Tokamak zk-EVM 2024 Q1 Report

Tokamak zk-SNARK paper has been released

Hi, this is Jake, leading the Tokamak zk-EVM project. We share our progress for the first quarter of 2024.

• About the Tokamak zk-EVM project

The main achievement of the first quarter was the publication of a paper on Tomakak zk-SNARK.

• The paper is archived in Cryptology ePrint Archive, https://eprint.iacr.org/2024/507.
• Compared to the previous SNARKs such as PlonK and Marlin, Tokamak zk-SNARK has reduced reliance on preprocessing by the verifier.
• In other words, as a polynomial interactive oracle proof, we have reduced reliance on the polynomial oracle.

What’s the benefit of Tokamak zk-SNARK?

• One challenging problem in zk-EVM development is how to instantiate or eliminate the verifier’s preprocessing required by a SNARK
• Adopting universal circuits such as Scroll and Linea was a solution to eliminate the preprocessing at the cost of the very complex circuit size.
• However, unlike them, our zk-EVM does not use a universal circuit to track the state transitions of EVM to keep the circuit much faster and lighter.
• Tokamak zk-SNARK has greatly reduced the amount of information that the verifier needs to preprocess, and based on this, we will instantiate the preprocessing through fault-proof protocols or secure multi-party computation.

Then, what kind of circuits does Tokamak zk-EVM use?

• Rather than a universal circuit, we deal with field-programmable circuits.
• A circuit is field-programmable if it can be derived from a subcircuit library and uniquely characterized by a low-degree wire map.
• A subcircuit library is a set of subcircuits, each of which is a circuit of a predefined arithmetic operation (Subcircuits are similar to custom gates in PlonK, but more general because subcircuits allow for more complex operations).
• Here, each predefined arithmetic operation is a stand-alone execution of each arithmetic and logical instruction in the EVM (instructions 0x01–0x20).
• A circuit is then represented by placing copies of the subcircuits and the wiring between them, where a wire map defines the wiring.

Progress of subcircuit library development

• Apart from theory development, we have been implementing and optimizing our subcircuit library. You can find our work here.

What’s next?

• Development of secure multiparty computation for verifiable wire maps
• Documentation of our zk-EVM specification

Contact us

We are actively seeking creative researchers and developers, please contact us at hr@tokamak.network. Also, we welcome contacting jake@tokamak.network for technical discussions.