Cryptology ePrint Archive: Report 2016/710

Keymill: Side-Channel Resilient Key Generator

Mostafa Taha, Arash Reyhani-Masoleh and Patrick Schaumont

Abstract: In the crypto community, it is widely acknowledged that any cryptographic scheme that is built with no countermeasure against side-channel analysis (SCA) can be easily broken. In this paper, we challenge this intuition. We investigate a novel approach in the design of cryptographic primitives that promotes inherent security against side-channel analysis without using redundant circuits. We propose Keymill, a new keystream generator that is immune against SCA attacks. Security of the proposed scheme depends on mixing key bits in a special way that expands the size of any useful key hypothesis to the full entropy, which enables SCA-security that is equivalent to the brute force. Doing so, we do not propose a better SCA countermeasure, but rather a new one. The current solution focuses exclusively on side-channel analysis and works on top of any unprotected block cipher for mathematical security. The proposed primitive is generic and can turn any block cipher into a protected mode using only 775 equivalent NAND gates, which is almost half the area of the best countermeasure available in the literature.

Category / Keywords: implementation / Side-Channel Analysis, Keystream Generator

Original Publication (in the same form): Selected Areas in Cryptography (SAC 2016)

Date: received 18 Jul 2016

Contact author: mtaha at vt edu

Available format(s): PDF | BibTeX Citation

Version: 20160718:143745 (All versions of this report)

Short URL: ia.cr/2016/710