Type-based information flow analysis for $π$-calculus with a dynamically extensible security lattice

2026-06-25

AI Summary

This work addresses the challenge of ensuring information-flow security when dynamically extending security lattices in concurrent systems. By extending an existing type system, it introduces—for the first time within the π-calculus—a scalable security lattice mechanism that supports runtime insertion of new security levels. The authors rigorously establish non-interference through reduction semantics and bisimulation equivalence. This approach overcomes the limitations of traditional static, binary security lattices by providing a formal verification framework that guarantees strict information isolation between high- and low-security levels, even as security policies are dynamically adjusted at runtime.

Abstract

We develop a type system for secure information flow where new security levels can be created and inserted into the security lattice dynamically, i.e., even in the middle of an execution of a system. Our system is formalized by extending Kobayashi's type-based secure information flow analysis for Milner's pi-calculus, which is one of the most expressive models (or "languages") supporting both sequential and concurrent computations, with concise syntax, reduction-based semantics, and bisimulation equivalence as a robust formalization of secrecy as non-interference. The development required careful treatment of extensions of lattices themselves as well as deliberate generalization from the simple 2-element lattice (consisting of only High and Low) in the original system.

Problem

• information flow
• security lattice
• pi-calculus
• dynamic extensibility
• non-interference

Innovation

• dynamic security lattice
• type-based information flow
• pi-calculus
• non-interference
• concurrent computation