path: root/core/utils/penalty-helper.go

// Copyright 2019 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 utils

import (
    "errors"

    "github.com/dexon-foundation/dexon-consensus/core/types"
    typesDKG "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
)

var (
    // ErrInvalidDKGMasterPublicKey means the DKG MasterPublicKey is invalid.
    ErrInvalidDKGMasterPublicKey = errors.New("invalid DKG master public key")
    // ErrPayloadNotEmpty means the payload of block is not empty.
    ErrPayloadNotEmpty = errors.New("payload not empty")
)

// NeedPenaltyDKGPrivateShare checks if the proposer of dkg private share
// should be penalized.
func NeedPenaltyDKGPrivateShare(
    complaint *typesDKG.Complaint, mpk *typesDKG.MasterPublicKey) (bool, error) {
    if complaint.IsNack() {
        return false, nil
    }
    if mpk.ProposerID != complaint.PrivateShare.ProposerID {
        return false, nil
    }
    ok, err := VerifyDKGMasterPublicKeySignature(mpk)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, ErrInvalidDKGMasterPublicKey
    }
    ok, err = VerifyDKGComplaintSignature(complaint)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, nil
    }
    ok, err = mpk.PublicKeyShares.VerifyPrvShare(
        typesDKG.NewID(complaint.PrivateShare.ReceiverID),
        &complaint.PrivateShare.PrivateShare)
    if err != nil {
        return false, err
    }
    return !ok, nil
}

// NeedPenaltyForkVote checks if two votes are fork vote.
func NeedPenaltyForkVote(vote1, vote2 *types.Vote) (bool, error) {
    if vote1.ProposerID != vote2.ProposerID ||
        vote1.Type != vote2.Type ||
        vote1.Period != vote2.Period ||
        vote1.Position != vote2.Position ||
        vote1.BlockHash == vote2.BlockHash {
        return false, nil
    }
    ok, err := VerifyVoteSignature(vote1)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, nil
    }
    ok, err = VerifyVoteSignature(vote2)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, nil
    }
    return true, nil
}

// NeedPenaltyForkBlock checks if two blocks are fork block.
func NeedPenaltyForkBlock(block1, block2 *types.Block) (bool, error) {
    if block1.ProposerID != block2.ProposerID ||
        block1.Position != block2.Position ||
        block1.Hash == block2.Hash {
        return false, nil
    }
    if len(block1.Payload) != 0 || len(block2.Payload) != 0 {
        return false, ErrPayloadNotEmpty
    }
    verifyBlock := func(block *types.Block) (bool, error) {
        err := VerifyBlockSignatureWithoutPayload(block)
        switch err {
        case nil:
            return true, nil
        case ErrIncorrectSignature:
            return false, nil
        case ErrIncorrectHash:
            return false, nil
        default:
            return false, err
        }
    }
    ok, err := verifyBlock(block1)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, nil
    }
    ok, err = verifyBlock(block2)
    if err != nil {
        return false, err
    }
    if !ok {
        return false, nil
    }
    return true, nil
}