Verify Zama TFHE bootstrapping in RISC Zero

This repo is a fork of Louis Tremblay Thibault's VFHE implementation (https://github.com/tremblaythibaultl/vfhe).

VFHE is exploring how to verify VFHE bootstrapping off the shelf in ZK by porting an existing Rust library of FHE---called toy FHE (https://github.com/tremblaythibaultl/ttfhe)---out of the box. There is a demand for very efficient verification of such FHE operation, which is needed for FHE ZK-Rollup as well as FHE mining.

We have been experimenting with the VFHE library, mainly on how to make it more efficient so that the proof generation time can be reduced.

Roadmap

For the purpose of checkpointing the library, a few branches are created, reflecting different versions of this library. People can compare between these branches and the latest version.

• The branch article-1 is the unoptimized version from the Part I article, which uses the TFHE implementation out of the box. It also has the code from the profiler0 tool from the Part II article. The output from the profiler is here.

• An incoming release of the code would apply short polynomial representations. Then, with Karatsuba.

Articles

This repo is associated with a few articles that describe the entire journey.

• Tech Deep Dive: Verifying FHE in RISC Zero, Part I (here), which talks about the following.
  • How to load constant parameters into the guest in a zero-copy manner
  • How to use Ghidra to analyze the executable file from RISC Zero

License

Louis uses the Apache 2 license. We intend to do the same.