2024 Symposium Posters

Primary Investigator:
Christina Garman

Project Members
Michael Rosenberg, Jacob White, Christina Garman, Ian Miers

Frequently, users on the web need to show that they are, for example, not a robot, old enough to access an age restricted video, or eligible to download an ebook from their local public library without being tracked. Anonymous credentials were developed to address such concerns. However, existing schemes do not handle the realities of deployment or the complexities of real-world identity assurance. Instead, they implicitly make assumptions such as there being an issuing authority for anonymous credentials that, for real applications, requires sophisticated cryptographic tokens. In reality, there are often multiple trust sources for a given identity attribute, their credentials have distinctively different formats, and many, if not all, issuers are unwilling to adopt new protocols. We present and build zk-creds, a protocol that uses general-purpose zero-knowledge proofs to 1) remove the need for credential issuers to hold signing keys: credentials can be issued to a bulletin board instantiated as a transparency log, Byzantine system, or even a blockchain; 2) convert existing identity documents into anonymous credentials without modifying documents or coordinating with their issuing authority; 3) allow for flexible, composable, and complex identity statements over multiple credentials. Concretely, identity assertions using zk-creds take less than 150ms in a real-world scenario of using a passport to anonymously access age-restricted videos.