How I can manage something like session and cookie in iphone native application?

How I can manage something like sessio开发者_StackOverflow中文版n and cookie in iphone native application?

For example:

If I login into iphone app, now I do nothing for say 10 mins, then after 10 mins whenever I perform any activity in that app, I must be logged out.

This is what we found in facebook, gmail and yahoo websites, but I want to implement such a feature in iphone native application...

Your suggestion will be well appreciated...