These are some crackmes. I wrote them to familiarize myself with reverse engineering, and to show off specific concepts and techniques. I wrote a tutorial about these crackmes as well.
To work with them, run make <name> where <name> is one of crackme01, crackme02, etc. Figure out how to make the crackme exit with the status code 0.
Don't ruin it for yourself by reading the source code! Enjoy.
These CRACKMEs are written in C. I intend soon to rewrite them all in Rust and give a short tutorial on cracking Rust programs.