Room P3.10, Mathematics Building

Pedro Adão, Instituto Superior Técnico

Expanded logics of formal encryption

Two distinct views of cryptography have been developed over the years, in two mostly separate communities, Formal Methods and Computational/Probabilistic Communities. The relation between these two approaches was previously explored in a paper by Abadi and Rogaway in 2000 where they proved the computational soundness of formal encryption with respect to a special type of cryptosystems. We present expansions of the Abadi-Rogaway logic and establish their soundness and completeness for a variety of interpretations. Two such interpretations are discussed in detail: a purely probabilistic one that interprets formal expressions in the One-Time Pad cryptosystem, and another one in the so-called type-2 (which-key revealing) cryptosystems based on computational complexity.