This is a software copy protection imitation, which uses a key file. The key file contain a user (or customer) name and a serial number.
There are two tasks:
(Easy) with the help of any debugger, force the program to accept a changed key file.
(Medium) your goal is to modify the user name to another, without patching the program.
More challenges: //challenges.re/; about solutions: //challenges.re/#Solutions.