Disjunction Category Labels

Paper in proceeding, 2011

We present disjunction category (DC) labels, a new label format for enforcing information flow in the presence of mutually distrusting parties. DC labels can be ordered to form a lattice, based on propositional logic implication and conjunctive normal form. We introduce and prove soundness of decentralized privileges that are used in declassifying data, in addition to providing a notion of privilege-hierarchy. Our model is simpler than previous decentralized information flow control (DIFC) systems and does not rely on a centralized principal hierarchy. Additionally, DC labels can be used to enforce information flow both statically and dynamically. To demonstrate their use, we describe two Haskell implementations, a library used to perform dynamic label checks, compatible with existing DIFC systems, and a prototype library that enforces information flow statically, by leveraging the Haskell type checker.