Using node.js to decrypt data encrypted using c#

问题

I'm facing a issue now which need you guys help.

I use c# to do some encryption. Then need to use node.js to decry-pt it. But I just found that I can't do it correctly base on my c# encryption algorithm. If you guys have any solution, please help me.

Here is my c# encryption code:

public static string Encrypt(string text, String password, string salt, string hashAlgorithm, int passwordIterations, string initialVector, int keySize)
{
    if (string.IsNullOrEmpty(text))
        return "";

    var initialVectorBytes = Encoding.ASCII.GetBytes(initialVector);
    var saltValueBytes = Encoding.ASCII.GetBytes(salt);
    var plainTextBytes = Encoding.UTF8.GetBytes(text);
    var derivedPassword = new PasswordDeriveBytes(password, saltValueBytes, hashAlgorithm, passwordIterations);
    var keyBytes = derivedPassword.GetBytes(keySize / 8);
    var symmetricKey = new RijndaelManaged();
    symmetricKey.Mode = CipherMode.CBC;
    byte[] cipherTextBytes = null;
    using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, initialVectorBytes))
    {
        using (var memStream = new MemoryStream())
        {
            using (var cryptoStream = new CryptoStream(memStream, encryptor, CryptoStreamMode.Write))
            {
                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
                cryptoStream.FlushFinalBlock();
                cipherTextBytes = memStream.ToArray();
                memStream.Close();
                cryptoStream.Close();
            }
        }
    }
    symmetricKey.Clear();
    return Convert.ToBase64String(cipherTextBytes);
}
public static string Decrypt(string text, String password, string salt, string hashAlgorithm, int passwordIterations, string initialVector, int keySize)
{
    if (string.IsNullOrEmpty(text))
        return "";

    var initialVectorBytes = Encoding.ASCII.GetBytes(initialVector);
    var saltValueBytes = Encoding.ASCII.GetBytes(salt);
    var cipherTextBytes = Convert.FromBase64String(text);
    var derivedPassword = new PasswordDeriveBytes(password, saltValueBytes, hashAlgorithm, passwordIterations);
    var keyBytes = derivedPassword.GetBytes(keySize / 8);
    var symmetricKey = new RijndaelManaged();
    symmetricKey.Mode = CipherMode.CBC;
    var plainTextBytes = new byte[cipherTextBytes.Length];
    var byteCount = 0;
    using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, initialVectorBytes))
    {
        using (var memStream = new MemoryStream(cipherTextBytes))
        {
            using (var cryptoStream = new CryptoStream(memStream, decryptor, CryptoStreamMode.Read))
            {

                byteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                memStream.Close();
                cryptoStream.Close();
            }
        }
    }
    symmetricKey.Clear();
    return Encoding.UTF8.GetString(plainTextBytes, 0, byteCount);    
}

If anyone can give me a same function for nodejs, that's will be really help. Anyway, thanks for read this post.

回答1:

First, we'll do the PasswordDeriveBytes function with Node.js. This is crypto.pbkdf2:

// assumes HMAC-SHA1
crypto.pbkdf2(password, salt, iterations, keySize / 8, function(err, key) {
    if(err) /* handle error */
    // ...
});

Next, use crypto.createDecipheriv to create a decryptor:

// find algorithm from the available ciphers; see crypto.getCiphers()
var decipher = crypto.createDecipheriv(/* algorithm */, key, initialVector);

Then use decipher.update and decipher.final to feed it the data. They will return portions of decrypted data to you.

回答2:

Having the exact same scenario I was able to get to a successful "C# encrypt => Node decrypt" solution using the code provided by @icktoofay above, but with the PasswordDeriveBytes replaced with Rfc2898DeriveBytes

My code is roughly:

private byte[] saltBytes = ASCIIEncoding.ASCII.GetBytes(salt);

public string Encrypt<T>(string value, string password) where T: SymmetricAlgorithm, new() {
  byte[] valueBytes = UTF8Encoding.UTF8.GetBytes(value);

  byte[] encrypted = null;
  using (T cipher = new T()) {
    var db = new Rfc2898DeriveBytes(password, saltBytes);
    db.IterationCount = iterationsConst;
    var key = db.GetBytes(keySizeConst / 8);

    cipher.Mode = CipherMode.CBC;

    using (ICryptoTransform encryptor = cipher.CreateEncryptor(key, vectorBytes)) {
      using (MemoryStream ms = new MemoryStream()) {
        using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write)) {
          cs.Write(valueBytes, 0, valueBytes.Length);
          cs.FlushFinalBlock();
          encrypted = ms.ToArray();
        }
      }
    }
    cipher.Clear();
  }
  return Convert.ToBase64String(encrypted);
}

JavaScript:

var crypto = require('crypto');
var base64 = require('base64-js');
var algorithm = 'AES-256-CBC';

[...]

var saltBuffer = new Buffer(salt);
var passwordBuffer = new Buffer(password);

[...]

var encodedBuffer = new Buffer(base64.toByteArray(encryptedStringBase64Encoded));

crypto.pbkdf2(passwordBuffer, saltBuffer, iterations, keySize / 8, function(err, key) {
  var decipher = crypto.createDecipheriv(algorithm, key, iv);
  var dec = Buffer.concat([decipher.update(encodedBuffer), decipher.final()]);
  return dec;
});

and is actually a combination of a few examples I found on the Internet.

Because I had a problem with the Buffer's implementation of Base64 in some specific cases ('+' sign at the beginning of the encoded string), I used base64-js from https://github.com/beatgammit/base64-js, which seems to work fine.

来源：https://stackoverflow.com/questions/16270740/using-node-js-to-decrypt-data-encrypted-using-c-sharp

标签

node.js

encryption

cryptography

rijndael