Testing the hypothesis: d'Agapeyeff accidentally double-decrypted instead of double-encrypting. Recovery = apply double columnar transposition (encrypt) to the decoded pairs.
| col 1 | col 2 | col 3 | col 4 | col 5 | |
|---|---|---|---|---|---|
| row 6 | 61 | 6217 | 6312 | 6416 | 6511 |
| row 7 | 711 | 729 | 73 | 7414 | 7517 |
| row 8 | 8120 | 8217 | 8315 | 8411 | 8517 |
| row 9 | 9112 | 923 | 932 | 941 | 95 |
| row 0 | 01 | 02 | 03 | 041 | 05 |
Grey number = pair code · right number = frequency · dim = unused in cipher
0/18 active pairs mapped
How it works
1. Map each pair to a letter using the Polybius square (left).
2. Arrange the 196 decoded letters into a grid of key-length columns, then read columns in alphabetical key order — twice.
★ Double Encrypt should produce readable English if the hypothesis and key are correct.
196 unmapped pairs shown as ?
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