67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package aes
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import (
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"crypto/cipher"
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"strconv"
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)
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// The AES block size in bytes.
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const BlockSize = 16
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// A cipher is an instance of AES encryption using a particular key.
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type aesCipher struct {
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enc []uint32
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dec []uint32
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}
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type KeySizeError int
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func (k KeySizeError) Error() string {
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return "crypto/aes: invalid key size " + strconv.Itoa(int(k))
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}
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// NewCipher creates and returns a new cipher.Block.
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// The key argument should be the AES key,
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// either 16, 24, or 32 bytes to select
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// AES-128, AES-192, or AES-256.
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func NewCipher(key []byte) (cipher.Block, error) {
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k := len(key)
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switch k {
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default:
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return nil, KeySizeError(k)
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case 16, 24, 32:
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break
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}
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n := k + 28
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c := &aesCipher{make([]uint32, n), make([]uint32, n)}
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expandKey(key, c.enc, c.dec)
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return c, nil
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}
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func (c *aesCipher) BlockSize() int { return BlockSize }
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func (c *aesCipher) Encrypt(dst, src []byte) {
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if len(src) < BlockSize {
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panic("crypto/aes: input not full block")
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}
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if len(dst) < BlockSize {
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panic("crypto/aes: output not full block")
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}
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encryptBlock(c.enc, dst, src)
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}
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func (c *aesCipher) Decrypt(dst, src []byte) {
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if len(src) < BlockSize {
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panic("crypto/aes: input not full block")
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}
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if len(dst) < BlockSize {
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panic("crypto/aes: output not full block")
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}
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decryptBlock(c.dec, dst, src)
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}
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