Requirements and Secure Serialization for Selective Disclosure Verifiable Credentials

Abstract

AbstractThe emergence of the Verifiable Credentials recommendation from W3C allows the adoption of credential systems in a much wider range of user-centric applications and use cases. With this shift to user-centric credential systems, Selective Disclosure has been proposed and used to cryptographically secure user privacy. Although much work has been undertaken in creating selective disclosure supporting cryptographic protocols, those schemas are not directly applicable for credentials. Implementations rely on canonicalization algorithms to transform a credential to the necessary data format, which will be used by the cryptographic layer. Those algorithms are often used without the necessary cryptographic and security considerations, leading to insecure implementations. In this work we define three necessary security properties for the canonicalization algorithms. We also propose a mathematical model for JSON credentials, which we use to prove the security of a proposed canonicalization algorithm.KeywordsSelf-Sovereign Identity (SSI)PrivacyJSONCanonicalizationLinked dataJSON LDAnonymous credentials