Title: Securing and controlling access to digital data
Patent application publication number: 20070030963
Publication date: February 8, 2007
Filing date: August 4, 2005
Link to PDF: 
(23 pages)
AIPW Summary: This application relates to the security code lock on an iPod (see Figure 7B). In general, content is locked and can be unlocked using any movement-detecting input means (e.g., joystick, touch pad, keyboard) that permits a user to enter a security code.