I have tried to write some interesting and perhaps even original crackmes.Unless explicitly stated, I have used no anti-debugging code, no obfuscating
hide-a-tree-in-the-forest code, no stupid jumps, encryptors or packers.
I have tried to keep the file sizes small. However, all crackmes include source code (in encrypted form; you'll know the password for the source archive when you have cracked the particular crackme). The source code also includes all the resources used by the crackme. That's why the file sizes are what they are.
Name/Serial. My first crackme. I don't know how to explain this one without giving away all the nifty stuff about it. Let's say that a skilled cracker should not have too much trouble cracking this. But figuring out what's going on should be rather hard. Writing a keygen without knowing what's going on IS possible, Giggling Granny managed to do that
:-). A dead listing approach (preferably using IDA) will probably be very helpful, especially combined with a live debugger trace (who said softice?)
Name/Keyfile. Known as the "patience" crackme. Sporting a very clear and easy design, it should be possible for you to figure out the format of the keyfile in a reasonable amount of time (Cardenal Mendoza refers to this part of the keygen as fun.) However, and I forgot to mention this at first, to code a keyfile generator, you will need to create brute forcing program. This is certainly not RSA, but people seem to fear the word "bruteforce", and the thought of programming. The crackme has recently been updated to include a hint that will be very useful when programming the bruteforcer. Whether you find this hint or not is a matter of interest in the subject
Name / 2-part serial. The "pheer" crackme; whatever that means. My first attempt at introducing some obfuscation - hopefully interesting obfuscation rather than a shitload of trees so you can't see the forest.
FIXED -- Sorry for releasing a crackme with bugs... but please download the fix :(.
Keyfile. Lots of funny tricks. No dumb anti-debug. A bit of obfuscation, a bit of stuff that will make tracing a little harder (not really anti debugging, though :D). Well, just download it and have a look for yourself.