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

// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core 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-core 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-core library. If not, see
// <http://www.gnu.org/licenses/>.

package core

import (
    "testing"

    "github.com/stretchr/testify/suite"

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

type DKGTSIGProtocolTestSuite struct {
    suite.Suite

    nIDs    types.NodeIDs
    dkgIDs  map[types.NodeID]dkg.ID
    prvKeys map[types.NodeID]crypto.PrivateKey
}

type testDKGReceiver struct {
    s *DKGTSIGProtocolTestSuite

    prvKey         crypto.PrivateKey
    complaints     map[types.NodeID]*types.DKGComplaint
    mpk            *types.DKGMasterPublicKey
    prvShare       map[types.NodeID]*types.DKGPrivateShare
    antiComplaints map[types.NodeID]*types.DKGPrivateShare
}

func newTestDKGReceiver(
    s *DKGTSIGProtocolTestSuite, prvKey crypto.PrivateKey) *testDKGReceiver {
    return &testDKGReceiver{
        s:              s,
        prvKey:         prvKey,
        complaints:     make(map[types.NodeID]*types.DKGComplaint),
        prvShare:       make(map[types.NodeID]*types.DKGPrivateShare),
        antiComplaints: make(map[types.NodeID]*types.DKGPrivateShare),
    }
}

func (r *testDKGReceiver) ProposeDKGComplaint(complaint *types.DKGComplaint) {
    var err error
    complaint.Signature, err = r.prvKey.Sign(hashDKGComplaint(complaint))
    r.s.Require().NoError(err)
    r.complaints[complaint.PrivateShare.ProposerID] = complaint
}

func (r *testDKGReceiver) ProposeDKGMasterPublicKey(
    mpk *types.DKGMasterPublicKey) {
    var err error
    mpk.Signature, err = r.prvKey.Sign(hashDKGMasterPublicKey(mpk))
    r.s.Require().NoError(err)
    r.mpk = mpk
}

func (r *testDKGReceiver) ProposeDKGPrivateShare(
    prv *types.DKGPrivateShare) {
    var err error
    prv.Signature, err = r.prvKey.Sign(hashDKGPrivateShare(prv))
    r.s.Require().NoError(err)
    r.prvShare[prv.ReceiverID] = prv
}

func (r *testDKGReceiver) ProposeDKGAntiNackComplaint(
    prv *types.DKGPrivateShare) {
    var err error
    prv.Signature, err = r.prvKey.Sign(hashDKGPrivateShare(prv))
    r.s.Require().NoError(err)
    r.antiComplaints[prv.ReceiverID] = prv
}

func (s *DKGTSIGProtocolTestSuite) setupDKGParticipants(n int) {
    s.nIDs = make(types.NodeIDs, 0, n)
    s.prvKeys = make(map[types.NodeID]crypto.PrivateKey, 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.prvKeys[nID] = prvKey
        id := dkg.NewID(nID.Hash[:])
        ids = append(ids, id)
        s.dkgIDs[nID] = id
    }
}

func (s *DKGTSIGProtocolTestSuite) newProtocols(k, n int, round 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.prvKeys[nID])
        protocols[nID] = newDKGProtocol(
            nID,
            receivers[nID],
            round,
            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 := 3
    n := 10
    round := uint64(1)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

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

    msgHash := crypto.Keccak256Hash([]byte("🏖🍹"))
    tsig := newTSigProtocol(gpk, msgHash)
    for nID, shareSecret := range shareSecrets {
        psig := &types.DKGPartialSignature{
            ProposerID:       nID,
            Round:            round,
            Hash:             msgHash,
            PartialSignature: shareSecret.sign(msgHash),
        }
        var err error
        psig.Signature, err = s.prvKeys[nID].Sign(hashDKGPartialSignature(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) TestNackComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

    byzantineID := s.nIDs[0]

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(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(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)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

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

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

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

    // These messages are not valid.
    err = protocol.processPrivateShare(&types.DKGPrivateShare{
        ProposerID: types.NodeID{Hash: common.NewRandomHash()},
        ReceiverID: targetID,
        Round:      round,
    })
    s.Equal(ErrNotDKGParticipant, err)
    receivers[byzantineID].ProposeDKGPrivateShare(&types.DKGPrivateShare{
        ProposerID: byzantineID,
        ReceiverID: targetID,
        Round:      round,
    })
    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(&types.DKGPrivateShare{
        ProposerID:   byzantineID,
        ReceiverID:   targetID,
        Round:        round,
        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)
}

// TestAntiComplaint tests if a nack complaint is received,
// create an anti complaint.
func (s *DKGTSIGProtocolTestSuite) TestAntiComplaint() {
    k := 3
    n := 10
    round := uint64(1)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

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

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(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(
        []*types.DKGComplaint{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]*types.DKGComplaint)
    s.Require().NoError(protocols[targetID].processPrivateShare(antiComplaint))
    s.Len(receivers[targetID].complaints, 0)

    receivers[thirdPerson].complaints = make(map[types.NodeID]*types.DKGComplaint)
    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)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

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

    for _, receiver := range receivers {
        gov.AddDKGMasterPublicKey(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([]*types.DKGComplaint{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(
        []*types.DKGComplaint{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([]*types.DKGComplaint{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)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

    byzantineID := s.nIDs[0]

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

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

    gpk, err := NewDKGGroupPublicKey(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 := NewDKGGroupPublicKey(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 := NewDKGGroupPublicKey(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)
    gov, err := test.NewGovernance(5, 100)
    s.Require().NoError(err)

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

    byzantineID := s.nIDs[0]

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

    // DKG is fininished.
    gpk, err := NewDKGGroupPublicKey(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("🏖🍹"))
    tsig := newTSigProtocol(gpk, msgHash)
    byzantineID2 := s.nIDs[1]
    byzantineID3 := s.nIDs[2]
    for nID, shareSecret := range shareSecrets {
        psig := &types.DKGPartialSignature{
            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()
        }
        var err error
        psig.Signature, err = s.prvKeys[nID].Sign(hashDKGPartialSignature(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 TestDKGTSIGProtocol(t *testing.T) {
    suite.Run(t, new(DKGTSIGProtocolTestSuite))
}