Summary: As the cost and size of computing machinery continue to shrink, it will become commonplace to add computers to everyday objects and to use them to lock in customers and limit their freedom of use in ways analogous to the ways that digital-restrictions management schemes are currently being used. This is already happening with printers and print cartridges: Many printers perform a cryptographic handshake with any cartridge that is inserted and refuse to work with cartridges that are not approved by the printer manufacturer.

Thinking ahead, Felten envisions three similar opportunities for lock-in:

1) A pen may refuse to dispense ink unless it's being used with licensed paper. The pen would handshake with the paper by short-range RFID or through physical contact. (2) A shoe may refuse to provide some features, such as high-tech cushioning of the sole, unless used with licensed shoelaces. Again, this could be done by short-range RFID or physical contact. (3) The scratchy side of a velcro connector may refuse to stick to the fuzzy size unless the fuzzy side is licensed. The scratchy side of velcro has little hooks to grab loops on the fuzzy side; the hooks may refuse to function unless the license is in order. For example, Apple could put PRMed scratchy-velcro onto the iPod, in the hope of extracting license fees from companies that make fuzzy-velcro for the iPod to stick to.