Authentication without password on Moodle

Actually I am trying to integrate my system with moodle. I need a functionality that supposed to work like that: 1. Login into my system (same username as in moodle db) 2. User decide to switch to moodle, so his clicking a link to script (on moodle server - both systems are on other servers), and I getting all data from database about user that I want to log in (whole row from database) ... 3. Because password is encrypted, I can't redirect now to login form with post params, because it won't work. Is there any good and easy way to achieve this goal? I have username and hashed and eventually hashed password. I am using moodle 1.9 (system requirments). Thanks in advance for any help, Regards David