Researchers at Sandia National Laboratory, Albuquerque, N.M., have developed a tamper-proof seal that will tell users if anyone has opened a container or tried to defeat the seal. Originally developed to protect nuclear arms and help support the arms-control and non-proliferation treaties, it could be sized to protect cargo containers, trucks, or even a medicine bottle.
The seal uses physical unclonable functions, the small defects that are part of any manufacturing process and which creep in due to variations in materials’ properties and tolerances. The current prototypes are about the size of a credit card and are covered by a film containing a suitably complex circuit. The resistances of the circuit changes if someone tries to lift, slide, or remove the film. A digital reader can check the seal remotely, but it needs a private key that will generate the right response from the seal. If the seal has been tampered with, the key changes, and the seal will not provide the proper response, letting users know there has been tampering with the seal.
While the seal cannot prevent tampering, it can reveal that it has taken place. The seal also cannot be counterfeited, as each seal will have a unique response.
Sandia is now looking to license the technology.