github.com/adnan-c/fabric_e2e_couchdb@v0.6.1-preview.0.20170228180935-21ce6b23cf91/accesscontrol/crypto/ecdsa/ecdsa.go (about)

     1  /*
     2  Copyright IBM Corp. 2016 All Rights Reserved.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  		 http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package ecdsa
    18  
    19  import (
    20  	"crypto/ecdsa"
    21  	"encoding/asn1"
    22  	"math/big"
    23  
    24  	"github.com/hyperledger/fabric/accesscontrol/crypto"
    25  )
    26  
    27  type x509ECDSASignatureVerifierImpl struct {
    28  }
    29  
    30  // ECDSASignature represents an ECDSA signature
    31  type ECDSASignature struct {
    32  	R, S *big.Int
    33  }
    34  
    35  func (sv *x509ECDSASignatureVerifierImpl) Verify(certificate, signature, message []byte) (bool, error) {
    36  	// Interpret vk as an x509 certificate
    37  	cert, err := derToX509Certificate(certificate)
    38  	if err != nil {
    39  		return false, err
    40  	}
    41  
    42  	// TODO: verify certificate
    43  
    44  	// Interpret signature as an ECDSA signature
    45  	vk := cert.PublicKey.(*ecdsa.PublicKey)
    46  
    47  	return sv.verifyImpl(vk, signature, message)
    48  }
    49  
    50  func (sv *x509ECDSASignatureVerifierImpl) verifyImpl(vk *ecdsa.PublicKey, signature, message []byte) (bool, error) {
    51  	ecdsaSignature := new(ECDSASignature)
    52  	_, err := asn1.Unmarshal(signature, ecdsaSignature)
    53  	if err != nil {
    54  		return false, err
    55  	}
    56  
    57  	h, err := computeHash(message, vk.Params().BitSize)
    58  	if err != nil {
    59  		return false, err
    60  	}
    61  
    62  	return ecdsa.Verify(vk, h, ecdsaSignature.R, ecdsaSignature.S), nil
    63  }
    64  
    65  func NewX509ECDSASignatureVerifier() crypto.SignatureVerifier {
    66  	return &x509ECDSASignatureVerifierImpl{}
    67  }