Cipher Challenge
The Hidden Square
Polybius cipher. Each two-digit group identifies one cell in a 5 × 5 square: row first, then column. Rows and columns are numbered 1–5, I and J share one cell, and `/` marks a word break. The square was initialized from an undisclosed keyword by keeping each letter’s first appearance, then appending unused letters in alphabetical order.
Source & status
- Origin
- Original to Decipher
- Solution
- Established
Ciphertext
21 15 14 13 / 44 24 51 15 33 24 / 24 21 24 45 41 33 22 45 / 41 24 21 24 13 33 12 25 31 32 / 44 24 12 45 15 14 / 51 22 33 24 53 / 45 15 35 21 42 / 12 14 14 15 35 14 45 24 / 15 14 21 32 / 12 / 51 24 43 / 11 24 53 53 12 13 24 53 / 12 13 33 24 24 42 / 22 14 / 12 42 54 12 14 45 24 / 45 21 24 15 55 24 14 35 53 / 12 14 42 / 42 24 11 15 45 21 24 22 41 35 53 / 42 24 54 22 53 24 42 / 12 / 11 15 33 24 / 51 21 24 55 22 44 21 24 / 53 32 53 41 24 11 / 12 14 42 / 25 15 21 32 44 22 35 53 / 21 12 41 24 33 / 24 55 25 21 12 22 14 24 42 / 12 14 42 / 33 24 51 22 14 24 42 / 22 41 / 41 31 24 32 / 42 22 54 22 42 24 42 / 41 31 24 / 12 21 25 31 12 44 24 41 / 12 45 33 15 53 53 / 51 22 54 24 / 41 12 44 21 24 41 53 / 12 / 53 24 14 42 24 33 / 33 12 22 53 24 42 / 41 15 33 45 31 24 53 / 15 14 / 41 31 24 / 21 24 51 41 / 41 15 / 14 12 11 24 / 12 / 41 12 44 21 24 41 / 41 31 24 14 / 41 15 33 45 31 24 53 / 15 14 / 41 31 24 / 33 22 13 31 41 / 41 15 / 14 12 11 24 / 12 / 21 24 41 41 24 33 / 22 14 / 41 31 12 41 / 43 12 32 / 12 / 43 12 41 45 31 11 12 14 / 15 14 / 12 / 42 22 53 41 12 14 41 / 25 24 12 52 / 45 15 35 21 42 / 41 33 12 14 53 11 22 41 / 35 14 24 55 25 24 45 41 24 42 / 14 24 43 53 / 22 14 53 41 24 12 42 / 15 51 / 45 31 15 15 53 22 14 13 / 51 33 15 11 / 12 / 33 22 13 22 42 / 21 22 53 41 / 11 15 42 24 33 14 / 54 24 33 53 22 15 14 53 / 12 33 33 12 14 13 24 / 41 31 24 / 21 12 41 22 14 / 12 21 25 31 12 44 24 41 / 51 33 15 11 / 12 / 41 31 33 15 35 13 31 / 23 / 22 14 / 12 / 51 22 54 24 / 44 32 / 51 22 54 24 / 53 34 35 12 33 24 / 43 22 41 31 / 15 14 24 / 53 31 12 33 24 42 / 25 21 12 45 24 / 51 15 33 / 41 31 24 / 41 43 15 / 21 24 41 41 24 33 53 / 41 31 12 41 / 45 12 14 14 15 41 / 51 22 41 / 24 12 45 31 / 21 24 41 41 24 33 / 44 24 45 15 11 24 53 / 12 / 25 12 22 33 / 15 51 / 45 15 15 33 42 22 14 12 41 24 53 / 12 / 53 22 11 25 21 24 / 22 42 24 12 / 35 53 24 51 35 21 / 22 14 / 53 22 13 14 12 21 21 22 14 13 / 45 33 32 25 41 15 13 33 12 25 31 32 / 12 14 42 / 53 41 24 13 12 14 15 13 33 12 25 31 32