Electrical computers and digital processing systems: support – Multiple computer communication using cryptography – Particular communication authentication technique
Reexamination Certificate
1997-12-02
2001-04-03
Hayes, Gail O. (Department: 2766)
Electrical computers and digital processing systems: support
Multiple computer communication using cryptography
Particular communication authentication technique
C708S250000, C708S255000, C380S051000
Reexamination Certificate
active
06212638
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for generating identification symbols, numbers or codes for authenticating goods or the like, which provides multiple levels of security among agents, vendors, sub-vendors and customers.
In many regions of the world, the widespread sale and distribution of counterfeit goods presents a tremendous problem to the manufacturer of the authentic goods. One known technique for preventing counterfeiting is to provide the authentic goods with identification numbers or marks which cannot be readily copied. For example, it is known to mark goods with randomly selected ID numbers which, because of their random selection, arguably cannot be predicted or anticipated by a counterfeiter. Unfortunately, it is well known in cryptography that randomly selected numbers are not truly random. Thus, without proper measures, it is possible for counterfeiters to determine the pattern of “random” generation, and thereby defeat the random marking system.
Even if the random ID numbers could not be predicted, other security problems can nevertheless enable counterfeiters to acquire this set of numbers. In particular, the manufacturer of the goods has knowledge of the randomly selected, valid ID numbers, and the list of ID numbers may also be provided to resellers of the goods so that they may confirm the authenticity of the goods. Under these circumstances, it is often not difficult for a counterfeiter to obtain the list of valid ID numbers in an illegitimate manner.
In view of the foregoing, a need therefore exists for an improved method for marking goods to prevent counterfeiting which employ numbers or codes that cannot be readily predicted nor detected by potential counterfeiters.
SUMMARY OF THE INVENTION
The present invention satisfies the foregoing need by providing a method for generating identification symbols, numbers or codes (IDs) for authentication of goods and other objects, in which special functions are employed to select the IDs which make them unpredictable. The term unpredictable means that knowledge of one or more of the IDs cannot be employed to predict or determine the identity of other valid IDs. In addition, multiple sets of the IDs are employed in such a manner that no one individual has complete knowledge of any particular set, thereby greatly improving security against illegitimate acquisition of the IDs.
In the method, one or more sets of multi digit symbols, such as numbers, letters, characters and/or their combinations, is/are generated by an agent using algorithms which select the symbols in such a manner that they are unpredictable. To generate the unpredictable set of symbols, the algorithms employ functions known as Nyquist functions which are derived from the Nyquist sampling theorem. In particular, the Nyquist sampling theorem states that a cyclic, e.g., sinusoidal, function for a deterministic curve cannot be identified if sampling points in the curve are taken less than two per cycle. Thus, if a selection function is employed to generate a set of symbols such that each symbol represents a point along a curve defined by a cyclic function, and less than two points are selected for each cycle of the curve, then the resulting set of symbols will be unpredictable.
To enhance unpredictability, certain subsets of the IDs are then selected by the agent from each original set, again by using special Nyquist functions, which create subsets that are also unpredictable. These subsets are delivered to the vendors or the manufacturers of the goods or products to be authenticated. The vendors or manufacturers protect their products by marking each of them with one or more of the symbols in the subsets. The selection functions employed by the agent for creating the subsets are controlled by secret keys known only by the agent. In this manner, the agent can generate different subsets of symbols for different vendors or manufacturers. To enhance security of the IDs, the vendors and manufacturers, using certain selection functions with their own secret keys, each select their own sub-subset of symbols which are used to mark the goods each vendor or manufacturer sells.
Using the foregoing technique, the subject method provides three-way attack resistance from counterfeiters. First, a customer who purchases the goods from a vendor can verify that the goods are genuine by checking whether the symbols on the goods are valid. This is preferably accomplished through comparison to symbols stored in an authorized database which may be accessed by any suitable means, such as a telephone or the Internet, for example. Since the symbols are generated using the special Nyquist functions as selection and check functions, it is impossible for a customer to determine the functions by which the symbols on the goods were generated. Thus, regardless of how the original sets of symbols generated by the agent were selected, the customer cannot determine the identity of the symbols within the sub-subset since they have no knowledge of the hash functions employed to form the sub-subset.
Similarly, the method is resistant to counterfeiting by individuals associated with either the agent or a vendor. In particular, an individual who is associated with the agent and has knowledge of both the original sets of symbols and the secret keys employed to generate the subsets of symbols, cannot determine the identity of the sub-subsets of symbols since only the vendor or manufacturer possesses knowledge of the secret key employed to form the sub-subsets. Conversely, a potential counterfeiter having access to the vendor's secret key cannot determine the identity of the sub-subsets without having knowledge of the subsets of symbols which were provided by the agent to the vendor.
As a further deterrent, whenever a customer communicates with the database to determine whether their set of symbols is valid, that set of symbols can then be marked as “used” so that if any attempt is made by a counterfeiter to use the same symbols on different goods, this will quickly be detected when the purchaser of the counterfeit goods checks the symbols against those stored in the database.
Preferably, multiple sets of symbols are employed for each ID to accelerate checking speed, and automatically invalidate used symbols. In particular, the size of one of the sets is considerably smaller than the other, and this smaller set is examined by comparing its value to the value stored in the database. Because of its smaller size, the first set of symbols can be quickly checked against those in the database to verify whether they have been used previously. If so, it can be concluded that both sets of symbols are invalid since at least one of the sets is invalid.
The present invention also employs a special fire wall technique for permitting customer access to the ID database to verify the authenticity of their ID symbols. In this technique, when a customer accesses the database, they are prompted to enter the ID symbols to be checked. Each ID symbol, when converted to digital form, has a preset number of bytes, and a digital counter is employed to count the total number of bytes entered by the customer. As soon as the number of bytes entered equals the total number of bytes in the ID, the system is triggered to switch off input from the customer so that the customer cannot enter any further data. The system then allows only a communication of one of two signals, “yes” or “no”, indicating whether the entered set of symbols is valid or not. With this arrangement, there is no way for individuals to access the agent's main computer system in an effort to determine the original sets of symbols and the agent's secret keys.
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patent: 5592561 (1997-0
Lee George C.
Liang Zhong
Hayes Gail O.
Jones Tullar & Cooper PC
Tucker Christopher M.
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