According to Dimension Labs, Dimension Labs has officially announced the Dimension protocol on the 21st, which is developed based on the "Ether 3.0" proposed by Alexander, an Ether protocol researcher, and will be used in the DimensionChain public chain.


 
In our recent research, we found that most protocols are designed in a partially synchronized BFT model, which claims that communication between nodes will eventually become synchronized and that no more than a given fraction of nodes, say 1∕3 (which is optimal in this model) is dishonest and may violate the protocol in an arbitrary way. Current state-of-the-art protocols such as Hotstuff, Tendermint, and Streamlet are close to being near optimal in terms of bandwidth, finalized latency, and, equally important, simplicity. However, some of the actual properties of such blockchain systems are not captured by this classical model. Thus, there is still a lot of room for improvement.
 
On the other hand, aside from these occasional offline periods, it is fair to assume that, on the basis of economic incentives, the vast majority, if not all, of nodes in real-world systems honestly follow the rules of the protocol. Driven by this realization, there has been some work to design security protocols in the classical sense, while attempting to provide better guarantees in "typical" scenarios. It is in this context that we propose a new protocol, the Dimension protocol.
 
The security of the Dimension protocol is still formalized on the basis of the partially synchronized BFT model, so that especially when 1∕3 of the nodes are Byzantine, it achieves security and effectiveness in the most demanding environments. However, on top of that, the Dimension protocol offers the following two features that make it more attractive for real-world deployments
 
Feature 1: It allows reaching the final outcome of a block with a "confidence" well above the typical threshold of 1∕3 during a period of honest participation of a large percentage of nodes. As an example, if a block reaches a final confidence level of 0.8, then at least 80% of the nodes need to violate the protocol in order to restore the block from the chain. This is in contrast to the classic notion of finality, which is binary: either a block is finalized or it is not.
 
Feature 2: The second practical improvement of the Dimension protocol is that it enables flexibility. Nodes participating in the Dimension protocol may be configured with different security trade-offs between the number of allowed Byzantine nodes and the number of crashed nodes. Thus, flexibility means that despite different configurations, all nodes run a single version of the protocol and perform the same actions, except that the final decision they make depends on the parameters chosen.
 
Technically, the Dimension protocol can be classified as a DAG-based protocol, in which nodes jointly maintain a common history of protocol messages, forming a directed acyclic graph that represents the order of causality. In its design, the Dimension protocol is derived from the CBC-Dimension consensus and significantly improves it by using a new finality mechanism, a message creation schedule, and a spam prevention mechanism. We believe that the conceptual simplicity of the DAG-based protocol and the practical features of the Dimension protocol make it a solid choice for a consensus engine based on blockchain proofs.