Question

我已经在nodejs中重新实现了AES c ++解密。

“缓冲区”包含加密的内容。 “ decryptKey”包含解密“ buffer”的密钥。 “ expectedOutput”包含预期的输出。

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

为简化起见，我添加了c ++代码，并向三种不同的算法（AES-128-ECB，AES-192-ECB，AES-256-ECB）添加了测试。没有解密结果与C ++输出匹配。

我想念什么？

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
*/

这里有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：

基于以下答案的解决方案

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

已被弃用的 crypto.createDecypher() 派生来自 password 参数的密钥：

crypto.createDecipher()的实现使用OpenSSL函数EVP_BytesToKey派生密钥，其摘要算法设置为MD5，一次迭代且无盐。

您要使用的是原始键。为此，您应该改用crypto.createDecipheriv()：

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

（在ECB模式下，IV可以为空）

当然，密钥长度必须匹配请求的算法（128、192或256位）。您的密钥是128位，因此只有aes-128-ecb将起作用。

Answer 2

您需要将false传递给setAutoPadding的原因是，您的密文没有填充。您尚未包括生成密文的加密代码，但是我可以从它的长度得知它没有被填充，因为使用PKCS＃7填充加密时，一个块大小的明文会生成密文。长度为两个块大小，而不是单个块。

使用aes_crypt_ecb进行解密的原因是，看起来aes_crypt_ecb仅执行单个块加密/解密，因此不不会执行任何填充或取消填充操作。不过，如果Javscript代码传递了true到setAutoPadding函数，则将期望填充（可能是PKCS＃7）。当然会失败，因为您的加密没有使用填充。

理想情况下，您应该修改加密代码，以便在进行加密时使用正确的填充，因为这比不使用填充要安全得多。否则，在进行解密时，您需要确保对setAutoPadding的调用传递了false，因此Javascript知道没有填充。

C ++ AES解密和Nodejs AES解密产生不同的输出

2 个答案: