for fun, while debugging this lib we pay out of the ass for at work, I decided to look at the license keys

It's converted from base 64, then you XOR it all with a secret byte, then you XOR everything with the first byte

if you know how XOR works, it means you end up doing

array[i] ^ 0xCA ^ array[0] ^ 0xCA

or, simplified

array[i] ^ array[0]

whoops