The Cipher Challenge Contest
Four degrees of difficulty, from pen & paper to complex mathematical problems
Solved Level 1 challenge Advent-Challenge — Part 1
Solved Level 1 challenge Hill Cipher with Sudoku Key
Solved Level 1 challenge Cryptanalysis Hacking Puzzles — Part 1
Solved Level 1 challenge Recycled One-Time Pad
Solved Level 1 challenge Number Sequence — Part 6
Solved Level 1 challenge Multilingual Monoalphabetic Substitution
Solved Level 1 challenge Number Sequence — Part 3
Solved Level 1 challenge Number Sequence — Part 2
Four degrees of difficulty, from pen & paper to complex mathematical problems