Ethereum in its current implementation is using PoW, but its upcoming Casper implementation will include a switch to PoS. Other promising protocols like IOTA are upcoming, but are not yet mature enough for production. Furthermore, in later stages of CLM hybrid solutions are in discussion, i.e. submitting the hash value on the public blockchain, while keeping sensitive metadata and the documents themselves in a secured permissioned-only private DLT like Corda. Here the consensus mechanisms are notary nodes, and various consensus algorithms can be used depending on client preferences and requirements.