NodeJS | Crypto Encryption is not producing correct results - node.js

Question

I have a tricky problem to resolve. Not sure how to explain it correctly but will try my best. So here is what I am trying to do: I am trying to use a 3rd Party API, which wants me to encrypt a value and submits it. I successfully achieved it through C# code using the following block:
public string Encrypt(byte[] dataToEncrypt, byte[] keyBytes)
{
AesManaged tdes = new AesManaged();
tdes.KeySize = 256;
tdes.BlockSize = 128;
tdes.Key = keyBytes;
tdes.Mode = CipherMode.ECB;
tdes.Padding = PaddingMode.PKCS7;
ICryptoTransform crypt = tdes.CreateEncryptor();
byte[] cipher = crypt.TransformFinalBlock(dataToEncrypt, 0, dataToEncrypt.Length);
tdes.Clear();
return Convert.ToBase64String(cipher, 0, cipher.Length);
}
Now, I am trying to achieve the same in Node. I wrote the following function.
encrypt(buffer){
var buffbytes = new Buffer('my app key goes here to be used as password','utf8'); //converts the app key into buffer stream
return this.encrypt_key(new Buffer(buffer,'utf8'), buffbytes);
},
encrypt_key(buffer, keybytes){
var cipher = crypto.createCipher('aes-128-ecb',keybytes);
var crypted = cipher.update(buffer,'utf8','base64');
crypted = crypted+ cipher.final('base64');
return crypted;
},
This encryption code works fine. It encrypts it fine, but it doesn't encrypt it similar to what c# code does. When I take the encrypted text from C# code, and inject the encrypted result into the API call, it passes through fine, but when I use my encrypted result into the API call, it fails mentioning that the format of my key is incorrect.
I would like to know if these code blocks are same or not. I assume it is same, because both code using 128 bit AES, ECB Cipher and default padding for Crypto Node module is PKCS5 which is same as PKCS7 for 128 bit encryption. Please Help!
Edit: 9/19/2017
Fixed as per #smarx solution:
encrypt(buffer){
var buffbytes = new Buffer(helper.Constants.AppKey,'utf8'); //converts the app key into buffer stream
return this.encrypt_key(new Buffer(buffer,'utf8'), helper.Constants.AppKey);
},
encrypt_key(buffer, key){
var cipher = crypto.createCipheriv('aes-256-ecb',key,new Buffer(0));
var crypted = cipher.update(buffer,'utf8','base64');
crypted = crypted+ cipher.final('base64');
console.log('printed: ', crypted);
return crypted;
},

Answer 1

In your Node.js code, you're using the wrong cipher algorithm. Use aes-256-ecb, since you're using a 256-bit key. Also, be sure to use createCipheriv, since createCipher expects a password from which it derives an encryption key.
One-line fix:
const cipher = crypto.createCipheriv('aes-256-ecb', key, new Buffer(0));
The below two programs produce identical output (Q9VZ73VKhW8ZvdcBzm05mw==).
C#:
var key = System.Text.Encoding.UTF8.GetBytes("abcdefghijklmnopqrstuvwxyz123456");
var data = System.Text.Encoding.UTF8.GetBytes("Hello, World!");
var aes = new AesManaged {
Key = key,
Mode = CipherMode.ECB,
};
Console.WriteLine(Convert.ToBase64String(
aes.CreateEncryptor().TransformFinalBlock(data, 0, data.Length)));
Node.js:
const crypto = require('crypto');
const key = 'abcdefghijklmnopqrstuvwxyz123456';
const data = 'Hello, World!';
const cipher = crypto.createCipheriv('aes-256-ecb', key, new Buffer(0));
console.log(cipher.update(data, 'utf-8', 'base64') + cipher.final('base64'));