I have a piece of software im learning on and an authentication box comes up with customer code : AC76F-111B6-7F3C5
im guessing its not crypkey any ideas anyone ? not sure were to start with this one . Underneath the customer code there is a box to put a vendor key in. Which tools can I use to find out the vendor key this one is just pure learning purposes.

kind regards

Ross

A disassembler and a debugger would probably be a good start.

Thanks I have got ollydbg just got to learn how to use it properly and which executable modules to look in ? Thanks for your reply.

You may want to look at Lena's tut. I believe the first one or first two (don't recall) covers trial-version/hardcoded code. The point is that it may give you an idea on how to work this one.