TheCodeBreakers
on "The Decipherment of French Writing"—a rather ominous portent in a
book dedicated to the Count Albrecht von Roon, the Prussian minister of
war who molded the army that humbled France only seven years later.)
The polyalphabetic solution opened the doors to the cryptology of today.
But the 95-page volume seems to have stirred almost no comment at the
time. Kasiski himself lost interest in cryptology. He became an avid
amateur anthropologist, joining the Natural Science Society of Danzig,
unearthing prehistoric graves, and reporting on his work to learned
journals. (One of his scholarly articles was cited in the Encyclopaedia
Britannica.) Kasiski died on May 22, 1881, almost certainly without
realizing that he had wrought a revolution in cryptology.
That revolution began when Kasiski shrewdly noted a phenomenon:
the conjunction of a repeated portion of the key with a repetition in the
plaintext produces a repetition in the ciphertext:
key RTJNRTJNRUNRUNRTJNRUNRUNRTJNRtJNRUN
annaabi.ee 
