Single sign-on has to store different credentials as different applications support different user authentication mechanisms. For this purpose centralized authentication servers are used. Although it is difficult to implement, it has a lot of benefits:
Avoids the need for multiple log-ins and saves time
Reduces the need to remember different username and password combinations
Reduces IT costs by lowering the number of help desk calls regarding forgotten passwords
Since single sign-on provides access to multiple systems at once, security issues can arise if the user credentials are not well protected. Hence methods like smart cards and one-time password tokens are employed. The One- time password method is very effective in preventing unauthorized access. Since authentication systems are highly critical and its unavailability can prevent access to systems, SSO is undesirable for systems which require guaranteed access all the time like security.