picoCTF is a free computer security game targeted at middle and high school students. The game consists of a series of challenges centered around a unique storyline where participants must reverse engineer, break, hack, decrypt, or do whatever it takes to solve the challenge.

The world's longest-running and most prestigious hacking competition. Teams compete in a grueling 72-hour attack-defense competition where they must both attack other teams' services and defend their own.

A massive CTF event featuring challenges across all categories. Join thousands of hackers worldwide in this epic cybersecurity competition.

Google's annual Capture The Flag competition featuring challenging puzzles and real-world security scenarios. Open to participants worldwide.