Mastering Ethereum, 2nd Edition

Chapter 17. Zero-Knowledge Proofs

In this chapter, we’ll explore the fascinating world of zero-knowledge cryptography and see how it perfectly applies to the Ethereum roadmap, making it possible to really scale and accommodate mass-adoption demand for block space. Zero-knowledge technology is a very complex topic and relies on lots of mathematical rules that we won’t be able to explain in detail. The goal of this chapter is to make sure you can understand why zero-knowledge cryptography offers a unique opportunity for Ethereum and fits well into the scaling roadmap. By the end of the chapter, you’ll know how zero-knowledge cryptography works on a high level, what its useful properties are, and how Ethereum is going to use it to improve the protocol.

History

Zero-knowledge proofs were introduced in the paper “The Knowledge Complexity of Interactive Proof-Systems” by Shafi Goldwasser, Silvio Micali, and Charles Rackoff in 1985, where they describe a zero-knowledge proof as a way to prove to another party that you know something is true without revealing any information besides the fact that your statement is actually true.

Even though zero-knowledge proofs were discovered in the 1980s, their practical use cases were very limited. Everything changed in 2011 with the arrival of the BIT+11 paper that introduced SNARKs (succinct noninteractive arguments of knowledge) as a theoretical framework for creating zero-knowledge proofs for arbitrary computations. Two years later, in 2013, ...