The Central Authentication Service (CAS) enables the user to make avail of a group of web services that require authorization. When logging in to one of such services the user is redirected to the CAS site, where after logging in he/she gains unencumbered access to all the services that cooperate with CAS. CAS utilizes a single repository of accounts, one shared by all services.

When using the Central Authentication Service you must remember that:

• the log-in page must always have the same form. Any change in appearance should prompt heightened caution;
• the page must be "secure", evidence of which is the prefix https://
• the page must be protected with a certificate of the home university.

If you encounter the log-in form on a page that does not meet the above conditions, this may indicate that someone has created a counterfeit service in the aim of stealing user passwords. In such case you must refrain from logging in and inform the service administrator of the problem at once.

Central Authentication Service allow change forgotten password. If you want to reset your forgotten password use forgotten password option on main login page, next type in your user ID and e-mail address (in APS domain). If this data will be correct then CAS send to you message with information how to reset your password.

If after logging in you see a message reading Unauthorized. User <account_name> is not registered in this system, this means that the account is unknown. In order to clear up such a problem, you will need to contact the Student's Office of your home university.