Tornado.cash Trusted Setup Ceremony app

zk-SNARKs require a pre-existing setup between the prover and verifier. A set of public parameters define the “rules of the game” for the construction of zk-SNARKs. This app allows everyone to contribute with your source of entropy so that tornado.cash can be trustless.

Environment variables

The app can use .env.development and .env.production. What file will be used depends on NODE_ENV variable. For command yarn dev the .env.development is used. The yarn start uses .env.production.

ENV_VAR	Description
DISABLE_S3	Disable contributions uploading to AWS S3. true or false
AWS_ACCESS_KEY_ID	AWS access key
AWS_SECRET_ACCESS_KEY	AWS secret key
AWS_S3_BUCKET	AWS S3 bucket where the contributions will be uploaded
MYSQL_USER	Mysql user the app uses. Notice, you don't need mysql db for development. The app will use local sqlite db in dev mode. Local db is stored in db.development.sqlite file.
MYSQL_PASSWORD	Mysql password for MYSQL_USER
MYSQL_DATABASE	Mysql database
TWITTER_CONSUMER_KEY	Twitter consumer API key. Twitter app
TWITTER_CONSUMER_SECRET	Twitter consumer API secret
TWITTER_CALLBACK_URL	Twitter callback URL. The app handles the /api/oauth_callback/twitter endpoint. Feel free to change domain name and protocol though
GITHUB_CLIEND_ID	Github client id. How to create Github OAuth app
GITHUB_CLIENT_SECRET	Github client secret
GITHUB_CALLBACK_URL	Github callback URL. The app handles the /api/oauth_callback/github endpoint. Feel free to change domain name and protocol though
SESSION_SECRET	A random string that will be used by express-session to sign the session ID cookie.

Development setup

$ yarn install

# Edit all necessary environment variables. See the explanation above.
$ cp .env.example .env.development

# serve with hot reload at localhost:3000
$ yarn dev

Production setup

Follow instructions in the Initialize ceremony section to generate current.params ceremony file.

# Edit all necessary environment variables. See the explanation above.
$ cp .env.example .env.production

# Run Nginx + Letsencrypt containers to serve https requests to the app
$ cd frontend 
$ docker-compose up -d
$ cd ..

# Set VIRTUAL_HOST and LETSENCRYPT_HOST variables in the app's docker-compose.yml file
# Run the app and mysql database containers. It will use the MYSQL_USER, MYSQL_PASSWORD and MYSQL_DATABASE vars you specified in .env.production file.
$ docker-compose up -d

# Note. At start it builds client side stuff. It takes 30 seconds or so, during this time you will get 502 error.

Initialize ceremony (current.params file creation):

1. git clone https://github.com/tornadocash/phase2-bn254 && cd phase2-bn254
2. git checkout wasm
3. go to ./powersoftau/src/bn256/mod.rs and change REQUIRED_POWER to 15 (it's going to fit 36k constaints snark)
4. cd powersoftau
5. run ./test.sh. After this step you will get many phase1radix* files.
6. Download withdraw.json for required circuit to ./phase2 folder
7. cd ../phase2
8. cp ../powersoftau/phase1radix* .
9. cargo run --release --bin new withdraw.json current.params
10. The current.params file is your initial challenge file.
11. copy current.params, withdraw.json and phase1radix* to ./server/snark_files folder.
12. mv withdraw.json circuit.json

In case of WASM module changes

1. go to phase2 folder in phase2-bn254 (ceremony branch for now) and run the following command:
2. wasm-pack build --release --target web -- --no-default-features --features wasm
3. it will generate wasm modules in pkg folder, then you need to copy it to this project
4. cp -r pkg/* <path_to_current_project>/lib/phase2 && cp pkg/phase2_bg.wasm <path_to_current_project>/static/_nuxt/lib/phase2/

Example: wasm-pack build --release --target web -- --no-default-features --features wasm && cp -r pkg/* ../../trusted-setup-nuxt/lib/phase2 && cp pkg/phase2_bg.wasm ../../trusted-setup-nuxt/static/_nuxt/lib/phase2/

Initialize REAL ceremony

1. Choose what contribition to use for the ceremony (it should already exist). Also choose what hash of future ethereum block we will use, tweet about it and calculate the VDF.

2. Make sure your machine has at least 150 GB RAM and 200 GB SSD.

3. Download the response file of the contribution. You can use aria2c accelerator for it.

4. git clone https://github.com/tornadocash/phase2-bn254 && cd phase2-bn254

5. git checkout stable

6. cd powersoftau

7. cargo run --release --bin beacon_constrained <challenge_file> last_response 28 256 <VDF output>

8. cargo run --release --bin prepare_phase2 last_response 28 256 it will generate radix* files. You can abort execution after phase1radix2m15 calculation.

9. cd ../phase2

10. Make sure sure that withdraw.circom has additional constaints

11. wget https://github.com/tornadocash/tornado-core/releases/download/v2.0/withdraw.json -O circuit.json

12. cp ../powersoftau/phase1radix2m15 .

13. cargo run --release --bin new circuit.json current.params

14. The current.params file is your initial challenge file.

15. copy current.params, circuit.json and phase1radix* to ./server/snark_files folder.

16. Then the phase2 goes. see Production setup

17. Before next step you can download all contributions and verify all of them localy.

18. Copy last contribution to phase2-bn254/phase2 folder as result.params

19. npx snarkjs setup --protocol groth

20. cargo run --release --bin export_keys result.params vk.json pk.json

21. cargo run --release --bin copy_json proving_key.json pk.json transformed_pk.json

22. cargo run --release --bin generate_verifier result.params Verifier.sol

23. git clone git@github.com:tornadocash/tornado-core.git

24. cd tornado-core && git checkout phase2

25. Copy transformed_pk.json, vk.json and Verifier.sol to tornado-core project to the build/circuits folder.

26. Change solidity version to 0.5.17 in Verifier.sol

27. npm run build:circuit:compile

28. mv transformed_pk.json withdraw_proving_key.json

29. mv vk.json withdraw_verification_key.json

30. npm i

31. npm run build:circuit:bin

32. That's it you can use Verifier.sol, withdraw.json, withdraw_verification_key.json and withdraw_proving_key.bin to deploy contract and the UI.

Note.

1. Your also need to use special version of websnark lib on the UI.
2. update WASM module.