Single sign-on (SSO) is a property of access control of multiple related, but independent software systems. With this property a user logs in once and gains access to all systems without being prompted to log in again at each of them. 

Benefits of using single signon include:

•     Reducing password fatigue from different user name and password combinations
•     Reducing time spent re-entering passwords for the same identity
•     Reducing IT costs due to lower number of IT help desk calls about passwords

SSO uses centralized authentication servers that all other applications and systems utilize for authentication purposes, and combines this with techniques to ensure that users do not have to actively enter their credentials more than once.

SSO users do not need to remember so many passwords to log in to different systems or applications.