path: root/core/dkg-tsig-protocol_test.go

// Copyright 2018 The dexon-consensus Authors
// This file is part of the dexon-consensus library.
//
// The dexon-consensus library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus library. If not, see
// <http://www.gnu.org/licenses/>.

package core

import (
    "testing"

    "github.com/stretchr/testify/suite"

    "github.com/dexon-foundation/dexon-consensus/common"
    "github.com/dexon-foundation/dexon-consensus/core/crypto"
    "github.com/dexon-foundation/dexon-consensus/core/crypto/dkg"
    "github.com/dexon-foundation/dexon-consensus/core/crypto/ecdsa"
    "github.com/dexon-foundation/dexon-consensus/core/test"
    "github.com/dexon-foundation/dexon-consensus/core/types"
    typesDKG "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
    "github.com/dexon-foundation/dexon-consensus/core/utils"
)

type DKGTSIGProtocolTestSuite struct {
    suite.Suite

    nIDs    types.NodeIDs
    dkgIDs  map[types.NodeID]dkg.ID
    signers map[types.NodeID]*utils.Signer
}

type testDKGReceiver struct {
    s *DKGTSIGProtocolTestSuite

    signer         *utils.Signer
    complaints     map[types.NodeID]*typesDKG.Complaint
    mpk            *typesDKG.MasterPublicKey
    prvShare       map[types.NodeID]*typesDKG.PrivateShare
    antiComplaints map[types.NodeID]*typesDKG.PrivateShare
    ready          []*typesDKG.MPKReady
    final          []*typesDKG.Finalize
}

func newTestDKGReceiver(s *DKGTSIGProtocolTestSuite,
    signer *utils.Signer) *testDKGReceiver {
    return &testDKGReceiver{
        s:              s,
        signer:         signer,
        complaints:     make(map[types.NodeID]*typesDKG.Complaint),
        prvShare:       make(map[types.NodeID]*typesDKG.PrivateShare),
        antiComplaints: make(map[types.NodeID]*typesDKG.PrivateShare),
    }
}

func (r *testDKGReceiver) ProposeDKGComplaint(complaint *typesDKG.Complaint) {
    complaint = test.CloneDKGComplaint(complaint)
    err := r.signer.SignDKGComplaint(complaint)
    r.s.Require().NoError(err)
    r.complaints[complaint.PrivateShare.ProposerID] = complaint
}

func (r *testDKGReceiver) ProposeDKGMasterPublicKey(
    mpk *typesDKG.MasterPublicKey) {
    mpk = test.CloneDKGMasterPublicKey(mpk)
    err := r.signer.SignDKGMasterPublicKey(mpk)
    r.s.Require().NoError(err)
    r.mpk = mpk
}

func (r *testDKGReceiver) ProposeDKGPrivateShare(
    prv *typesDKG.PrivateShare) {
    prv = test.CloneDKGPrivateShare(prv)
    err := r.signer.SignDKGPrivateShare(prv)
    r.s.Require().NoError(err)
    r.prvShare[prv.ReceiverID] = prv
}

func (r *testDKGReceiver) ProposeDKGAntiNackComplaint(
    prv *typesDKG.PrivateShare) {
    prv = test.CloneDKGPrivateShare(prv)
    err := r.signer.SignDKGPrivateShare(prv)
    r.s.Require().NoError(err)
    r.antiComplaints[prv.ReceiverID] = prv
}

func (r *testDKGReceiver) ProposeDKGMPKReady(ready *typesDKG.MPKReady) {
    r.ready = append(r.ready, ready)
}

func (r *testDKGReceiver) ProposeDKGFinalize(final *typesDKG.Finalize) {
    r.final = append(r.final, final)
}

func (s *DKGTSIGProtocolTestSuite) setupDKGParticipants(n int) {
    s.nIDs = make(types.NodeIDs, 0, n)
    s.signers = make(map[types.NodeID]*utils.Signer, n)
    s.dkgIDs = make(map[types.NodeID]dkg.ID)
    ids := make(dkg.IDs, 0, n)
    for i := 0; i < n; i++ {
        prvKey, err := ecdsa.NewPrivateKey()
        s.Require().NoError(err)
        nID := types.NewNodeID(prvKey.PublicKey())
        s.nIDs = append(s.nIDs, nID)
        s.signers[nID] = utils.NewSigner(prvKey)
        id := dkg.NewID(nID.Hash[:])
        ids = append(ids, id)
        s.dkgIDs[nID] = id
    }
}

func (s *DKGTSIGProtocolTestSuite) newGov(
    pubKeys []crypto.PublicKey,
    round, reset uint64) *test.Governance {
    // NOTE: this method doesn't make the tip round in governance to the input
    //       one.
    gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
        pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
    s.Require().NoError(err)
    for i := uint64(0); i < reset; i++ {
        s.Require().NoError(gov.State().RequestChange(test.StateResetDKG,
            common.NewRandomHash()))
    }
    s.Require().Equal(gov.DKGResetCount(round), reset)
    return gov
}

func (s *DKGTSIGProtocolTestSuite) newProtocols(k, n int, round, reset uint64) (
    map[types.NodeID]*testDKGReceiver, map[types.NodeID]*dkgProtocol) {
    s.setupDKGParticipants(n)

    receivers := make(map[types.NodeID]*testDKGReceiver, n)
    protocols := make(map[types.NodeID]*dkgProtocol, n)
    for _, nID := range s.nIDs {
        receivers[nID] = newTestDKGReceiver(s, s.signers[nID])
        protocols[nID] = newDKGProtocol(
            nID,
            receivers[nID],
            round,
            reset,
            k,
        )
        s.Require().NotNil(receivers[nID].mpk)
    }
    return receivers, protocols
}

// TestDKGTSIGProtocol will test the entire DKG+TISG protocol including
// exchanging private shares, recovering share secret, creating partial sign and
// recovering threshold signature.
// All participants are good people in this test.
func (s *DKGTSIGProtocolTestSuite) TestDKGTSIGProtocol() {
    k := 2
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    for _, receiver := range receivers {
        s.Require().Len(receiver.prvShare, n)
        for nID, prvShare := range receiver.prvShare {
            s.Require().NoError(protocols[nID].processPrivateShare(prvShare))
        }
    }

    for _, protocol := range protocols {
        protocol.proposeNackComplaints()
    }

    for _, recv := range receivers {
        s.Require().Len(recv.complaints, 0)
    }

    for _, receiver := range receivers {
        for _, complaint := range receiver.complaints {
            gov.AddDKGComplaint(round, complaint)
        }
    }

    for _, protocol := range protocols {
        s.Require().NoError(protocol.processNackComplaints(
            gov.DKGComplaints(round)))
    }

    for _, recv := range receivers {
        s.Require().Len(recv.antiComplaints, 0)
    }

    for _, protocol := range protocols {
        protocol.enforceNackComplaints(gov.DKGComplaints(round))
    }

    for _, recv := range receivers {
        s.Require().Len(recv.complaints, 0)
    }

    // DKG is fininished.
    gpk, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round),
        k)
    s.Require().NoError(err)
    s.Require().Len(gpk.QualifyIDs, n)
    qualifyIDs := make(map[dkg.ID]struct{}, len(gpk.QualifyIDs))
    for _, id := range gpk.QualifyIDs {
        qualifyIDs[id] = struct{}{}
    }

    for nID := range gpk.QualifyNodeIDs {
        id, exist := gpk.IDMap[nID]
        s.Require().True(exist)
        _, exist = qualifyIDs[id]
        s.Require().True(exist)
    }

    shareSecrets := make(
        map[types.NodeID]*dkgShareSecret, len(qualifyIDs))

    for nID, protocol := range protocols {
        _, exist := qualifyIDs[s.dkgIDs[nID]]
        s.Require().True(exist)
        var err error
        shareSecrets[nID], err = protocol.recoverShareSecret(gpk.QualifyIDs)
        s.Require().NoError(err)
    }

    npks, err := typesDKG.NewNodePublicKeys(round,
        gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round), k)
    s.Require().NoError(err)
    msgHash := crypto.Keccak256Hash([]byte("🏖🍹"))
    tsig := newTSigProtocol(npks, msgHash)
    for nID, shareSecret := range shareSecrets {
        psig := &typesDKG.PartialSignature{
            ProposerID:       nID,
            Round:            round,
            Hash:             msgHash,
            PartialSignature: shareSecret.sign(msgHash),
        }
        err := s.signers[nID].SignDKGPartialSignature(psig)
        s.Require().NoError(err)
        s.Require().NoError(tsig.processPartialSignature(psig))
        if len(tsig.sigs) >= k {
            break
        }
    }

    sig, err := tsig.signature()
    s.Require().NoError(err)
    s.True(gpk.VerifySignature(msgHash, sig))
}

func (s *DKGTSIGProtocolTestSuite) TestErrMPKRegistered() {
    k := 2
    n := 10
    round := uint64(1)
    reset := uint64(2)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)
    notRegisterID := s.nIDs[0]
    errRegisterID := s.nIDs[1]

    for ID, receiver := range receivers {
        if ID == notRegisterID {
            continue
        }
        if ID == errRegisterID {
            _, mpk := dkg.NewPrivateKeyShares(k)
            receiver.ProposeDKGMasterPublicKey(&typesDKG.MasterPublicKey{
                Round:           round,
                Reset:           reset,
                DKGID:           typesDKG.NewID(ID),
                PublicKeyShares: *mpk,
            })
        }
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for ID, protocol := range protocols {
        err := protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round))
        if ID == notRegisterID {
            s.Require().Equal(ErrSelfMPKNotRegister, err)
        } else if ID == errRegisterID {
            s.Require().Equal(ErrSelfPrvShareMismatch, err)
        } else {
            s.Require().NoError(err)
        }
    }

    for ID, receiver := range receivers {
        if ID == notRegisterID || ID == errRegisterID {
            continue
        }
        s.Require().Len(receiver.prvShare, n-1)
        for nID, prvShare := range receiver.prvShare {
            s.Require().NoError(protocols[nID].processPrivateShare(prvShare))
        }
    }

    for ID, protocol := range protocols {
        if ID == notRegisterID {
            continue
        }
        protocol.proposeNackComplaints()
    }

    for ID, recv := range receivers {
        if ID == notRegisterID || ID == errRegisterID {
            continue
        }
        s.Require().Len(recv.complaints, 1)
        for _, complaint := range recv.complaints {
            s.Require().True(complaint.IsNack())
            s.Require().Equal(errRegisterID, complaint.PrivateShare.ProposerID)
        }
    }

    for _, receiver := range receivers {
        for _, complaint := range receiver.complaints {
            gov.AddDKGComplaint(round, complaint)
        }
    }

    s.Require().Len(gov.DKGComplaints(round), n-1)

    for ID, protocol := range protocols {
        err := protocol.processNackComplaints(gov.DKGComplaints(round))
        if ID == notRegisterID {
            s.Require().Equal(ErrSelfMPKNotRegister, err)
        } else if ID == errRegisterID {
            s.Require().Equal(ErrSelfPrvShareMismatch, err)
        } else {
            s.Require().NoError(err)
        }
    }

    for _, recv := range receivers {
        s.Require().Len(recv.antiComplaints, 0)
    }

    for _, protocol := range protocols {
        protocol.enforceNackComplaints(gov.DKGComplaints(round))
    }

    for ID, recv := range receivers {
        if ID == notRegisterID || ID == errRegisterID {
            continue
        }
        s.Require().Len(recv.complaints, 1)
        for _, complaint := range recv.complaints {
            s.Require().True(complaint.IsNack())
            s.Require().Equal(errRegisterID, complaint.PrivateShare.ProposerID)
        }
    }

    // DKG is fininished.
    gpk, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round),
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk.QualifyIDs, n-2)
    qualifyIDs := make(map[dkg.ID]struct{}, len(gpk.QualifyIDs))
    for _, id := range gpk.QualifyIDs {
        qualifyIDs[id] = struct{}{}
    }

    for nID := range gpk.QualifyNodeIDs {
        if nID == notRegisterID || nID == errRegisterID {
            continue
        }
        id, exist := gpk.IDMap[nID]
        s.Require().True(exist)
        _, exist = qualifyIDs[id]
        s.Require().True(exist)
    }

}

func (s *DKGTSIGProtocolTestSuite) TestNackComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    for senderID, receiver := range receivers {
        s.Require().Len(receiver.prvShare, n)
        if senderID == byzantineID {
            continue
        }
        for nID, prvShare := range receiver.prvShare {
            s.Require().NoError(protocols[nID].processPrivateShare(prvShare))
        }
    }

    for _, protocol := range protocols {
        protocol.proposeNackComplaints()
    }

    for _, recv := range receivers {
        complaint, exist := recv.complaints[byzantineID]
        s.True(complaint.IsNack())
        s.Require().True(exist)
        s.True(utils.VerifyDKGComplaintSignature(complaint))
    }
}

// TestComplaint tests if the received private share is not valid, a complaint
// should be proposed.
func (s *DKGTSIGProtocolTestSuite) TestComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]
    targetID := s.nIDs[1]
    receiver := receivers[targetID]
    protocol := protocols[targetID]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    // These messages are not valid.
    err = protocol.processPrivateShare(&typesDKG.PrivateShare{
        ProposerID: types.NodeID{Hash: common.NewRandomHash()},
        ReceiverID: targetID,
        Round:      round,
        Reset:      reset,
    })
    s.Equal(ErrNotDKGParticipant, err)
    receivers[byzantineID].ProposeDKGPrivateShare(&typesDKG.PrivateShare{
        ProposerID: byzantineID,
        ReceiverID: targetID,
        Round:      round,
        Reset:      reset,
    })
    invalidShare := receivers[byzantineID].prvShare[targetID]
    invalidShare.ReceiverID = s.nIDs[2]
    err = protocol.processPrivateShare(invalidShare)
    s.Equal(ErrIncorrectPrivateShareSignature, err)
    delete(receivers[byzantineID].prvShare, targetID)

    // Byzantine node is sending incorrect private share.
    receivers[byzantineID].ProposeDKGPrivateShare(&typesDKG.PrivateShare{
        ProposerID:   byzantineID,
        ReceiverID:   targetID,
        Round:        round,
        Reset:        reset,
        PrivateShare: *dkg.NewPrivateKey(),
    })
    invalidShare = receivers[byzantineID].prvShare[targetID]
    s.Require().NoError(protocol.processPrivateShare(invalidShare))
    s.Require().Len(receiver.complaints, 1)
    complaint, exist := receiver.complaints[byzantineID]
    s.True(exist)
    s.Equal(byzantineID, complaint.PrivateShare.ProposerID)

    // Sending the incorrect private share again should not complain.
    delete(receiver.complaints, byzantineID)
    s.Require().NoError(protocol.processPrivateShare(invalidShare))
    s.Len(receiver.complaints, 0)
}

// TestDuplicateComplaint tests if the duplicated complaint is process properly.
func (s *DKGTSIGProtocolTestSuite) TestDuplicateComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, _ := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]
    victomID := s.nIDs[1]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    // Test for nack complaints.
    complaints := make([]*typesDKG.Complaint, k+1)
    for i := range complaints {
        complaints[i] = &typesDKG.Complaint{
            ProposerID: byzantineID,
            Round:      round,
            Reset:      reset,
            PrivateShare: typesDKG.PrivateShare{
                ProposerID: victomID,
                Round:      round,
                Reset:      reset,
            },
        }
        s.Require().True(complaints[i].IsNack())
    }

    gpk, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), complaints,
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk.QualifyIDs, n)
}

// TestAntiComplaint tests if a nack complaint is received,
// create an anti complaint.
func (s *DKGTSIGProtocolTestSuite) TestAntiComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]
    targetID := s.nIDs[1]
    thirdPerson := s.nIDs[2]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    // Creating Nack complaint.
    protocols[targetID].proposeNackComplaints()
    protocols[thirdPerson].proposeNackComplaints()
    complaint, exist := receivers[targetID].complaints[byzantineID]
    s.Require().True(exist)
    s.Require().True(complaint.IsNack())
    s.Require().Equal(byzantineID, complaint.PrivateShare.ProposerID)

    complaint2, exist := receivers[thirdPerson].complaints[byzantineID]
    s.Require().True(exist)
    s.Require().True(complaint2.IsNack())
    s.Require().Equal(byzantineID, complaint2.PrivateShare.ProposerID)

    // Creating an anti-nack complaint.
    err = protocols[byzantineID].processNackComplaints(
        []*typesDKG.Complaint{complaint})
    s.Require().NoError(err)
    s.Require().Len(receivers[byzantineID].antiComplaints, 1)
    antiComplaint, exist := receivers[byzantineID].antiComplaints[targetID]
    s.Require().True(exist)
    s.Require().Equal(targetID, antiComplaint.ReceiverID)

    // The anti-complaint should be successfully verified by all others.
    receivers[targetID].complaints = make(map[types.NodeID]*typesDKG.Complaint)
    s.Require().NoError(protocols[targetID].processPrivateShare(antiComplaint))
    s.Len(receivers[targetID].complaints, 0)

    receivers[thirdPerson].complaints = make(map[types.NodeID]*typesDKG.Complaint)
    s.Require().NoError(protocols[thirdPerson].processPrivateShare(antiComplaint))
    s.Len(receivers[thirdPerson].complaints, 0)
}

// TestEncorceNackComplaint tests if the nack complaint is enforced properly.
func (s *DKGTSIGProtocolTestSuite) TestEncorceNackComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]
    targetID := s.nIDs[1]
    thirdPerson := s.nIDs[2]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    // Creating nack complaint.
    protocols[targetID].proposeNackComplaints()
    complaint, exist := receivers[targetID].complaints[byzantineID]
    s.Require().True(exist)
    s.Require().True(complaint.IsNack())
    s.Require().Equal(byzantineID, complaint.PrivateShare.ProposerID)

    // Encorce nack complaint.
    protocols[thirdPerson].enforceNackComplaints([]*typesDKG.Complaint{complaint})
    complaint2, exist := receivers[thirdPerson].complaints[byzantineID]
    s.Require().True(exist)
    s.Require().True(complaint2.IsNack())
    s.Require().Equal(byzantineID, complaint2.PrivateShare.ProposerID)

    // Received valid private share, do not enforce nack complaint.
    delete(receivers[thirdPerson].complaints, byzantineID)
    err = protocols[byzantineID].processNackComplaints(
        []*typesDKG.Complaint{complaint})
    s.Require().NoError(err)
    antiComplaint, exist := receivers[byzantineID].antiComplaints[targetID]
    s.Require().True(exist)
    s.Require().Equal(targetID, antiComplaint.ReceiverID)
    s.Require().NoError(protocols[thirdPerson].processPrivateShare(antiComplaint))
    protocols[thirdPerson].enforceNackComplaints([]*typesDKG.Complaint{complaint})
    _, exist = receivers[thirdPerson].complaints[byzantineID]
    s.Require().False(exist)
}

// TestQualifyIDs tests if there is a id with t+1 nack complaints
// or a complaint, it should not be in the qualifyIDs.
func (s *DKGTSIGProtocolTestSuite) TestQualifyIDs() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, _ := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    // Test for nack complaints.
    complaints := make([]*typesDKG.Complaint, k+1)
    for i := range complaints {
        nID := s.nIDs[i]
        complaints[i] = &typesDKG.Complaint{
            ProposerID: nID,
            Round:      round,
            Reset:      reset,
            PrivateShare: typesDKG.PrivateShare{
                ProposerID: byzantineID,
                Round:      round,
                Reset:      reset,
            },
        }
        s.Require().True(complaints[i].IsNack())
    }

    gpk, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), complaints,
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk.QualifyIDs, n-1)
    for _, id := range gpk.QualifyIDs {
        s.NotEqual(id, byzantineID)
    }

    gpk2, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), complaints[:k],
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk2.QualifyIDs, n)

    // Test for complaint.
    complaints[0].PrivateShare.Signature = crypto.Signature{Signature: []byte{0}}
    s.Require().False(complaints[0].IsNack())
    gpk3, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), complaints[:1],
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk3.QualifyIDs, n-1)
    for _, id := range gpk3.QualifyIDs {
        s.NotEqual(id, byzantineID)
    }
}

// TestPartialSignature tests if tsigProtocol can handle incorrect partial
// signature and report error.
func (s *DKGTSIGProtocolTestSuite) TestPartialSignature() {
    k := 3
    n := 10
    round := uint64(1)
    reset := uint64(3)
    _, pubKeys, err := test.NewKeys(5)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)

    receivers, protocols := s.newProtocols(k, n, round, reset)

    byzantineID := s.nIDs[0]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(round, receiver.mpk)
    }

    for _, protocol := range protocols {
        s.Require().NoError(
            protocol.processMasterPublicKeys(gov.DKGMasterPublicKeys(round)))
    }

    for senderID, receiver := range receivers {
        s.Require().Len(receiver.prvShare, n)
        if senderID == byzantineID {
            continue
        }
        for nID, prvShare := range receiver.prvShare {
            s.Require().NoError(protocols[nID].processPrivateShare(prvShare))
        }
    }

    for _, protocol := range protocols {
        protocol.proposeNackComplaints()
    }

    for _, recv := range receivers {
        s.Require().Len(recv.complaints, 1)
        complaint, exist := recv.complaints[byzantineID]
        s.Require().True(exist)
        gov.AddDKGComplaint(round, complaint)
    }

    // DKG is fininished.
    gpk, err := typesDKG.NewGroupPublicKey(round,
        gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round),
        k,
    )
    s.Require().NoError(err)
    s.Require().Len(gpk.QualifyIDs, n-1)
    qualifyIDs := make(map[dkg.ID]struct{}, len(gpk.QualifyIDs))
    for _, id := range gpk.QualifyIDs {
        qualifyIDs[id] = struct{}{}
    }

    shareSecrets := make(
        map[types.NodeID]*dkgShareSecret, len(qualifyIDs))

    for nID, protocol := range protocols {
        _, exist := qualifyIDs[s.dkgIDs[nID]]
        if nID == byzantineID {
            exist = !exist
        }
        s.Require().True(exist)
        var err error
        shareSecrets[nID], err = protocol.recoverShareSecret(gpk.QualifyIDs)
        s.Require().NoError(err)
    }

    msgHash := crypto.Keccak256Hash([]byte("🏖🍹"))
    npks, err := typesDKG.NewNodePublicKeys(round,
        gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round), k)
    s.Require().NoError(err)
    tsig := newTSigProtocol(npks, msgHash)
    byzantineID2 := s.nIDs[1]
    byzantineID3 := s.nIDs[2]
    for nID, shareSecret := range shareSecrets {
        psig := &typesDKG.PartialSignature{
            ProposerID:       nID,
            Round:            round,
            Hash:             msgHash,
            PartialSignature: shareSecret.sign(msgHash),
        }
        switch nID {
        case byzantineID2:
            psig.PartialSignature = shareSecret.sign(
                crypto.Keccak256Hash([]byte("💣")))
        case byzantineID3:
            psig.Hash = common.NewRandomHash()
        }
        err := s.signers[nID].SignDKGPartialSignature(psig)
        s.Require().NoError(err)
        err = tsig.processPartialSignature(psig)
        switch nID {
        case byzantineID:
            s.Require().Equal(ErrNotQualifyDKGParticipant, err)
        case byzantineID2:
            s.Require().Equal(ErrIncorrectPartialSignature, err)
        case byzantineID3:
            s.Require().Equal(ErrMismatchPartialSignatureHash, err)
        default:
            s.Require().NoError(err)
        }
    }

    sig, err := tsig.signature()
    s.Require().NoError(err)
    s.True(gpk.VerifySignature(msgHash, sig))
}

func (s *DKGTSIGProtocolTestSuite) TestProposeReady() {
    prvKey, err := ecdsa.NewPrivateKey()
    s.Require().NoError(err)
    recv := newTestDKGReceiver(s, utils.NewSigner(prvKey))
    nID := types.NewNodeID(prvKey.PublicKey())
    protocol := newDKGProtocol(nID, recv, 1, 3, 2)
    protocol.proposeMPKReady()
    s.Require().Len(recv.ready, 1)
    ready := recv.ready[0]
    s.Equal(&typesDKG.MPKReady{
        ProposerID: nID,
        Round:      1,
        Reset:      3,
    }, ready)
}

func (s *DKGTSIGProtocolTestSuite) TestProposeFinalize() {
    prvKey, err := ecdsa.NewPrivateKey()
    s.Require().NoError(err)
    recv := newTestDKGReceiver(s, utils.NewSigner(prvKey))
    nID := types.NewNodeID(prvKey.PublicKey())
    protocol := newDKGProtocol(nID, recv, 1, 3, 2)
    protocol.proposeFinalize()
    s.Require().Len(recv.final, 1)
    final := recv.final[0]
    s.Equal(&typesDKG.Finalize{
        ProposerID: nID,
        Round:      1,
        Reset:      3,
    }, final)
}

func (s *DKGTSIGProtocolTestSuite) TestTSigVerifierCache() {
    k := 3
    n := 10
    round := uint64(10)
    reset := uint64(0)
    _, pubKeys, err := test.NewKeys(n)
    s.Require().NoError(err)
    gov := s.newGov(pubKeys, round, reset)
    gov.CatchUpWithRound(round)
    for i := 0; i < 10; i++ {
        round := uint64(i + 1)
        receivers, protocols := s.newProtocols(k, n, round, reset)

        for _, receiver := range receivers {
            gov.AddDKGMasterPublicKey(round, receiver.mpk)
        }

        for _, protocol := range protocols {
            protocol.proposeMPKReady()
        }
        for _, recv := range receivers {
            s.Require().Len(recv.ready, 1)
            gov.AddDKGMPKReady(recv.ready[0].Round, recv.ready[0])
        }
        s.Require().True(gov.IsDKGMPKReady(round))

        for _, protocol := range protocols {
            protocol.proposeFinalize()
        }

        for _, recv := range receivers {
            s.Require().Len(recv.final, 1)
            gov.AddDKGFinalize(recv.final[0].Round, recv.final[0])
        }
        s.Require().True(gov.IsDKGFinal(round))
    }

    cache := NewTSigVerifierCache(gov, 3)
    for i := 0; i < 5; i++ {
        round := uint64(i + 1)
        ok, err := cache.Update(round)
        s.Require().NoError(err)
        s.True(ok)
    }
    s.Len(cache.verifier, 3)

    for i := 0; i < 2; i++ {
        round := uint64(i + 1)
        _, exist := cache.Get(round)
        s.False(exist)
    }

    for i := 3; i < 5; i++ {
        round := uint64(i + 1)
        _, exist := cache.Get(round)
        s.True(exist)
    }

    ok, err := cache.Update(uint64(1))
    s.Require().Equal(ErrRoundAlreadyPurged, err)

    cache.Delete(uint64(5))
    s.Len(cache.verifier, 2)
    _, exist := cache.Get(uint64(5))
    s.False(exist)

    cache = NewTSigVerifierCache(gov, 1)
    ok, err = cache.Update(uint64(3))
    s.Require().NoError(err)
    s.Require().True(ok)
    s.Equal(uint64(3), cache.minRound)

    ok, err = cache.Update(uint64(5))
    s.Require().NoError(err)
    s.Require().True(ok)
    s.Equal(uint64(5), cache.minRound)

}

func (s *DKGTSIGProtocolTestSuite) TestUnexpectedDKGResetCount() {
    // MPKs and private shares from unexpected reset count should be ignored.
    k := 2
    n := 10
    round := uint64(1)
    reset := uint64(3)
    receivers, protocols := s.newProtocols(k, n, round, reset)
    var sourceID, targetID types.NodeID
    for sourceID = range receivers {
        break
    }
    for targetID = range receivers {
        break
    }
    // Test private share
    s.Require().NoError(protocols[targetID].processMasterPublicKeys(
        []*typesDKG.MasterPublicKey{
            receivers[targetID].mpk,
            receivers[sourceID].mpk}))
    receivers[sourceID].ProposeDKGPrivateShare(&typesDKG.PrivateShare{
        ProposerID:   sourceID,
        ReceiverID:   targetID,
        Round:        round,
        Reset:        reset + 1,
        PrivateShare: *dkg.NewPrivateKey(),
    })
    err := protocols[targetID].processPrivateShare(
        receivers[sourceID].prvShare[targetID])
    s.Require().IsType(ErrUnexpectedDKGResetCount{}, err)
    // Test MPK.
    _, mpk := dkg.NewPrivateKeyShares(k)
    receivers[sourceID].ProposeDKGMasterPublicKey(&typesDKG.MasterPublicKey{
        Round:           round,
        Reset:           reset + 1,
        DKGID:           typesDKG.NewID(sourceID),
        PublicKeyShares: *mpk,
    })
    err = protocols[sourceID].processMasterPublicKeys(
        []*typesDKG.MasterPublicKey{receivers[sourceID].mpk})
    s.Require().IsType(ErrUnexpectedDKGResetCount{}, err)
}

func TestDKGTSIGProtocol(t *testing.T) {
    suite.Run(t, new(DKGTSIGProtocolTestSuite))
}

func BenchmarkGPK4_7(b *testing.B)    { benchmarkDKGGroupPubliKey(4, 7, b) }
func BenchmarkGPK9_13(b *testing.B)   { benchmarkDKGGroupPubliKey(9, 13, b) }
func BenchmarkGPK17_24(b *testing.B)  { benchmarkDKGGroupPubliKey(17, 24, b) }
func BenchmarkGPK81_121(b *testing.B) { benchmarkDKGGroupPubliKey(81, 121, b) }

func benchmarkDKGGroupPubliKey(k, n int, b *testing.B) {
    round := uint64(1)
    reset := uint64(0)
    _, pubKeys, err := test.NewKeys(n)
    if err != nil {
        panic(err)
    }
    gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
        pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
    if err != nil {
        panic(err)
    }

    for _, pk := range pubKeys {
        _, pubShare := dkg.NewPrivateKeyShares(k)
        gov.AddDKGMasterPublicKey(round, &typesDKG.MasterPublicKey{
            ProposerID:      types.NewNodeID(pk),
            Round:           round,
            Reset:           reset,
            DKGID:           typesDKG.NewID(types.NewNodeID(pk)),
            PublicKeyShares: *pubShare,
        })
    }

    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        // DKG is fininished.
        gpk, err := typesDKG.NewGroupPublicKey(round,
            gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round),
            k,
        )
        if err != nil {
            panic(err)
        }
        if len(gpk.QualifyIDs) != n {
            panic("not enough of qualify id")
        }
    }
}

func BenchmarkNPKs4_7(b *testing.B)    { benchmarkDKGNodePubliKeys(4, 7, b) }
func BenchmarkNPKs9_13(b *testing.B)   { benchmarkDKGNodePubliKeys(9, 13, b) }
func BenchmarkNPKs17_24(b *testing.B)  { benchmarkDKGNodePubliKeys(17, 24, b) }
func BenchmarkNPKs81_121(b *testing.B) { benchmarkDKGNodePubliKeys(81, 121, b) }

func benchmarkDKGNodePubliKeys(k, n int, b *testing.B) {
    round := uint64(1)
    reset := uint64(0)
    _, pubKeys, err := test.NewKeys(n)
    if err != nil {
        panic(err)
    }
    gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
        pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
    if err != nil {
        panic(err)
    }

    for _, pk := range pubKeys {
        _, pubShare := dkg.NewPrivateKeyShares(k)
        gov.AddDKGMasterPublicKey(round, &typesDKG.MasterPublicKey{
            ProposerID:      types.NewNodeID(pk),
            Round:           round,
            Reset:           reset,
            DKGID:           typesDKG.NewID(types.NewNodeID(pk)),
            PublicKeyShares: *pubShare,
        })
    }

    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        // DKG is fininished.
        npks, err := typesDKG.NewNodePublicKeys(round,
            gov.DKGMasterPublicKeys(round), gov.DKGComplaints(round),
            k,
        )
        if err != nil {
            panic(err)
        }
        if len(npks.QualifyIDs) != n {
            panic("not enough of qualify id")
        }
    }
}