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 Certi cation Authority (CA). We challenge this assumption

and create the rst 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.