WO2007010224A1

WO2007010224A1 - Visual authentification of optical storage medium

Info

Publication number: WO2007010224A1
Application number: PCT/GB2006/002640
Authority: WO
Inventors: James Leslie Board
Original assignee: De La Rue International Limited
Priority date: 2005-07-18
Filing date: 2006-07-17
Publication date: 2007-01-25
Also published as: GB0514701D0

Abstract

Self-verification apparatus comprises an optical data storage medium (10) provided with a first member (12) of a visual authentication device. A second member (5) of the visual authentication device is fixed to or generated by an article (2) separate from the optical data storage medium. When the first and second members (12, 5) are viewed together, they cooperate to present a verification image to a viewer, the verification image not being visible when the first and second members are viewed separately.

Description

VISUAL AUTHENTIPICATION OF OPTICAL STORAGE MEDIUM

The invention relates to self-verification apparatus, particularly for use with an optical data storage medium such as a CD or DVD. It is becoming increasingly easier to produce copies of proprietary software provided on optical data storage media such as a CD or DVD as a result of CD and DVD writing devices becoming widely available. As a result of this, software suppliers are providing increasingly sophisticated methods to prevent illegal copying by incorporating anti-copy features into the software. Another approach is to enable counterfeit storage media to be identified by incorporating highly complex security features into the optical data storage media themselves.

For example, US-A-2004/0255317 describes various methods for incorporating security features in a radially inner, normally unused portion, of a compact disc. Examples of these security features include encrypted, printed serial numbers; digital fingerprints or watermarks; holograms; polarized filters; photo-luminescent coatings (detectable by specially tuned lasers); microscopic taggants, i.e., microscopic markers not found in the base material but added to the base material to indicate the object's origin or authenticity; and radio-frequency identification (RFID) devices.

The problem with these approaches is that it is not easy for the average user to determine whether or not he has been given a counterfeit product. Special devices are usually required to analyse the security feature or they need to be viewed by highly skilled personnel.

There is a need therefore for a relatively straightforward method to enable average users to be able to readily detect counterfeit optical data storage media. In accordance with the present invention, we provide a self-verification apparatus comprising an optical data storage medium provided with a first member of a visual authentication device; and a second member of the visual authentication device fixed to or generated by an article separate from the optical data storage medium whereby when the first and second members are viewed together, they cooperate to present a verification image to a viewer, the verification image not being visible when the first and second members are viewed separately.

We have realised that a fair degree of reassurance can be provided to a user that he is in possession of a genuine optical data storage medium by utilising a relatively simple authentication device rather than the highly complex devices of the prior art. It is recognised that a sophisticated counterfeiter might be able to produce apparently genuine counterfeit copies but the present invention is not intended to prevent this but rather deal with slightly less sophisticated copying by providing a system which is not straightforward for the average person to duplicate.

Essentially, the invention provides a quick way for the average user to establish that there is a link between the first and second members, one of which is provided on or in the optical data storage medium, leading to a reasonable degree of certainty that he is handling a genuine product.

The concept of a two-part visual authentication device is known and there are many conventional methods of achieving this. All of these are suitable for use in the present invention. Typically, these are utilised in the context of revealing a hidden image in a security printed document or the like using a handheld viewer or revealer. The hidden images and the type of revealer can take several forms. The following approaches are described in the prior art.

WO 01/87632 discloses a print feature consisting of an array of dots in which a security pattern or code is produced by displacing some of the dots with respect to the rest. This cannot be seen with the naked eye. The pattern can be made visible by viewing through a planar device carrying transparent and opaque areas of the same periodicity as the printed dots.

WO 97/20298 discloses a method and apparatus for producing Scrambled Indicia®. This process encodes a message or image into an area of print using digital techniques. The message cannot be seen by unaided eye. When the print is viewed using a lenticular screen of the correct characteristics the hidden image/message is revealed. In some cases different images can be seen at different angles of view. Such scrambled indicia can be incorporated into print or into holographic originations. Enschede's microSAM® feature uses screen angle modulation to encode a message or image by modifying the print structure in a manner undetectable by the unaided eye. When the feature is viewed through the correct revealer the hidden message or pattern is seen. The revealer in this case is a piece of plastic film ruled with parallel black lines of the correct pitch and thickness. WO 01/39138 discloses methods and apparatus for authenticating security documents such as banknotes, passports etc. According to this method, a screen pattern is printed onto a surface. A revealing device is designed so that when it is placed over the printing, it produces a clearly visible message or image caused by the moire effect. The revealing screen may be a line structure or a microlens array. GB 1407065 describes a security document carrying a pair of metameric inks which match under one illuminant, say North Sky light, but mismatch under another type of illuminant, such as tungsten. For such a set of inks it is also possible to see a difference in the appearance of the two pairs of such inks by viewing under coloured filters. Commonly, a red filter is used for viewing features. Any mismatch in the absence of a viewer is hidden by overprinting the ink pair by a discontinuous red print design which drops out under the filter.

EP 930979 discloses a self-verifying document and describes a number of methods by which a transparent region on the document can be used to authenticate a document. Microlenses, diffraction gratings, colour filters and moire effects are all referred to.

In all the above effects the security benefits rely on the fact that when the document is copied the structure of the hidden images are not precisely replicated by the copying process. For example this will occur if the resolution of the original image is significantly greater than the resolution of the device used to replicate the image.

In some applications of the invention, the article can be supplied separately from the optical data storage medium such that one is equivalent to the known security feature and the other equivalent to the known revealer. However, in particular preferred aspects of the current invention, the article is related to the optical data storage medium. For example, the article may comprise packaging for the optical data storage medium. In this case, the second member may be printed directly or indirectly on the packaging and when the optical data storage medium is removed from the packaging, the two members can be viewed together to check whether the verification image is revealed. In the preferred approach, the first member is provided in or on a transparent portion of the optical storage data medium so that the second member can be viewed through the transparent portion.

Thus a revealer on the optical data storage medium can be used to authenticate the certificate of authenticity or fiscal stamp applied to the packaging supplied with the optical storage medium. In another approach, the packaging comprises a transparent window containing the second member so that when the optical data storage medium is packaged, the two members cooperate together to generate the verification image. Thus, the purchaser will see the verification image at the time of purchase and it will disappear when the optical data storage medium is removed from the packaging. In other examples, the data stored on the optical data storage medium is to be used on a processor and may for example comprise a software program. In that event, the second member may be provided as a label attached to a processor with which the optical data storage medium is to be associated. For example a personal computer will typically have an operating system preinstalled and will have a certificate of authenticity applied to its outer case for authentication by the user. The computer will also be supplied with a set of DVD's or CD's on which the software associated with the certificate of authenticity is stored, these being supplied as a backup in case the user should need to reinstall the software. In this instance the label adhered to the computer has a hidden image printed on it which can be verified by the viewer integrated into the optically data storage media.

Alternatively the second member could be displayed on a display such as a monitor. Of course, the display on a monitor could be used simply to verify the optical data storage medium even if it has no connection with any associated processor. In one approach, the second member is computed by the processor in accordance with a preprogramed algorithm. This algorithm may generate the same second member each time it is activated or may vary the second member, for example by taking account of the time of varying parameter. Thus, in the case of game playing software, the time varying parameter may vary according to the state of the game. In an alternative approach, the processor can obtain the second member from a remote source, for example via the Internet. Thus, a purchaser or user of the optical data storage medium could enter an identifier of that storage medium which is communicated to the remote source, the identifier being used as an index to locate the appropriate second member which is then transmitted to the processor for display. In all these preferred aspects, it will be understood that it is not necessary to supply a separate "revealer" since the optical data storage medium and the article are associated with each other.

The region of the optical data storage medium with the first member is usually transparent but does not need to be 100% transparent. It will typically allow a level of transmission as the user views the coded image to be decoded through this region. For example one might use a semi-transparent metal layer or a transparent coloured layer.

The verification image can take a variety of forms but, for ease of recognition, typically comprises one or more of indicia, for example alphanumerics, a graphical device, logos, serial numbers, authentication keys, patterns and the like. Some examples of self-verification apparatus according to the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 illustrates schematically a personal computer and associated optical data storage media; Figure 2 is a plan view of a security label affixed to the housing of the personal computer shown in Figure 1 ;

Figure 3 illustrates one of the optical data storage media in more detail. Figures 4A-4C illustrate first and second members of another example of a visual authentication device and the combined members respectively; and, Figures 5A-5C and 6A-6C are views similar to Figures 4A-4C respectively but of third and fourth examples of visual authentication devices.

Figure 1 shows a security label 1 applied to the housing 2 of a personal computer. The security label 1 , shown in detail in Figure 2, is a certificate of authenticity for the operating systems pre-installed on the computer by the computer manufacturer. The security label 1 comprises a security substrate 3 having a security thread 4 and optionally other embedded security features (not shown). The secure substrate 3 is printed with a range of security features including a hidden image feature such as Scrambled Indicia® 5 forming a "second member" of a visual authentication device. Scrambled Indicia® is a technology developed and marketed by Graphic Security Systems Corp and has been widely used on a range of security applications previously. See also WO97/20298. The security label 1 has also been provided with an identifier, for example a barcode 6 and a serial number 7. The identifier can be used by an inspector to authenticate the validity of the label 1. The identifier can also be used by the software owner to validate, or unlock the software application. Alternatively the identifier might be required to access on line help, updates and upgrades to the software.

The computer is supplied with one or more back up CD's or DVD's 10, one of which is shown in detail in Figure 3. These can be used in the event the operating system should need to be reinstalled. A revealer 12 for the Scrambled Indicia® 5, forming a "first member" of the visual authentication device, is integrated into one or more of the CD's or DVD's in a transparent inner ring region 14. In this example the revealer 12 has been integrated directly into the CD/DVD during the manufacture of the CD/DVD. Forthe Scrambled Indicia® feature 5 the revealer comprises a lens structure which can be formed by embossing. An example is described in WO-A-97/20298. It is therefore relatively straightforward to modify the stamping device used to emboss CD/DVD's to incorporate a revealer device in the inner ring region 14 that is not normally embossed.

The CD/DVD 10 can then be used to authenticate the label 1 attached to the

PC housing 2. The user simply takes the CD/DVD 10 and places it such that the transparent inner ring region 14 containing the revealer 12 is over the Scrambled

Indicia 5 on the label 1. When the Scrambled Indicia® is viewed through the revealer an image, message or code is revealed constituting a verification image.

As an alternative to forming the revealer during the stamping process of the CD/DVD 10 is may be applied subsequently in a separate process. For example it may be applied as a transparent label, by a casting process or by a relief printing process. Other methods are described in US-A-2004/0255317.

A variety of other visual authentication devices could be used.

1. The revealer in the inner ring 14 could be a combination of a scrambled indicia lens structure and a metameric (e.g. red) filter. Such a device would be capable of decoding or revealing both a metameric hidden image and a scrambled indicia hidden image. Alternatively the hidden image could be a complex combination of the metameric and scrambled indicia features.

2. As a further development of 1 above the revealer could be a combination of two lens structures interlocked and thus capable of unlocking two different codes. By interlocked we mean the two lens structures are interleaved or superposed upon each other in some way. If the two structures are carefully selected and superposed correctly then it is possible to use a single revealer to reveal two differently encoded images.

3. The revealer could be used to reveal a hidden image that is concealed within a holographic or diffractive element in a similar manner to the previously described hidden images. Alternatively, the hidden image could be concealed within a demetallisation pattern. The demetallisation essentially being equivalent to the printed structures referred to earlier.

4. The revealer could comprise both left and right light polarising segments that can then be used to view a liquid crystal ink feature. Such liquid crystal ink features can be printed with SICPA Oasis inks. The ink is available in both right and left handed forms so can be used to produce hidden features.

5. The revealer 12 in the inner ring 14 could comprise a microlens array which when placed overthe hidden image magnifies or reconstructs information. Othertypes of lens could be used e.g. simple magnifiers, or fresnel lenses. 6. Composite verification images could be used, generated in accordance with the techniques described in PCT/GB05/01640.

As can be seen therefore, the current invention is not limited to the use of Scrambled Indicia® but could make use of many different hidden feature and revealer technologies. Where a metameric, dot screen or line screen approach is used the revealer can be printed (instead of embossed) on to the CD. This printing step can be done later in the replication process. Additionally this presents the opportunity for each label to carry a unique pattern that requires a unique decoder. This would further enhance the security of the invention. Some further examples of apparatus according to the invention will now be described.

Figure 4A illustrates a document or item of packaging 30 carrying an area of print 31 within which is hidden an image, for example using the Scrambled Indicia process. Figure 4B illustrates a CD or DVD 32 with a revealer 33 provided in an inner, transparent ring portion.

Figure 4C illustrates the result of overlaying the CD/DVD 32 on the document or packaging 30 with the revealer 33 located so that the hidden image 34 is revealed and the message can be read. In the case of packaging, it will be understood that if the area of print 31 is provided in a transparent window of the packaging 30 then it can be arranged such that the message or hidden image 34 can be viewed while the CD/DVD is in its packaged condition. This provides an indication of authenticity. In that case, it is usually necessary for a window to be provided on the opposite surface of the packaging to that carrying the print 31 so that a light path exists through both leaves of the packaging and the inner ring 33 of the CD/DVD.

Figures 5A and 5B illustrate a first member and a second member respectively of a visual authentication device, utilising a metameric effect. Thus, the first member 40 (Figure 5A) is printed using a pair of metameric inks which appear indistinguishable to the naked eye. However, when this metameric print is viewed through a revealer 42, the two inks can be distinguished and a serial number 44 provided using one of the inks (Figure 5C) can be revealed. In the case of the CD/DVD application, the revealer or filter 42 could be provided in the inner ring of the CD as a printed or dyed region.

In the Figure 6 example, a hidden image 50 (Figure 6A) is created by first printing a background line pattern 52 of a given frequency. Onto this is superposed a message comprising letters made up of a line screen having the same frequency as that of the background but shifted to the left slightly. The revealer 54 is also a line screen of the same frequency and by lining up the revealer 54 correctly with the hidden image 50, the term VALID appears (Figure 6C). Of course other methods are possible including the use of multiple line frequencies, dots instead of lines, or more complex screen techniques.

Claims

1. Self-verification apparatus comprising an optical data storage medium provided with a first member of a visual authentication device; and a second member of the visual authentication device fixed to or generated by an article separate from the optical data storage medium whereby when the first and second members are viewed together, they cooperate to present a verification image to a viewer, the verification image not being visible when the first and second members are viewed separately.

2. Apparatus according to claim 1 , wherein one of the members of the visual authentication device comprises one or more lens structures, for example microlens array(s), and the other member comprises one or more corresponding verification images encoded into a background.

3. Apparatus according to claim 1 or claim 2, wherein one of the members includes one or more colour filters and the other of the members comprises multiple coloured indicia chosen such that when viewed through the one member only certain portions of the indicia are visible so as to define the verification image.

4. Apparatus according to any of the preceding claims, wherein one of the members provides a first part of a composite verification image and the other of the members provides a second part of the composite verification image.

5. Apparatus according to any of the preceding claims, wherein one of the members comprises respectively left and right polarising segments, and the other of the members comprises a corresponding arrangement of left and right polarised liquid crystal inks.

6. Apparatus according to any of the preceding claims, wherein one of the members includes a colour filter and the other of the members comprises one or more metameric inks.

7. Apparatus according to any of claims 2 to 6, wherein the one of the members is provided by the first member and the other of the members is provided by the second member.

8. Apparatus according to any of the preceding claims, wherein the first member is provided on or in a transparent part of the optical data storage medium so that the second member can be viewed through the transparent portion.

9. Apparatus according to any of claims 1 to 4, or claim 7 or claim 8 when dependent on any of claims 1 to 4, wherein the article comprises an electronic display on which the second member can be displayed.

10. Apparatus according to claim 9, wherein the display is coupled to a processor that computes the second member in accordance with a preprogramed algorithm.

11. Apparatus according to claim 10₁ wherein the preprogramed algorithm takes account of a time varying parameter.

12. Apparatus according to claim 10 or claim 11 , wherein the time varying parameter varies according to a game played using the processor.

13. Apparatus according to claim 9, wherein the display is coupled to a processor that obtains data defining the second member from a remote source, for example via the Internet.

14. Apparatus according to any of claims 1 to 8, wherein the second member is printed directly or indirectly on the article.

15. Apparatus according to claim 14, wherein the second member is printed on a label affixed to the article.

16. Apparatus according to any of claims 1 to 8, 14 or 15, wherein the article comprises packaging for the optical data storage medium.

17. Apparatus according to claim 16, wherein the packaging includes a transparent window within which the second member is provided.

18. Apparatus according to claim 17, wherein the optical data storage medium is located in the packaging with the first and second members aligned so that the verification image is visible from outside the package.

19. Apparatus according to any of claims 1 to 15, wherein the article comprises a processor storing software, the optical data storage medium storing a back-up version of the software.

20. Apparatus according to any of the preceding claims, wherein the verification image comprises one or more of indicia, for example alphanumerics, a graphical device, logos, serial numbers, authentication keys and patterns.

21. Apparatus according to any of the preceding claims, wherein the optical data storage medium comprises one of a CD and DVD.

22. Apparatus according to claim 21 , wherein the first member is provided in or on a radially inner, annular portion of the CD or DVD.