The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 2 challenge Unusual encryption using a diophantine equation
Solved Level 2 challenge Partial Key Exposure with RSA — Part 1
Solved Level 2 challenge RSA: Two different keys — same ciphertext
Solved Level 2 challenge PX-1000 Encryption – Part 1
Solved Level 2 challenge Holographic Encryption — Part 2
Solved Level 2 challenge Hill Cipher
Solved Level 2 challenge Monoalphabetic Substitution with Nostradamus Flavor
Solved Level 2 challenge Differential Cryptanalysis — Part 2
Four degrees of difficulty, from pen & paper to complex mathematical problems