1. Field of the Invention
The present invention generally relates to security of consumer goods and, more particularly, to the use of smart tags in maintaining product security.
2. Background Description
There is a need for certain products to be equipped with some apparatus which can provide information about the current state of the product as a result of events the product was subjected to prior to becoming in the possession of a potential consumer. Examples include the state of medical or food products prior to their being used by a consumer.
Also, consumers sometimes have the right and/or the need to know whether a product is brand new or not. This is especially true of expensive items. There is also a need for a product to be equipped by some apparatus which can record some aspects of the product history, for example in the case of automobiles where today odometers indicate, not very securely, one aspect of the history of the automobile.
Another context for the invention is the fact that, in some cases, the containers of some products are reused by the manufacturer, and the consumer would like to know if the product in the container is new or not, and if the container has been reused by a third, unauthorized, party. There is also a need for a method to detect whether the product has deteriorated, either because of defects, or because its expiration date has passed, or because of unwanted change in the environment, for instance in the form of excessive cold, heat or humidity. These scenarios require an apparatus which can detect the physical forces a product was subjected to as a result of use, handling, tampering or environmental factors. For either human intervention or environmental factors, it may be important in some circumstances that the recorded history of such events be very difficult to modify or counterfeit.
The prior art contains many methods involving seals and enclosures which allow one to detect when a package has been tampered with. Such prior art go way back in history, and a multitude of improvements, with very general or very specific uses, have been proposed which benefit from the general progress of technology. For example, U.S. Pat. No. 5,159,629 to Glen P. Double and Steve H. Weingart describes an intrusion barrier for protecting an electronic assembly from tampering. The prior art also contains methods of recording chronological information such as a data logger which stores information on a product as described in U.S. Pat. No. 5,010,560 to Mark A. Janney, Roger Newey, and Irwin J. Robinson.
However, these methods do not overcome the problem of providing a tamper evident history of a product and/or of its environment. The prior art does not allow the information about the history of a product and/or of its environment to be securely recorded and kept.
It is therefore an object of the present invention to provide a novel improvement on the prior art of tamper evident packaging which can detect when a product has been tampered with and resists the efforts of a tamperer, or anyone else who would benefit from hiding the tampering, or to hide the signs of tampering.
In the following, terms such as xe2x80x9cimpossible to changexe2x80x9d or xe2x80x9ctamper-proofxe2x80x9d should be understood to describe situations in which sufficient resistance to tampering is provided to make successful attacks rare due to cost/benefit issues, since codes, etc., can theoretically be broken if sufficient resources are brought to bear on the attack.
The invention uses a smart card, as described in U.S. Pat. Nos. 3,971,916, 4,007,355, 4,092,524, and 4,102,493 to Roland Moreno, or, more generally, a smart token, in combination with sensors attached to the product and/or to the smart card: upon tampering, or as a response to other circumstances, the sensors generate signals which are encrypted and recorded in the memory or storage device of the smart card attached to the product.
Recall that, for example, by using a zero-knowledge protocol, a smart card can be authenticated but cannot be duplicated. This technology has been disclosed for instance in U.S. Pat. No. 5,140,634 to Guillou, et al. This is the property which characterizes a smart card. Accordingly, in the rest of the present disclosure, any electronic component with these properties and which has some memories and/or some processing capabilities, will be called xe2x80x9ca smart tokenxe2x80x9d or xe2x80x9ca smart cardxe2x80x9d, even if it does not actually take any form resembling a card. A general reference to smart card technology and applications can be found in Smart Cards: A Guide to Building and Managing Smart Card Applications, by Henry Dreifus and J. Thomas Monk, John Wiley and Sons, 1998.
When the product or its packaging is tampered with, some attribute of the product or its environment changes. This change is what is detected by (at least some of) the sensors attached to a smart card, and the smart card will record this change irreversibly by erasing or writing some information within the smart card memory. The smart card also can be made duplication resistant by using a zero-knowledge protocol so that only the manufacturer of the original product, and/or possibly a trusted third party, for example, can produce or buy such smart cards. The smart card also can record the history of these changes in its internal memory.