Tacit PayTacit

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 the single 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. circuit, transact.circom (2 inputs, 2 outputs, 44,414 constraints), over the BN254 curve. It builds on the Hermez ceremony 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., using powersOfTau28_hez_final_16.ptau, which contains 54 Perpetual Powers of Tau participant contributions and one public randomness beacon.

Tacit’s own server coordinated Phase 2 from its website. It opened to everyone on 26 September 2026 at 18:21 UTC and closed 18 hours later. The hashA fixed-length fingerprint of variable-size input, produced by a hash function. of Bitcoin blockAn ordered list of transactions and chain-related metadata that gets bundled together and published to the L1/DA layer. Nodes execute the transactions contained within blocks to change the rollup chain’s state. Protocol rules dictate what constitutes a valid block, and invalid blocks are skipped over. 968840 sealed it as a beacon. The transcript lists 176 contributions. 171 are named “anonymous” and 5 are Tacit test entries. A contributor proves only a key they generate themselves. The coordinator accepts any number of contributions from one key, so the contributions identify no participants. We found no public announcement of the ceremony. The final key verifies against the circuit and the Phase 1 file with snarkjs, and its contribution hashes equal the transcript’s.

• Phase 1 file description (54 contributions and a beacon): https://github.com/iden3/snarkjs#7-prepare-phase-2.
• Ceremony bundle with transcript, keys and verifierAn entity in a ZK-Rollup, often a smart contract, that verifies zero-knowledge proofs submitted by a prover.: IPFS bafybeia4yvn…ypfy
• Transcript, 171 contributions named “anonymous”: transcript.json
• Open ceremony without an eligibility proof: worker/src/index.js#L9747-L9751
• Repeat contributions from one key: worker/src/index.js#L11231-L11234
• Ceremony opened: 27b575a4, closed and sealed: ed2ffbf0
• Rebuild and check instructions: docs/EVM-POOL.md#rebuild-and-check-it