The CBC Casper protocol, pioneered by Ethereum Researcher Vlad Zamfir, is now hitting the highway with new solutions to the longstanding problems of safety and liveness. Together these will improve Ethereum’s network performance and security as it makes the transition to a Proof-of-Stake network.
The protocol was among the early innovations in the on-going quest to solve the “nothing at stake” dilemma, often considered as the fatal flaw of Proof-of-Stake (PoS) consensus solutions. The idea that anyone staking on the network could act maliciously because they have nothing to lose — no equipment or electricity expenditures — has haunted PoS solutions since their inception.
By punishing malicious network actors, Casper incentivizes accurate verification with greater profitability for honest actors in a PoS network. Now, with the release of CasperLabs Highway to the public via an open-source license, the specification will offer further refinements to ensuring a safe and live network.
Shared on the CasperLabs blog, the team goes into technical detail about the offered solutions to the problems of “safety” and “liveness”. In a nutshell, a protocol is deemed “safe” if it makes reliable and consistent decisions. A protocol is “live” if it continues to make decisions, and is guaranteed to keep doing so. The new CasperLabs Highway specification ensures this safety and liveness. It efficiently detects safety, prescribes a strategy for the creation of protocol messages, and proves the liveness of the protocol with results from the messages in a dynamic system.
The team goes over the details of how the new specification works, which consists of levels of agreement using a “pseudorandom leader sequence” and a “dynamic round length system.” In each round, a pseudo-randomly selected leader issues a message which is carried through to others who then issue another message, resulting in a decision. These rounds are dynamic and therefore not fixed in a linear sequence in time, which makes the process much more efficient and practical.
Using the metaphor of a highway, the blog explains the consensus process works like cars moving from lane to lane as they travel, rather than being fixed in a single lane. With this approach, the team hopes to take another step forward in the effort to overcome the scaling trilemma: decentralization, security, and mass adoption of blockchain.