Learn and talk about Akelarre (cipher), Block ciphers, Broken block ciphers

Akelarre
General
Designers	G. Álvarez, D. de la Guía, F. Montoya, A. Peinado
First published	1996
Derived from	IDEA, RC5
Cipher detail
Key sizes	128 bits
Block sizes	128 bits
Structure	Substitution-permutation network
Rounds	4
Best public cryptanalysis
Susceptible to ciphertext-only attack

Akelarre is a block cipher proposed in 1996, combining the basic design of IDEA with ideas from RC5. It was shown to be susceptible to a ciphertext-only attack in 1997.

Akelarre is a 128-bit block cipher with a variable key-length which must be some multiple of 64 bits. The number of rounds is variable, but four are suggested. The round function of Akelarre is similar to IDEA in structure.

After the successful cryptanalysis of Akelarre, its designers responded with an updated variant called Ake98. This cipher differs from the original Akelarre in the new AR-box (Addition-Rotation box), the swapping of words at the end of a round, and the addition of subkeys at the beginning of each round. In 2004, Jorge Nakahara, Jr. and Daniel Santana de Freitas found large classes of weak keys for Ake98. These weak keys allow a cryptanalysis faster than exhaustive search using only 71 known plaintexts, for up to 11.5 rounds of Ake98.

References[edit]

G. Álvarez Marañón, A. Fúster Sabater, D. Guía Martínez, F. Montoya Vitini, A. Peinado Domínguez (1996). "Akelarre: a New Block Cipher Algorithm" (PDF/PostScript). Proceedings of SAC'96, Third Annual Workshop on Selected Areas in Cryptography. Queen's University, Kingston, Ontario. pp. 1–14.
Niels Ferguson and Bruce Schneier (August 1997). "Cryptanalysis of Akelarre" (PDF). Proceedings of SAC'97, Fourth Annual Workshop on Selected Areas in Cryptography. Carleton University. pp. 201–212.
Lars Knudsen and Vincent Rijmen (August 1997). "Two Rights Sometimes Make a Wrong" (PDF/PostScript). Proceedings of SAC'97, Fourth Annual Workshop on Selected Areas in Cryptography. Carleton University. pp. 213–223.
Lars Knudsen and Vincent Rijmen (April 2000). "Ciphertext-only Attack on Akelarre". Cryptologia 24 (2): 135–147. doi:10.1080/01611190008984238.
J. Nakahara Jr., and D.S. de Freitas (2004). "Cryptanalysis of Ake98" (gzipped PDF). INDOCRYPT 2004, 5th International Conference on Cryptology in India. Chennai: Springer-Verlag. pp. 162–174. Retrieved 2007-02-05.

v t e Block ciphers (security summary)

Common algorithms	AES Blowfish DES Triple DES Serpent Twofish

Less common algorithms	Camellia CAST-128 IDEA RC2 RC5 SEED Skipjack TEA XTEA

Other algorithms	3-Way Akelarre Anubis ARIA BaseKing BassOmatic BATON BEAR and LION CAST-256 CIKS-1 CIPHERUNICORN-A CIPHERUNICORN-E CLEFIA CMEA Cobra COCONUT98 Crab Cryptomeria/C2 CRYPTON CS-Cipher DEAL DES-X DFC E2 FEAL FEA-M FROG G-DES GOST Grand Cru Hasty Pudding cipher Hierocrypt ICE IDEA NXT Intel Cascade Cipher Iraqi KASUMI KeeLoq KHAZAD Khufu and Khafre KN-Cipher Ladder-DES Libelle LOKI97 LOKI89/91 Lucifer M6 M8 MacGuffin Madryga MAGENTA MARS Mercy MESH MISTY1 MMB MULTI2 MultiSwap New Data Seal NewDES Nimbus NOEKEON NUSH PRESENT Q RC6 REDOC Red Pike S-1 SAFER SAVILLE SC2000 SHACAL SHARK SMS4 Spectr-H64 Square SXAL/MBAL Threefish Treyfer UES Xenon xmx XXTEA Zodiac

Design	Feistel network Key schedule Product cipher S-box P-box SPN

Attack (cryptanalysis)	Brute force MITM Linear Differential (Impossible Truncated Higher-order) Integral Boomerang Mod n Related-key Slide Rotational Timing XSL Interpolation Partitioning Davies' Rebound

Standardization	AES process CRYPTREC NESSIE

Misc	Avalanche effect Block size Initialization vector Key size Modes of operation Padding Piling-up lemma Weak key EFF DES cracker Key whitening

v t e Cryptography

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Akelarre (cipher)

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