AES-CTR在Go中加密，在CryptoJS中解密

Question

我在用CryptoJS加密的Go lang中解密文本时遇到了问题。

下面是Go代码：iN

package main

import (
    "crypto/aes"
    "crypto/cipher"
    "encoding/base64"
    "fmt"
)

func main() {
    key := []byte("1234567890123456")
    plaintext := []byte("text can be a random lenght")

    block, err := aes.NewCipher(key)
    if err != nil {
        panic(err)
    }

    // The IV needs to be unique, but not secure. Therefore it's common to
    // include it at the beginning of the ciphertext.
    // BTW (only for test purpose) I don't include it

    ciphertext := make([]byte, len(plaintext))

    iv := []byte{'\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f','\x0f'}

    stream := cipher.NewCTR(block, iv)
    stream.XORKeyStream(ciphertext, plaintext) 

    // CTR mode is the same for both encryption and decryption, so we can
    // also decrypt that ciphertext with NewCTR.
        base := base64.StdEncoding.EncodeToString(ciphertext)
    fmt.Printf("encodedHEX: %x\n", ciphertext)
    fmt.Printf("encodedBASE: %s\n", base)

    plaintext2 := make([]byte, len(plaintext))
    stream = cipher.NewCTR(block, iv)
    stream.XORKeyStream(plaintext2, ciphertext)

    fmt.Printf("decoded: %s\n", plaintext2)
}

以下是JS代码：http://jsfiddle.net/Ltkxm64n/

var key = CryptoJS.enc.Hex.parse('31323334353637383930313233343536');
var iv = CryptoJS.enc.Hex.parse('0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f');
var encrypted = CryptoJS.AES.encrypt("text can be a random lenght", key, {
  mode: CryptoJS.mode.CTR,
  iv: iv
});

console.log(encrypted.ciphertext.toString());
console.log(encrypted.toString());

var decrypted = CryptoJS.AES.decrypt(encrypted, key, {
  mode: CryptoJS.mode.CTR,
  iv: iv
});
console.log(decrypted.toString(CryptoJS.enc.Utf8)); 
// text can be a random lenght

这两种方法都能很好地加密和解密，但是当我将base64密文从GO复制到JS (反之亦然)时，它就不能工作了。我还注意到，js输出的第一部分与Go输出相同，但js输出中的字节数比Go输出中的字节多。

我的目的是加密GO中的一些文本，然后将Base64密文发送到能够解密它的JS。

谢谢

Answer 1

好的，下面是解决这个问题的方法：

1. 将不填充js添加到源列表中：http://crypto-js.googlecode.com/svn/tags/3.1/build/components/pad-nopadding.js
2. 加密/解密时指定参数：padding: CryptoJS.pad.NoPadding

CTR模式在加密前不需要填充纯文本。

从多个AES块生成的密钥流被裁剪以匹配XORing之前的纯文本长度。

看起来CryptoJS用纯文本生成密钥流到xor，但没有修剪它，因为不带padding: CryptoJS.pad.NoPadding的CryptoJS生成的密文长度总是16字节的倍数(与AES块大小完全相同)。

​

var key = CryptoJS.enc.Hex.parse('31323334353637383930313233343536');
var iv = CryptoJS.enc.Hex.parse('0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f');
var encrypted = CryptoJS.AES.encrypt("text can be a random lenght", key, {
  mode: CryptoJS.mode.CTR,
  iv: iv,
  padding: CryptoJS.pad.NoPadding
});

document.getElementById("id").innerHTML = encrypted.ciphertext.toString();
document.getElementById("id2").innerHTML = encrypted.toString();

var decrypted = CryptoJS.AES.decrypt(encrypted, key, {
  mode: CryptoJS.mode.CTR,
  iv: iv,
  padding: CryptoJS.pad.NoPadding
});
document.getElementById("decrypt").innerHTML = decrypted.toString(CryptoJS.enc.Utf8); // text can be a random lenght

<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/aes.js"></script>
<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/components/mode-ctr.js"></script>
<script src="http://crypto-js.googlecode.com/svn/tags/3.1/build/components/pad-nopadding.js"></script>
<p> Ciphertext in HEX: </p>
<p id="id"> </p>
<p> Ciphertext in BASE64: </p>
<p id="id2"> </p>
<p> PlainText: </p>
<p id="decrypt"></p>

​

Answer 2

在对明文进行编码之前，必须向明文添加填充内容。

例如：

func addPadding(data []byte, blocksize int) []byte {

    padSize := len(data) % blocksize
    if padSize == 0 {
        return data
    }
    padSize = blocksize - padSize
    return append(data, bytes.Repeat([]byte{byte(padSize)}, padSize)...)
}
//in main
    plaintext := []byte("text can be a random lenght")
    plaintext = addPadding(plaintext, aes.BlockSize)