Codebreaker – recover the unknown key

Crack an unknown Caesar shift or Vigenère keyword in limited attempts. Analyse feedback, refine your theory and recover the key.

A deduction game, not random guessing

Every attempt is evidence

Test a key, compare the result and narrow the remaining possibilities. A strict attempt limit rewards a planned line of reasoning.

Two different attacks

Caesar challenges ask for one alphabet shift; Vigenère challenges ask you to trace a repeating keyword across positions. Each mode demands a different strategy.

Think like a cryptanalyst

Use letter frequency, repeated patterns and probable plaintext fragments. Record what each experiment proves before making the next move.