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

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

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

// SignBlock signs a types.Block.
func (au *Authenticator) SignBlock(b *types.Block) (err error) {
    b.ProposerID = types.NewNodeID(au.pubKey)
    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 = types.NewNodeID(au.pubKey)
    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 != types.NewNodeID(au.pubKey) {
        err = ErrInvalidProposerID
        return
    }
    b.CRSSignature, err = au.prvKey.Sign(hashCRS(b, crs))
    return
}

// VerifyBlock verifies the signature of types.Block.
func (au *Authenticator) VerifyBlock(b *types.Block) (err error) {
    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(crypto.Keccak256Hash(pubKey.Bytes())) {
        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)
}