OPRF Service

This is a monorepo containing:

• circom: A collection of Circom circuits and test vectors for them.
• contracts: An implementation of the required smart contracts.
• docs: A typst document serving as a writeup of the overall scheme.
• noir: A collection of Noir circuits.
• oprf-client: A crate implementing a client lib for the OPRF service.
• oprf-core: A crate implementing a verifiable OPRF based on the TwoHashDH OPRF construction + a threshold variant of it.
• oprf-dev-client: A crate implementing common dev client functionality.
• oprf-key-gen: A crate implementing a OPRF key generation instance.
• oprf-service: A crate implementing a service lib for the OPRF service.
• oprf-test-utils: A crate implementing test utils.
• oprf-types: A crate implementing types that are shared between client, service, and the blockchain.

Dev Dependencies

• just
• docker-compose
• anvil and forge, install with foundryup

Setup

Forge

To install the dependencies for the smart contracts run the following command:

cd contracts && forge install

Test & Run

For development, we provide a just command that runs the full test suite for the entire workspace. This includes Circom tests, smart contract tests, and a complete end-to-end test using the example binaries.

just all-tests

To run the tests against a local setup, use:

just run-setup

This command does multiple things in order:

1. start localstack and anvil docker containers
2. create private keys for OPRF nodes and store them in AWS secrets manager
3. deploy the OprfKeyRegistry smart contract
4. register the OPRF nodes at the OprfKeyRegistry contract
5. start 3 OPRF nodes
6. start 3 OPRF key-gen instances

Log files for all processes can be found in the created logs directory. You can kill the setup with Ctrl+C, which kills all processes and stops all docker containers. You can then use the dev client to send requests using the following command:

just run-dev-client test

Secret Management

The OPRF service supports two secret manager backends for storing OPRF key shares and wallet credentials.

Postgres Secret Manager (Default)

The Postgres backend stores OPRF key shares in a PostgreSQL database while using AWS Secrets Manager only for the wallet private key. This is the recommended approach for production deployments, especially when managing many OPRF keys.

Required environment variables:

• TACEO_OPRF_NODE__POSTGRES__CONNECTION_STRING – PostgreSQL connection string (e.g., postgres://user:password@host:5432/dbname)
• TACEO_OPRF_NODE__POSTGRES__SCHEMA – Database schema to use
• Standard AWS credentials (for wallet key retrieval)

Database setup:

The Postgres secret manager automatically runs migrations on startup to create the required tables:

• oprf_shares – Stores OPRF key shares per epoch
• evm_address – Stores EVM address mappings

Security considerations:

• The connection string contains credentials and should be treated as a secret
• Use SSL/TLS connections in production (?sslmode=require)
• Ensure the database is not publicly accessible
• The wallet private key is always stored in AWS Secrets Manager for additional security

AWS Secrets Manager

For simpler deployments with a small number of OPRF keys, you can use AWS Secrets Manager to store all secrets.

Required environment variables:

• Standard AWS credentials (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION)