Privacy-Preserving Blueprints

The chapter delves into the intricate balance between privacy and accountability in cryptography, with a focus on the study of anonymous credentials. It introduces a new feature called privacy-preserving blueprints, which allows users to prove possession of credentials without revealing additional information. The chapter explores the technical aspects of this feature, including the use of cryptographic commitments and non-interactive zero-knowledge proofs. It also presents a high-level definition of privacy-preserving blueprints and discusses the security properties required for such schemes. The chapter highlights the practical applications of this technology, such as in anonymous e-cash systems, and provides a detailed roadmap for constructing secure blueprint schemes. Additionally, it discusses the challenges and solutions involved in implementing these schemes, including the use of homomorphic encryption and non-interactive secure computation. The chapter concludes by presenting a corollary that demonstrates the realizability of secure blueprint schemes given the existence of certain cryptographic primitives.