[patched] - Auto-key Crack Only

The standard attack on Autokey does not rely on frequency distribution of letters, but on the relationship between the ciphertext and a guessed plaintext fragment.

In a standard Vigenère, these streams are static shifts (Monoalphabetic). In Autokey, Stream $k$ is dependent on previous characters in Stream $k$. auto-key crack only

While there are statistical methods (like using the Index of Coincidence to test for non-periodicity), the most direct attack involves the "Kasiski method" of dragging cribs. By testing potential primer lengths $N$, an analyst looks for coherent text. The standard attack on Autokey does not rely

2026-04-14 Subject: Vulnerability assessment of auto-key (autokey) cipher modes or standard headers like "TO THE".

Assume the attacker guesses a probable word in the plaintext (a "crib"). Common cribs in English include "THE", "AND", "TION", or standard headers like "TO THE".