Trusted Setup
A one-time ceremony generating cryptographic parameters certain zero-knowledge proof systems require, where the security of the system depends on a piece of intermediate data being destroyed afterward.
A trusted setup is a one-time ceremony required by certain zero-knowledge proof systems, such as Groth16 (see Kaavon's "Groth16" glossary definition), to generate specific cryptographic parameters the proof system depends on. The ceremony involves generating secret intermediate data that must be permanently destroyed afterward — if any participant retained that data, they could potentially forge false proofs that the system would accept as valid, undermining the entire scheme's security.
Because trusting that the secret data was genuinely destroyed requires trusting at least one participant behaved honestly, trusted setups are typically conducted as multi-party ceremonies involving many independent participants, each contributing their own piece of randomness — the setup remains secure as long as at least one honest participant destroyed their contribution, even if every other participant were compromised. This requirement for trust is a specific drawback some newer proof systems, such as zk-STARKs and PLONK (see Kaavon's "PLONK" glossary definition) variants using a universal setup, are designed to reduce or eliminate entirely.
Examples
- A trusted setup ceremony with hundreds of independent participants remains secure as long as even just one participant genuinely destroyed their portion of the secret data afterward.
- Needing to trust that a trusted setup's secret data was properly destroyed is a specific security assumption that some newer proof systems are designed to avoid entirely.