58 lines
1.2 KiB
Go
58 lines
1.2 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package ssh
|
|
|
|
// Message authentication support
|
|
|
|
import (
|
|
"crypto/hmac"
|
|
"crypto/sha1"
|
|
"crypto/sha256"
|
|
"hash"
|
|
)
|
|
|
|
type macMode struct {
|
|
keySize int
|
|
new func(key []byte) hash.Hash
|
|
}
|
|
|
|
// truncatingMAC wraps around a hash.Hash and truncates the output digest to
|
|
// a given size.
|
|
type truncatingMAC struct {
|
|
length int
|
|
hmac hash.Hash
|
|
}
|
|
|
|
func (t truncatingMAC) Write(data []byte) (int, error) {
|
|
return t.hmac.Write(data)
|
|
}
|
|
|
|
func (t truncatingMAC) Sum(in []byte) []byte {
|
|
out := t.hmac.Sum(in)
|
|
return out[:len(in)+t.length]
|
|
}
|
|
|
|
func (t truncatingMAC) Reset() {
|
|
t.hmac.Reset()
|
|
}
|
|
|
|
func (t truncatingMAC) Size() int {
|
|
return t.length
|
|
}
|
|
|
|
func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
|
|
|
|
var macModes = map[string]*macMode{
|
|
"hmac-sha2-256": {32, func(key []byte) hash.Hash {
|
|
return hmac.New(sha256.New, key)
|
|
}},
|
|
"hmac-sha1": {20, func(key []byte) hash.Hash {
|
|
return hmac.New(sha1.New, key)
|
|
}},
|
|
"hmac-sha1-96": {20, func(key []byte) hash.Hash {
|
|
return truncatingMAC{12, hmac.New(sha1.New, key)}
|
|
}},
|
|
}
|