CLEFIA

CLEFIA

General
Designers	Sony
First published	2007
Certification	CRYPTREC (Candidate)
Cipher detail
Key sizes	128, 192, or 256 bits
Block sizes	128 bits
Structure	Feistel network
Rounds	18, 22, or 26
Best public cryptanalysis
An improbable differential attack requiring 2126.83 chosen plaintexts breaks 13 rounds with a complexity of 2126.83 encryptions for the key size of length 128 bits (Tezcan, 2010). [1] Similar attacks apply for 14 and 15 rounds of CLEFIA for the key sizes 192 and 256 bits, respectively.

CLEFIA is a proprietary block cipher algorithm, developed by Sony. ^[2] Its name is derived from the French word clef, meaning "key". The block size is 128-bits, and the key size can be 128-bit, 192-bit or 256-bits. It is intended to be used in DRM systems. It is among the cryptographic techniques recommended candidate for Japanese government use by CRYPTREC revision in 2013.

Standardization

CLEFIA is included in the following standards.

• ISO/IEC 29192-2:2019, Information security - Lightweight cryptography - Part 2: Block ciphers ^[3]

References

1. Tezcan, Cihangir. "The Improbable Differential Attack: Cryptanalysis of Reduced-Round CLEFIA". Proceedings of INDOCRYPT, 2010. Lecture Notes in Computer Science. Springer-Verlag. Archived from the original on 2013-02-03.
2. "Sony Develops "CLEFIA" - New Block Cipher Algorithm Based on State-of-the-art Design Technologies" . Retrieved 2007-03-26.
3. "ISO/IEC 29192-2:2019, Information security - Lightweight cryptography - Part 2: Block ciphers".

Further reading

• Wao Wang; Xiaoyun Wang (12 December 2007). "Improved Impossible Differential Cryptanalysis of CLEFIA" . Retrieved 25 October 2010.
• Cihangir Tezcan (8 August 2010). "The Improbable Differential Attack: Cryptanalysis of Reduced Round CLEFIA" . Retrieved 25 October 2010.

External links

• CLEFIA website
• 256bit Ciphers - CLEFIA Reference implementation and derived code
• Sony Introduces CLEFIA
• Implementation of 128-bit CLEFIA codec and hash function