mirror of https://go.googlesource.com/go
83 lines
2.0 KiB
Go
83 lines
2.0 KiB
Go
// Copyright 2009 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 aes
|
|
|
|
import (
|
|
"crypto/cipher"
|
|
"crypto/internal/alias"
|
|
"crypto/internal/boring"
|
|
"strconv"
|
|
)
|
|
|
|
// The AES block size in bytes.
|
|
const BlockSize = 16
|
|
|
|
// A cipher is an instance of AES encryption using a particular key.
|
|
type aesCipher struct {
|
|
l uint8 // only this length of the enc and dec array is actually used
|
|
enc [28 + 32]uint32
|
|
dec [28 + 32]uint32
|
|
}
|
|
|
|
type KeySizeError int
|
|
|
|
func (k KeySizeError) Error() string {
|
|
return "crypto/aes: invalid key size " + strconv.Itoa(int(k))
|
|
}
|
|
|
|
// NewCipher creates and returns a new [cipher.Block].
|
|
// The key argument should be the AES key,
|
|
// either 16, 24, or 32 bytes to select
|
|
// AES-128, AES-192, or AES-256.
|
|
func NewCipher(key []byte) (cipher.Block, error) {
|
|
k := len(key)
|
|
switch k {
|
|
default:
|
|
return nil, KeySizeError(k)
|
|
case 16, 24, 32:
|
|
break
|
|
}
|
|
if boring.Enabled {
|
|
return boring.NewAESCipher(key)
|
|
}
|
|
return newCipher(key)
|
|
}
|
|
|
|
// newCipherGeneric creates and returns a new cipher.Block
|
|
// implemented in pure Go.
|
|
func newCipherGeneric(key []byte) (cipher.Block, error) {
|
|
c := aesCipher{l: uint8(len(key) + 28)}
|
|
expandKeyGo(key, c.enc[:c.l], c.dec[:c.l])
|
|
return &c, nil
|
|
}
|
|
|
|
func (c *aesCipher) BlockSize() int { return BlockSize }
|
|
|
|
func (c *aesCipher) Encrypt(dst, src []byte) {
|
|
if len(src) < BlockSize {
|
|
panic("crypto/aes: input not full block")
|
|
}
|
|
if len(dst) < BlockSize {
|
|
panic("crypto/aes: output not full block")
|
|
}
|
|
if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
|
|
panic("crypto/aes: invalid buffer overlap")
|
|
}
|
|
encryptBlockGo(c.enc[:c.l], dst, src)
|
|
}
|
|
|
|
func (c *aesCipher) Decrypt(dst, src []byte) {
|
|
if len(src) < BlockSize {
|
|
panic("crypto/aes: input not full block")
|
|
}
|
|
if len(dst) < BlockSize {
|
|
panic("crypto/aes: output not full block")
|
|
}
|
|
if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
|
|
panic("crypto/aes: invalid buffer overlap")
|
|
}
|
|
decryptBlockGo(c.dec[:c.l], dst, src)
|
|
}
|