From Sixteenth-Century Cryptography to the New Millennium — The Last 500 Years - Codes: The Guide to Secrecy from Ancient to Modern Times - page 77

4. Cryptosystems must be amenable to being sent by telegraph.
5. The mechanisms of the cryptosystem must be easily portable and entirely
operable by a single entity.
6. The cryptosystem must be easy to use, without reference to any manuals, or
the need for deep mental effort.
These six tenets are, of course, utopian in nature. Even modern-day ciphers
would struggle to achieve all six conditions (where we can replace telegraph by
computer in condition 4). Also, the second condition basically says (and this is
implicit in his aforementioned principle) that secrecy lies in the keys and not
in the cipher itself. Later, when we delve into modern ciphers, we will see that
this is as true today as ever. “Key Management”, as it has come to be known,
is essential since a cryptanalyst who can break a key is better off than one who
knows only the cryptosystem itself. Kerckhoffs' topic stands tall as one of the
great topics on cryptology.
We close this section with a story about a French military oQcer at the end
of the nineteenth century, wherein cryptology played a crucial role.
The Dreyfus Affair
On October 15, 1894, Captain Alfred Dreyfus was arrested and charged
with high treason by the French government which claimed evidence that he
had given military secrets to German and Italian oQcials. An Italian military
attache, Colonel Alessandro Panizzardi, later sent a cryptogram to Rome, which
was intercepted by French cryptanalysts. Part of the deciphered message said:
“If Captain Dreyfus has not had relations with you, it would be wise to have
the ambassador deny it oQcially, or avoid press comment.” This seemed to
indicate that Panizzardi disavowed any contact with Dreyfus. In order to be
certain, the French decided to trick Panizzardi into sending a telegram whose
contents were known to them, for then they would have the key to decryption
of what he had sent. Panizzardi bought the ruse, enciphered the telegram, and
sent it to Rome. Subsequently, the French were able to verify the deciphering
of the original message. Nevertheless, this failed to exonerate Dreyfus, since
certain individuals would rather have had an innocent man go to prison than to
admit an error had been made in his arrest. Thus, they prevented the telegram
from being admitted at his trial. Hence, Dreyfus was convicted of treason, and
sent to Devil's Island. Upon appeal, the telegram was admitted, but it would
take several years before he would see justice. When exoneration did come, it
included reinstatement in the Legion of Honour. The true criminal in the matter
was arrested. Major Ferdinand Walsin Esterhazy had used several cardboard
(Cardano) grilles that implicated him in having secret correspondence with a
German attache.
We now turn to the dawn of the twentieth century, with a world war brewing
and a major sequence of turning points for the advancement of cryptology. Stay
tuned, for the stories get better.