Match C# MD5 hashing algorithm with node.js

Question

Match C# MD5 hashing algorithm with node.js

I am having trouble matching a C# hashing algorithm with node, the problem seems to be the Unicode encoding. Is there a way to convert a string to Unicode then hash it and output it as hexadecimal? Unfortunately I cannot change the c# code, it is out of my control.

node algorithm

function createMd5(message) {
    var crypto = require("crypto");
    var md5 = crypto.createHash("md5");        
    return md5.update(message).digest('hex');
}

c# hashing algorithm

 private static string GetMD5(string text)
    {
        UnicodeEncoding UE = new UnicodeEncoding();
        byte[] hashValue;
        byte[] message = UE.GetBytes(text);
        using (MD5 hasher = new MD5CryptoServiceProvider())
        {
            string hex = "";
            hashValue = hasher.ComputeHash(message);
            foreach (byte x in hashValue)
            {
                hex += String.Format("{0:x2}", x);
            }

            return hex.ToLower();

        }
    }

c#
node.js
md5

Answer 1

Your suspicion of this being an encoding problem is correct. You can fix your node code with the following alteration, which will convert your message string into utf-16 (which is what .NET's default encoding is):

function createMd5(message) {
    var crypto = require("crypto");
    var md5 = crypto.createHash("md5");        
    return md5.update(new Buffer(message, 'ucs-2')).digest('hex');
}