Firebird Friday Joke #7 is devoted to the often confusion of newbies in Firebird 3: the ability to have users with the same names but different passwords in different user managers.
If you have enabled 2 User Managers in firebird.conf
AuthServer = Srp, Legacy_Auth
UserManager = Srp, Legacy_UserManager
you can create one user with Srp (as default plugin), and another with Legacy_UserManager.
SQL> CREATE USER newuser PASSWORD '12345';
SQL> CREATE USER newuser PASSWORD '67890' using plugin Legacy_UserManager;
SQL> exit;
and then log in to the database with the same usernames, but different passwords
Then, try the following
E:\testFB\Firebird_3_0>isql localhost/3058:d:\o30copy.fdb -user newuser -pass 12345
Database: localhost/3058:d:\o30copy.fdb, User: NEWUSER
SQL> exit;
E:\testFB\Firebird_3_0>isql localhost/3058:d:\o30copy.fdb -user newuser -pass 67890
Database: localhost/3058:d:\o30copy.fdb, User: NEWUSER
SQL> exit;
We can identify these users:
SQL> select SEC$USER_NAME, SEC$PLUGIN from sec$users;
SEC$USER_NAME SEC$PLUGIN
=============================== ===============================
NEWUSER Srp
NEWUSER Legacy_UserManager
But we cannot tell which user has what password :)