Cryptopals

Learn security through challenges. SSH-based hacking games.

Learn cybersecurity through hands-on exercises. Guided hacking rooms.

Bruce Schneier's security blog. Cryptographer and security expert writing since 2004.

Founder of Signal. Writing on cryptography, privacy, security, and the intersection of technology and society.

Cryptographer, Go security lead. Creator of mkcert. Deep technical posts on cryptography and security.

Matthew Green's blog on cryptography and security. Accessible explanations of complex crypto topics.