path: root/core/authenticator.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 (
    "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"
)

// Authenticator verify data owner.
type Authenticator struct {
    prvKey     crypto.PrivateKey
    pubKey     crypto.PublicKey
    proposerID types.NodeID
}

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

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

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

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

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

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

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

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

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

// VerifyBlock verifies the signature of types.Block.
func (au *Authenticator) VerifyBlock(b *types.Block) (err error) {
    payloadHash := crypto.Keccak256Hash(b.Payload)
    if payloadHash != b.PayloadHash {
        err = ErrIncorrectHash
        return
    }
    hash, err := hashBlock(b)
    if err != nil {
        return
    }
    if hash != b.Hash {
        err = ErrIncorrectHash
        return
    }
    pubKey, err := crypto.SigToPub(b.Hash, b.Signature)
    if err != nil {
        return
    }
    if !b.ProposerID.Equal(types.NewNodeID(pubKey)) {
        err = ErrIncorrectSignature
        return
    }
    return
}

// VerifyVote verifies the signature of types.Vote.
func (au *Authenticator) VerifyVote(v *types.Vote) (bool, error) {
    return verifyVoteSignature(v)
}

// VerifyCRS verifies the CRS signature of types.Block.
func (au *Authenticator) VerifyCRS(b *types.Block, crs common.Hash) (bool, error) {
    return verifyCRSSignature(b, crs)
}