Optimistic signature aggregation by leader

consensus/spos/bls/export_test.go

@@ -269,6 +269,10 @@ func (sr *subroundEndRound) DoEndRoundJobByParticipant(cnsDta *consensus.Message
 	return sr.doEndRoundJobByParticipant(cnsDta)
 }
 
+func (sr *subroundEndRound) DoEndRoundJobByLeader() bool {
+	return sr.doEndRoundJobByLeader()
+}
+
 func (sr *subroundEndRound) HaveConsensusHeaderWithFullInfo(cnsDta *consensus.Message) (bool, data.HeaderHandler) {
 	return sr.haveConsensusHeaderWithFullInfo(cnsDta)
 }
@@ -293,6 +297,16 @@ func (sr *subroundEndRound) IsOutOfTime() bool {
 	return sr.isOutOfTime()
 }
 
+func (sr *subroundEndRound) VerifyNodesOnAggSigVerificationFail(multiSigner crypto.MultiSigner) error {
+	return sr.verifyNodesOnAggSigVerificationFail(multiSigner)
+}
+
+func (sr *subroundEndRound) ComputeAggSigOnValidNodes(
+	multiSigner crypto.MultiSigner,
+) ([]byte, []byte, error) {
+	return sr.computeAggSigOnValidNodes(multiSigner)
+}
+
 // GetStringValue gets the name of the message type
 func GetStringValue(messageType consensus.MessageType) string {
 	return getStringValue(messageType)

consensus/spos/bls/subroundEndRound.go

@@ -11,6 +11,7 @@ import (
 	"github.com/ElrondNetwork/elrond-go-core/core/check"
 	"github.com/ElrondNetwork/elrond-go-core/data"
 	"github.com/ElrondNetwork/elrond-go-core/display"
+	crypto "github.com/ElrondNetwork/elrond-go-crypto"
 	"github.com/ElrondNetwork/elrond-go/common"
 	"github.com/ElrondNetwork/elrond-go/consensus"
 	"github.com/ElrondNetwork/elrond-go/consensus/spos"
@@ -197,6 +198,30 @@ func (sr *subroundEndRound) doEndRoundJobByLeader() bool {
 		return false
 	}
 
+	currentMultiSigner := sr.MultiSigner()
+	err = currentMultiSigner.SetAggregatedSig(sig)
+	if err != nil {
+		log.Debug("doEndRoundJobByLeader.SetAggregatedSig", "error", err.Error())
+		return false
+	}
+
+	err = currentMultiSigner.Verify(sr.GetData(), bitmap)
+	if err != nil {
+		log.Debug("doEndRoundJobByLeader.Verify", "error", err.Error())
+
+		err = sr.verifyNodesOnAggSigVerificationFail(currentMultiSigner)
+		if err != nil {
+			log.Debug("doEndRoundJobByLeader.verifyNodesOnAggSigVerificationFail", "error", err.Error())
+			return false
+		}
+
+		bitmap, sig, err = sr.computeAggSigOnValidNodes(currentMultiSigner)
+		if err != nil {
+			log.Debug("doEndRoundJobByLeader.computeAggSigOnValidNodes", "error", err.Error())
+			return false
+		}
+	}
+
 	err = sr.Header.SetPubKeysBitmap(bitmap)
 	if err != nil {
 		log.Debug("doEndRoundJobByLeader.SetPubKeysBitmap", "error", err.Error())
@@ -281,6 +306,77 @@ func (sr *subroundEndRound) doEndRoundJobByLeader() bool {
 	return true
 }
 
+// TODO:
+//	- slashing for invalid sig shares
+//	- handle sig share verifications concurrently
+func (sr *subroundEndRound) verifyNodesOnAggSigVerificationFail(
+	multiSigner crypto.MultiSigner,
+) error {
+	pubKeys := sr.ConsensusGroup()
+
+	for i, pk := range pubKeys {
+		isJobDone, err := sr.JobDone(pk, SrSignature)
+		if err != nil || !isJobDone {
+			continue
+		}
+
+		sigShare, err := multiSigner.SignatureShare(uint16(i))
+		if err != nil {
+			return err
+		}
+
+		isSuccessfull := true
+		err = multiSigner.VerifySignatureShare(uint16(i), sigShare, sr.GetData(), nil)
+		if err != nil {
+			isSuccessfull = false
+
+			err = sr.SetJobDone(pk, SrSignature, false)
+			if err != nil {
+				return err
+			}
+		}
+
+		log.Trace("verifyNodesOnAggSigVerificationFail: verifying signature share", "public key", pk, "is successfull", isSuccessfull)
+	}
+
+	return nil
+}
+
+func (sr *subroundEndRound) computeAggSigOnValidNodes(
+	multiSigner crypto.MultiSigner,
+) ([]byte, []byte, error) {
+	threshold := sr.Threshold(sr.Current())
+	numValidSigShares := sr.ComputeSize(SrSignature)
+
+	if numValidSigShares < threshold {
+		return nil, nil, fmt.Errorf("%w: number of valid sig shares lower than threshold, numSigShares: %d, threshold: %d",
+			spos.ErrInvalidNumSigShares, numValidSigShares, threshold)
+	}
+
+	bitmap := sr.GenerateBitmap(SrSignature)
+	err := sr.checkSignaturesValidity(bitmap)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	sig, err := multiSigner.AggregateSigs(bitmap)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	err = multiSigner.SetAggregatedSig(sig)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	err = multiSigner.Verify(sr.GetData(), bitmap)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return bitmap, sig, nil
+}
+
 func (sr *subroundEndRound) createAndBroadcastHeaderFinalInfo() {
 	cnsMsg := consensus.NewConsensusMessage(
 		sr.GetData(),