Electrical computers and digital processing systems: support – Multiple computer communication using cryptography – Particular communication authentication technique
Reexamination Certificate
1999-12-02
2004-06-08
Smithers, Matthew (Department: 2137)
Electrical computers and digital processing systems: support
Multiple computer communication using cryptography
Particular communication authentication technique
C713S177000, C713S178000, C713S179000, C713S186000, C382S115000, C382S232000, C382S250000
Reexamination Certificate
active
06748533
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to systems for protecting the legitimacy of an article and in particular to systems for verifying the authenticity of an electronic document or article against forgery.
BACKGROUND
Verifying the authenticity of a document or article is a well-known problem that is made increasingly more difficult with the widespread use of sophisticated reproduction technologies. This is particularly the case in relation to digital media. Sophisticated reproduction systems are readily available. Even home computer systems are capable of performing reproduction functions that until not very long ago were only capable of being performed by large institutions, such as government agencies and large corporations, due to the resources that were required. Thus, technology capable of facilitating the counterfeiting or misuse of documents is widespread. Consequently, attempts have been made to provide methods and systems for verifying the authenticity of documents and articles such as identification cards against forgery or fraud.
U.S. Pat. No. 5,719,939 describes a system and method for verifying the legitimacy of a product against forgery. A pattern of overlying individual fibres is embedded in a transparent base material, so that the fibres form differing geometrical configurations. The fibres are capable of being optically scanned through a surface of the transparent base material. Subsequently, an inspector may scan the product and compare the obtained data with the stored data in an attempt to verify the authenticity of the product.
However, the security of the method disclosed in U.S. Pat. No. 5,719,939 is heavily dependent on the different geometrical configurations of the particular fibres. If the configurations are too simple, security cannot be guaranteed. On the other hand, if the configurations are too complex, the costs of the system increase significantly.
U.S. Pat. No. 5,742,685 discloses a method for verifying an identification card and recording a verification of the same. An image of a person whom the identification card is to identify is scanned to produce a digital signal associated with a text message. They are compressed, encrypted, and then coded as a two-dimensional barcode. The barcode is then printed on the back of the identification card. To verify the validity of the card, the barcode is scanned, decoded, decrypted, expanded and displayed. To perform verification, the resulting displayed image and text are compared with the corresponding information printed on the card.
While the method of U.S. Pat. No. 5,742,685 utilises a cryptographic connection between the printed image and the text on the one hand and the printed barcode on the other, there are several disadvantages of this method, relating to the practicability and complexity of the method. One such difficulty is how to compress an entire image to a size that satisfies the requirements of encryption and barcode encoding, while maintaining image quality. Significant compression can cause a significant degradation in the capacity to the recovered image with the original image. A further disadvantage is that a separate encryption/decryption key is required
There is therefore a need for an improved technique of verifying the authenticity of an article, especially an electronic document.
SUMMARY
In accordance with a first aspect of the invention, a method of embedding linked watermarks in an article requiring protection against forgery is disclosed. The method includes the steps of: extracting information from a first portion of the article; encrypting the extracted information from the first portion; generating a watermark using the encrypted information; rendering the watermark to a second portion of the article; and repeating the extracting, encrypting, generating and rendering steps with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
Preferably, the watermark is generated based on a selected watermark generating mechanism dependent upon the encrypted information. Further, each of the watermarks can be generated based on different watermark generation mechanism. Still more preferably, seeds for generating a watermark can be obtained from only one portion of the article or several selected portions of the article.
Preferably, the information is extracted directly from text and/or from one or more invariant features of an image. The image can depict biometric data of a person associated with the article.
Preferably, the article is an electronic document. It can also be a printed document.
In accordance with a second aspect of the invention, there is disclosed an apparatus for embedding linked watermarks in an article requiring protection against forgery. The apparatus includes: a device for extracting information from a first portion of the article; a device for encrypting the extracted information from the first portion; a device for generating a watermark using the encrypted information; a device for rendering the watermark to a second portion of the article; and a device for controlling repeated operation of the extracting, encrypting, generating and rendering devices with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
In accordance with a third aspect of the invention, there is disclosed a computer program product having a computer readable medium having a computer program recorded therein for embedding linked watermarks in an article requiring protection against forgery, the computer program product including: a module for extracting information from a first portion of the article; a module for encrypting the extracted information from the first portion; a module for generating a watermark using the encrypted information; a module for rendering the watermark to a second portion of the article; and a module for controlling repeated operation of the extracting, encrypting, generating and rendering modules with another portion of the article until all relevant information of the article has been processed and a cryptographic link is formed thereby.
In accordance with a fourth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article includes: two or more portions for containing information, the information including text, biometric data, or both; two or more watermarks, each watermark printed in a respective one of the portions and being dependent upon information in a different portion, whereby a cryptographic link is formed between the two or more portions.
Preferably, the article is an electronic document. It can also be a printed document.
In accordance with a fifth aspect of the invention, there is disclosed an article requiring protection against forgery or fraud. The article is formed by the steps of: extracting information from a first portion of the article, the article having two or more portions for containing information, the information including text, biometric data, or both; encrypting the extracted information from the first portion; generating a watermark using the encrypted information; rendering the watermark to a second portion of the article; and repeating the extracting, encrypting, generating and rendering steps with another portion of the article until all relevant information of the article has been processed so that two or more watermarks are formed, each watermark being rendered in a respective one of the portions and being dependent upon information extracted from a different portion, whereby a cryptographic link is formed between the two or more portions.
In accordance with a sixth aspect of the invention, there is disclosed a method of forming an article requiring protection against forgery. The method includes the steps of: generating an invisible watermark dependent upon information contained in the article; and rendering the watermark within an official seal placed on the article, the official seal
Deng Huijie Robert
Sun Qibin
Wu Jiankang
Fields Courtney D.
Kent Ridge Digital Labs
Smithers Matthew
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