CLEFIA is a symmetric-key block cipher algorithm for encrypting data via a complicated conversion sequence. Symmetric-key block ciphers are used in a wide range of applications. For example, they prevent unauthorized parties from accessing sensitive information, protect data integrity through the detection of forgery, and provide authentication by confirming the identity of users and devices.

CLEFIA has the same interface as the current US encryption standard AES. Data is encrypted in 128-bit blocks, and users can choose from among 128 bits, 192 bits or 256 bits.

CLEFIA masterfully brings together conventional symmetric-key block cipher design techniques with several cutting-edge design techniques to deliver a finely-tuned balance between advanced security and implementation performance.

Key features of CLEFIA design:
① Generalized Feistel structure
② F-functions based on the Diffusion Switching Mechanism (DSM)
③ Key scheduling part that can be shared with the data processing part
④ Two types of non-linear transformation functions(S-boxes) within each F-function
⑤ shuffling function (“DoubleSwap”) for the key scheduling part

See the CLEFIA website for additional technology-related information.

CLEFIA has attained the world’s highest level of performance (announced in March, 2007[1]) having overcome the difficult challenge of efficient implementation in both hardware and software. CLEFIA boasts extremely advanced hardware gate efficiency in when implemented in hardware and in software, CLEFIA facilitates high-speed execution regardless of CPU type. Hardware gate efficiency in hardware implementation is a particularly important feature of CLEFIA’s implementation performance. That is, CLEFIA delivers superior processing speed performance per gate.

The table below shows CLEFIA’s hardware implementation performance using a 128-bit key. The hardware implementation achieves a minimum throughput of 700Mbps with 5,000 or fewer gates, or a minimum throughput of 1.6Gbps with 6,000 or fewer gates. This performance translates to excellent hardware gate efficiency two or more times more advanced than AES or other 128-bit block ciphers[1]. CLEFIA is an encryption technology capable of demonstrating spectacularly high speeds, even in environments with limited resources such as those only capable of using fewer gates.

Sony has also committed to developing international standards to enhance the reliability and usability of CLEFIA technology. As a result, CLEFIA was adopted as an international standard in “Lightweight cryptography Part 2: Block ciphers” (ISO/IEC 29192-2) by ISO/IEC JTC 1/SC 27 in 2012. Sony will leverage this recognition as an ISO/IEC international standard by actively promoting the use of CLEFIA in a broad variety of devices and services

[1]

Taizo Shirai, Kyoji Shibutani, Toru Akishita, Shiho Moriai, and Tetsu Iwata, “The 128-bit Blockcipher CLEFIA.”　FSE 2007, LNCS 4593, pp. 181-195, Springer-Verlag, 2007.