Basics of zk-SNARK
zk-SNARK stands for "Zero-Knowledge Succinct Non-Interactive ARgument of Knowledge". It's a cryptographic proof protocol that allows one party (the prover) to convince an another party (the verifier) that they possess certain information, without even revealing the information itself.
In this tutorial, we will gradually implement two of the most popular zk-SNARK protocols: Pinocchio and Groth16. The structure of this guide closely follows the excellent tutorial by, Petkus, Maksym. "Why and how zk-snark works.", as well as the fantastic eBook "The RareSkills Book of Zero Knowledge".
Key Components of zk-SNARKs
- Zero-Knowledge: The prover demonstrates the validity of a statement without revealing any additional information.
- Succinct: Proofs are small in size, and verification is computationally efficient.
- Non-Interactive: Requires no back-and-forth between the prover and verifier.
How zk-SNARKs Work
zk-SNARKs rely on polynomial equations as cryptographic puzzles. The prover generates a proof based on these equations, which are designed to be solvable only by someone with the required knowledge. The verifier can easily check the validity of the proof without accessing the underlying data. Randomness plays a key role in ensuring each proof is unique and secure.
Applications of zk-SNARKs
- Private Transactions: Users can prove they have sufficient funds without revealing their account balance or transaction history7.
- Anonymous Voting: Voters can prove they've voted without disclosing their choice7.
- Blockchain and Smart Contracts: Enhancing privacy and scalability in blockchain networks.
- Identity Verification: Proving identity without revealing personal information.
- Secure Financial Transactions: Enabling confidential financial operations.
- Data Privacy in Healthcare: Protecting sensitive medical information while allowing necessary verifications.