TheCodeBreakers
It provided a
priming key. This consisted of a single letter, known to both encipherer
and decipherer, with which the decipherer could decipher the first
cryptogram letter and so get a start on his, work. With this, he would get
the first plaintext letter, then use this as the key to decipher the second
cryptogram letter, use that plaintext as the key to decipher the third
cryptogram letter, and so on.
key DA UNO MD ELETERNE
plain au nom de léternel
cipher XI AHG UP TMLSHIXT
The system works well and affords fair guarantees of security; it has
been embodied in a number of modern cipher machines.
In spite of Vigenere's clear exposition of his technique, it was entirely
forgotten and only entered the stream of cryptology late in the 19th
century after it had been reinvented. Writers on cryptology then added