Overview of Zero Knowledge Proofs
Zero knowledge proofs have been proposed as a way to limit information leakage on public ledger systems (blockchain). This includes efforts by financial institutions like ING (www.ingwb.com) and cryptocurrencies like Zcoin (zcoin.io) and Zcash (z.cash). The goal of financial institutions like ING is to eliminate the need for providing more information than is strictly needed for financial transactions that are processed in a public ledger. In November 2018, ING announced the “initial release of its Zero-Knowledge Range Proof solution – a specific ZKP that has been proven to be ten times more efficient than other ZKPs.” Such a proof would enable someone to prove his/her age range, for example, without providing any additional information about other aspects of one’s identity. Another interesting example would be the ability to prove geographic location (EU citizen for example), without having to provide the specific country of citizenship. For cryptocurrencies like Zcoin, and Zcash the goal is to eliminate the possibility of tracking cryptocurrency transactions. Zcoin and Zcash both use zero-knowledge to prevent tracking of transactions on the blockchain. Zcoin provides the ability to anonymize a coin, thereby eliminating the possibility of linking through multiple transactions the inputs and outputs of transactions. Zcoin also relies on a trusted setup which means there is an initial phase in which trust in a central authority is required. The initial ING zero knowledge range proof proposal also relied on a trusted setup, but ING made improvements earlier this year that eliminate the need for a trusted setup. Other deployments of zero knowledge proofs include those by the Sovrin (sovrin.org) network , the recent public release by EY (ey.com) and efforts by Altoros among others.
ASU’s Project Description
Our main objective is to identify the limitations and possibilities for using zero knowledge proofs in blockchain systems. To that end, we will: (1) survey existing work on the use of zero knowledge proofs in blockchain systems, commercial, non-profit and academic; (2) identify meaningful performance measures for zero-knowledge proofs, both performance and security measures; (3) identify proposed applications of zero knowledge proofs; and (4) develop a proposal for the use of zero-knowledge proofs in cryptocurrencies with a mix of master nodes and general miners like the DASH network.
Rida A. Bazzi, Associate Professor, CIDSE