[Paper Review] PoAh: A Novel Consensus Algorithm for Fast Scalable Private Blockchain for Large-scale IoT Frameworks

Deepak Puthal, Saraju P. Mohanty+2 more|arXiv (Cornell University)|Jan 21, 2020

Blockchain Technology Applications and Security6 references34 citations

TL;DR

The paper introduces PoAh, a lightweight consensus algorithm using an authentication-based mechanism to replace PoW in private IoT blockchains, validated via simulation and a Raspberry Pi testbed.

ABSTRACT

In today's connected world, resource constrained devices are deployed for sensing and decision making applications, ranging from smart cities to environmental monitoring. Those recourse constrained devices are connected to create real-time distributed networks popularly known as the Internet of Things (IoT), fog computing and edge computing. The blockchain is gaining a lot of interest in these domains to secure the system by ignoring centralized dependencies, where proof-of-work (PoW) plays a vital role to make the whole security solution decentralized. Due to the resource limitations of the devices, PoW is not suitable for blockchain-based security solutions. This paper presents a novel consensus algorithm called Proof-of-Authentication (PoAh), which introduces a cryptographic authentication mechanism to replace PoW for resource constrained devices, and to make the blockchain application-specific. PoAh is thus suitable for private as well as permissioned blockchains. Further, PoAh not only secures the systems, but also maintains system sustainability and scalability. The proposed consensus algorithm is evaluated theoretically in simulation scenarios, and in real-time hardware testbeds to validate its performance. Finally, PoAh and its integration with the blockchain in the IoT and edge computing scenarios is discussed. The proposed PoAh, while running in limited computer resources (e.g. single-board computing devices like the Raspberry Pi) has a latency in the order of 3 secs.

Motivation & Objective

• Address security and scalability needs of blockchain in resource-constrained IoT and edge environments.
• Propose a lightweight consensus mechanism that replaces PoW with cryptographic authentication.
• Demonstrate PoAh’s feasibility and performance through simulations and real hardware testbeds.

Proposed method

• Propose Proof-of-Authentication (PoAh) as a cryptographic authentication-based consensus for IoT and edge devices.
• Use ElGamal cryptography for signing, MAC verification, and encryption within the block validation flow.
• Implement a trusted-node based authentication process to validate and broadcast authenticated blocks.
• Assign and adjust node trust values to mitigate false authentications and resist 51% attacks.
• Evaluate PoAh’s performance via Python-based simulations and a 6-node Raspberry Pi testbed.

Experimental results

Research questions

• RQ1 Can PoAh provide secure and fast block validation for resource-constrained IoT devices compared with PoW/PoS?
• RQ2 Does PoAh reduce energy and time consumption for block validation while maintaining blockchain security in IoT scenarios?
• RQ3 How does the trusted-node authentication mechanism affect scalability and resilience to attacks in IoT blockchains?

Key findings

• Simulation results show PoAh average authentication time of 3.34 seconds over 500 iterations.
• Hardware testbed with six Raspberry Pi devices demonstrates PoAh operation with real-time data and authentication workflows.
• PoAh reduces energy and time costs by replacing hash-inversion PoW with fast cryptographic authentication.
• Trusted nodes authenticate blocks before broadcasting, addressing instability and 51% attack concerns in IoT networks.