Final Report Summary - PAC (Proofs and Computation)
More to the point, the main research achievements of this project have been to advance the theoretical understanding of proof systems of computational integrity that are based on additively homomorphic encryption (also known as pre-processing Succinct Noninteractive ARguements of Knowledge, or SNARKs) and on hash-based Probabilistically Checkable Proof (PCP) systems (also known as Computationally Sound (CS) proofs). We initiated the implementation in code of these systems and reported initial applications, most notably in areas related to Bitcoin and crypto-currencies. A concrete example is Zerocash, the first decentralized anonymous payment systems based on Bitcoin. Zerocash is a new protocol that works on the transaction layer of Bitcoin and hides payer, payee and payment amount. Consequently, it makes any cryptocurrency using it more fungible and better suited for use in practice. Recall that in Bitcoin (and its offspring) all financial transactions are publicly displayed, and this public display is a serious impediment to adoption because businesses and individuals prefer need their financial information to be kept private.