Full-text Search for Verifiable Credential Metadata on Distributed\n Ledgers

Abstract

Self-sovereign Identity (SSI) powered by distributed ledger technologies\nenables more flexible and faster digital identification workflows, while at the\nsame time limiting the control and influence of central authorities. However, a\nglobal identity solution must be able to handle myriad credential types from\nmillions of issuing organizations. As metadata about types of digital\ncredentials is readable by everyone on the public permissioned ledger with\nHyperledger Indy, anyone could find relevant and trusted credential types for\ntheir use cases by looking at the records on the blockchain. To this date, no\nefficient full-text search mechanism exists that would allow users to search\nfor credential types in a simple and efficient fashion tightly integrated into\ntheir applications. In this work, we propose a full-text search framework based\non the publicly available metadata on the Hyperledger Indy ledger for\nretrieving matching credential types. The proposed solution is able to find\ncredential types based on textual input from the user by using a full-text\nsearch engine and maintaining a local copy of the ledger. Thus, we do not need\nto rely on information about credentials coming from a very large candidate\npool of third parties we would need to trust, such as the website of a company\ndisplaying its own identifier and a list of issued credentials. We have also\nproven the feasiblity of the concept by implementing and evaluating a prototype\nof the full-text credential metadata search service.\n