https://docs.radixdlt.com/alpha/learn/whitepapers/tempo
The conclusion in the paper:
“This paper has proposed a method for determining total order of events within a distributed system, without relying on trust, that is scalable, efficient and agnostic to its operating environment. To reduce overhead and increase performance, our solution defines a structured, shardable architecture that limits state transfer information to only members of the network that need it. A peer-to peer network provides the means for communication and information routing via a reliable and robust gossip protocol. Nodes maintain a logical clock when witnessing events and periodically produce a tamper-proof commitment representing those events. When witnessing events, nodes collaborate to create Temporal Proofs which contain verifiable space-time coordinates which are used to construct vector clocks and determine when an event was first seen by the network. Nodes can join and leave the network at will and rely on detectable consistency anomalies to synchronize and bring them up to date.”
The periodically produced commitment log is done with a Merkle tree.