Which consensus method uses a time-based randomness in a trusted execution environment?

The consensus method that utilizes a time-based randomness in a trusted execution environment is Proof of Elapsed Time (PoET). PoET is designed primarily for blockchain networks that require a secure and energy-efficient way to achieve consensus among nodes.

In PoET, each participant in the network gets a waiting period that is generated randomly. This randomness is derived from a trusted execution environment (TEE), such as Intel's Software Guard Extensions (SGX). The TEE ensures that the process of generating the wait times is secure and tamper-resistant, meaning that no malicious actor can manipulate the results to gain an advantage in the consensus process.

Once the waiting time expires, the participant is allowed to propose the next block, which is a fair method because it doesn’t require extensive computational resources, unlike Proof of Work. Instead of relying on computing power to win the right to add a block, PoET allows participants to trust the randomness provided by the TEE, making it an efficient and secure consensus mechanism suitable for permissioned blockchain applications.