C++ AES Decrypt 和 Nodejs AES Decrypt 产生不同的输出

Question

我已经在 nodejs 中重新实现了这个 AES c++ 解密。

“缓冲区”包含加密内容。“decryptKey”包含解密“缓冲区”的 key 。“expectedOutput”包含预期的输出。

为了绕过 Node 抛出的错误解密异常，我不得不在我的 crypt 对象中禁用 autoPadding。

为了简化，我添加了 c++ 代码，并为三种不同的算法(AES-128-ECB、AES-192-ECB、AES-256-ECB)添加了测试。没有一个解密结果与 C++ 输出匹配。

我错过了什么？

var crypto = require('crypto');

var buffer = new Buffer([
    0x5e,0x51,0xa3,0x53,0x9d,0xe7,0xe5,0xd3,
    0xee,0x30,0xbb,0xf8,0x0c,0x72,0x9f,0x80
]);


var decryptKey = new Buffer([
    0x36, 0x46, 0xb4, 0xf6, 
    0x8e, 0x6d, 0xdc, 0xf4, 
    0xb0, 0x31, 0x7e, 0x81, 
    0x6b, 0x5d, 0x96, 0x55
])

/*
After looking to my C++ code I noticed that despite of providing a 32 length key the 128 argument ensures that only the first 16 bytes are used
var decryptKey = new Buffer([
    0x36, 0x46, 0xb4, 0xf6, 
    0x8e, 0x6d, 0xdc, 0xf4, 
    0xb0, 0x31, 0x7e, 0x81, 
    0x6b, 0x5d, 0x96, 0x55, // 16
    0x15, 0x9c, 0x78, 0x54, 
    0x8c, 0xca, 0x3e, 0x39, 
    0x2d, 0x49, 0x75, 0x5d, 
    0xa1, 0x1a, 0xc3, 0xe3  // 32
])*/

var expectedOutput = new Buffer([
    0xc8,0x6c,0x8f,0x2b,0xe8,0x21,0xc4,0x2e,
    0xfb,0x4a,0x8e,0x8b,0xc3,0x94,0x19,0xc2
]);

// aes_context aes_ctx;
function decrypt(data, password, algorithm, padding){
  if (padding === void 0) padding = true;
  algorithm = algorithm || 'aes-128-ecb';

  //aes_setkey_dec( &aes_ctx, digest, 128 );
  var crypt = crypto.createDecipher(algorithm,password);
  crypt.setAutoPadding(padding);
  // aes_crypt_ecb( &aes_ctx, AES_DECRYPT, buffer, buffer );
  var res = crypt.update(data, null, 'hex')
  res += crypt.final('hex');

  return new Buffer(res,'hex');
}

// aes_setkey_dec( &aes_ctx, digest, 128 );
var algoList = [
    'aes-128-ecb',
    'aes-192-ecb',
    'aes-256-ecb'
];

for (var i = 0; i<= 1; i++){
    console.log('\n ******* AUTO PADDING: ' + (padding ? 'ON': 'OFF') + ' ********* ');
    var padding = i === 0;
    for (let algo of algoList){
        try {
            var output = decrypt(buffer, decryptKey, algo, padding);
            console.log(algo + ' => ' + output.toString('hex') + ' < ' + (Buffer.compare(expectedOutput, output) === 0 ? 'ok' : 'ko'))
        } catch (err){
            console.log('Failed to perform ' + algo + ' with autopadding ' + (padding ? ' on ': ' off ') + ' due to ' + err.message);
        }
    }
}

/*
 ******* AUTO PADDING: OFF *********
Failed to perform aes-128-ecb with autopadding  on  due to error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt
Failed to perform aes-192-ecb with autopadding  on  due to error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt
Failed to perform aes-256-ecb with autopadding  on  due to error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt

 ******* AUTO PADDING: ON *********
aes-128-ecb => d9817f142f9bca262b67f6a6be570345 < ko
aes-192-ecb => 9181784373bb6060c04c9ba75de26322 < ko
aes-256-ecb => c5945203368de477e5f0dbeedeb2189f < ko
*/

这是c++代码

#include "aes.h"
#include "sha2.h"

int main(int argc, char *argv[]) {


    unsigned char data[16] = { 
        0x5e,0x51,0xa3,0x53,0x9d,0xe7,0xe5,0xd3,0xee,0x30,0xbb,0xf8,0x0c,0x72,0x9f,0x80 
    };

    unsigned char key[32] = {
        0x36, 0x46, 0xb4, 0xf6,
        0x8e, 0x6d, 0xdc, 0xf4,
        0xb0, 0x31, 0x7e, 0x81,
        0x6b, 0x5d, 0x96, 0x55, // 16
        0x15, 0x9c, 0x78, 0x54,
        0x8c, 0xca, 0x3e, 0x39,
        0x2d, 0x49, 0x75, 0x5d,
        0xa1, 0x1a, 0xc3, 0xe3  // 32
    };

    aes_context aes_ctx;
    aes_setkey_dec(&aes_ctx, key, 128);
    aes_crypt_ecb(&aes_ctx, AES_DECRYPT, data, data);

    for (int i = 0; i< sizeof(data); ++i)
        std::cout << std::hex << (int)data[i];

    /* Output => c86c8f2be821c42efb4a8e8bc39419c2*/
}

引用资料:

• https://tls.mbed.org/discussions/generic/question-about-using-aes
• http://aes.online-domain-tools.com/link/133660agcLyPgFri4s/ - 在线解密示例

---

解决方案基于下面的答案

var crypto = require('crypto')
var buffer = new Buffer([
    0x5e,0x51,0xa3,0x53,0x9d,0xe7,0xe5,0xd3,
    0xee,0x30,0xbb,0xf8,0x0c,0x72,0x9f,0x80
]);


var decryptKey = new Buffer([
    0x36, 0x46, 0xb4, 0xf6, 
    0x8e, 0x6d, 0xdc, 0xf4, 
    0xb0, 0x31, 0x7e, 0x81, 
    0x6b, 0x5d, 0x96, 0x55
])

var expectedOutput = new Buffer([
    0xc8,0x6c,0x8f,0x2b,0xe8,0x21,0xc4,0x2e,
    0xfb,0x4a,0x8e,0x8b,0xc3,0x94,0x19,0xc2
]);

// aes_context aes_ctx;
function decrypt(data, password, algorithm, padding){
  if (padding === void 0) padding = true;
  algorithm = algorithm || 'aes-128-ecb';

  //aes_setkey_dec( &aes_ctx, digest, 128 );
  var crypt = crypto.createDecipheriv(algorithm,password, new Buffer([]));//new Buffer(32).fill(0).byteLength
  crypt.setAutoPadding(padding);
  // aes_crypt_ecb( &aes_ctx, AES_DECRYPT, buffer, buffer );
  var res = crypt.update(data, null,'hex')
  + crypt.final('hex');

  return new Buffer(res,'hex');
}

// aes_setkey_dec( &aes_ctx, digest, 128 );
var output = decrypt(buffer, decryptKey, 'aes-128-ecb', false);
console.log(Buffer.compare(expectedOutput, output) === 0 ? 'ok' : 'ko');

Answer 1

已弃用 crypto.createDecypher() 从密码参数中导出 key :

The implementation of crypto.createDecipher() derives keys using the OpenSSL function EVP_BytesToKey with the digest algorithm set to MD5, one iteration, and no salt.

您想要的是使用原始 key 。为此你应该使用 crypto.createDecipheriv()相反:

  var crypt = crypto.createDecipheriv(algorithm,password,new Buffer([]));

(在 ECB 模式下，IV 可以为空)

当然， key 长度必须与请求的算法相匹配(128、192 或 256 位)。您的 key 是 128 位，因此只有 aes-128-ecb 可以工作。