llXorBase64Strings - how is it implemented?

Hi all. I need to implement function outside SL (in C#) that mimics the behaviour of this function. I've implemented one similar to the one shown in the Wiki entry, but neither
that Python version, nor my C# version, work under some circumstances.
It looks like something to do with padding as it only seems to go wrong when s2 has to be repeated to make it longer that s1 (in at about that position), but not always.

Does anyone have an alternative implementation or some idea exactly how it is implemented?

Thanks.

I have noticed strange behaviour too with XOR in SL. If you send a string from SL to FL using llXorBase64 you can get it in the remote and you can decode it without a problem, but when sending a string from FL to SL, the XOR does not manage well the last characters in the string.

I developed a XOR function in perl that does the same that in LSL (cycling the key if the data is greater in length).

By now, I'm enclosing my strings ( {string}) to detect start and end, so I can ignore the strange data at the end of the string.

Guys i am trying to do the same thing in C#. any chance of some sample code or have you found a better way to secure the data?