MULTI2 [SEP] designer
MULTI2
MULTI2 is a block cipher, developed by Hitachi in 1988. Designed for general-purpose cryptography, its current use is encryption of high-definition television broadcasts in Japan.
Cipher details.
MULTI2 is a symmetric key algorithm with variable number of rounds. It has a block size of 64 bits, and a key size of 64 bits. A 256-bit implementation-dependent substitution box constant is used during key schedule. Scramble and descramble is done by repeating four basic functions (involutions).
History.
for interactive interfaces like data broadcasting (ARIB STD-B24) and electronic program guides (EPG).
Introduction Interfaces and Encryption.
The ISDB specification describes a lot of (network) interfaces, but most importantly the Common Interface for Conditional Access System (CAS). While ISDB has examples of implementing various kinds of CASes, in Japan CAS called "B-CAS" is used. (ARIB STD-B25) defines the Common Scrambling Algorithm (CSA) system called MULTI2 required for (de-)scrambling television.
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