Nontransitive Policies Transpiled
Paper in proceeding, 2021

Nontransitive Noninterference (NTNI) and Nontransitive Types (NTT) are a new security condition and enforcement for policies which, in contrast to Denning's classical lattice model, assume no transitivity of the underlying flow relation. Nontransitive security policies are a natural fit for coarse-grained information-flow control where labels are specified at module rather than variable level of granularity.
While the nontransitive and transitive policies pursue different goals and have different intuitions, this paper demonstrates that nontransitive noninterference can in fact be reduced to classical transitive noninterference. We develop a lattice encoding that establishes a precise relation between NTNI and classical noninterference. Our results make it possible to clearly position the new NTNI characterization with respect to the large body of work on noninterference. Further, we devise a lightweight program transformation that leverages standard flow-sensitive information-flow analyses to enforce nontransitive policies. We demonstrate several immediate benefits of our approach, both theoretical and practical. First, we improve the permissiveness over (while retaining the soundness of) the nonstandard NTT enforcement. Second, our results naturally generalize to a language with intermediate inputs and outputs. Finally, we demonstrate the practical benefits by utilizing state-of-the-art flow-sensitive tool JOANA to enforce nontransitive policies for Java programs.


Seyed Mohammad Mehdi Ahmadpanah

Chalmers, Computer Science and Engineering (Chalmers), Information Security

Aslan Askarov

Aarhus University

Andrei Sabelfeld

Chalmers, Computer Science and Engineering (Chalmers), Information Security

6th IEEE European Symposium on Security and Privacy (EuroS&P'21)

9781665414913 (ISBN)

6th IEEE European Symposium on Security and Privacy
Online, ,

WebSec: Securing Web-driven Systems

Swedish Foundation for Strategic Research (SSF) (RIT17-0011), 2018-03-01 -- 2023-02-28.

Subject Categories

Transport Systems and Logistics

Other Physics Topics

Biomedical Laboratory Science/Technology



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