Zero-knowledge proofs for scalability and privacy in a supply-chain

Abstract

In this thesis, the aim is to understand the possibilities and limitations of Zero Knowledge Proofs (ZKP) in blockchain technology. The first chapters focus on the presentation of distributed ledger systems and the tools that will be used, with particular reference to Remix, the IDE of choice for programming smart contracts in Solidity, and Sepolia, the Ethereum Testnet where the smart contracts were deployed. Subsequently, zero knowledge proofs are defined, their characteristics are explained, and the difference between interactive and non-interactive proofs is discussed; the latter will be emphasized as they are the most interesting in this context. The thesis then moves on to possible theoretical application contexts, with a particular focus on verifiable computation. Zokrates, a framework used to implement the non-interactive ZKP protocol, will be presented, explaining its language, features, functioning, and differences compared to other programming languages. A focal point for explaining how to implement verifiable computation will be introducing the various representations of an arithmetic circuit, fundamentally of textual and matrix types. Through various tests, the limitations of Zokrates and, to some extent, the entire arithmetic circuits sector for ZKP were highlighted. The thesis concludes with a possible implementation on the subject and an attack that this technology may be able to avoid.