Simple obfuscation of string in .NET?

Question

I need to send a string of about 30 chars over the internet which will probably end up as an ID in a another company's database.

While the string itself will not be identifying, I would still like it not to be recognisable in any way.

What is the easiest way to obfuscate such a string in .NET, so that it can be easily reversed when necessary?

Answer 1

How about something classical (with a modern twist).

public static string Caesar(this string source, Int16 shift)
{
    var maxChar = Convert.ToInt32(char.MaxValue);
    var minChar = Convert.ToInt32(char.MinValue);

    var buffer = source.ToCharArray();

    for (var i = 0; i < buffer.Length; i++)
    {
        var shifted = Convert.ToInt32(buffer[i]) + shift;

        if (shifted > maxChar)
        {
            shifted -= maxChar;
        }
        else if (shifted < minChar)
        {
            shifted += maxChar;
        }

        buffer[i] = Convert.ToChar(shifted);
    }

    return new string(buffer);
}

Which obviously you would use like this

var plain = "Wibble";
var caesered = plain.Caesar(42);
var newPlain = caesered.Caesar(-42);

Its quick, your key is just an Int16 and it will prevent the casual observer from copy pasting the value but, its not secure.

Answer 2

How about:

    Convert.ToBase64String(Encoding.UTF8.GetBytes(myString));

and its converse:

    Encoding.UTF8.GetString(Convert.FromBase64String(myObfuscatedString));

as long as you don't mind an increase in the length of your string