diff --git a/doc/quickstart.md b/doc/quickstart.md
index ddb5c9a3717b8a7f666ce59dc237fc2f1063e19a..b22be82b48c759ad460a3d4b355f3960b8ce2ffd 100644
--- a/doc/quickstart.md
+++ b/doc/quickstart.md
@@ -98,3 +98,13 @@ After the whole process is finished, SOCTools can be accessed by going to https:
 * 8888 - haproxy-stats
 * 5443 - User Management UI
 
+## Authentication
+
+Most of the tools use single-sign-on authentication via Keycloak.
+The preferred way to authenticate is to use the client certificate of given user (browser should ask to select the certificate).
+Alternatively, the primary/admin user (the one configured during installation) can use its username and password - the password is stored in `secrets/passwords/[username]`.
+
+The same username and password is used to access the User Management UI, where more user accounts can be created.
+Such users should authenticate using their client certificate, which they can download from a link they receive via email.
+
+The haproxy-stats page (needed only for debugging/statistics) can be accessed by `haproxy` username and password found in `secrets/passwords/haproxy_stats`.