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Hierocrypt-L1
General
Designers	Toshiba
First published	2000
Related to	Hierocrypt-3
Certification	CRYPTREC
Cipher detail
Key sizes	128 bits
Block sizes	64 bits
Structure	Nested SPN
Rounds	6.5
Best public cryptanalysis
Integral attack against 3.5 rounds

Hierocrypt-3
General
Designers	Toshiba
First published	2000
Related to	Hierocrypt-L1
Certification	CRYPTREC
Cipher detail
Key sizes	128, 192, or 256 bits
Block sizes	128 bits
Structure	Nested SPN
Rounds	6.5, 7.5, or 8.5
Best public cryptanalysis
Integral attack against 3.5 rounds

In cryptography, Hierocrypt-L1 and Hierocrypt-3 are block ciphers created by Toshiba in 2000. They were submitted to the NESSIE project, but were not selected. Both algorithms are among the cryptographic techniques recommended for Japanese government use by CRYPTREC.

The Hierocrypt ciphers are very similar, differing mainly in block size: 64 bits for Hierocrypt-L1, 128 bits for Hierocrypt-3. Hierocrypt-L1's key size is 128 bits, while Hierocrypt-3 can use keys of 128, 192, or 256 bits. The number of rounds of encryption also varies: Hierocrypt-L1 uses 6.5 rounds, and Hierocrypt-3 uses 6.5, 7.5, or 8.5, depending on the key size.

The Hierocrypt ciphers use a nested substitution-permutation network (SPN) structure. Each round consists of parallel applications of a transformation called the XS-box, followed by a linear diffusion operation. The final half-round replaces the diffusion with a simple post-whitening. The XS-box, which is shared by the two algorithms, is itself an SPN, consisting of a subkey XOR, an S-box lookup, a linear diffusion, another subkey XOR, and another S-box lookup. The diffusion operations use two MDS matrices, and there is a single 8×8-bit S-box. The key schedule uses the binary expansions of the square roots of some small integers as a source of "nothing up my sleeve numbers".

No analysis of the full ciphers has been announced, but certain weaknesses were discovered in the Hierocrypt key schedule, linear relationships between the master key and some subkeys. There has also been some success applying integral cryptanalysis to reduced-round Hierocrypt variants; attacks faster than exhaustive search have been found for 3.5 rounds of each cipher.

References [edit]

Security evaluation of NESSIE first phase (PDF)

P. Barreto, V. Rijmen, J. Nakahara Jr., B. Preneel, J. Vandewalle, H.Y. Kim (April 2001). "Improved SQUARE attacks against reduced-round HIEROCRYPT" (PDF/PostScript). 8th International Workshop on Fast Software Encryption (FSE 2001). Yokohama, Japan: Springer-Verlag. pp. 165–173. Retrieved 8 February 2007.

External links [edit]

256bit Ciphers - HIEROCRYPT Reference implementation and derived code

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'

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

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Hierocrypt

References [edit]

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