Fresh re-keying II: Securing multiple parties against side-channel and fault attacks

Abstract

Security-aware embedded systems are widespread nowadays and many applications, such as payment, pay-TV and automotive applications rely on them. These devices are usually very resource constrained but at the same time likely to operate in a hostile environment. Thus, the implementation of low-cost protection mechanisms against physical attacks is vital for their market relevance. An appealing choice, to counteract a large family of physical attacks with one mechanism, seem to be protocol-level countermeasures. At last year's Africacrypt, a fresh re-keying scheme has been presented which combines the advantages of re-keying with those of classical countermeasures such as masking and hiding. The contribution of this paper is threefold: most importantly, the original fresh re-keying scheme was limited to one low-cost party (e.g. an RFID tag) in a two party communication scenario. In this paper we extend the scheme to n low-cost parties and show that the scheme is still secure. Second, one unanswered question in the original paper was the susceptibility of the scheme to algebraic SPA attacks. Therefore, we analyze this property of the scheme. Finally, we implemented the scheme on a common 8-bit microcontroller to show its efficiency in software. © 2011 IFIP International Federation for Information Processing.