I've made a small C++ application I am selling. My problem is that people are trying to crack it often.
I know its really simple, but I wasn't aware people was interested in cracking and leaking what I made. I am giving out licenses based on a date in the future, e.g. 2023-12-18 19:51:49 (18th of December 2023). I am then taking the string string and RC4 encrypt it and base64 encode it. This results in some "license": 0qAhemNdtHL5zI3D+B8zx1/psQ== they can insert into their config.
The small application then decodes and decrypts the "license" and parses the time. It then comepares with time-now, also from http://just-the-time.appspot.com.
A guy wrote me that he easily cracked it by just changing the time returned by http://just-the-time.appspot.com. How would you mitigate this? If I am looking at the local time on the PCs people may just easier adjust the time.
Hope someone can help or lead me into a direction where I can read about this subject!