Open-sourcing Anonymous Credential Service

What this post added

Introduced the Anonymous Credential Service (ACS) as a highly available multitenant service for de-identified authentication. Detailed the two-phase protocol (token issuance and token redemption) based on VOPRFs and blind signatures. Discussed challenges in scaling the protocol, including token redemption counting, key rotation strategies, and the implementation of key transparency using attribute-based VOPRFs and key derivation functions. Provided an overview of the ACS library components and a demonstration of its use in a real system.