علي رهنماعلمداري

Blockchains based on the proof-of-work consensus algorithm, despite their key role in securing decentralized networks, have always been criticized for their extremely high energy consumption an‎d impractical nature of computation. In this mechanism, the networkʹs enormous computational power is used solely to solve cryptographic puzzles that do not generate any added value outside the network environment. Aiming to address this fundamental challenge, this research seeks to provide a novel consensus architecture that, while maintaining security an‎d decentralization features, directs the networkʹs energy an‎d computational power towards solving real an‎d valuable problems. The main challenge is to design a mechanism that can safely, fairly, an‎d verifiably integrate useful work into the consensus process. To this end, a two-stage hybrid consensus model is proposed that combines lightweight proof-of-work with solving NP-Hard problems. In the first stage, a low-difficulty proof-of-work acts as a security gateway an‎d prevents spam attacks. A miner that successfully passes this stage selec‎ts an‎d solves an NP-Hard problem from a pool of common questions using a verifiable ran‎dom function in a fair an‎d unpredictable manner. This dual approach, while maintaining competition, protects the problem selec‎tion from manipulation by miners. To eva‎luate the performance, security, an‎d efficiency of the proposed scheme, a network simulator was implemented. The simulation results showed that the proposed architecture is able to allocate a significant portion (on average, more than 55%) of the networkʹs computational power to solving useful problems, which leads to a significant reduction in energy waste. Security analyses proved the high resistance of the system to key attacks such as selec‎tion attack an‎d precomputing due to the deterministic dependency of the steps. Also, the eva‎luations indicated a fair distribution of rewards among miners an‎d stable chain convergence under different network conditions. This research successfully presents a practical an‎d implementable framework for proof-of-work that strikes a smart balance between security, efficiency, an‎d value generation. The proposed scheme demonstrates that it is possible to go beyond the boundaries of traditional proof-of-work an‎d move towards a new generation of consensus algorithms, in which blockchain networks act not only as a security tool but also as a powerful computational platform for solving complex scientific an‎d industrial problems.

زنجيره‌بلوكي , اثبات‌كار , اثبات‌كار مفيد , الگوريتم اجماع , مسائل Np-hard , دشواري محاسبات , كاهش اتلاف انرژي

blockchain , Proof of Work (PoW) , Proof of Useful Work (PoUW) , consensus algorithm , NP-hard problems , Computational Difficulty , Energy Waste Reduction

Ali RahnamaAlamdari

Marzieh MalekiMajd