Uma heurística para a detecção de ataques ao mecanismo de consenso por Prova de Trabalho em Blockchain

Abstract

Blockchain’s concept emerged in 2008 as a distributed network structure, capable of guaranteeing security for transactions made using the Bitcoin digital currency, without the need for intermediaries to validate them. Although its beginning was linked to the cryptocurrencies, its use has diversified. There are several projects using Blockchain technology, such as document validation, electronic voting and the tokenization of non- perishable goods. With its increasing use, concerns arise about possible attacks that could threaten the integrity of the chain and compromise data security. One of the most well- known attacks is called in the literature as Selfish Miner, where some malicious nodes can deflect their behavior from the pattern by not immediately disclosing their newly mined blocks, keeping a blockchain private, with the goal of succeeding in overcoming the honest chain at the time of publication, which may result in a disproportionate share of rewards for those nodes. Another attack is called Stalker Miner, a variation of the selfish mining strategy that aims to prevent the publication of a specific block or transaction of a node, not necessarily for economic purposes. The objective of this dissertation is to present a heuristic to detect the presence of selfish mining attack (and its variations) in Blockchain using the Proof-of-Work (PoW) algorithm, based on the increase of the forks, with a certain height, which is displayed when the network is under the influence of such attacks. The detection algorithm was able to accurately identify 99,98% of the selfish mining attack attempts and 99,85% of the pursuer’s attack cases. The evaluation of the algorithm was performed through the number of False Positive and True Positive identified after the identification of the occurrence of the attack.