Bls (#105)

* bls signature for basic account

* benchmark for bls and ed25519

* added bls sig verify cost to genesis

* Revert "Merge branch 'fetchai:master' into bls"

This reverts commit a5dd8ea, reversing
changes made to 082e071.

* format using go tools

* nuisance golangci-lint errors

* POP interfaces in accounts and authentication

* add bls multsig operations

* fixed golangci-lint error

* changes after comments

crypto/keys/bls12381/bls12381.go

@@ -112,7 +112,7 @@ func GenPrivKey() *PrivKey {
 	return &PrivKey{Key: genPrivKey(crypto.CReader())}
 }
 
-// genPrivKey generates a new secp256k1 private key using the provided reader.
+// genPrivKey generates a new bls12381 private key using the provided reader.
 func genPrivKey(rand io.Reader) []byte {
 	var ikm [SeedSize]byte
 	_, err := io.ReadFull(rand, ikm[:])

crypto/keys/bls12381/multisig.go

@@ -0,0 +1,102 @@
+package bls12381
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	blst "github.com/supranational/blst/bindings/go"
+)
+
+func aggregatePublicKey(pks []*PubKey) (*blst.P1Affine, error) {
+	pubkeys := make([]*blst.P1Affine, len(pks))
+	for i, pk := range pks {
+		pubkeys[i] = new(blst.P1Affine).Deserialize(pk.Key)
+		if pubkeys[i] == nil {
+			return nil, fmt.Errorf("failed to deserialize public key")
+		}
+	}
+
+	aggregator := new(blst.P1Aggregate)
+	b := aggregator.Aggregate(pubkeys, false)
+	if !b {
+		return nil, fmt.Errorf("failed to aggregate public keys")
+	}
+	apk := aggregator.ToAffine()
+
+	return apk, nil
+}
+
+// AggregateSignature combines a set of verified signatures into a single bls signature
+func AggregateSignature(sigs [][]byte) ([]byte, error) {
+	sigmas := make([]*blst.P2Affine, len(sigs))
+	for i, sig := range sigs {
+		sigmas[i] = new(blst.P2Affine).Uncompress(sig)
+		if sigmas[i] == nil {
+			return nil, fmt.Errorf("failed to deserialize the %d-th signature", i)
+		}
+	}
+
+	aggregator := new(blst.P2Aggregate)
+	b := aggregator.Aggregate(sigmas, false)
+	if !b {
+		return nil, fmt.Errorf("failed to aggregate signatures")
+	}
+	aggSigBytes := aggregator.ToAffine().Compress()
+	return aggSigBytes, nil
+}
+
+// VerifyMultiSignature assumes public key is already validated
+func VerifyMultiSignature(msg []byte, sig []byte, pks []*PubKey) error {
+	return VerifyAggregateSignature([][]byte{msg}, sig, [][]*PubKey{pks})
+}
+
+func Unique(msgs [][]byte) bool {
+	if len(msgs) <= 1 {
+		return true
+	}
+	msgMap := make(map[string]bool, len(msgs))
+	for _, msg := range msgs {
+		s := base64.StdEncoding.EncodeToString(msg)
+		if _, ok := msgMap[s]; ok {
+			return false
+		}
+		msgMap[s] = true
+	}
+	return true
+}
+
+func VerifyAggregateSignature(msgs [][]byte, sig []byte, pkss [][]*PubKey) error {
+	n := len(msgs)
+	if n == 0 {
+		return fmt.Errorf("messages cannot be empty")
+	}
+
+	if len(pkss) != n {
+		return fmt.Errorf("the number of messages and public key sets must match")
+	}
+
+	if !Unique(msgs) {
+		return fmt.Errorf("messages must be pairwise distinct")
+	}
+
+	apks := make([]*blst.P1Affine, len(pkss))
+	for i, pks := range pkss {
+		apk, err := aggregatePublicKey(pks)
+		if err != nil {
+			return fmt.Errorf("cannot aggregate public keys: %s", err.Error())
+		}
+		apks[i] = apk
+	}
+
+	sigma := new(blst.P2Affine).Uncompress(sig)
+	if sigma == nil {
+		return fmt.Errorf("failed to deserialize signature")
+	}
+
+	dst := []byte("BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_POP_")
+	if !sigma.AggregateVerify(true, apks, false, msgs, dst) {
+		return fmt.Errorf("failed to verify signature")
+	}
+
+	return nil
+}

crypto/keys/bls12381/multisig_test.go

@@ -0,0 +1,124 @@
+package bls12381_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	bls "github.com/cosmos/cosmos-sdk/crypto/keys/bls12381"
+)
+
+func TestBlsMultiSig(t *testing.T) {
+	total := 5
+	pks := make([]*bls.PubKey, total)
+	sigs := make([][]byte, total)
+	msg := []byte("hello world")
+	for i := 0; i < total; i++ {
+		sk := bls.GenPrivKey()
+		pk, ok := sk.PubKey().(*bls.PubKey)
+		require.True(t, ok)
+
+		sig, err := sk.Sign(msg)
+		require.Nil(t, err)
+
+		pks[i] = pk
+		sigs[i] = sig
+	}
+
+	aggSig, err := bls.AggregateSignature(sigs)
+	require.Nil(t, err)
+
+	assert.Nil(t, bls.VerifyMultiSignature(msg, aggSig, pks))
+
+}
+
+func TestBlsAggSig(t *testing.T) {
+	total := 5
+	pks := make([][]*bls.PubKey, total)
+	sigs := make([][]byte, total)
+	msgs := make([][]byte, total)
+	for i := 0; i < total; i++ {
+		msgs[i] = []byte(fmt.Sprintf("message %d", i))
+		sk := bls.GenPrivKey()
+		pk, ok := sk.PubKey().(*bls.PubKey)
+		require.True(t, ok)
+
+		sig, err := sk.Sign(msgs[i])
+		require.Nil(t, err)
+
+		pks[i] = []*bls.PubKey{pk}
+		sigs[i] = sig
+	}
+
+	aggSig, err := bls.AggregateSignature(sigs)
+	require.Nil(t, err)
+
+	assert.Nil(t, bls.VerifyAggregateSignature(msgs, aggSig, pks))
+
+}
+
+func benchmarkBlsVerifyMulti(total int, b *testing.B) {
+	pks := make([]*bls.PubKey, total)
+	sigs := make([][]byte, total)
+	msg := []byte("hello world")
+	for i := 0; i < total; i++ {
+		sk := bls.GenPrivKey()
+		pk, ok := sk.PubKey().(*bls.PubKey)
+		require.True(b, ok)
+
+		sig, err := sk.Sign(msg)
+		require.Nil(b, err)
+
+		pks[i] = pk
+		sigs[i] = sig
+	}
+
+	aggSig, err := bls.AggregateSignature(sigs)
+	require.Nil(b, err)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bls.VerifyMultiSignature(msg, aggSig, pks)
+	}
+}
+
+func BenchmarkBlsVerifyMulti8(b *testing.B)   { benchmarkBlsVerifyMulti(8, b) }
+func BenchmarkBlsVerifyMulti16(b *testing.B)  { benchmarkBlsVerifyMulti(16, b) }
+func BenchmarkBlsVerifyMulti32(b *testing.B)  { benchmarkBlsVerifyMulti(32, b) }
+func BenchmarkBlsVerifyMulti64(b *testing.B)  { benchmarkBlsVerifyMulti(64, b) }
+func BenchmarkBlsVerifyMulti128(b *testing.B) { benchmarkBlsVerifyMulti(128, b) }
+
+func benchmarkBlsVerifyAgg(total int, b *testing.B) {
+	pks := make([][]*bls.PubKey, total)
+	sigs := make([][]byte, total)
+	msgs := make([][]byte, total)
+	for i := 0; i < total; i++ {
+		msgs[i] = []byte(fmt.Sprintf("message %d", i))
+		sk := bls.GenPrivKey()
+		pk, ok := sk.PubKey().(*bls.PubKey)
+		require.True(b, ok)
+
+		sig, err := sk.Sign(msgs[i])
+		require.Nil(b, err)
+
+		pks[i] = []*bls.PubKey{pk}
+		sigs[i] = sig
+	}
+
+	aggSig, err := bls.AggregateSignature(sigs)
+	require.Nil(b, err)
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		bls.VerifyAggregateSignature(msgs, aggSig, pks)
+	}
+}
+
+func BenchmarkBlsVerifyAgg8(b *testing.B)   { benchmarkBlsVerifyAgg(8, b) }
+func BenchmarkBlsVerifyAgg16(b *testing.B)  { benchmarkBlsVerifyAgg(16, b) }
+func BenchmarkBlsVerifyAgg32(b *testing.B)  { benchmarkBlsVerifyAgg(32, b) }
+func BenchmarkBlsVerifyAgg64(b *testing.B)  { benchmarkBlsVerifyAgg(64, b) }
+func BenchmarkBlsVerifyAgg128(b *testing.B) { benchmarkBlsVerifyAgg(128, b) }

docs/core/proto-docs.md

@@ -1147,6 +1147,7 @@ type for additional functionality (e.g. vesting).
 | `pub_key` | [google.protobuf.Any](#google.protobuf.Any) |  |  |
 | `account_number` | [uint64](#uint64) |  |  |
 | `sequence` | [uint64](#uint64) |  |  |
+| `pop_is_valid` | [bool](#bool) |  |  |
 
 
 

proto/cosmos/auth/v1beta1/auth.proto

@@ -23,6 +23,7 @@ message BaseAccount {
       [(gogoproto.jsontag) = "public_key,omitempty", (gogoproto.moretags) = "yaml:\"public_key\""];
   uint64 account_number = 3 [(gogoproto.moretags) = "yaml:\"account_number\""];
   uint64 sequence       = 4;
+  bool pop_is_valid     = 5;
 }
 
 // ModuleAccount defines an account for modules that holds coins on a pool.

types/errors/errors.go

@@ -134,6 +134,9 @@ var (
 	// supported.
 	ErrNotSupported = Register(RootCodespace, 37, "feature not supported")
 
+	// ErrInvalidPop to doc
+	ErrInvalidPop = Register(RootCodespace, 38, "invalid pop for public key")
+
 	// ErrPanic is only set when we recover from a panic, so we know to
 	// redact potentially sensitive system info
 	ErrPanic = Register(UndefinedCodespace, 111222, "panic")

x/auth/ante/ante.go

@@ -28,6 +28,7 @@ func NewAnteHandler(
 		NewDeductFeeDecorator(ak, bankKeeper),
 		NewSigGasConsumeDecorator(ak, sigGasConsumer),
 		NewSigVerificationDecorator(ak, signModeHandler),
+		NewSetPopValidDecorator(ak),
 		NewIncrementSequenceDecorator(ak),
 	)
 }

x/auth/ante/sigverify.go

@@ -318,6 +318,40 @@ func (svd SigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simul
 	return next(ctx, tx, simulate)
 }
 
+// SetPopValidDecorator handles the validation status of the proof-of-possession (POP) of an individual public key.
+// A valid transaction and signature can be viewed as a POP for the signer's public key.
+// POP is required when forming a compact multisig group in order to prevent rogue public key attacks.
+type SetPopValidDecorator struct {
+	ak AccountKeeper
+}
+
+func NewSetPopValidDecorator(ak AccountKeeper) SetPopValidDecorator {
+	return SetPopValidDecorator{
+		ak: ak,
+	}
+}
+
+func (spvd SetPopValidDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (sdk.Context, error) {
+	sigTx, ok := tx.(authsigning.SigVerifiableTx)
+	if !ok {
+		return ctx, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "invalid transaction type")
+	}
+
+	for _, addr := range sigTx.GetSigners() {
+		acc := spvd.ak.GetAccount(ctx, addr)
+		pk := acc.GetPubKey()
+
+		switch pk.(type) {
+		case *bls12381.PubKey, *secp256k1.PubKey, *ed25519.PubKey:
+			if err := acc.SetPopValid(true); err != nil {
+				return ctx, sdkerrors.Wrap(sdkerrors.ErrInvalidPop, err.Error())
+			}
+		}
+	}
+
+	return next(ctx, tx, simulate)
+}
+
 // IncrementSequenceDecorator handles incrementing sequences of all signers.
 // Use the IncrementSequenceDecorator decorator to prevent replay attacks. Note,
 // there is no need to execute IncrementSequenceDecorator on RecheckTX since

x/auth/types/account.go

@@ -32,6 +32,7 @@ func NewBaseAccount(address sdk.AccAddress, pubKey cryptotypes.PubKey, accountNu
 		Address:       address.String(),
 		AccountNumber: accountNumber,
 		Sequence:      sequence,
+		PopIsValid:    false,
 	}
 
 	err := acc.SetPubKey(pubKey)
@@ -117,6 +118,20 @@ func (acc *BaseAccount) SetSequence(seq uint64) error {
 	return nil
 }
 
+// SetPopValid - Implements sdk.AccountI.
+func (acc *BaseAccount) SetPopValid(isValid bool) error {
+	if acc.PubKey == nil {
+		return errors.New("public key is not set yet")
+	}
+	acc.PopIsValid = isValid
+	return nil
+}
+
+// GetPopValid - Implements sdk.AccountI.
+func (acc *BaseAccount) GetPopValid() bool {
+	return acc.PopIsValid
+}
+
 // Validate checks for errors on the account fields
 func (acc BaseAccount) Validate() error {
 	if acc.Address == "" || acc.PubKey == nil {
@@ -222,6 +237,11 @@ func (ma ModuleAccount) SetSequence(seq uint64) error {
 	return fmt.Errorf("not supported for module accounts")
 }
 
+// SetPopValid - Implements AccountI
+func (ma ModuleAccount) SetPopValid(isValid bool) error {
+	return fmt.Errorf("not supported for module accounts")
+}
+
 // Validate checks for errors on the account fields
 func (ma ModuleAccount) Validate() error {
 	if strings.TrimSpace(ma.Name) == "" {
@@ -324,6 +344,9 @@ type AccountI interface {
 	GetSequence() uint64
 	SetSequence(uint64) error
 
+	GetPopValid() bool
+	SetPopValid(bool) error
+
 	// Ensure that account implements stringer
 	String() string
 }