Working through the exercises in Cryptography Engineering (Schneier, Ferguson & Kohno) I have stalled on the following exercise: Consider a new block cipher, DES2, that consists only of two ...
DES uses 16 rounds of feistel networks but not considered secure . Where Luby Rackoff constructions which are inspired by DES its proven by Patarin that 7 rounds is secure . Is there a relation ...
I don't understand what an active s-box is (in reference of design criteria 8 of the DES). Because according to DES, all 8 s-boxes are used every round. But this is not what active means. So my ...
There is a problem with using DES as the block cipher in OFB mode, eg: the feedback that goes back into the next round will be encrypted with the same key $k$ resulting back into the plaintext IV used ...
I couldn't understand the avalanche effect in DES. Could someone explain how avalanche effect happens in DES