International Association for Cryptologic Research (IACR)
Abstract
Blockchain technologies rely on a public ledger, where typically all transactions are pseudoanonymous
and fully traceable. This poses a major flaw in its large scale adoption of cryptocurrencies, the primary
application of blockchain technologies, as most individuals do not want to disclose their finances to the pub-
lic. Motivated by the explosive growth in private-Blockchain research, this Statement-of-Knowledge (SOK)
explores the ways to obtain privacy in this public ledger ecosystem. The authors first look at the underly-
ing technology underling all zero-knowledge applications on the blockchain: zk-SNARKs (zero-knowledge
Succinct Non-interactive ARguments of Knowledge). We then explore the two largest privacy coins as of
today, ZCash and Monero, as well as TornadoCash, a popular Ethereum Tumbler solution. Finally, we look at
the opposing incentives behind privacy solutions and de-anonymization techniques, and the future of privacy
on the blockchain
