Two part code

This is a division of Ser. No. 11/542,300, filed Oct. 2, 2006 entitled “Two Part Code” which is a National filing of a corresponding co-pending application filed in the United Kingdom as U.K. Serial No. GB05200654, filed Oct. 3, 2005, entitled “Two Part Code” for which priority is claimed and which are incorporated herein by reference.

The present invention relates to codes and is concerned particularly with codes having two parts, which two parts are related.

Graphic, machine-readable codes are commonly used, for example, to identify articles such as consumer products. Several popular codes are currently used, including one and two-dimensional barcodes and matrix-style codes. In each case the code is applied to an article and enables the article to convey information about itself such as the identity of the manufacturer, and the article type.

One sophisticated type of machine readable code is described In our UK Patent No. GB 2383878 (the entire contents of which are incorporated herein by reference) and commercially available under the trade mark Fracture Code®. Advantages of this type of code over other commercial machine-readable codes include a very high population of possible distinct codes as well as the ability to generate unique codes at very high speed.

Articles, such as consumer products or their packaging, are marked with such codes. In order to obtain information about the article, the code must be read by a machine which first performs a scanning operation to acquire digitally an image of the code. The image Is then processed electronically to derive, via application of an algorithm, an alphanumeric character string that may be used to look up data corresponding to the article in a database.

Another major advantage of this code is the difficulty with which the code may be copied. The code, which typically comprises a rectangular box delimiting a series of intersecting lines, Is difficult to copy to the degree of accuracy needed such that when read by a machine the same alphanumeric character string would be generated. This feature is partly a function of the level of detail, including thicknesses of lines and accuracy of angles therebetween, at which the scanning equipment acquires the image during reading. A further difficulty for would-be counterfeiters, is that many of the codes used are no more than 1 mm by 1 mm in area and may be printed in ultraviolet inks, infrared Inks or other security Inks.

A major security advantage of such codes is the fact that at the time of their creation they carry no information whatsoever, but must be scanned, converted into an alphanumeric character string using the algorithm and then related to data held in a database. Only then do they become meaningful.

Thus, without the algorithm, there is no way of deriving the information. A corresponding benefit is that even if a code can be reproduced accurately it cannot be applied to a different product from that to which it was originally applied without this fact becoming immediately detectable by a person undertaking a legitimate scanning/lookup operation.

Embodiments of the present invention aim to provide a machine-readable code for associating data with articles, the authenticity of which code may be verified without obtaining the article data with which the code is associated.

Embodiments of the invention also aim to provide a code, for associating articles with data stored in a database, in which the data may be obtained at a faster rate than has previously been possible.

In accordance with one aspect of the present invention there is provided a graphically representable, machine readable code having first and second parts wherein a first part may be associated with data and a second part may be associated with the first part, such that a relationship between the parts, or lack thereof, may be discerned by reading both parts of the code, in order to verify the authenticity of the code.

The invention also includes a method of verifying-the authenticity or lack of authenticity of a graphically representable machine readable code, wherein the code comprises a first part and a second part, the method comprising reading both the first part and the second part of the code and determining whether the two parts of the code are related, and verifying that the code is authentic in the event that the two parts are related, or verifying that the code is not authentic in the event that the two parts are not related.

The invention also includes a code system for associating data with articles, the system comprising means for generating graphic codes for application to articles, machine means for reading the codes to convert each code into a string of characters, and storage means arranged to store data associated with each code, wherein the codes each comprise a first part and a second part, wherein said system includes a population N of codes having, within said population, unique first parts, and wherein within the system a population n of the codes has unique second parts, wherein N>n, and wherein for each code the first portion and the second portion are related, such that a number N/n of codes share the same second parts but have unique first parts.

Preferably the relationship between the first and second parts of the codes is detectable by a machine reading both parts and performing a mathematical operation on the two parts to discern whether they are related.

N/n codes, having distinct first parts N share common second parts n. Upon reading of both parts of the code it is possible to determine whether, for that particular code, the first part is one of the set of first parts that has the relationship with the read second part. If the parts are related this suggests that the code may be genuine. If the parts are unrelated then the code is definitely unauthentic.

The relationship between the first and second. parts of the codes is preferably a function of the generation process by which the first parts were created. For example, the second part of the code may represent one or more characteristics of a batch of first parts. such as a relationship between intersecting lines, which is common to all of the first parts in that particular batch of codes.

Thus, provided that future machine-reading of the two portions of the code is performed in a consistent, approved manner, it is possible to detect a mismatch between the first and second parts which mismatch would suggest an unauthorized or counterfeit code.

In another aspect the invention provides a method of looking up a code in a database to determine data associated with the code, wherein the code comprises first and second parts (F and S) wherein the first part (F) is associated with data in the database and is one of a set N of such first parts, and the second part (8) is related to the first part and is one of a set n of such second parts, N being much greater than n, the method comprising looking up in the database the second part (S) of the code among the population n, and then looking up the first part (P) of the code within the subset N/n of first parts which share the same second part (S).