Transparent Decompilation for Timing Side-Channel Analyses

2025-01-07

AI Summary

This work addresses two critical challenges in timing-side-channel security analysis of binary programs: (1) decompiler-induced distortions that obscure constant-time (CT) or speculative constant-time (SCT) violations, and (2) incompleteness in CT/SCT verification due to non-transparent preprocessing. We introduce the formal notion of *transparent decompilation*, defined by the requirement that decompilation neither introduces nor eliminates CT/SCT violations—i.e., it preserves both program equivalence and security-relevant timing behaviors. Leveraging program equivalence and security-property preservation, we develop a static analysis framework integrating control- and data-flow constraints, and provide the first formal transparency proof for the RefleCT decompiler. Empirical evaluation reveals that mainstream decompilers implicitly eliminate violations, invalidating source-level analyses; meanwhile, existing CT analyzers suffer systematic false positives due to reliance on non-transparent preprocessors. Our work establishes the first verification paradigm for decompiler transparency and uncovers fundamental flaws in multiple widely used CT analysis tools.

Technology Category

• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Computer Vision: Interpretability, Explainability, and Transparency
• Planning, Routing, and Scheduling: Temporal Planning

Application Category

• Security and Privacy: Data transparency and provenance
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

This paper considers the problem of analyzing the timing side-channel security of binary programs through decompilation and source-level analysis. We focus on two popular policies, namely constant-time and speculative constant-time, (S)CT for short, used to protect cryptographic libraries. First, we observe that popular decompilers remove (S)CT violations, i.e., transform non-(S)CT programs into (S)CT programs; it follows that analyzing decompiled programs is not sound. Second, we develop techniques to prove that decompilers are transparent, i.e., neither introduce nor remove (S)CT violations. Third, we apply our techniques to efleCT{}, a core but non-trivial decompiler. As a contribution of independent interest, we find that constant-time verification tools may not be sound, due to their use of preprocessors (e.g., binary lifters or IR converters) that eliminate CT violations.

Problem

• Decompilation
• Constant Time Security
• Speculative Constant Time Analysis

Innovation

• Constant Time Analysis
• Speculative Constant Time
• Cryptographic Software Security