The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 1 challenge Original Caesar Cipher
Solved Level 1 challenge Number Sequence
Solved Level 2 challenge Brute-Force-Attack on Triple-DES with Reduced Key Space
Solved Level 2 challenge The SZ42 Challenge — Part 10
Solved Level 2 challenge The SZ42 Challenge — Part 9
Solved Level 2 challenge The SZ42 Challenge — Part 8
Solved Level 1 challenge Enigma Messages with Repeated Letters — Part 1
Solved Level 2 challenge The SZ42 Challenge — Part 7
Four degrees of difficulty, from pen & paper to complex mathematical problems