>I perhaps didn't explain that very well. Each character represents a module.
>
>For each module, I extract the relevant character from the string and take the ascii value of that character. I can then use bittest on that number to see which bits are set for that module e.g. 0 has no bits set, 1 has one bit set, 3 has 2 bits set etc. Each bit represents a particular user right in that module.

Space conservation gone mad...

This is Y2K all over again. 8-)
What happens if you want to add another user access level? move to a 9 bit character set?

Anyway - reading through this thread I had a thought
Are any of the user access levels mutually exclusive?

Bit   Setting
0     View
1     Edit
2     Insert
3     Delete
4     Errm.
5
6
7

If the user has Edit, Insert & Delete then maybe you could assume they also have view
This would free up bit 0 which means you could test for chr(255)