Explanation/Reference:
A homegroup is a group of PCs on a home network that can share devices (such as printers), and libraries (such as your Documents, Pictures, Music, and Video libraries). Using a homegroup makes sharing easier.
Your homegroup is protected with a password, which you can change at any time.
Reference: Homegroup Password - View in Windows 8
http://www.eightforums.com/tutorials/15855-homegroup-password-view-windows-8-a.html