Discussió:Xifratge de Vigenère

Vulnerability of Vigenère method

Maybe it should be noted somewhere that the Vigenère method, combined with the 3 Shannon's requirements is indeed invulnerable.

Just recalling the 3 Shannon requirements:

1. Size of the key should be longer or equal to the text to encrypt
2. The key should be used only once
3. Key should be perfectly random

More generally, any poly-alphabetic substitution method respecting the 3 Shannon's requirements is invulnerable.

Don't know if this comment should go here or in some other article. Saw a reference to Shannon in Bloc d'un sol ús.

The best approach would be to have an entry for Shannon's requirements for an invulnerable cryptographic method, but my catalan does not allow me to do such an entry. :-( Nikator (disc.) 12:59, 6 des 2013 (CET)