id0-rsa
Write code to break poorly implemented cryptography
id0-rsa is a list of problems about badly implemented cryptography. Each problem gives you data such as ciphertexts, keys or hashes and a short story, and you write a program in any language to recover the answer.
Free · No login · Browser · Intermediate
About id0-rsa
It trains applied cryptography, including hashing, RSA, PGP and classical ciphers, through programming. Tutorial problems ease you in, so it suits programmers who are new to crypto as well as people who already know it.
It runs in the browser and you solve problems with your own tools. There is a leaderboard and a login for tracking solves.
On Breakpoint since 25 Oct 2026.
Made this game? Claim it →
Tips and discussion
No tips yet. Solved it? Share how, and wrap answers in ||spoilers||.