Sawtooth supports pluggable consensus algorithms but offers their own method —Proof of Elapsed Time (PoET). The PoET consensus has each validating participant wait a random amount of time. The first person to finish waiting becomes the leader of the new block. This provides a secure authority mechanism without the computational race and energy draw of Proof of Work (PoW).
The Linux Foundation, Hyperledger/1.0.4, Sawtooth Lake