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// 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 dkg
import (
"bytes"
"encoding/json"
"fmt"
"io"
"github.com/dexon-foundation/dexon/rlp"
"github.com/dexon-foundation/dexon-consensus/common"
"github.com/dexon-foundation/dexon-consensus/core/crypto"
cryptoDKG "github.com/dexon-foundation/dexon-consensus/core/crypto/dkg"
"github.com/dexon-foundation/dexon-consensus/core/types"
)
// Errors for typesDKG package.
var (
ErrNotReachThreshold = fmt.Errorf("threshold not reach")
ErrInvalidThreshold = fmt.Errorf("invalid threshold")
)
// NewID creates a DKGID from NodeID.
func NewID(ID types.NodeID) cryptoDKG.ID {
return cryptoDKG.NewID(ID.Hash[:])
}
// PrivateShare describe a secret share in DKG protocol.
type PrivateShare struct {
ProposerID types.NodeID `json:"proposer_id"`
ReceiverID types.NodeID `json:"receiver_id"`
Round uint64 `json:"round"`
Reset uint64 `json:"reset"`
PrivateShare cryptoDKG.PrivateKey `json:"private_share"`
Signature crypto.Signature `json:"signature"`
}
// Equal checks equality between two PrivateShare instances.
func (p *PrivateShare) Equal(other *PrivateShare) bool {
return p.ProposerID.Equal(other.ProposerID) &&
p.ReceiverID.Equal(other.ReceiverID) &&
p.Round == other.Round &&
p.Reset == other.Reset &&
p.Signature.Type == other.Signature.Type &&
bytes.Compare(p.Signature.Signature, other.Signature.Signature) == 0 &&
bytes.Compare(
p.PrivateShare.Bytes(), other.PrivateShare.Bytes()) == 0
}
// MasterPublicKey decrtibe a master public key in DKG protocol.
type MasterPublicKey struct {
ProposerID types.NodeID `json:"proposer_id"`
Round uint64 `json:"round"`
Reset uint64 `json:"reset"`
DKGID cryptoDKG.ID `json:"dkg_id"`
PublicKeyShares cryptoDKG.PublicKeyShares `json:"public_key_shares"`
Signature crypto.Signature `json:"signature"`
}
func (d *MasterPublicKey) String() string {
return fmt.Sprintf("MasterPublicKey{KP:%s Round:%d Reset:%d}",
d.ProposerID.String()[:6],
d.Round,
d.Reset)
}
// Equal check equality of two DKG master public keys.
func (d *MasterPublicKey) Equal(other *MasterPublicKey) bool {
return d.ProposerID.Equal(other.ProposerID) &&
d.Round == other.Round &&
d.Reset == other.Reset &&
d.DKGID.GetHexString() == other.DKGID.GetHexString() &&
d.PublicKeyShares.Equal(&other.PublicKeyShares) &&
d.Signature.Type == other.Signature.Type &&
bytes.Compare(d.Signature.Signature, other.Signature.Signature) == 0
}
type rlpMasterPublicKey struct {
ProposerID types.NodeID
Round uint64
Reset uint64
DKGID []byte
PublicKeyShares *cryptoDKG.PublicKeyShares
Signature crypto.Signature
}
// EncodeRLP implements rlp.Encoder
func (d *MasterPublicKey) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, rlpMasterPublicKey{
ProposerID: d.ProposerID,
Round: d.Round,
Reset: d.Reset,
DKGID: d.DKGID.GetLittleEndian(),
PublicKeyShares: &d.PublicKeyShares,
Signature: d.Signature,
})
}
// DecodeRLP implements rlp.Decoder
func (d *MasterPublicKey) DecodeRLP(s *rlp.Stream) error {
var dec rlpMasterPublicKey
if err := s.Decode(&dec); err != nil {
return err
}
id, err := cryptoDKG.BytesID(dec.DKGID)
if err != nil {
return err
}
*d = MasterPublicKey{
ProposerID: dec.ProposerID,
Round: dec.Round,
Reset: dec.Reset,
DKGID: id,
PublicKeyShares: *dec.PublicKeyShares.Move(),
Signature: dec.Signature,
}
return err
}
// NewMasterPublicKey returns a new MasterPublicKey instance.
func NewMasterPublicKey() *MasterPublicKey {
return &MasterPublicKey{
PublicKeyShares: *cryptoDKG.NewEmptyPublicKeyShares(),
}
}
// UnmarshalJSON implements json.Unmarshaller.
func (d *MasterPublicKey) UnmarshalJSON(data []byte) error {
type innertMasterPublicKey MasterPublicKey
d.PublicKeyShares = *cryptoDKG.NewEmptyPublicKeyShares()
return json.Unmarshal(data, (*innertMasterPublicKey)(d))
}
// Complaint describe a complaint in DKG protocol.
type Complaint struct {
ProposerID types.NodeID `json:"proposer_id"`
Round uint64 `json:"round"`
Reset uint64 `json:"reset"`
PrivateShare PrivateShare `json:"private_share"`
Signature crypto.Signature `json:"signature"`
}
func (c *Complaint) String() string {
if c.IsNack() {
return fmt.Sprintf("DKGNackComplaint{CP:%s Round:%d Reset %d PSP:%s}",
c.ProposerID.String()[:6], c.Round, c.Reset,
c.PrivateShare.ProposerID.String()[:6])
}
return fmt.Sprintf("DKGComplaint{CP:%s Round:%d Reset %d PrivateShare:%v}",
c.ProposerID.String()[:6], c.Round, c.Reset, c.PrivateShare)
}
// Equal checks equality between two Complaint instances.
func (c *Complaint) Equal(other *Complaint) bool {
return c.ProposerID.Equal(other.ProposerID) &&
c.Round == other.Round &&
c.Reset == other.Reset &&
c.PrivateShare.Equal(&other.PrivateShare) &&
c.Signature.Type == other.Signature.Type &&
bytes.Compare(c.Signature.Signature, other.Signature.Signature) == 0
}
type rlpComplaint struct {
ProposerID types.NodeID
Round uint64
Reset uint64
IsNack bool
PrivateShare []byte
Signature crypto.Signature
}
// EncodeRLP implements rlp.Encoder
func (c *Complaint) EncodeRLP(w io.Writer) error {
if c.IsNack() {
return rlp.Encode(w, rlpComplaint{
ProposerID: c.ProposerID,
Round: c.Round,
Reset: c.Reset,
IsNack: true,
PrivateShare: c.PrivateShare.ProposerID.Hash[:],
Signature: c.Signature,
})
}
prvShare, err := rlp.EncodeToBytes(&c.PrivateShare)
if err != nil {
return err
}
return rlp.Encode(w, rlpComplaint{
ProposerID: c.ProposerID,
Round: c.Round,
Reset: c.Reset,
IsNack: false,
PrivateShare: prvShare,
Signature: c.Signature,
})
}
// DecodeRLP implements rlp.Decoder
func (c *Complaint) DecodeRLP(s *rlp.Stream) error {
var dec rlpComplaint
if err := s.Decode(&dec); err != nil {
return err
}
var prvShare PrivateShare
if dec.IsNack {
copy(prvShare.ProposerID.Hash[:], dec.PrivateShare)
prvShare.Round = dec.Round
prvShare.Reset = dec.Reset
} else {
if err := rlp.DecodeBytes(dec.PrivateShare, &prvShare); err != nil {
return err
}
}
*c = Complaint{
ProposerID: dec.ProposerID,
Round: dec.Round,
Reset: dec.Reset,
PrivateShare: prvShare,
Signature: dec.Signature,
}
return nil
}
// PartialSignature describe a partial signature in DKG protocol.
type PartialSignature struct {
ProposerID types.NodeID `json:"proposer_id"`
Round uint64 `json:"round"`
Hash common.Hash `json:"hash"`
PartialSignature cryptoDKG.PartialSignature `json:"partial_signature"`
Signature crypto.Signature `json:"signature"`
}
// MPKReady describe a dig ready message in DKG protocol.
type MPKReady struct {
ProposerID types.NodeID `json:"proposer_id"`
Round uint64 `json:"round"`
Reset uint64 `json:"reset"`
Signature crypto.Signature `json:"signature"`
}
func (ready *MPKReady) String() string {
return fmt.Sprintf("DKGMPKReady{RP:%s Round:%d Reset:%d}",
ready.ProposerID.String()[:6],
ready.Round,
ready.Reset)
}
// Equal check equality of two MPKReady instances.
func (ready *MPKReady) Equal(other *MPKReady) bool {
return ready.ProposerID.Equal(other.ProposerID) &&
ready.Round == other.Round &&
ready.Reset == other.Reset &&
ready.Signature.Type == other.Signature.Type &&
bytes.Compare(ready.Signature.Signature, other.Signature.Signature) == 0
}
// Finalize describe a dig finalize message in DKG protocol.
type Finalize struct {
ProposerID types.NodeID `json:"proposer_id"`
Round uint64 `json:"round"`
Reset uint64 `json:"reset"`
Signature crypto.Signature `json:"signature"`
}
func (final *Finalize) String() string {
return fmt.Sprintf("DKGFinal{FP:%s Round:%d Reset:%d}",
final.ProposerID.String()[:6],
final.Round,
final.Reset)
}
// Equal check equality of two Finalize instances.
func (final *Finalize) Equal(other *Finalize) bool {
return final.ProposerID.Equal(other.ProposerID) &&
final.Round == other.Round &&
final.Reset == other.Reset &&
final.Signature.Type == other.Signature.Type &&
bytes.Compare(final.Signature.Signature, other.Signature.Signature) == 0
}
// IsNack returns true if it's a nack complaint in DKG protocol.
func (c *Complaint) IsNack() bool {
return len(c.PrivateShare.Signature.Signature) == 0
}
// GroupPublicKey is the result of DKG protocol.
type GroupPublicKey struct {
Round uint64
QualifyIDs cryptoDKG.IDs
QualifyNodeIDs map[types.NodeID]struct{}
IDMap map[types.NodeID]cryptoDKG.ID
GroupPublicKey *cryptoDKG.PublicKey
Threshold int
}
// VerifySignature verifies if the signature is correct.
func (gpk *GroupPublicKey) VerifySignature(
hash common.Hash, sig crypto.Signature) bool {
return gpk.GroupPublicKey.VerifySignature(hash, sig)
}
// CalcQualifyNodes returns the qualified nodes.
func CalcQualifyNodes(
mpks []*MasterPublicKey, complaints []*Complaint, threshold int) (
qualifyIDs cryptoDKG.IDs, qualifyNodeIDs map[types.NodeID]struct{}, err error) {
if len(mpks) < threshold {
err = ErrInvalidThreshold
return
}
// Calculate qualify members.
disqualifyIDs := map[types.NodeID]struct{}{}
complaintsByID := map[types.NodeID]map[types.NodeID]struct{}{}
for _, complaint := range complaints {
if complaint.IsNack() {
if _, exist := complaintsByID[complaint.PrivateShare.ProposerID]; !exist {
complaintsByID[complaint.PrivateShare.ProposerID] =
make(map[types.NodeID]struct{})
}
complaintsByID[complaint.PrivateShare.ProposerID][complaint.ProposerID] =
struct{}{}
} else {
disqualifyIDs[complaint.PrivateShare.ProposerID] = struct{}{}
}
}
for nID, complaints := range complaintsByID {
if len(complaints) >= threshold {
disqualifyIDs[nID] = struct{}{}
}
}
qualifyIDs = make(cryptoDKG.IDs, 0, len(mpks)-len(disqualifyIDs))
if cap(qualifyIDs) < threshold {
err = ErrNotReachThreshold
return
}
qualifyNodeIDs = make(map[types.NodeID]struct{})
for _, mpk := range mpks {
if _, exist := disqualifyIDs[mpk.ProposerID]; exist {
continue
}
qualifyIDs = append(qualifyIDs, mpk.DKGID)
qualifyNodeIDs[mpk.ProposerID] = struct{}{}
}
return
}
// NewGroupPublicKey creats a GroupPublicKey instance.
func NewGroupPublicKey(
round uint64,
mpks []*MasterPublicKey, complaints []*Complaint,
threshold int) (
*GroupPublicKey, error) {
qualifyIDs, qualifyNodeIDs, err :=
CalcQualifyNodes(mpks, complaints, threshold)
if err != nil {
return nil, err
}
mpkMap := make(map[cryptoDKG.ID]*MasterPublicKey, cap(qualifyIDs))
idMap := make(map[types.NodeID]cryptoDKG.ID)
for _, mpk := range mpks {
if _, exist := qualifyNodeIDs[mpk.ProposerID]; !exist {
continue
}
mpkMap[mpk.DKGID] = mpk
idMap[mpk.ProposerID] = mpk.DKGID
}
// Recover Group Public Key.
pubShares := make([]*cryptoDKG.PublicKeyShares, 0, len(qualifyIDs))
for _, id := range qualifyIDs {
pubShares = append(pubShares, &mpkMap[id].PublicKeyShares)
}
groupPK := cryptoDKG.RecoverGroupPublicKey(pubShares)
return &GroupPublicKey{
Round: round,
QualifyIDs: qualifyIDs,
QualifyNodeIDs: qualifyNodeIDs,
IDMap: idMap,
Threshold: threshold,
GroupPublicKey: groupPK,
}, nil
}
// NodePublicKeys is the result of DKG protocol.
type NodePublicKeys struct {
Round uint64
QualifyIDs cryptoDKG.IDs
QualifyNodeIDs map[types.NodeID]struct{}
IDMap map[types.NodeID]cryptoDKG.ID
PublicKeys map[types.NodeID]*cryptoDKG.PublicKey
Threshold int
}
// NewNodePublicKeys creats a NodePublicKeys instance.
func NewNodePublicKeys(
round uint64,
mpks []*MasterPublicKey, complaints []*Complaint,
threshold int) (
*NodePublicKeys, error) {
qualifyIDs, qualifyNodeIDs, err :=
CalcQualifyNodes(mpks, complaints, threshold)
if err != nil {
return nil, err
}
mpkMap := make(map[cryptoDKG.ID]*MasterPublicKey, cap(qualifyIDs))
idMap := make(map[types.NodeID]cryptoDKG.ID)
for _, mpk := range mpks {
if _, exist := qualifyNodeIDs[mpk.ProposerID]; !exist {
continue
}
mpkMap[mpk.DKGID] = mpk
idMap[mpk.ProposerID] = mpk.DKGID
}
// Recover qualify members' public key.
pubKeys := make(map[types.NodeID]*cryptoDKG.PublicKey, len(qualifyIDs))
for _, recvID := range qualifyIDs {
pubShares := cryptoDKG.NewEmptyPublicKeyShares()
for _, id := range qualifyIDs {
pubShare, err := mpkMap[id].PublicKeyShares.Share(recvID)
if err != nil {
return nil, err
}
if err := pubShares.AddShare(id, pubShare); err != nil {
return nil, err
}
}
pubKey, err := pubShares.RecoverPublicKey(qualifyIDs)
if err != nil {
return nil, err
}
pubKeys[mpkMap[recvID].ProposerID] = pubKey
}
return &NodePublicKeys{
Round: round,
QualifyIDs: qualifyIDs,
QualifyNodeIDs: qualifyNodeIDs,
IDMap: idMap,
PublicKeys: pubKeys,
Threshold: threshold,
}, nil
}
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