What is Proof of Work?
Proof of work is described as a system allowing every node to work out difficult hash puzzles with a large number of computer calculations. In the bitcoin network, a distributed ledger system, nodes/miners figure out complex mathematical equations so as to process and validate the BTC transactions, which is also called mining. The first node that works out the solution of the hash/mathematical puzzle will be the block generator and get rewards. With POW, cyber-attacks that aim at exhausting the resources of a computer system can be deterred.
Pros & Cons of Proof of Work
1. POW algorithm is easy to accomplish and the threshold is low for nodes.
2.Protect blockchain system from DDoS attacks (denial-of-service) which sending multiple malicious and fake requests.
1. Energy consumption and huge cost. Specialized computer hardware is required to calculate complex hash puzzles, which consumes a lot of energy and leads to expensive energy charges.
2. In case the 51% computing power/mining hash rate is controlled by a group of miners, they can control the whole network to prevent new transactions from being confirmed and double-spend the cryptocurrency.
Due to the disadvantages of Proof of work, many consensus mechanisms such s POS, DPOS, etc. get on the stage of blockchain as well as cryptocurrency. And which one will be the most useful one, let's stay tuned.