The Crypto Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 1 challenge Enigma Messages
Solved Level 1 challenge A hidden word — Part 2
Solved Level 1 challenge Double Columnar Transposition
Solved Level 1 challenge Playfair with hints about the grid
Solved Level 1 challenge Number Sequence — Part 3
Solved Level 1 challenge Letter to the Templars — Part 1
Solved Level 1 challenge Number Sequence — Part 2
Solved Level 1 challenge Caesar Encryption
Four degrees of difficulty, from pen & paper to complex mathematical problems