Commit 27f7691

@@ -71,6 +71,10 @@ Inspired by [Open Policy Agent][4] deployments. This experiment:
 * Uses lua bindings in nginx to connect to a local client process.
 * The client process proxies requests to a gRPC based policy decision service.
 
+## Questions
+
+1. What is the unique identifier for each security principal across service boundaries? (i.e. bigint, ulid, uuid, email)
+
 [1]: https://gitlab.com/gitlab-org/gitlab/-/blob/e1f6db024561e35462ac8d9f54b8f9678f6ed6ee/app/models/ability.rb#L73
 [2]: https://gitlab.com/gitlab-org/gitlab/-/tree/master/app/policies
 [3]: https://casbin.org/