The Libra Mission

A simple global currency and financial infrastructure that empowers billions of people.

Problems:

1.7 billion adults globally remain outside of the financial system with no access to a traditional bank
Payday loans can charge annualised interest rates of 400 percent or more, and finance charges can be as high as $30 just to borrow $100.

Blockchains and cryptocurrencies have a number of unique properties that can potentially address some of these problems of accessibility and trustworthiness.

Existing blockchain systems have yet to reach mainstream adoption due to their volatility and lack of scalability, so I think Facebook Libra is a giant step towards banking unbanked people with a lower-cost, more accessible, and more connected global financial system.

Does this project need to use blockchain technology?

Yes, Facebook Libra has its own Blockchain, the Libra Blockchain with their own state machine replication algorithm called LibraBFT and a programming language called MOVE  for implementing custom transaction logic and "smart contracts"on the Libra Blockchain.

Can this project be realised and feasible to implement?

Absolutely, when Libra project was announced, they had everything in test-net, available for developers, and ready to Go.

Does anyone need this project?

I believe Billions of people around the world for their day-to-day financial needs.

Is this project protected from commonly known attacks?

Yes. The Libra Blockchain uses LibarBFT consensus protocol. Facebook has implemented this protocol and move programming language by keeping scalability and security in mind as a top priority.

Quality of whitepaper?

Facebook Libra white paper and other technical documents are so detailed, explaining the whole ecosystem clearly.

LibraBFT Consensus

The LibraBFT consensus is based on a HotStuff: Byzantine fault-tolerant consensus protocol, so all nodes implement this protocol to maintain the replica of the blockchain. LibraBFT made some improvements on HotStuff protocol. Some of the key properties of LibraBFT protocol;

First: LibraBFT maintains consistency among honest validators, even if up to one-third of the validators are corrupt.

Second: Consistency is guaranteed even in cases of network asynchrony.

Third: All transactions become irreversibly committed to the blockchain.

Fourth: LibraBFT supports both linearity and responsiveness while HotStuff protocol was not able to support these two desirable properties simultaneously. Linearity guarantees that commit incur only linear communication fashion, which is the optimal solution. Responsiveness means that the leader has no built-in delay and advances as soon as it collects responses from validators.

...and the Fifth important property is Sustainability: Current public blockchains consume vast amounts of energy as trust depends on computational power.LibraBFT is designed as a proof-of-stake system, and incentives reward to good behaviours and punish wrongdoings from stakeholders. Computational costs in LibraBFT consist of cryptographic signatures, a standard concept with efficient implementations.

Libra Protocol

The heart of the Libra protocol is the two fundamental concepts: Transactions and States

At any point in time, the blockchain has a "state".

Executing a transaction changes the state of the blockchain. All of the data in the Libra Blockchain is stored in a single-versioned distributed database.

The blockchain is represented as an ever-growing Merkle tree of transactions.

The Validator Node

Clients of the Libra Blockchain create transactions and submit them to a validator node. Validator nodes decide which transactions will be added to the blockchain and in which order.Let’s see the logical components of a validator

Admission Control

  • Admission Control is an entry point to the validator node. Any request made by a client to the validator node goes to Admission Control first.
  • It performs initial checks on the requests like duplication of request, replays the transaction etc.

Mempool

  • Mempool is a buffer that holds the transactions that are “waiting” to be executed.

Consensus

  • The consensus component is responsible for ordering blocks of transactions and agreeing on the results of execution

Execution

  • The execution component utilizes the virtual machine to execute transactions.
  • It maintains the in-memory representation of the result until consensus commits the block to the distributed database.

Virtual Machine

  • Admission Control and Mempool use the Virtual Machine component to perform validation checks on transactions.

Overall Opinion

I strongly believe that despite Libra going through government and regulators objections at the moment; it will come into the mainstream with some changes and rule the world of cryptocurrency. The only cryptocurrency which can surpass the Bitcoin is the Facebook Libra. This is off-course my strong opinion, I can be totally wrong. We will know as time flies away :-)

Libra Whitepaper: https://libra.org/en-US/white-paper/

Github: https://github.com/libra  

Libra Association: https://libra.org/en-US/association/  

Libra's commitment to move to permissionless blockchain:  https://libra.org/en-US/permissionless-blockchain/#overview