The 128-bit Blockcipher

CLEFIA is a new cipher algorithm developed by Sony.

What is CLEFIA?

CLEFIA is an efficient, highly secure block cipher which was presented in 2007. The block length is 128 bits, while key length of 128 bits, 192 bits, and 256 bits can be selected. To make the CLEFIA more reliable, the algorithm specification of CLEFIA is publicly available to enable public evaluations by cryptographers in worldwide. CLEFIA is the internationally-standardized cipher in ISO/IEC 29192 Lightweight cryptography.

High Performance

Based on a cutting-edge cipher design technique, Sony's CLEFIA block cipher maintains a high security level while providing both world-leading hardware and software implementation capabilities, the combination of which had proved difficult until now. When implemented in hardware it achieves the world's highest hardware gate efficiency. When implemented in software it can realize high speed performance on a wide variety of processors.

Advanced Design

CLEFIA is realized by harmonizing traditional design techniques and newly established design techniques. The 4-branch generalized Feistel structure enables us to implement these F-functions compactly both in hardware and software. CLEFIA employs Diffusion Switching Mechanism, which ensures immunity against major attacks. Moreover, the sharing of functions between the data processing part and the key scheduling part means lower cost because the gate size is reduced.


  • January 26, 2012
    News Release. Sony's ‘CLEFIA’ Encryption Technology Adopted as an International Standard.
  • June 15, 2011
    Compact hardware implementation results are updated.
  • March 23, 2011
    CLEFIA website is renovated. Contents are enriched, and the layout of the webpage is re-designed.
  • March 16, 2011
    The specification of CLEFIA is published as RFC 6114Open in new window by the IETF.
  • March 2, 2011
    The first evaluation result of CLEFIA is reported during the CRYPTREC symposium 2011.
  • January 25, 2011
    Sony presents two technical reports on CLEFIA at the 2011 symposium on cryptography and information security (SCIS 2011).

    "Update of the Security Evaluation of CLEFIA against Differential Attack and Linear Attack"
    "Compact Hardware Implementation of the 128-bit Blockcipher CLEFIA"