Just a few months ago, social media giant Facebook announced its entry into the cryptospace with its native cryptocurrency, Libra. However, in light of Facebook’s history, the SEC has been drowning the firm in regulatory obligations. Since then, Facebook has been striving to up its game in order to fulfil all the requirements put forth by the SEC.
Facebook’s Libra uses a “robust and efficient state machine replication system” devised for the Libra Blockchain called LibraBFT. In order to achieve scalability and security, the LibraBFT is based on HotStuff, a protocol that elevates the advancements in Byzantine Fault Tolerance [BFT].
In a recent update about the same, Libra revealed LibraBFTv2, the latest version of the aforementioned protocol. According to the blog post, the latest protocol shelters optimizations that were created to minimize networking, while promoting commit latency of the blockchain.
The blog post further detailed the mechanism of LibraBFT, according to which the ultimatum is to achieve round synchronization between the nodes using LibraBFT. The duration of time where a particular leader is esteemed to drive progress by offering a block [B], accumulating votes [V] and broadcasting a quorum certificate [C], is what a round is. The purpose of the round synchronization is to carry out the same round with an adequately long overlap, further allowing the leader of a particular round to succeed.
The above image indicates,
“In the optimistic case (aka “happy path”), LibraBFTv2 reduces the overhead of round synchronization to a single message per node per round (see green arrows in the picture).”
Further, the difference between version 1 and version 2 of the LibraBFT was highlighted in the post. LibraBFTv1 was dependent on “probabilistic gossip,” which guaranteed uniform propagation of quorum certificates [C]; this was required to gain round synchronization. However, this mechanism seemed to complicate debugging.
However, LibraBFTv2, in contrast to the first version, gained round synchronization without using probabilistic gossip. The blog post further detailed the new mechanisms that the latest version was using. The post read,
“First, the new protocol introduces a new type of failsafe mechanisms that regularly pull missing data in case no progress is made. Second, LibraBFTv2 simplifies the constraints on block proposals.”
This new version that Libra has rolled out has revealed that this protocol would perform “way under Byzantine [worst-case] scenarios.”