Robert Hanssen's Palm III PDA

Origins
Robert Hanssen was a former FBI employee who was tried and convicted on spying for Soviet and Russian intelligence agencies for 22 years, from 1979 to 2001. He was arrested February 18, 2001 at a park near his home in Virginia. He received more than a million dollars in cash and diamonds over the twenty-two year period and is now currently serving a life sentence without parole. His PDA was one way he communicated with the Russians, using a steganographic technique called 40-track mode. It changed the capacity by decreasing it, so all his secret messages would have been in the lost data space.

Effects
The PDA lets the writer have their messages only display for them and no one else when they touch it. This is ineffective when in contact of the hands of a lawful person, with any messages appearing for them to view.