James W. Gray

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We set out a logic for reasoning about multilevel security of probabilistic systems. This logic includes modalities for time, knowledge, and probability. In earlier work we g a v e syntactic deenitions of multilevel security and showed that their semantic interpretations are equivalent to independently motivated information-theoretic deenitions. This paper(More)
We set out a modal logic for reasoning about multilevel security of probabilistic systems. This logic contains expressions for time, probability, and knowledge. Making use of the Halpern-Tuttle framework for reasoning about knowledge and probability, we give a semantics for our logic and prove it is sound. We give two syntactic deenitions of perfect(More)
We use standard linear-time temporal logic to specify cryptographic protocols, model the system penetrator, and specify correctness requirements. The requirements are speciied as standard safety properties, for which standard proof techniques apply. In particular, we are able to prove that the system penetrator cannot obtain a session key by any logical or(More)
We use standard linear-time temporal logic to specify cryptographic protocols, model the system penetrator, and specify correctness requirements. The requirements are speciied as standard safety properties, for which standard proof techniques apply. In particular, we are able to prove that the system penetrator cannot obtain a session key by a n y logical(More)
We develop an approach to deriving concrete engineering advice for cryptographic protocols from provable-security-style proofs of security. The approach is illustrated with a simple, yet useful protocol. The proof is novel and is the first published proof that provides an exact relationship between a high-level protocol and multiple cryptographic primitives.