SD-BLS: Privacy Preserving Selective Disclosure and Unlinkable Revocation of Verifiable Credentials

It is of critical importance to design digital identity systems that ensure the privacy of citizens as well as protecting them from issuer corruption. Unfortunately, what Europe's and USA's public sectors are currently developing does not offer such basic protections. We aim to solve this issue and propose a method for untraceable selective disclosure and privacy preserving revocation of digital credentials, using the unique homomorphic characteristics of second order Elliptic Curves and Boneh-Lynn-Shacham (BLS) signatures. Our approach ensures that users can selectively reveal only the necessary credentials, while protecting their privacy across multiple presentations. We also aim to protect users from issuer corruption, by making it possible to apply a threshold for revocation to require collective agreement among multiple revocation issuers.