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Last month, Facebook announced that it’s going to launch its own cryptocurrency, Libra and Calibra, a payment platform that sits on top of the cryptocurrency, unveiling its plans to develop an entirely new ecosystem for digital transactions. It also developed a new programming language, “Move” for implementing custom transaction logic and “smart contracts” on the Libra Blockchain. The Move language is written entirely in Rust.

Although Facebook’s media garnered a massive media attention and had investors and partners from the likes of PayPal, loan platform Kiva, Uber, and Lyft, it had its own share of concerns. The US administration is worried about a non-governmental currency in the hands of big tech companies. Early July, the US congress asked Facebook to suspend the implementation of Libra until the ramifications were investigated. Last week, at the U.S. House Committee on Financial Services hearing, investigating Libra’s security related challenges, Congressman Denver Riggleman posed an important question to David Marcus, head of Calibra, asking why the Rust language was chosen for Libra.

Riggleman: I was really surprised about the Rust language. So my first question is, why was the Rust language chosen as the implementation language for Libra? Do you believe it’s mature enough to handle the security challenges that will affect these large cryptocurrency transactions?

Marcus: The Libra association will own the repository for the code. While there are many flavors and branches being developed by third parties, only safe and verified code will actually be committed to the actual Libra code base which is going to be under the governance of the Libra association.


Riggleman: It looks like Libra was built on the nightly build of the Rust programming language. It’s interesting because that’s not how we did releases at the DoD. What features of Rust are only available in the nightly build that aren’t in the official releases of Rust? Does Facebook see it as a concern that they are dependent on unofficially released features of the Rust programming language? Why the nightly releases? Do you see this as a function of the prototyping phase of this?

Marcus: Congressman, I don’t have the answers to your very technical questions but I commit that we will get back to you with more details on your questions.

Marcus appeared before two US congressional hearing sessions last week where he was constantly grilled by legislators. The grilling led to a dramatic alteration in the strategy of Libra. Marcus has clarified that Facebook won’t move forward with Libra until all concerns are addressed. The original vision of Facebook with Libra was to be an open and largely decentralized network which would be beyond the reach of regulators. Instead, regulatory compliance would be the responsibility of exchanges, wallets, and other services called the Libra association.

Post the hearing Marcus has stated that the Libra Association would have a deliberately limited role in regulatory matters. Per ArsTechnica, Calibra, would follow US regulations on consumer protection, money laundering, sanctions, and so forth. But Facebook didn’t seem to have plans for the Libra Association, Facebook, or any associated entity to police illegal activity on the Libra network as a whole.

This video clipping sparked quite the discussion on Hacker News and Reddit with people applauding the QnA session.

Some appreciated that legislators are now asking tough questions like these.

It’s cool to see a congressman who has this level of software dev knowledge and is asking valid questions.

Denver Riggleman was an Air Force intelligence officer for 11 years, then he became an NSA contractor. I’m not surprised he’s asking reasonable questions.

I don’t think I’ve ever heard of a Congressman going to GitHub, poking around in some open source code, and then asking very cogent and relevant questions about it. This video is incredible if only because of that.”

Others commented on why Congress may have trust issues with using a young programming language like Rust for something like Libra, which requires layers of privacy and security measures.

“Traditionally, government people have trust issues with programming languages as the compiler is, itself, an attack vector. If you are using a nightly release of the compiler, it may be assumed by some that the compiler is not vetted for security and could inject unstable or malicious code into another critical codebase. Also, Rust is considered very young for security type work, people rightly assume there are unfound weaknesses due to the newness of the language and related libraries”, reads one comment from Hacker News.

Another adds, “Governments have issues with non-stable code because it changes rapidly, is untested and a security risk. Facebook moves fast and break things.”

Rust was declared as the most loved programming language by developers in the Stack Overflow survey 2019. This year more or less most major platforms have  jumped on the bandwagon of writing or rewriting its components in the Rust programming language. Last month, post the release of Libra, Calibra tech lead Ben Maurer took to Reddit to explain why Facebook chose the programming language Rust.

Per Maurer, “As a project where security is a primary focus, the type-safety and memory-safety of Rust were extremely appealing. Over the past year, we’ve found that even though Rust has a high learning curve, it’s an investment that has paid off. Rust has helped us build a clean, principled blockchain implementation.

Part of our decision to choose Rust was based on the incredible momentum this community has achieved. We’ll need to work together on challenges like tooling, build times, and strengthening the ecosystem of 3rd-party crates needed by security-sensitive projects like ours.”

Not just Facebook, last week, Microsoft announced plans to replace their C and C++ code with Rust calling it a “modern safer system programming language” with great memory safety features. In June, Brave ad-blocker also released a new engine written in Rust which gives 69x better performance. Airbnb has introduced PyOxidizer, a Python application packaging and distribution tool written in Rust.

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Content Marketing Editor at Packt Hub. I blog about new and upcoming tech trends ranging from Data science, Web development, Programming, Cloud & Networking, IoT, Security and Game development.