github.com/annchain/OG@v0.0.9/deprecated/ogcrypto/ecies/params.go (about)

     1  // Copyright (c) 2013 Kyle Isom <kyle@tyrfingr.is>
     2  // Copyright (c) 2012 The Go Authors. All rights reserved.
     3  //
     4  // Redistribution and use in source and binary forms, with or without
     5  // modification, are permitted provided that the following conditions are
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     7  //
     8  //    * Redistributions of source code must retain the above copyright
     9  // notice, this list of conditions and the following disclaimer.
    10  //    * Redistributions in binary form must reproduce the above
    11  // copyright notice, this list of conditions and the following disclaimer
    12  // in the documentation and/or other materials provided with the
    13  // distribution.
    14  //    * Neither the name of Google Inc. nor the names of its
    15  // contributors may be used to endorse or promote products derived from
    16  // this software without specific prior written permission.
    17  //
    18  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    19  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    20  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    21  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    22  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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    24  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    25  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    26  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    27  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    28  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    29  
    30  package ecies
    31  
    32  // This file contains parameters for ECIES encryption, specifying the
    33  // symmetric encryption and HMAC parameters.
    34  
    35  import (
    36  	"crypto"
    37  	"crypto/aes"
    38  	"crypto/cipher"
    39  	"crypto/elliptic"
    40  	"crypto/sha256"
    41  	"crypto/sha512"
    42  	"fmt"
    43  	"github.com/btcsuite/btcd/btcec"
    44  	"hash"
    45  )
    46  
    47  var (
    48  	DefaultCurve                  = S256()
    49  	ErrUnsupportedECDHAlgorithm   = fmt.Errorf("ecies: unsupported ECDH algorithm")
    50  	ErrUnsupportedECIESParameters = fmt.Errorf("ecies: unsupported ECIES parameters")
    51  )
    52  
    53  type ECIESParams struct {
    54  	Hash      func() hash.Hash // hash function
    55  	hashAlgo  crypto.Hash
    56  	Cipher    func([]byte) (cipher.Block, error) // symmetric cipher
    57  	BlockSize int                                // block size of symmetric cipher
    58  	KeyLen    int                                // length of symmetric key
    59  }
    60  
    61  // Standard ECIES parameters:
    62  // * ECIES using AES128 and HMAC-SHA-256-16
    63  // * ECIES using AES256 and HMAC-SHA-256-32
    64  // * ECIES using AES256 and HMAC-SHA-384-48
    65  // * ECIES using AES256 and HMAC-SHA-512-64
    66  
    67  var (
    68  	ECIES_AES128_SHA256 = &ECIESParams{
    69  		Hash:      sha256.New,
    70  		hashAlgo:  crypto.SHA256,
    71  		Cipher:    aes.NewCipher,
    72  		BlockSize: aes.BlockSize,
    73  		KeyLen:    16,
    74  	}
    75  
    76  	ECIES_AES256_SHA256 = &ECIESParams{
    77  		Hash:      sha256.New,
    78  		hashAlgo:  crypto.SHA256,
    79  		Cipher:    aes.NewCipher,
    80  		BlockSize: aes.BlockSize,
    81  		KeyLen:    32,
    82  	}
    83  
    84  	ECIES_AES256_SHA384 = &ECIESParams{
    85  		Hash:      sha512.New384,
    86  		hashAlgo:  crypto.SHA384,
    87  		Cipher:    aes.NewCipher,
    88  		BlockSize: aes.BlockSize,
    89  		KeyLen:    32,
    90  	}
    91  
    92  	ECIES_AES256_SHA512 = &ECIESParams{
    93  		Hash:      sha512.New,
    94  		hashAlgo:  crypto.SHA512,
    95  		Cipher:    aes.NewCipher,
    96  		BlockSize: aes.BlockSize,
    97  		KeyLen:    32,
    98  	}
    99  )
   100  
   101  var paramsFromCurve = map[elliptic.Curve]*ECIESParams{
   102  	S256():          ECIES_AES128_SHA256,
   103  	elliptic.P256(): ECIES_AES128_SHA256,
   104  	elliptic.P384(): ECIES_AES256_SHA384,
   105  	elliptic.P521(): ECIES_AES256_SHA512,
   106  }
   107  
   108  func AddParamsForCurve(curve elliptic.Curve, params *ECIESParams) {
   109  	paramsFromCurve[curve] = params
   110  }
   111  
   112  // ParamsFromCurve selects parameters optimal for the selected elliptic curve.
   113  // Only the curves P256, P384, and P512 are supported.
   114  func ParamsFromCurve(curve elliptic.Curve) (params *ECIESParams) {
   115  	return paramsFromCurve[curve]
   116  }
   117  
   118  // S256 returns an instance of the secp256k1 curve.
   119  func S256() elliptic.Curve {
   120  	return btcec.S256()
   121  }