AES encryption method in NodeJS similar to C sharp function

Question

I have a function written in C#. Basically the function is used to generate a token on the basis of parameters like text and key.

public string Encrypt(string input, string key) {
     byte[] keyArray = UTF8Encoding.UTF8.GetBytes(key);
     byte[] toEncrptArray = UTF8Encoding.UTF8.GetBytes(input);
     Aes kgen = Aes.Create("AES");
     kgen.Mode = CipherMode.ECB;
     kgen.Key = keyArray;
     ICryptoTransform cTransform = kgen.CreateEncryptor();
     byte[] resultArray = cTransform.TransformFinalBlock(toEncrptArray, 0, toEncrptArray.Length);

     return Convert.ToBase64String(resultArray, 0, resultArray.Length);
   }

I'm trying to search any same alternative for the above function in NodeJS or run this function inside the NodeJS script through any compiler.

I have tried the crypto-js module in NodeJS but got a different token string. Please suggest the alternative function or any idea about running this function inside the NodeJS script.

My Recent code in NodeJS :

First Method :

var CryptoJS = require("crypto-js");

// Encrypt
var ciphertext = CryptoJS.AES.encrypt("<input>", "<key>").toString();

Second Method :

var crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = '<key>';

function encrypt(text){
  var cipher = crypto.createCipher(algorithm,password)
  var crypted = cipher.update(text,'utf8','hex')
  crypted += cipher.final('hex');
  return crypted;
}

Both the method is giving different token if compared to C# function.

This is simply AES with ECB mode (ECB is insecure by the way). This can be implemented both with CryptoJS and the crypto module from NodeJS. Post your most recent code. — Topaco
– Topaco, Commented Jul 2, 2020 at 8:38
@Topaco: Added recent Nodejs code in the question asked. Please take a look and suggest it. — shiva
– shiva, Commented Jul 2, 2020 at 9:03

Terry Lennox · Accepted Answer · 2020-07-02 09:12:50Z

4

The AES algorithm used in the C# code is AES 128-bit in ECB mode.

We can perform the same encryption in Node.js (and decrypt as well if we wish), using the following code:

Node.js Code

const crypto = require("crypto");

function encrypt(plainText, key, outputEncoding = "base64") {
    const cipher = crypto.createCipheriv("aes-128-ecb", key, null);
    let encrypted = cipher.update(plainText, 'utf8', outputEncoding)
    encrypted += cipher.final(outputEncoding);
    return encrypted;
}

function decrypt(cipherText, key, outputEncoding = "utf8") {
    const cipher = crypto.createDecipheriv("aes-128-ecb", key, null);
    let encrypted = cipher.update(cipherText)
    encrypted += cipher.final(outputEncoding);
    return encrypted;
}

const KEY = Buffer.from("abcdefghijklmnop", "utf8");

console.log("Key length (bits):", KEY.length * 8);
const encrypted = encrypt("hello world", KEY, "base64");
console.log("Encrypted string (base64):", encrypted);

// And if we wish to decrypt as well:
const decrypted = decrypt(Buffer.from(encrypted, "base64"), KEY, "utf8")
console.log("Decrypted string:", decrypted);

C# Code

using System;
using System.Text;
using System.Security.Cryptography;

public class Program
{
    public static void Main()
    {
        Console.WriteLine("Result: " + Encrypt("hello world", "abcdefghijklmnop"));
    }
    
    public static string Encrypt(string input, string key) {
     byte[] keyArray = UTF8Encoding.UTF8.GetBytes(key);
     byte[] toEncrptArray = UTF8Encoding.UTF8.GetBytes(input);
     Aes kgen = Aes.Create("AES");
     kgen.Mode = CipherMode.ECB;
     kgen.Key = keyArray;
     ICryptoTransform cTransform = kgen.CreateEncryptor();
     byte[] resultArray = cTransform.TransformFinalBlock(toEncrptArray, 0, toEncrptArray.Length);

     return Convert.ToBase64String(resultArray, 0, resultArray.Length);
   }
}

The results for the encryption (with plaintext and key as above) are:

.Net: f7sSBDV0N6MOpRJLpSJL0w==
Node.js: f7sSBDV0N6MOpRJLpSJL0w==

Obviously we must not use this key in production!

edited Jul 2, 2020 at 9:12

answered Jul 2, 2020 at 9:04

Terry Lennox

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2 Comments

shiva Over a year ago

Thanks @Terry You saved a lot of my time. It's working fine as of my expectations

Terry Lennox Over a year ago

No problem! It can be very tricky getting encryption / decryption working in the same way in different languages!

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