Hawkynt

SC2000

Fujitsu Laboratories block cipher combining an SPN half-round (subkey XOR plus a bit-sliced 4-bit S-box layer) with pairs of Feistel rounds built from 6-bit and 5-bit S-boxes and a 32x32 GF(2) diffusion matrix. 128-bit block; 6.5 rounds for a 128-bit key and 7.5 for 192/256-bit keys. Submitted to NESSIE and listed by CRYPTREC.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Block Cipher
Security status	🎓 Educational Only
Complexity	Expert
Inventor	Takeshi Shimoyama, Hirotaka Yanami, Kazuhiro Yokoyama, Masahiko Takenaka, Kouichi Itoh, Jun Yajima, Naoya Torii, Hidema Tanaka
Year	2000
Origin	🇯🇵 Japan
Source	algorithms/block/sc2000.js

Parameters

Parameter	Supported values
Key sizes	16 bytes (128 bits) to 32 bytes (256 bits) in steps of 8 bytes
Block sizes	16 bytes (128 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Reduced-round differential and boomerang attacks	Attacks are published against reduced-round variants; the full cipher is unbroken but CRYPTREC has moved it off its recommended list.	Use AES or another currently recommended cipher.

Documentation

• SC2000 specification (CRYPTREC)
• The Block Cipher SC2000 (FSE 2001)
• SC2000 (Fujitsu)

References

• Fujitsu NESSIE submission package (includes the official test vectors)
• Security Analysis of the Block Cipher SC2000 (CRYPTREC, 2012)

Test vectors

7 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — CRYPTREC specification appendix A — 128-bit zero key and plaintext

Field	Value
key	00000000000000000000000000000000
input	00000000000000000000000000000000
expected	fae4baa3bb72c4c060b9a4a5c4b2ab32

Vector 2 — NESSIE submission testvectors128.txt — single key bit set

Field	Value
key	80000000000000000000000000000000
input	00000000000000000000000000000000
expected	3fcb3bc9dbe00a8bf28d69d7f67102a7

Vector 3 — NESSIE submission testvectors128.txt — single plaintext bit set

Field	Value
key	00000000000000000000000000000000
input	80000000000000000000000000000000
expected	b75cd863b9cb21c7cebd9e1014bf774f

Vector 4 — NESSIE submission testvectors128.txt — repeating 0x01 key and plaintext

Field	Value
key	01010101010101010101010101010101
input	01010101010101010101010101010101
expected	ee5c548ea5ef353b896a780e324be38d

Vector 5 — NESSIE submission testvectors128.txt — repeating 0x09 key and plaintext

Field	Value
key	09090909090909090909090909090909
input	09090909090909090909090909090909
expected	8839d41b099a817ef8f9ffe6b88455ce

Vector 6 — NESSIE submission testvectors192.txt — 192-bit zero key and plaintext

Field	Value
key	000000000000000000000000000000000000000000000000
input	00000000000000000000000000000000
expected	6c2bab231cb641ed3ac8d4b0ea69ee3b

Vector 7 — NESSIE submission testvectors256.txt — 256-bit zero key and plaintext

Field	Value
key	0000000000000000000000000000000000000000000000000000000000000000
input	00000000000000000000000000000000
expected	6c2bab231cb641ed3ac8d4b0ea69ee3b

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