Access Control and Declassification

Abstract

We integrate programming constructs for managing confidentiality in an ML-like imperative and higher-order programming language, dealing with both access control and information flow control. Our language includes in particular a construct for declassifying information, and constructs for granting, restricting or testing the read access level of a program. We introduce a type and effect system to statically check access rights and information flow. We show that typable programs are secure, that is, they do not attempt at making illegal read accesses, nor illegal information leakage. This provides us with a natural restriction on declassification, namely that a program may only declassify information that is has the right to read.