Federated Secret Handshakes with Support for Revocation

Secret Handshakes are well-established cryptographic primitives that help two mistrusting users to establish initial trust by proving and verifying possession of given properties, such as group membership. All the Secret Handshake schemes to date assume the existence of a single, centralized Certification Authority (CA). We challenge this assumption and create the first Secret Handshake scheme that can be managed by a federation of separate and mistrusting CAs, that collaborate in the setup of the scheme yet retaining strict control over subsets of the property in the system. The security of the scheme is proved without random oracles.