The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 1 challenge Affine Codes / Modulo Arithmetic with N / Extended Euclid
Solved Level 2 challenge Letter to the Templars — Part 3
Solved Level 1 challenge A hidden word
Solved Level 1 challenge Letter to the Templars — Part 1
Solved Level 1 challenge Bigram Substitution – Part 1 (Tutorial)
Solved Level 1 challenge New Year's Greetings — Part 4
Solved Level 1 challenge New Year's Greetings — Part 3
Solved Level 1 challenge New Year's Greetings — Part 2
Four degrees of difficulty, from pen & paper to complex mathematical problems