Using Biometrics to Fight Credential Fraud

Verifiable credentials are an exciting innovation in decentralized and self-sovereign identity. However, the ease of copying digital files and sharing cryptographic keys makes an old problem from physical credential space more pressing: How do we prevent a credential from being used by someone other than its legitimate holder? Biometrics provide an answer - but they also introduce some complexity as well as trust and privacy concerns that need careful treatment. In this article, we explore three patterns of biometric use with verifiable credentials, identify appropriate use cases for each, and recommend best practices that make the patterns trustworthy, robust, and interoperable.