Specifications
| Format | Challenges |
|---|---|
| Level | Intermediate, Advanced |
| Price | Free |
| Access | No registration |
| Activity | Active |
| Language | EN |
| Category | Cryptography |
Cryptography exercises that climb from raw bytes and XOR to AES, Diffie-Hellman, RSA and DSA, then hashing and the group theory underneath. You implement the primitive yourself; nothing is simulated and nothing is submitted. The site sits in the open and publishes no task counter.
Pros & cons
Pros
- Each set depends on the one before it
- The breaks reproduce real published mistakes, not invented ones
- Runs in the open, with no account and no submission step
Cons
- It opens at the primitives: without modular arithmetic you stall early
- English only, and the community writeup trail is thinner than on CryptoHack
- No grader either: a wrong implementation just fails and says nothing
Who it fits
Suits someone who can already explain how a cipher works and wants to learn where it breaks. It is the second half of a cryptography course rather than the first.
Getting started
- Clear the opening sets before touching any solutions, later ones assume them
- Take the tasks in order inside each set: difficulty climbs task by task
- Write the primitive yourself and check it against a reference implementation
History
The tasks were written from real cryptographic mistakes rather than assembled for tidiness, and each reproduces a known failure, which is why several have held up better than their difficulty suggested. The material runs in a plain text editor and has not been rewritten. Checked.
