SC2000

This article is about the encryption cipher. For the game, see SimCity 2000.

SC2000
General
Designers	Fujitsu
First published	2000
Certification	CRYPTREC (Candidate)
Cipher detail
Key sizes	128, 192, or 256 bits
Block sizes	128 bits
Structure	combination SPN and Feistel network
Rounds	6.5 or 7.5
Best public cryptanalysis
Differential and linear attacks exist against SC2000 reduced to 4.5 rounds

In cryptography, SC2000 is a block cipher invented by a research group at Fujitsu Labs. It was submitted to the NESSIE project, but was not selected. It was among the cryptographic techniques recommended for Japanese government use by CRYPTREC in 2003, however, has been dropped to "candidate" by CRYPTREC revision in 2013.

The algorithm uses a key size of 128, 192, or 256 bits. It operates on blocks of 128 bits using 6.5 or 7.5 rounds of encryption. Each round consists of S-box lookups, key additions, and an unkeyed two-round Feistel network. There are 3 S-boxes: a 4×4-bit one used at the beginning of each round, and a 5×5-bit one and 6×6-bit one used in the Feistel network.

No analysis of the full SC2000 has been announced, but a reduced version of 4.5 rounds is susceptible to linear cryptanalysis, and a reduced version of 5 rounds is susceptible to differential cryptanalysis.^[1]^[2]^[3]

In 2014 Alex Biryukov and Ivica Nikolić found a weakness in the key schedule of SC2000 which allows an attacker to find colliding keys which result in identical encryptions in just 2³⁹ time for 256 bit keys. They proved that there are 2⁶⁸ colliding key pairs and the whole set can be found in 2⁵⁸ time.^[4]

References

↑ Lars Knudsen, Håvard Raddum (7 March 2001). "A first report on Whirlpool, NUSH, SC2000, Noekeon, Two-Track-MAC and RC6" (PDF). Retrieved 8 February 2007.
↑ Hitoshi Yanami, Takeshi Shimoyama, Orr Dunkelman (2000). Differential and Linear Cryptanalysis of a Reduced-Round SC2000 (PDF/PostScript). Proceedings of Second Open NESSIE Workshop. Retrieved 8 February 2007.
↑ Jiqiang Lu (July 2011). "Differential Attack on Five Rounds of the SC2000 Block Cipher." (PDF). Journal of Computer Science and Technology. Retrieved 30 January 2012.
↑ Alex Biryukov; Ivica Nikolić (10 November 2014). "Colliding Keys for SC2000-256" (PDF). line feed character in |title= at position 19 (help)

External links

256bit Ciphers - SC2000 Reference implementation and derived code

Block ciphers (security summary)

Common algorithms	AES Blowfish DES (Internal Mechanics, Triple DES) Serpent Twofish

Less common algorithms	Camellia CAST-128 IDEA RC2 RC5 RC6 SEED ARIA Skipjack TEA XTEA

Other algorithms	3-Way Akelarre Anubis BaseKing BassOmatic BATON BEAR and LION CAST-256 Chiasmus 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 Kuznyechik Ladder-DES Libelle LOKI (97, 89/91) Lucifer M6 M8 MacGuffin Madryga MAGENTA MARS Mercy MESH MISTY1 MMB MULTI2 MultiSwap New Data Seal NewDES Nimbus NOEKEON NUSH PRESENT Prince Q RC6 REDOC Red Pike S-1 SAFER SAVILLE SC2000 SHACAL SHARK Simon SM4 Speck Spectr-H64 Square SXAL/MBAL Threefish Treyfer UES Xenon xmx XXTEA Zodiac

Design	Feistel network Key schedule Lai-Massey scheme Product cipher S-box P-box SPN Avalanche effect Block size Key size Key whitening (Whitening transformation)

Attack (cryptanalysis)	Brute-force (EFF DES cracker) MITM (Biclique attack, 3-subset MITM attack) Linear (Piling-up lemma) Differential (Impossible Truncated Higher-order) Differential-linear Distinguishing (Known-key) Integral/Square Boomerang Mod n Related-key Slide Rotational Timing XSL Interpolation Partitioning Davies' Rebound Weak key Tau Chi-square Time/memory/data tradeoff

Standardization	AES process CRYPTREC NESSIE

Utilization	Initialization vector Mode of operation Padding

Cryptography

History of cryptography Cryptanalysis Outline of cryptography

Symmetric-key algorithm Block cipher Stream cipher Public-key cryptography Cryptographic hash function Message authentication code Random numbers Steganography

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