gtsocial-umbx

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mac.go (1477B)

      1 // Copyright 2012 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 package ssh
      6 
      7 // Message authentication support
      8 
      9 import (
     10 	"crypto/hmac"
     11 	"crypto/sha1"
     12 	"crypto/sha256"
     13 	"crypto/sha512"
     14 	"hash"
     15 )
     16 
     17 type macMode struct {
     18 	keySize int
     19 	etm     bool
     20 	new     func(key []byte) hash.Hash
     21 }
     22 
     23 // truncatingMAC wraps around a hash.Hash and truncates the output digest to
     24 // a given size.
     25 type truncatingMAC struct {
     26 	length int
     27 	hmac   hash.Hash
     28 }
     29 
     30 func (t truncatingMAC) Write(data []byte) (int, error) {
     31 	return t.hmac.Write(data)
     32 }
     33 
     34 func (t truncatingMAC) Sum(in []byte) []byte {
     35 	out := t.hmac.Sum(in)
     36 	return out[:len(in)+t.length]
     37 }
     38 
     39 func (t truncatingMAC) Reset() {
     40 	t.hmac.Reset()
     41 }
     42 
     43 func (t truncatingMAC) Size() int {
     44 	return t.length
     45 }
     46 
     47 func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
     48 
     49 var macModes = map[string]*macMode{
     50 	"hmac-sha2-512-etm@openssh.com": {64, true, func(key []byte) hash.Hash {
     51 		return hmac.New(sha512.New, key)
     52 	}},
     53 	"hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash {
     54 		return hmac.New(sha256.New, key)
     55 	}},
     56 	"hmac-sha2-256": {32, false, func(key []byte) hash.Hash {
     57 		return hmac.New(sha256.New, key)
     58 	}},
     59 	"hmac-sha1": {20, false, func(key []byte) hash.Hash {
     60 		return hmac.New(sha1.New, key)
     61 	}},
     62 	"hmac-sha1-96": {20, false, func(key []byte) hash.Hash {
     63 		return truncatingMAC{12, hmac.New(sha1.New, key)}
     64 	}},
     65 }