path: root/core/utils/signer.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 utils

import (
    "errors"

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

// Errors for signer.
var (
    ErrInvalidProposerID  = errors.New("invalid proposer id")
    ErrIncorrectHash      = errors.New("hash of block is incorrect")
    ErrIncorrectSignature = errors.New("signature of block is incorrect")
)

// Signer signs a segment of data.
type Signer struct {
    prvKey     crypto.PrivateKey
    pubKey     crypto.PublicKey
    proposerID types.NodeID
}

// NewSigner constructs an Signer instance.
func NewSigner(prvKey crypto.PrivateKey) (s *Signer) {
    s = &Signer{
        prvKey: prvKey,
        pubKey: prvKey.PublicKey(),
    }
    s.proposerID = types.NewNodeID(s.pubKey)
    return
}

// SignBlock signs a types.Block.
func (s *Signer) SignBlock(b *types.Block) (err error) {
    b.ProposerID = s.proposerID
    b.PayloadHash = crypto.Keccak256Hash(b.Payload)
    if b.Hash, err = HashBlock(b); err != nil {
        return
    }
    if b.Signature, err = s.prvKey.Sign(b.Hash); err != nil {
        return
    }
    return
}

// SignVote signs a types.Vote.
func (s *Signer) SignVote(v *types.Vote) (err error) {
    v.ProposerID = s.proposerID
    v.Signature, err = s.prvKey.Sign(hashVote(v))
    return
}

// SignCRS signs CRS signature of types.Block.
func (s *Signer) SignCRS(b *types.Block, crs common.Hash) (err error) {
    if b.ProposerID != s.proposerID {
        err = ErrInvalidProposerID
        return
    }
    b.CRSSignature, err = s.prvKey.Sign(hashCRS(b, crs))
    return
}

// SignDKGComplaint signs a DKG complaint.
func (s *Signer) SignDKGComplaint(complaint *typesDKG.Complaint) (err error) {
    complaint.ProposerID = s.proposerID
    complaint.Signature, err = s.prvKey.Sign(hashDKGComplaint(complaint))
    return
}

// SignDKGMasterPublicKey signs a DKG master public key.
func (s *Signer) SignDKGMasterPublicKey(
    mpk *typesDKG.MasterPublicKey) (err error) {
    mpk.ProposerID = s.proposerID
    mpk.Signature, err = s.prvKey.Sign(hashDKGMasterPublicKey(mpk))
    return
}

// SignDKGPrivateShare signs a DKG private share.
func (s *Signer) SignDKGPrivateShare(
    prvShare *typesDKG.PrivateShare) (err error) {
    prvShare.ProposerID = s.proposerID
    prvShare.Signature, err = s.prvKey.Sign(hashDKGPrivateShare(prvShare))
    return
}

// SignDKGPartialSignature signs a DKG partial signature.
func (s *Signer) SignDKGPartialSignature(
    pSig *typesDKG.PartialSignature) (err error) {
    pSig.ProposerID = s.proposerID
    pSig.Signature, err = s.prvKey.Sign(hashDKGPartialSignature(pSig))
    return
}

// SignDKGMPKReady signs a DKG ready message.
func (s *Signer) SignDKGMPKReady(ready *typesDKG.MPKReady) (err error) {
    ready.ProposerID = s.proposerID
    ready.Signature, err = s.prvKey.Sign(hashDKGMPKReady(ready))
    return
}

// SignDKGFinalize signs a DKG finalize message.
func (s *Signer) SignDKGFinalize(final *typesDKG.Finalize) (err error) {
    final.ProposerID = s.proposerID
    final.Signature, err = s.prvKey.Sign(hashDKGFinalize(final))
    return
}