Proof of access

Proof of access (PoA) is a proprietary consensus mechanism developed by Arweave and built around the existing proof of work (PoW) consensus mechanism. Unlike traditional PoW systems, which rely solely on the previous block to generate each consecutive block, the PoA algorithm incorporates data from a randomly selected prior block.

This means the PoA consensus mechanism requires each computer taking part in the network to check that a new bundle of transactions contains a randomly selected marker from an earlier bundle of transactions. When that marker is present, the new transaction can be added to the network, and the computer that added the new bundle is rewarded in cryptocurrency (which, in the case of PoA, is the Arweave cryptocurrency). PoA is intended to ensure computers on the network can verify all new transactions and that none of the previous transactions have been tampered with.

Meanwhile, because all miners on the network do not need to store all blocks, the PoA mechanism saves a significant amount of electricity during the mining process (when compared to PoW), and as the network expands, the energy consumption continues to decrease.