RailgunRailgun

CircuitA program written for the purpose of being proven within a proving system. A circuit is a mathematical representation of the computation to be executed, arithmetic circuits and zkVM execution trace are examples of circuits. Circuits can be written in different languages, ranging from low-level to high-level.-specific Phase 2For Groth16 trusted setup, phase 2 represents circuit-dependent part of the trusted setup. It generates a part of the secret cryptographic data required for Groth16 ZK protocol to work. If the outcome of phase 2 trusted setup ceremony is known, arbitrary proofs could be forged. trusted setupGeneration of a piece of data that must then be used for some cryptographic protocol to run. Generating this data requires some secret information. The "trust" comes from the fact the secret must be destroyed after the ceremony, otherwise cryptographic properties of the protocol could be broken. Once the data is generated, and the secrets are forgotten, no further participation from the creators of the ceremony is required. There are two types of trusted setups for SNARKs: (i) trusted setup per circuit where it is generated from scratch for each circuit, (ii) trusted universal setup per proving system where it can be used for several circuits. for Railgun’s 54 Groth16A zk-SNARK proving system introduced by Groth in 2016 that proves arithmetic circuits and requires a separate trusted setup for each circuit. It allows extremely efficient proof verification. circuits (parameterised by transaction input/output counts) over the BN254 curve. It builds on the Polygon zkEVM ceremony https://github.com/iden3/snarkjs/tree/master?tab=readme-ov-file as phase 1For Groth16 trusted setup, phase 1 represents circuit-independent part of the trusted setup (e.g. Perpetual Powers of Tau), which could be reused across different circuits. It generates a part of the secret cryptographic data required for Groth16 ZK protocol to work. If the outcome of phase 1 trusted setup ceremony is known, arbitrary proofs could be forged., which contains 55 participants.

A separate Phase 2 ceremony was publicly announced, open to anonymous and identified participants, and wrapped up in late December 2022.

Verified against the ceremony artifact IPFS hashA fixed-length fingerprint of variable-size input, produced by a hash function. QmWAySHYhaZqioKi1ufrPJC1n1ZVtHP2w4hLA9XqqJCFne: the /contributors directory contains 328 sequentially-numbered attestation files with GitHub or Twitter handles, and the /zkeys directory contains 54 final zkey files (one per circuit). Parsing the final zkey binary for the 1x1 circuit shows 304 Phase 2 contributions on that circuit.

• Phase 1 ceremony: https://github.com/iden3/snarkjs/tree/master?tab=readme-ov-file.
• Ceremony artifacts on IPFS: https://ipfs.io/ipfs/QmWAySHYhaZqioKi1ufrPJC1n1ZVtHP2w4hLA9XqqJCFne
• Ceremony announcement: https://medium.com/@Railgun_Project/railgun-project-begins-setup-ceremony-with-an-emphasis-on-security-d1c63117c312
• Advanced Circuit ceremony user guide: https://medium.com/@Railgun_Project/railgun-advanced-circuit-setup-ceremony-user-guide-32361c54242
• Docs overview of the trusted setup: https://docs.railgun.org/wiki/learn/privacy-system/trusted-setup-ceremony
• Railgun circuits repository with ceremony scripts: https://github.com/Railgun-Privacy/circuits-v2