从node.js中解密AES256加密数据，如何从密码中获取IV和Key [英] Decrypting AES256 encrypted data in .NET from node.js - how to obtain IV and Key from passphrase

问题描述

  var cipher = crypto .createCipher（'aes256'，'passphrase'）; 
 var encrypted = cipher.update（test，'utf8'，'base64'）+ cipher.final（'base64'）; 
 
 var decipher = crypto.createDecipher（'aes256'，'passphrase'）; 
 var plain = decipher.update（encrypted，'base64'，'utf8'）+ decipher.final（'utf8'）; 
  

我希望能够在C＃/ .NET中执行相同操作，以便我可以共享数据在两个单独的系统之间。但是我在.NET中看到的代码需要一个Key和IV来进入/解密。这些派生自node.js Crypto库中的密码短语？

解决方案

从 node.js源我发现这个：

  bool CipherInit（char * cipherType，char * key_buf，int key_buf_len）{
 cipher = EVP_get_cipherbyname（cipherType）; 
 if（！cipher）{
 fprintf（stderr，node-crypto：Unknown cipher％s\\\
，cipherType）; 
返回false; 
} 
 
 unsigned char key [EVP_MAX_KEY_LENGTH]，iv [EVP_MAX_IV_LENGTH]; 
 int key_len = EVP_BytesToKey（cipher，EVP_md5（），NULL，
（unsigned char *）key_buf，key_buf_len，1，key，iv）; 
  

我在这个问题可以这样使用：

  byte [] key，iv; 
 DeriveKeyAndIV（Encoding.ASCII.GetBytes（passphrase），null，1，out key，out iv）; 
 
 //这是node.js给我的base64加密数据
 var cryptotedBytes = Convert.FromBase64String（b3rbg + mniw7p9aiPUyGthg ==）; 
  

然后可以在 RijndaelManaged的实例中使用键和IV code>解密 encryptedtedBytes

I have the following code to encrypt/decrypt data in node.js, which is working:

var cipher = crypto.createCipher('aes256', 'passphrase');  
var encrypted = cipher.update("test", 'utf8', 'base64') + cipher.final('base64');

var decipher = crypto.createDecipher('aes256', 'passphrase');   
var plain = decipher.update(encrypted, 'base64', 'utf8') + decipher.final('utf8');

I would like to be able to do the same in C#/.NET so that I can share data between two seperate systems. However the code that I have seen in .NET requires a Key and IV to entrypt/decrypt. How are these derived from the passphrase in the node.js Crypto library?

解决方案

From the node.js source I found this:

 bool CipherInit(char* cipherType, char* key_buf, int key_buf_len) {
cipher = EVP_get_cipherbyname(cipherType);
if(!cipher) {
  fprintf(stderr, "node-crypto : Unknown cipher %s\n", cipherType);
  return false;
}

unsigned char key[EVP_MAX_KEY_LENGTH],iv[EVP_MAX_IV_LENGTH];
int key_len = EVP_BytesToKey(cipher, EVP_md5(), NULL,
  (unsigned char*) key_buf, key_buf_len, 1, key, iv);

I found a c# implementation of EVP_BytesToKey in this question which can be used like this:

byte[] key, iv;
DeriveKeyAndIV(Encoding.ASCII.GetBytes("passphrase"),null, 1, out key, out iv);

                     //this is what node.js gave me as the base64 encrypted data
var encrytedBytes = Convert.FromBase64String("b3rbg+mniw7p9aiPUyGthg==");

The key and IV can then be used in an instance of RijndaelManaged to decrypt encrytedBytes

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