Proof of Elapsed Time (PoET)

Developed by chip manufacturing giant Intel, Proof of Elapsed Time (PoET) is best described as a time-lottery-based consensus algorithm. Usually used on permissioned blockchain networks (which require participants to identify themselves), PoET leverages trusted computing to enforce random waiting times for block construction. This form of consensus mechanism gives all participants an equal chance of winning the reward and adding a new block to the blockchain.

A PoET mechanism starts by assigning and maintaining a randomly generated amount of time to each node, which must then sleep for this specific duration and will only be permitted to add a new block to the network once it has fulfilled the allotted ‘time’. This ensures that when a node’s waiting time has ended, and it ‘wakes up’, it can forge and submit a new block of transactions and a cryptographic test for verification.

In comparison to the Proof of Work (PoW) mechanism, PoET is much more time and energy efficient since it does not demand constant computation work from every node (or miner) to add a new block. Instead, PoET enables the nodes to pursue other tasks during the ‘sleep’ time, thereby improving the network efficiency.

An example of the PoET consensus algorithm is Hyperledger Sawtooth.