Meet Hodor, Matter Labs’ STARK Prover Implementation

Sean Medcalf
Sep 30, 2019 · 3 min read
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Our work on ZKPs has yielded a pleasant surprise — an open STARK implementation, which we have named Hodor. zk-STARKs are a form of non-interactive Zero-Knowledge Proof (ZKP) that do not require trusted setup and feature a quasi-linear proving time as well as poly-logarithmic verification time. They use a very specific arithmetization that is well-suited for a narrow application, e.g., evaluation proofs for verifiable delay functions (which Vitalik has described in his blog).

We did not set out to create such an implementation; it developed organically in the course of our work with ZKPs. Nevertheless, we believe the results can offer meaningful benefits to the developer community. It should also provide some insight for those who are not deeply familiar with zkSTARKs. You can view the full library on Github.

The library at this stage is largely a STARK-proving engine. It does not yet offer a large number of primitives to define the STARK circuit. But as soon as a problem is transformed into the required format, it will perform all the computation necessary to create a proof. Implementation of Hodor has also led us to ideas (used in our transparent polynomial commitment scheme, which we will discuss in greater detail soon) that can be applied to other proof systems such as PLONK and Marlin. The library is written in Rust and supports multicore operations.

Hodor is an early beta that can be improved through the addition of solid use cases. We hope members of the developer community will begin to flesh these out. Meanwhile, we are working to make proofs for our transparent commitment scheme even smaller and hope to share the results of these efforts soon.

Matter Labs will host a workshop and demonstration of Hodor at DevCon (More information on that below).

Learn more at D.FINE in Seoul and Devcon in Osaka

Matter Labs team is flying to Seoul to attend Korea Blockchain Week. Matter Labs will be present at the event, which takes place at the Grand Intercontinental Seoul Parnas, for the entire week. If you plan to attend, we’d love to meet and share ideas. Feel free to send contact us through Twitter direct message to set up a meeting.

We will remain in Asia following Korea Blockchain Week and travel to DevCon. The event, which needs no introduction, should be a wonderful gathering of talent and ideas and a showcase for new and exciting concepts being applied to and around blockchain technology. We look forward to actively participating in this exchange of ideas.

Specifically, our co-founders Alex Gluchowski and Alex Vlasov will host a workshop where they will present a demonstration of our new zk-STARK implementation Hodor. The workshop is meant as an informational and educational look at how STARKs work and the challenges they present. And we may have some news to share.

More to Come

The next two weeks are set to be a busy time for Matter Labs as we attend events and unveil new concepts. Coming off the recent close of our Seed round, we are laser-focused on research and development as well as on strengthening our ties with the developer and broader blockchain communities.

If you plan to be at either Korea Blockchain Week or DevCon, please feel free to reach out and set aside some time to speak with us.

Matter Labs

Matter Labs

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