The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 2 challenge ORYX Stream Cipher Part II
Solved Level 2 challenge ORYX Stream Cipher Part I
Solved Level 1 challenge Zodiac Cipher
Solved Level 1 challenge Advent-Challenge — Part 1
Solved Level 1 challenge Affine Codes / Modulo Arithmetic with N / Extended Euclid
Solved Level 1 challenge Number Sequence — Part 4
Solved Level 1 challenge Number Sequence — Part 3
Solved Level 2 challenge Assembly Point – Part 2
Four degrees of difficulty, from pen & paper to complex mathematical problems