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Specification and Verification of Side Channel Declassification

Josef Svenningsson (Institutionen för data- och informationsteknik, Datavetenskap (Chalmers)) ; David Sands (Institutionen för data- och informationsteknik, Datavetenskap (Chalmers))
Göteborg : Chalmers University of Technology, 2009. - 22 s.

Side channel attacks have emerged as a serious threat to the security of both networked and embedded systems -- in particular through the implementations of cryptographic operations. Side channels can be difficult to model formally, but with careful coding and program transformation techniques it may be possible to verify security in the presence of specific side-channel attacks. But what if a program intentionally makes a tradeoff between security and efficiency and leaks some information through a side channel? In this paper we study such tradeoffs using ideas from recent research on declassification. We present a semantic model of security for programs which allow for declassification through side channels, and show how side-channel declassification can be verified using off-the-shelf software model checking tools. Finally, to make it simpler for verifiers to check that a program conforms to a particular side-channel declassification policy we introduce a further tradeoff between efficiency and verifiability: by writing programs in a particular ``manifest form'' security becomes considerably easier to verify.

Denna post skapades 2010-01-13.
CPL Pubid: 107138