Bitcoin, which made the blockchain technology popular, developed the so-called Proof of Work (PoW) algorithm. In principle, each participant on the Bitcoin network can participate in the block generation. In order to confirm the transaction and enter a block into the blockchain, a miner has to provide an answer, or a proof, to a specific challenge. Miners use PoW to validate transactions and mining new coins, but its main goal is to block potential cyber-attacks or suspicious activities within the network.