Glossary
Trusted Setup
A one-time ceremony that generates the public parameters a SNARK needs, relying on participants to destroy secret randomness so proofs cannot be forged.
A trusted setup is the procedure that produces the structured reference string (SRS) that many SNARKs — Groth16, PLONK, and KZG-based schemes — need before any proof can be generated. The ceremony samples secret random values (often called "toxic waste") and uses them to compute public parameters. Crucially, the secrets must then be deleted: anyone who retains them could forge proofs that verify against the parameters.
To minimise this risk, setups run as multi-party computations where each participant contributes randomness and the result is secure as long as at least one participant is honest and destroys their share. Per-circuit setups (Groth16) must be repeated for every program, while universal setups (PLONK) and Powers-of-Tau ceremonies — like Ethereum's 2023 KZG ceremony with over 140,000 contributors — are reusable. STARKs avoid the requirement entirely.