The Digital Capabiity Publisher (DCP) Specification provides the ability to discover detailed service information (including associated digital certificates) for any given business identifier.
Specification: http://ausdigital.org/specs/ausdigital-dcp/1.0/
Community discussion/support: ausdigital.org
Open source reference implementation: https://github.com/test-point/testpoint-dcp/
Test suite: https://github.com/test-point/testpoint-dcp
Live test endpoint: https://dcp.testpoint.io/