Zero-Knowledge Application

Zero-knowledge application

Zero-knowledge application (zApp) is a decentralized application that makes use of privacy-enhancing technologies (PETs), but operates correctly despite incomplete information, due to verifiable computation and arguments of knowledge.

Use Cases

Privacy-Enhancing Technologies

We highlight some of PETs, whilst note that more specialized schemes and combinations thereof do exist.

Zero-knowledge proof (ZKP) allows to attest the integrity of computation over own secret data. It is the primary tool in Blacknet, herefrom zApp the abbreviation.

Homomorphic encryption (HE) permits computation over encrypted data. A curious consequence is possibility of lightweight wallet without loss of privacy.

Secure multiparty computation (SMC) enables joint computation over secrets. It could be crucial in financial applications, for example, to match bids and asks, keeping the price concealed.

Development

Development of zApps is ongoing R&D progress. We are looking to write a prototype with KiloNova the ZK-PCD (zero-knowledge proof-carrying data from folding schemes) instantiated on top of elliptic curves, although it also can work on top of lattices.

Summary

Verifiable computation solves the long standing problem of our design: application composability, also known as, two-way communication between applications. Zero-knowledge can not only add privacy to widely known dApp types, but also paves the way to new ones. Most advanced dApps, in fact, don’t fit into the pure ZK framework, and need to be accompanied with no less sophisticated FHE or SMC.

References

  1. Satoshi Nakamoto, Bitcoin P2P e-cash paper, .
  2. Dapper Labs, CryptoKitties | Collect and breed digital cats!, .
  3. Bitfinex_USD, The first dividend paying USD asset, .
  4. Samer Hassan, Primavera De Filippi, Decentralized Autonomous Organization, .
  5. Christopher Allen, The Path to Self-Sovereign Identity, .
  6. pdg744, Re: Run Doom on zkVM, .
  7. evoorhees, SatoshiDICE.com - Verified rolls, up to 65,000x winning, .
  8. Tim May, Untraceable Digital Cash, Information Markets, and BlackNet, .