The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 1 challenge Number Sequence — Part 5
Solved Level 3 challenge The SIGABA Challenge — Part 3
Solved Level 2 challenge The SIGABA Challenge — Part 2
Solved Level 2 challenge The SIGABA Challenge — Part 1
Solved Level 1 challenge Caesar Encryption
Solved Level 3 challenge Sigaba Part 2
Solved Level 1 challenge Strange Message from Thessaloniki
Solved Level 1 challenge How do you become a big cryptographer?
Four degrees of difficulty, from pen & paper to complex mathematical problems