Hashrate is a way to measure the processing power of the Bitcoin network.
Hashes are essential for secure transactions on the Bitcoin blockchain and as more ASICs come online to compete for block rewards, Bitcoin’s protocol will adjust the hash rate to make mining more difficult.
By doing so, the network becomes even more secure and even more difficult to attack.
An attack on the Bitcoin network would come in the form of a single entity able to control more than 51% of the hash rate, which becomes more expensive due to the capital expenditure required to buy ASICs, set up infrastructure and maintain their miners.
By the time the attacker has control of the hash rate, the smart cookies already on the network will know about it and it becomes a very costly exercise for the attacker if it doesn’t work.