Fatmike, this crackme sounds interesting, and with that list of “features” you're really pulling it off. The challenge of unpacking and cracking it, plus finding the serial or writing a keygen, looks like a good warm-up for a boring day.

The “self-made cipher” part is always a risk, because sometimes those homemade implementations are easier to crack than standard ones. If you really want a solid challenge, better combine with something more robust.

The disclaimer about Windows Defender returning false positives is a classic. Anything fun tends to scare AVs, so no surprise there.

I'll take a look at it and if I break it, I'll pass on the solution.