github.com/mysteriumnetwork/node@v0.0.0-20240516044423-365054f76801/identity/extractor.go (about)

     1  /*
     2   * Copyright (C) 2017 The "MysteriumNetwork/node" Authors.
     3   *
     4   * This program is free software: you can redistribute it and/or modify
     5   * it under the terms of the GNU General Public License as published by
     6   * the Free Software Foundation, either version 3 of the License, or
     7   * (at your option) any later version.
     8   *
     9   * This program is distributed in the hope that it will be useful,
    10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    12   * GNU General Public License for more details.
    13   *
    14   * You should have received a copy of the GNU General Public License
    15   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    16   */
    17  
    18  package identity
    19  
    20  import (
    21  	"github.com/ethereum/go-ethereum/crypto"
    22  	"github.com/pkg/errors"
    23  )
    24  
    25  // Extractor is able to message signer's identity
    26  type Extractor interface {
    27  	Extract(message []byte, signature Signature) (Identity, error)
    28  }
    29  
    30  // NewExtractor constructs Extractor instance
    31  func NewExtractor() *extractor {
    32  	return &extractor{}
    33  }
    34  
    35  type extractor struct{}
    36  
    37  // Extractor extracts identity which was used to sign given message
    38  func (extractor *extractor) Extract(message []byte, signature Signature) (Identity, error) {
    39  	signatureBytes := signature.Bytes()
    40  	if len(signatureBytes) == 0 {
    41  		return Identity{}, errors.New("empty signature")
    42  	}
    43  
    44  	recoveredKey, err := crypto.Ecrecover(messageHash(message), signatureBytes)
    45  	if err != nil {
    46  		return Identity{}, err
    47  	}
    48  
    49  	key, err := crypto.UnmarshalPubkey(recoveredKey)
    50  	if err != nil {
    51  		return Identity{}, err
    52  	}
    53  
    54  	recoveredAddress := crypto.PubkeyToAddress(*key).Hex()
    55  
    56  	return FromAddress(recoveredAddress), nil
    57  }