Secure information flow with random assignment and encryption

Geoffrey Smith
2006 Proceedings of the fourth ACM workshop on Formal methods in security - FMSE '06  
Type systems for secure information flow aim to prevent a program from leaking information from variables classified as H to variables classified as L. In this work we extend such a type system to address encryption and decryption; our intuition is that encrypting a H plaintext yields a L ciphertext. We argue that well-typed, polynomial-time programs in our system satisfy a computational probabilistic noninterference property, provided that the encryption scheme is IND-CCA secure. As a part of
more » ... ur proof, we first consider secure information flow in a language with a random assignment operator (but no encryption). We establish a result that may be of independent interest, namely, that well-typed, probabilistically total programs with random assignments satisfy probabilistic noninterference. We establish this result using a weak probabilistic bisimulation.
doi:10.1145/1180337.1180341 dblp:conf/ccs/Smith06 fatcat:dfkqjejy5fffbo74gyclcbyosa