Paper 2017/600

Bit-Sliding: A Generic Technique for Bit-Serial Implementations of SPN-based Primitives -- Applications to AES, PRESENT and SKINNY

Jeremy Jean, Amir Moradi, Thomas Peyrin, and Pascal Sasdrich

Abstract

Area minimization is one of the main efficiency criterion for lightweight encryption primitives. While reducing the implementation data path is a natural strategy for achieving this goal, Substitution-Permutation Network (SPN) ciphers are usually hard to implement in a bit-serial way (1-bit data path). More generally, this is hard for any data path smaller than its Sbox size, since many scan flip-flops would be required for storage, which are more area-expensive than regular flip-flops. In this article, we propose the first strategy to obtain extremely small bit-serial ASIC implementations of SPN primitives. Our technique, which we call bit-sliding, is generic and offers many new interesting implementation trade-offs. It manages to minimize the area by reducing the data path to a single bit, while avoiding the use of many scan flip-flops. Following this general architecture, we could obtain the first bit-serial and the smallest implementation of AES-128 to date (1563 GE for encryption only, and 1744 GE for encryption and decryption with IBM 130nm standard-cell library), greatly improving over the smallest known implementations (about 30% decrease), making AES-128 competitive to many ciphers specifically designed for lightweight cryptography. To exhibit the generality of our strategy, we also applied it to the PRESENT and SKINNY block ciphers, again offering the smallest implementations of these ciphers thus far, reaching an area as low as 1054 GE for a 64-bit block 128-bit key cipher. It is also to be noted that our bit-sliding seems to obtain very good power consumption figures, which makes this implementation strategy a good candidate for passive RFID tags.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
A minor revision of an IACR publication in CHES 2017
Keywords
Bit-serial implementationsbit-slidelightweight cryptographyAESSKINNYPRESENT
Contact author(s)
jean jeremy @ gmail com
amir moradi @ rub de
History
2017-06-26: revised
2017-06-23: received
See all versions
Short URL
https://ia.cr/2017/600
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2017/600,
      author = {Jeremy Jean and Amir Moradi and Thomas Peyrin and Pascal Sasdrich},
      title = {Bit-Sliding: A Generic Technique for Bit-Serial Implementations of SPN-based Primitives -- Applications to AES, PRESENT and SKINNY},
      howpublished = {Cryptology ePrint Archive, Paper 2017/600},
      year = {2017},
      note = {\url{https://eprint.iacr.org/2017/600}},
      url = {https://eprint.iacr.org/2017/600}
}
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