github.com/adnan-c/fabric_e2e_couchdb@v0.6.1-preview.0.20170228180935-21ce6b23cf91/orderer/sbft/simplebft/crypto.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 simplebft
    18  
    19  import (
    20  	"crypto/sha256"
    21  	"encoding/base64"
    22  
    23  	"github.com/golang/protobuf/proto"
    24  )
    25  
    26  func hash2str(h []byte) string {
    27  	return base64.RawStdEncoding.EncodeToString(h)
    28  }
    29  
    30  func hash(data []byte) []byte {
    31  	h := sha256.Sum256(data)
    32  	return h[:]
    33  }
    34  
    35  func merkleHashData(data [][]byte) []byte {
    36  	var digests [][]byte
    37  	for _, d := range data {
    38  		digests = append(digests, hash(d))
    39  	}
    40  	return merkleHashDigests(digests)
    41  }
    42  
    43  func merkleHashDigests(digests [][]byte) []byte {
    44  	for len(digests) > 1 {
    45  		var nextDigests [][]byte
    46  		var prev []byte
    47  		for _, d := range digests {
    48  			if prev == nil {
    49  				prev = d
    50  			} else {
    51  				h := sha256.New()
    52  				h.Write(prev)
    53  				h.Write(d)
    54  				nextDigests = append(nextDigests, h.Sum(nil))
    55  				prev = nil
    56  			}
    57  		}
    58  		if prev != nil {
    59  			nextDigests = append(nextDigests, prev)
    60  		}
    61  		digests = nextDigests
    62  	}
    63  
    64  	if len(digests) == 0 {
    65  		return nil
    66  	}
    67  	return digests[0]
    68  }
    69  
    70  ////////////////////////////////////////////////
    71  
    72  func (s *SBFT) sign(msg proto.Message) *Signed {
    73  	bytes, err := proto.Marshal(msg)
    74  	if err != nil {
    75  		panic(err)
    76  	}
    77  	sig := s.sys.Sign(bytes)
    78  	return &Signed{Data: bytes, Signature: []byte(sig)}
    79  }
    80  
    81  func (s *SBFT) checkSig(sig *Signed, signer uint64, msg proto.Message) error {
    82  	err := s.checkBytesSig(sig.Data, signer, sig.Signature)
    83  	if err != nil {
    84  		return err
    85  	}
    86  	err = proto.Unmarshal(sig.Data, msg)
    87  	if err != nil {
    88  		return err
    89  	}
    90  	return nil
    91  }
    92  
    93  func (s *SBFT) checkBytesSig(digest []byte, signer uint64, sig []byte) error {
    94  	return s.sys.CheckSig(digest, signer, sig)
    95  }