Authentication with built-in encryption by using moire intensity profiles between random layers
First Claim
1. A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of:
- a) creating on a document at least one basic screen with at least one basic screen dot shape;
b) superposing a master screen with a master screen dot shape and the basic screen, thereby producing a moire intensity profile; and
c) comparing said moire intensity profile with a reference moire intensity profile and depending on the result of the comparison, accepting or rejecting the document;
where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different.
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Accused Products
Abstract
This invention discloses new methods, security devices and apparatuses for authenticating documents and valuable articles which may be applied to any support, including transparent synthetic materials and traditional opaque materials such as paper. The invention relates to moire intensity profiles which occur in the superposition of specially designed random structures. By using specially designed random basic screen and random master screen, where at least the basic screen is comprised in the document, a moire intensity profile of a chosen shape becomes visible in their superposition, thereby allowing the authentication of the document. An important advantage of the present invention is that it can be incorporated into the standard document printing process, so that it offers high security at the same cost as standard state of the art document production. Another major advantage of the present invention is in its intrinsically incorporated encryption system due to the arbitrary choice of the random number sequences for the generation of the specially designed random dot screens that are used in this invention.
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Citations
57 Claims
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1. A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of:
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a) creating on a document at least one basic screen with at least one basic screen dot shape; b) superposing a master screen with a master screen dot shape and the basic screen, thereby producing a moire intensity profile; and c) comparing said moire intensity profile with a reference moire intensity profile and depending on the result of the comparison, accepting or rejecting the document; where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising:
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a) a master screen; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the master screen; and c) a comparing means operable for comparing the acquired moire intensity profile with a reference moire intensity profile; where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different. - View Dependent Claims (33, 34, 35, 36)
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37. A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of:
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a) creating on a document at least one basic screen with at least one basic screen dot shape; and b) superposing a master screen with a master screen dot shape and the basic screen, thereby producing a moire intensity profile which is apparent to a human eye; where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different. - View Dependent Claims (38, 39, 40)
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- 41. A security device for authentication of documents comprising at least one basic screen with at least one basic screen dot shape, that is located on the document, where the document authentication is done by superposing a master screen with a master screen dot shape and a basic screen, thereby producing a moire intensity profile and permitting the comparison of said moire intensity profile with a reference moire intensity profile and the acceptance or the rejection of the document depending on the result of the comparison, and where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different.
- 53. A security document protected by a security device, said security device comprising at least one basic screen with at least one basic screen dot shape, that is located on the document, where the document authentication is done by superposing a master screen with a master screen dot shape and a basic screen, thereby producing a moire intensity profile and permitting the comparison of said moire intensity profile with a reference moire intensity profile and the acceptance or the rejection of the document depending on the result of the comparison, and where each basic screen is a random basic screen comprising randomly located dots having basic screen dot shape, the master screen is a random master screen comprising randomly located dots having master screen dot shape, and the master and basic screens have essentially the same random dot locations, wherein the basic screen dot shape and the master screen dot shape are different.
Specification