In cryptography

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

, MMB (Modular Multiplication-based Block cipher) is a block cipher

Block cipher

In cryptography, a block cipher is a symmetric key cipher operating on fixed-length groups of bits, called blocks, with an unvarying transformation. A block cipher encryption algorithm might take a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext...

 designed by Joan Daemen

Joan Daemen

Joan Daemen |Limburg]], Belgium) is a Belgian cryptographer and one of the designers of Rijndael, the Advanced Encryption Standard , together with Vincent Rijmen. He has also designed or co-designed the MMB, Square, SHARK, NOEKEON, 3-Way, and BaseKing block ciphers...

 as an improved replacement for the IDEA cipher. Modular

Modular arithmetic

In mathematics, modular arithmetic is a system of arithmetic for integers, where numbers "wrap around" after they reach a certain value—the modulus....

 multiplication

Multiplication

Multiplication is the mathematical operation of scaling one number by another. It is one of the four basic operations in elementary arithmetic ....

 is the central element in the design. Weaknesses in the key schedule

Key schedule

[[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES [[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES [[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES ("[[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES ("...

 were identified by Eli Biham

Eli Biham

Eli Biham is an Israeli cryptographer and cryptanalyst, currently a professor at the Technion Israeli Institute of Technology Computer Science department. Starting from October 2008, Biham is the dean of the Technion Computer Science department, after serving for two years as chief of CS graduate...

, and this, together with the fact that the cipher had not been designed to resist linear cryptanalysis

Linear cryptanalysis

In cryptography, linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers...

, meant that other designs were pursued instead, such as 3-Way

3-Way

In cryptography, 3-Way is a block cipher designed in 1994 by Joan Daemen, who also designed Rijndael, the winner of NIST's Advanced Encryption Standard contest....

.

MMB has a key size

Key size

In cryptography, key size or key length is the size measured in bits of the key used in a cryptographic algorithm . An algorithm's key length is distinct from its cryptographic security, which is a logarithmic measure of the fastest known computational attack on the algorithm, also measured in bits...

 and block size

Block size (cryptography)

In modern cryptography, symmetric key ciphers are generally divided into stream ciphers and block ciphers. Block ciphers operate on a fixed length string of bits. The length of this bit string is the block size...

of 128 bits.

External links

• Paulo Barreto's comments on MMB
• Chapter of Daemen's PhD thesis dealing with MMB (Postscript format) (The specification of MMB appears in section 11.5)