Proof of Work (PoW) cryptocurrency is where it all began, and the type of currency still most commonly being used today.
PoW cryptocurrency, like Bitcoin, relies on the original concept of blockchain technology to process transactions.
The action of mining from nodes, verifying transactions and adding blocks to the chain is the work part of Proof of Work, while the proof is the public access to the ledger.
This system is popular because of its network design and resulting security capabilities – the larger the network, the more secure it becomes.
However, the fast-evolving nature of cryptocurrency has seen many innovations during its short time in use, including ways to avoid some issues with using PoW cryptocurrencies.
Every user on the network is connected through a node, and every node must work and complete a copy of every transaction for the blockchain to remain functionable.