Nightfall MPC Ceremony

Zero-knowledge proofs require a trusted setup. This setup generates a so-called "toxic waste" which could potentially allow to create fake proofs. To avoid this, one or two ceremonies needs to be held where this setup is generated via multi-party computation (MPC).

When using the groth16 proving scheme, a two-phase ceremony needs to be held:

Phase1, which is done for all circuits
Phase2, which is applied to a specific circuit only\

For phase1, as it's done for all circuits, Nightfall uses the Hermez Phase1 Ceremony and its files. You can know more on the Hermez blog post about it.

As a preparation for phase2 of the ceremony, which is coordinated on this repo, we downloaded the 2^20 file from Hermez Phase1 ceremony. We then applied the snarkjs setup phase for each circuit:

snarkjs groth16 setup <circuit>.r1cs pot20_final.ptau <circuit>_0000.zkey

Which gave us the first .zkey file with 0 contributions. This is the file you will find inside the circuits folder on this repo. If you ever write or modify one of the circuits, you need to do this again, and run the ceremony for that circuit only.

Nightfall3 MPC ceremony (phase 2)

For the second release of Nightfall, the team decided upon three main priorities:

Make the phase2 MPC easily orchestrated, with an MPC server that serves, verifies and receives the incoming contributions
Make this infrastructure easy to deploy and manually test, following the principles of Infrastructure as Code and GitOps
Make the contributions as easy as possible through a website that anyone can visit and contribute with 1 click

How can I contribute

If you simply want to contribute to the ceremony, just visit the live page at ceremony.polygon-nightfall.io and follow the instructions. It will take just a few minutes. If you want to know more, follow along.

Architecture

We make use of Terraform and Terraform Cloud in order to manage the provisioning of AWS resources. Under the terraform folder you can see the following:

A VPC, subnets and internet gateway on eu-west-3 are used
An EC2 instance is created, together with a load balancer and target group. The script server.sh is passed into it, which clones this repo and starts the server you can find on the serve folder. An existent certificate is used on the load balancer listener. A route53 record is added to an existing Zone ID.
A cloudfront distribution is also provisioned and set up with an existent certificate. Its record is also added to an existent Zone ID through route53.
An S3 bucket is created

These services are used with branch names thanks to Github Actions. Each new pull_request creates new resources, so manual testing can be performed on these branches without messing up with the ongoing mpc in main.

Github actions

As mentioned, Github Actions is the CI/CD pipeline that will do the following:

Deploy or update the infrastructure everytime there's a new pull_request, or a new commit on an open pull_request
Copy the first contribution of each circuit into the S3 bucket
Build the react frontend and copy the static page to the S3 bucket
Invalidate the cloudfront cache

How can I run a ceremony

As a requirement, you should have already configured:

Some ACM certificates in AWS certificate manager
A Route53 zoneID

You need to set up the following needed secrets in Github:

AUTH_KEY - Some random string (it can be anything, really) to protect your beacon routes on the backend. This is a work in progress.
AWS_ACCESS_KEY_ID - You need to provide an AWS access key for your own AWS environment, so github can invalidate your cloudfront cache
AWS_SECRET_ACCESS_KEY - Same thing
TF_API_TOKEN - The terraform cloud token, so the terraform process runs there

In terraform cloud, you need the following variables in "variable sets":

AWS_ACCESS_KEY_ID - So terraform can deploy your infrastructure
AWS_SECRET_ACCESS_KEY - Same
CERTIFICATE_ARN_BACKEND_DEV - The certificate ARN of your backend certificate, for the development branches (like api-.ceremony.polygon-nightfall.io)
CERTIFICATE_ARN_BACKEND_MAIN - Same, for the main branch (like api-ceremony.polygon-nightfall.io)
CERTIFICATE_ARN_FRONTEND_DEV - Same thing, for frontend (like .ceremony.polygon-nightfall.io)
CERTIFICATE_ARN_FRONTEND_MAIN - Same thing, for the main frontend branch (like ceremony.polygon-nightfall.io)
ROUTE_53_ZONE_ID - The zone ID you want to use for your route53 records

Once these requirements are met, just clone this repo and add whatever circuits you need to run your ceremony for on the circuits folder. Then, assuming your AWS account has enough permissions (the CI/CD will tell you otherwise), you should be able to simply run terraform deploy.

TODO

Make a ticketing system to allow people to report they're contributing, and allow others to wait (as contributions need to be synchronous)
Have proper unit and e2e testing