The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 2 challenge Cracking SHA1-Hashed Passwords
Solved Level 2 challenge Enigma Part 2
Solved Level 2 challenge Not-so-Secret Message from Malawi — Part I (RSA)
Solved Level 2 challenge RSA: Two different keys — same ciphertext
Solved Level 2 challenge Enigma Part 1
Solved Level 2 challenge Factorization Cipher — Part 2
Solved Level 2 challenge Broadcasting and low exponent — RSA Attack
Solved Level 1 challenge Enigma Messages with Repeated Letters — Part 5
Four degrees of difficulty, from pen & paper to complex mathematical problems