Make JAVA MD5 hash match C# MD5 hash

Question

My job is to rewrite a bunch of Java codes is C#. This is the JAVA code:

        public static String CreateMD5(String str) {
    try {
        byte[] digest = MessageDigest.getInstance("MD5").digest(str.getBytes("UTF-8"));
        StringBuffer stringBuffer = new StringBuffer();
        for (byte b : digest) {
    // i can not understand here
            stringBuffer.append(Integer.toHexString((b & 255) | 256).substring(1, 3));
        }
        return stringBuffer.toString();
    } catch (UnsupportedEncodingException | NoSuchAlgorithmException unused) {
        return null;
    }
}

Ok.As you can see this code is trying to make MD5 hash.But the thing i can not understand is the part that i have shown. I tried this code in C# to rewrite this JAVA code:

    public static string CreateMD5(string input)
    {
// Use input string to calculate MD5 hash
using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
{
    byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
    byte[] hashBytes = md5.ComputeHash(inputBytes);

    // Convert the byte array to hexadecimal string
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < hashBytes.Length; i++)
    {
        sb.Append(hashBytes[i].ToString("X2"));
    }
    return sb.ToString();
}
    }

Well both codes are making MD5 hash strings but the results are different.

Answer 1

There is a difference in encoding between the two code snippets you've shown - your Java code uses UTF-8, but your C# code uses ASCII. This will result in a different MD5 hash computation.

Change your C# code from:

byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);

to:

byte[] inputBytes = System.Text.Encoding.UTF8.GetBytes(input);

This should ™ fix your problem, provided there are no other code conversion errors.