OS X Lion and OS X Mountain Lion allow you to securely share files with another user without creating a new account for them.Instead,authentication is guaranteed by the user’s Apple ID.Separate password is set to provide a way for that Apple ID to share files and folders on your Mac.This option comes in handy when you only wish to share some files and you don’t want to grant a complete login to the Mac.
How to set an Apple ID as a valid sharing login
1) Open “System Preferences” from the Apple menu.
2) Click on “Sharing” and make sure that “File Sharing” is enabled,as shown by the checkbox next to it.
3) Under “Sharing Folders”,select an existing folder or add a new folder that you wish to share.
4) Under “Users’ click the “+” button.
5) Select “Address Book” and find the person whose Apple ID you wish to use as a valid share login,then click “Select”.
6) Set a password and close out of Sharing.
Using this set up user can now connect to the certain shared directory using only their Apple ID,there is no need to create an actual user account on the Mac anymore.At the same time, they cannot log into the Mac for purposes other than file sharing.
The login procedure is the same as connecting to any other Mac,just remind the connecting user their password will be different.
Connecting to a shared Mac with Apple ID as the login
1) From the OS X Finder,pull down the “Go” menu and select “Connect to Server”.
2) select “Registered Guest” and enter the Apple ID as the name.
3) Use the password that was set by the user in Sharing rather than the Apple ID password,then connect as usual.