Secure History Preservation Through Timeline Entanglement

TL;DR

This paper introduces Timeweave, a framework for secure, tamper-evident timelines that can be entangled across multiple distrustful services, enabling persistent temporal proofs even after service demise.

Contribution

It presents a novel framework and disk-based data structures for secure timeline entanglement across independent, distrustful systems, with efficient deployment in distributed environments.

Findings

Timeweave efficiently supports timeline entanglement with 2-8% overhead.

It enables persistent temporal proofs across distrustful services.

The system is scalable to hundreds of services.

Abstract

A secure timeline is a tamper-evident historic record of the states through which a system goes throughout its operational history. Secure timelines can help us reason about the temporal ordering of system states in a provable manner. We extend secure timelines to encompass multiple, mutually distrustful services, using timeline entanglement. Timeline entanglement associates disparate timelines maintained at independent systems, by linking undeniably the past of one timeline to the future of another. Timeline entanglement is a sound method to map a time step in the history of one service onto the timeline of another, and helps clients of entangled services to get persistent temporal proofs for services rendered that survive the demise or non-cooperation of the originating service. In this paper we present the design and implementation of Timeweave, our service development framework for timeline entanglement based on two novel disk-based authenticated data structures. We evaluate Timeweave's performance characteristics and show that it can be efficiently deployed in a loosely-coupled distributed system of a few hundred services with overhead of roughly 2-8% of the processing resources of a PC-grade system.