>Initially, the association (and validators) will consist of a geographically distributed and diverse set of Founding Members. These members are organizations chosen according to objective participation criteria, including that they have a stake in bootstrapping the Libra ecosystem and investing resources toward its success. Over time, membership eligibility will shift to become completely open and based only on the member’s holdings of Libra.
So it's not going to be Facebook's centralized servers, but Facebook + their friend's centralized servers. There are some vague promises, but this will start out just as centralized as Facebook Credits.
"Can't wait for a cryptocurrency with the ethics of Uber, the censorship resistance of Paypal, and the decentralization of Visa, all tied together with the proven privacy of Facebook."
It's secured via BFT PoS, which means if more than 1/3 of the validators are malicious, then the network halts until there's a supermajority (2/3). With BFT PoS blocks have finality, which means you need a supermajority of the validator set to "fork" the chain and rewrite the history.
so that we aren't cherry picking here, from the White paper:
> To ensure that Libra is truly open and always operates in the best interest of its users, our ambition is for the Libra network to become permissionless. The challenge is that as of today we do not believe that there is a proven solution that can deliver the scale, stability, and security needed to support billions of people and transactions across the globe through a permissionless network. One of the association’s directives will be to work with the community to research and implement this transition, which will begin within five years of the public launch of the Libra Blockchain and ecosystem.
So it's not going to be Facebook's centralized servers, but Facebook + their friend's centralized servers. There are some vague promises, but this will start out just as centralized as Facebook Credits.