Two�sh: A 128-Bit Block Cipher

[Nytro]

Twosh: A 128-Bit Block Cipher

Twosh: A 128-Bit Block Cipher

Bruce Schneier, John Kelseyy, Doug Whiting,z David Wagnerx, Chris Hall, Niels Ferguson

15 June 1998

Twosh is a 128-bit block cipher that accepts a variable-length key up to 256 bits. The cipher is a

16-round Feistel network with a bijective F function made up of four key-dependent 8-by-8-bit S-boxes,

a xed 4-by-4 maximum distance separable matrix over GF(28), a pseudo-Hadamard transform, bitwise

rotations, and a carefully designed key schedule. A fully optimized implementation of Twosh encrypts

on a Pentium Pro at 17.8 clock cycles per byte, and an 8-bit smart card implementation encrypts at

1660 clock cycles per byte. Twosh can be implemented in hardware in 14000 gates. The design of both

the round function and the key schedule permits a wide variety of tradeos between speed, software size,

key setup time, gate count, and memory. We have extensively cryptanalyzed Twosh; our best attack

breaks 5 rounds with 222:5 chosen plaintexts and 251 eort.

Download:

http://www.thc.org/root/docs/cryptography/twofish-paper.pdf

[cmiN]

Smecher ... si gost crypterul. Am postat mai mult fiindca am vazut ca au un articol foarte interesant legat de cum sa postezi "adecvat" pe un forum. Cine stie poate merge putin un update la regulament inspirat dupa el.