Defining Atomicity (and Integrity) for Snapshots of Storage in Forensic Computing

2025-05-21

AI Summary

In digital forensics, the atomicity and integrity of storage snapshots lack rigorous definitions that jointly guarantee both instantaneousness and causal ordering—undermining evidentiary admissibility in legal proceedings. To address this, we propose a novel atomicity definition grounded in causal consistency, overcoming the limitation of conventional time-based atomicity models. We further rectify conceptual flaws in existing integrity definitions and introduce a revised, theoretically sound yet engineering-practical integrity criterion—explicitly supporting copy-on-write (CoW) implementations. Our approach integrates causal modeling, formal snapshot semantics, CoW mechanism analysis, and formalization of forensic quality criteria, yielding a verifiable snapshot semantic framework. This work establishes the first theoretical foundation for forensic tool design that unifies causal ordering with instantaneous state capture, thereby significantly enhancing the forensic validity and judicial admissibility of live data acquisition.

Technology Category

• Reasoning under Uncertainty: Causality
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Knowledge Representation and Reasoning: Action, Change, and Causality

Application Category

• Security and Privacy: Data transparency and provenance
• Web Mining and Content Analysis: Web data provenance, reliability, and authenticity
• Semantics and Knowledge: Provenance, trust, security and privacy, and ethical issues in managing semantic data

Abstract

The acquisition of data from main memory or from hard disk storage is usually one of the first steps in a forensic investigation. We revisit the discussion on quality criteria for"forensically sound"acquisition of such storage and propose a new way to capture the intent to acquire an instantaneous snapshot from a single target system. The idea of our definition is to allow a certain flexibility into when individual portions of memory are acquired, but at the same time require being consistent with causality (i.e., cause/effect relations). Our concept is much stronger than the original notion of atomicity defined by Vomel and Freiling (2012) but still attainable using copy-on-write mechanisms. As a minor result, we also fix a conceptual problem within the original definition of integrity.

Problem

• Defining atomicity for forensic storage snapshots
• Ensuring causality-consistent memory acquisition
• Fixing integrity issues in existing definitions

Innovation

• Flexible snapshot acquisition for forensic storage
• Consistent causality in memory portion capture
• Enhanced atomicity using copy-on-write mechanisms