The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 2 challenge Alice's Birthday Party (Part 1)
Solved Level 1 challenge Number Sequence
Solved Level 2 challenge Monoalphabetic substitution with camouflage — Part 3
Solved Level 2 challenge A Cloaked Substitution Cipher — Part 1
Solved Level 2 challenge Homophonic Encryption — Part 3
Solved Level 2 challenge Homophonic Encryption — Part 4
Solved Level 2 challenge Modified Vigenère Cipher
Solved Level 2 challenge Spanish Strip Cipher — Part 2
Four degrees of difficulty, from pen & paper to complex mathematical problems