[Paper Review] SEPAR: A Privacy-Preserving Blockchain-based System for Regulating Multi-Platform Crowdworking Environments.

Mohammad Javad Amiri, Joris Duguépéroux+3 more|arXiv (Cornell University)|May 3, 2020

Blockchain Technology Applications and Security5 references4 citations

TL;DR

SEPAR is a privacy-preserving, blockchain-based multi-platform crowdworking system that enforces global regulations—such as work hour limits—across distributed platforms using lightweight anonymous tokens and a permissioned blockchain. It ensures privacy against covert adversaries through formalized security guarantees and achieves high performance and scalability via custom distributed consensus protocols.

ABSTRACT

Despite recent intensive research, existing crowdworking systems do not adequately address all the requirements of a real-world crowdworking environment. First, crowdworking platforms need to integrate within society and in particular to interface with legal and social institutions. Global regulations must be enforced, such as minimal and maximal work hours that participants can spend on crowdworking platforms. Second, crowdworking platforms are naturally distributed and need to collaborate with each other to process complex tasks, resulting in the rise of multi-platform crowdworking systems. Moreover, while collaborating to enforce global regulations or while processing complex tasks that require the transparent sharing of information about the tasks, the system needs to preserve the privacy of all participants. In this paper, we present SEPAR, a multi-platform crowdworking system that enforces global constraints on distributed independent entities. In SEPAR, Privacy is ensured using lightweight and anonymous tokens, while transparency is achieved using a permissioned blockchain shared across multiple platforms. To support fault tolerance and support collaboration among platforms, SEPAR provides a suite of distributed consensus protocols. The privacy guarantees of SEPAR against covert adversaries are formalized and thoroughly demonstrated, and the experiments reveal the efficiency of SEPAR in terms of performance and scalability.

Motivation & Objective

• Address the lack of integration between crowdworking platforms and legal/social institutions, particularly in enforcing global regulations like work hour limits.
• Enable secure collaboration among distributed, independent crowdworking platforms to process complex, multi-platform tasks.
• Preserve participant privacy during information sharing and regulatory enforcement in multi-platform environments.
• Design a system that supports fault tolerance and interoperability across platforms while maintaining transparency and compliance.

Proposed method

• Utilize lightweight, anonymous tokens to protect participant identities while enabling verification of compliance with global constraints such as work hours.
• Deploy a permissioned blockchain shared across multiple platforms to ensure transparency and immutability of regulatory enforcement and task processing.
• Design a suite of distributed consensus protocols to enable fault tolerance and coordination among independent platforms during collaborative task execution.
• Formalize privacy guarantees against covert adversaries using cryptographic reasoning to ensure strong security properties under adversarial conditions.
• Integrate the blockchain with token-based access control to bind privacy-preserving identities to regulatory-compliant actions.
• Optimize system performance and scalability through lightweight cryptographic operations and efficient consensus mechanisms tailored for crowdworking workloads.

Experimental results

Research questions

• RQ1 How can global regulations such as work hour limits be enforced across decentralized, independent crowdworking platforms?
• RQ2 What mechanisms can ensure participant privacy while enabling transparent collaboration among multiple platforms?
• RQ3 How can fault tolerance and system resilience be achieved in a multi-platform crowdworking environment with shared regulatory enforcement?
• RQ4 What is the performance and scalability trade-off of a blockchain-based system with anonymous tokens in a real-world crowdworking setting?

Key findings

• SEPAR successfully enforces global constraints such as maximum work hours across multiple independent crowdworking platforms using a shared permissioned blockchain.
• The system provides formal privacy guarantees against covert adversaries through the use of anonymous tokens and cryptographic verification.
• Experimental evaluation confirms SEPAR's efficiency in terms of performance and scalability, suitable for real-world deployment.
• The integration of distributed consensus protocols enables fault tolerance and reliable collaboration among platforms without compromising privacy.
• The use of lightweight tokens reduces overhead while maintaining strong privacy and compliance assurances.
• SEPAR demonstrates feasibility and practicality for deployment in complex, multi-platform crowdworking ecosystems with regulatory requirements.