.True(t, s256.IsOnCurve(p.X.int(), p.Y.int()),
require.True(t, s256.IsOnCurve(p.X.Int(), p.Y.Int()),
"should embed to a secp256k1 point")
output, err := p.Data()
require.NoError(t, err)
@ -94,8 +94,8 @@ func TestPoint_Embed(t *testing.T) {
}
func TestPoint_AddSubAndNeg(t *testing.T) {
zero := newPoint().Null()
p := newPoint()
zero := NewPoint().Null()
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
p.Pick(randomStreamPoint)
q := p.Clone()
@ -104,20 +104,20 @@ func TestPoint_AddSubAndNeg(t *testing.T) {
"subtracting a point from itself should give zero, "+
"got %v - %v = %v ≠ %v", q, q, p, zero)
p.Neg(q)
r := newPoint().Add(p, q)
r := NewPoint().Add(p, q)
require.True(t, r.Equal(zero),
"adding a point to its negative should give zero"+
" got %v+%v=%v≠%v", q, p, r, zero)
r.Neg(q)
p.Sub(q, r)
s := newPoint().Add(q, q)
s := NewPoint().Add(q, q)
require.True(t, p.Equal(s), "q-(-q)=q+q?"+
" got %v-%v=%v≠%v", q, r, p, s)
}
}
func TestPoint_Mul(t *testing.T) {
zero := newPoint().Null()
zero := NewPoint().Null()
multiplier := newScalar(bigZero)
one := newScalar(big.NewInt(int64(1)))
var p *secp256k1Point
@ -125,12 +125,12 @@ func TestPoint_Mul(t *testing.T) {
if i%20 == 0 {
p = nil // Test default to generator point
} else {
p = newPoint()
p = NewPoint()
p.Pick(randomStreamPoint)
}
multiplier.Pick(randomStreamPoint)
q := newPoint().Mul(one, p)
comparee := newPoint()
q := NewPoint().Mul(one, p)
comparee := NewPoint()
if p == (*secp256k1Point)(nil) {
comparee.Base()
} else {
@ -140,8 +140,8 @@ func TestPoint_Mul(t *testing.T) {
comparee, q)
q.Mul(multiplier, p)
negMultiplier := newScalar(bigZero).Neg(multiplier)
r := newPoint().Mul(negMultiplier, p)
s := newPoint().Add(q, r)
r := NewPoint().Mul(negMultiplier, p)
s := NewPoint().Add(q, r)
require.True(t, s.Equal(zero), "s*p+(-s)*p=0? got "+
"%v*%v + %v*%v = %v + %v = %v ≠ %v", multiplier, p,
)
@ -149,12 +149,12 @@ func TestPoint_Mul(t *testing.T) {
}
func TestPoint_Marshal(t *testing.T) {
p := newPoint()
p := NewPoint()
for i := 0; i < numPointSamples; i++ {
p.Pick(randomStreamPoint)
serialized, err := p.MarshalBinary()
require.Nil(t, err)
q := newPoint()
q := NewPoint()
err = q.UnmarshalBinary(serialized)
require.Nil(t, err)
require.True(t, p.Equal(q), "%v marshalled to %x, which "+
@ -186,9 +186,9 @@ func TestPoint_Marshal(t *testing.T) {
}
func TestPoint_BaseTakesCopy(t *testing.T) {
p := newPoint().Base()
p := NewPoint().Base()
p.Add(p, p)
q := newPoint().Base()
q := NewPoint().Base()
assert.False(t, p.Equal(q),
"modifying output from Base changes S256.G{x,y}")
}
@ -200,7 +200,7 @@ func TestPoint_EthereumAddress(t *testing.T) {
pInt, ok := big.NewInt(0).SetString(pString, 16)
require.True(t, ok, "failed to parse private key")
private := newScalar(pInt)
public := newPoint().Mul(private, nil)
public := NewPoint().Mul(private, nil)
address := EthereumAddress(public)
assert.Equal(t, fmt.Sprintf("%x", address),
"c2d7cf95645d33006175b78989035c7c9061d3f9")
@ -209,18 +209,18 @@ func TestPoint_EthereumAddress(t *testing.T) {
func TestIsSecp256k1Point(t *testing.T) {
p := curve25519.NewBlakeSHA256Curve25519(false).Point()
require.False(t, IsSecp256k1Point(p))
require.True(t, IsSecp256k1Point(newPoint()))
require.True(t, IsSecp256k1Point(NewPoint()))
}
func TestCoordinates(t *testing.T) {
x, y := Coordinates(newPoint())
x, y := Coordinates(NewPoint())
require.Equal(t, x, bigZero)
require.Equal(t, y, bigZero)
}
func TestValidPublicKey(t *testing.T) {
require.False(t, ValidPublicKey(newPoint()), "zero is not a valid key")
require.True(t, ValidPublicKey(newPoint().Base()))
require.False(t, ValidPublicKey(NewPoint()), "zero is not a valid key")
require.True(t, ValidPublicKey(NewPoint().Base()))
}
func TestGenerate(t *testing.T) {