Miners play a crucial role in any cryptocurrency system as they are responsible for grouping unconfirmed transactions into new blocks and adding them to the global ledger (the 'blockchain'). They provide the necessary computing power to secure a blockchain by computing vast numbers of hashes to find a valid block. Each valid block added by a miner to the blockchain generates a reward for the miner and makes it more difcult for an attacker to reorganise the ledger and double-spend already confirmed transactions.