WO2007040380A1 - Procede de generation d'une signature imprimee pour securiser le contenu de documents texte - Google Patents

Procede de generation d'une signature imprimee pour securiser le contenu de documents texte Download PDF

Info

Publication number
WO2007040380A1
WO2007040380A1 PCT/MX2005/000089 MX2005000089W WO2007040380A1 WO 2007040380 A1 WO2007040380 A1 WO 2007040380A1 MX 2005000089 W MX2005000089 W MX 2005000089W WO 2007040380 A1 WO2007040380 A1 WO 2007040380A1
Authority
WO
WIPO (PCT)
Prior art keywords
signature
document
word
stage
printed
Prior art date
Application number
PCT/MX2005/000089
Other languages
English (en)
Spanish (es)
Inventor
Sergio Antonio Fernandez Orozco
Leo Hendrik Reyes Lozano
Original Assignee
Fernandez Orozco Sergio Antoni
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fernandez Orozco Sergio Antoni filed Critical Fernandez Orozco Sergio Antoni
Priority to PCT/MX2005/000089 priority Critical patent/WO2007040380A1/fr
Publication of WO2007040380A1 publication Critical patent/WO2007040380A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
    • G06V30/10—Character recognition
    • G06V30/22—Character recognition characterised by the type of writing
    • G06V30/226—Character recognition characterised by the type of writing of cursive writing
    • G06V30/2264—Character recognition characterised by the type of writing of cursive writing using word shape
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3225—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document
    • H04N2201/3233—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of data relating to an image, a page or a document of authentication information, e.g. digital signature, watermark
    • H04N2201/3236—Details of authentication information generation

Definitions

  • This invention relates to the area of security and integrity of the content of printed text documents.
  • the objective of this invention is to protect the content of documents printed on common paper against malicious changes and counterfeits; However, it allows slight alterations of the document that do not change the message written on it. It describes a system and method that can generate a signature that can be attached in printed form to a text document to ensure that its content has not been modified maliciously. In addition, a system and method is described that allows to verify if a document signed by the previous procedure has been modified.
  • US 6,764,000 describes a system that uses a scanner to identify points of interest or signs (such as watermarks, holograms, serial numbers, patterns, colors, etc.) present in the document to be secured. These clues are compared to a database that has been previously built. If sufficient clues are similar to those stored, the document is classified as authentic. Unlike that method, the present invention does not require the use of a database to authenticate the document. In addition, the invention generates a signature from the content or message written in the original document. In US 6,934,845 an invention is described that uses an encoding based on the blanks of a document to hide a signature that allows the document to be authenticated.
  • points of interest or signs such as watermarks, holograms, serial numbers, patterns, colors, etc.
  • This invention requires that a document be used in electronic format to generate the signature, and the signature is not generated with the content of the document.
  • the present invention differs from that in that it does not require the document in electronic format and uses the content of the document to generate the authentication information.
  • the invention also does not use a coding based on blanks and is clearly visible.
  • US 6,427,921 describes a method and system that uses various types of overlapping patterns with the original image that it is desired to secure to produce a watermark. Unlike this method and system, the present invention uses the contents of the document to generate the signature that will authenticate it.
  • HKl 028662 a method is described for securing printed documents that requires the use of a laser to illuminate the questionable document and then verify that the reflected pattern meets certain characteristics.
  • the present invention does not require laser technology.
  • US Patent 6,785,405 describes a system that uses digital images of printed documents to verify their authenticity. The system performs the segmentation of the images and then compares these segments with images contained in a database obtaining a correlation number for each type of document and segment. This phase serves to categorize the document. With this information, authentication information is read that the same document must possess and this information is used to verify that the document is original. Unlike this system, the present invention does not require segmentation or correlation to be used. In addition, it does not require the use of a database with known images of documents.
  • AIp Vision SafePaper technology uses a watermark that is invisible to secure a document. Unlike HP technology, this watermark can be read with a scanner; but disappears when copied or reproduced by other means. On the other hand, this system can only sign electronic documents. The present invention allows copying of documents as long as the content is intact.
  • there are several methods that allow you to attach a digital signature to a printed document S. Bhattacharjee and M. Kutter describe one of these algorithms in "Compression Tolerant Image Authentication", IEEE inter. Conference on Image processing, USA, pp. 435-439, 1998.
  • Zhang describes a method (called Iterated Closest Points or ICP) to align two-dimensional figures in the article "Iterative Point Matching for Registration of Free-Form Curves and Surfaces", International Journal of Computer Vision, VoI. 13, No. 2, pp. 119-152, 1994.
  • Veltkamp and Hagedoom describe similar algorithms (such as Chamfer Matching) in "State-of-the-ari in shape matching", technical report UU-CS- 1999-27, Utretcht University, Netherlands, 1999.
  • figure alignment algorithms cannot be used by themselves to generate secure documents. In addition to these techniques, our invention uses other algorithms to achieve this goal.
  • the method presented in this document is based on recognizing the patterns and repetitions of the words of a text document to generate a signature that can be attached to the paper where the document is located. But at no time is an optical character recognizer (OCR) used, as these usually present some failures (due to noise in the digital image) or limitations (due to the need to use word dictionaries).
  • OCR optical character recognizer
  • Our method has the advantage that it is not required to have a digital document.
  • the methods based on correlation and wavelets use textures, which are very sensitive to non-malicious changes such as rotation, translation and scaling that may be present when scanning a document.
  • the method presented here is robust to this kind of changes. In addition, it does not require the use of special materials such as holograms, special inks or laser systems to sign a document.
  • the invention allows the document to be copied and transmitted by any electronic, electrical or mechanical method as long as the written message has not been modified.
  • Figure 1 shows a diagram of the method for printing secure documents.
  • Figure 2 shows a diagram of the method to verify the integrity of a signed document.
  • Figure 3 shows a diagram showing the internal parts of the signature generation stage.
  • the method to ensure the integrity of the content of printed text documents consists of:
  • a method for printing secure documents which, in turn, is constituted of an image acquisition stage 3, to convert a printed text document 1 into a digital image (hereinafter simply referred to as "image") -
  • image a digital image
  • This stage can be implemented with any device digitizer such as a scanner, a digital copier, a multifunction printer, digital camera, etc.
  • the image obtained in said acquisition stage passes to a signature generation stage 5, to generate the element that ensures the integrity of the document (hereinafter simply called “signature”).
  • signature generation stage to generate the element that ensures the integrity of the document (hereinafter simply called “signature”).
  • the sub-stages that make up this stage are described in detail later.
  • the signature generated by this stage is sent along with the image to the signature annexation and printing stage 6, to append said signature to the original document and thus produce a secure document printed on paper 7.
  • the printing stage can be implemented with a device as a printer, digital copier, plotter or similar.
  • this section of the system may contain an image raking stage (image raster processor, in English) 4, to convert an electronic document 2 (such as those generated by conventional programs such as Microsoft Word or Excel) into a digital image, in order to pass this image to the signature generation stage 5.
  • image raking stage image raster processor, in English
  • These raking processors are usually an integral part of the hardware of many printers or can be obtained with the driver of these devices.
  • a method for the verification of secure documents which, in turn, is made up of an image acquisition stage 9 (such as the one described in the previous section) that converts a printed document 8 into a digital image.
  • This image is Go to a signature analysis stage 10 to extract the signature contained in the document.
  • This stage can be a simple two-dimensional barcode reader.
  • the image of the document goes to the signature generation stage 11 (described in detail in the next section of this document), to obtain the integrity check (signature) element from the textual content of the document.
  • the signatures extracted by these modules are passed to the document certification stage 13 which is responsible for verifying that both signatures coincide to finally issue a certificate of authenticity 13 of the signed document.
  • Two stages of signature generation (5 and 11) that are, in turn, a binarization stage 14 that converts a color or grayscale image to black and white.
  • a noise elimination stage 15 which eliminates the noise of the binarized image in the previous module.
  • a horizontal alignment stage 16 that modifies the inclination of the image so that the lines of text appear horizontal.
  • a word segmentation stage 17 to find the two-dimensional limits of each word in the document.
  • a step identification step 18 to obtain the dominant traces of each word obtained in the previous module.
  • a line alignment step 19 to align the words obtained in previous modules with each other.
  • a combination and encryption stage 20 that combines the information obtained in these modules to obtain a signature that can be attached to the original document to ensure its content.
  • the user scans a printed document 1 at the image acquisition stage 3, or, through some electronic text editor (such as Word or Excel) generates a file 2 that is converted into an image by the processor image raking 4.
  • the image is passed to the signature generator method 5.
  • the signature generator first binarizes the image in step 14 to obtain a black and white bitmap.
  • the binarization method can be any of those described in "Comparison of Some Thresholding Algorithms for Text / Background Segmentation in Difflcult Document Images” by Leedham, Yan, Takru and Tan published in The Seventh International Conference on Document Analysis and Recognition, VoI. 2, pg. 859
  • step 15 eliminates all those small points that are produced by the noise in the measurement system.
  • Gonzalez and Woods describe several such algorithms in Chapter 5 of Image Restoration in Digital Image Processing. Second Edition, USA, New Jersey, Addison-Wesley, 2002.
  • the clean image is then aligned so that the lines of text appear horizontal in the image (step 16).
  • Some procedures to achieve this are described in Chapter 9: Optical Character Recognition in Algorithms for Image Processing and Computer Vision, by J. R. Parker, Wiley, 1996.
  • word segmenter 17 Once the document has been aligned in this way. It is passed to word segmenter 17.
  • a vertical histogram of the image is obtained. This histogram contains one entry for each line of the image. The amount of black pixels in that line is stored in each entry. In this way, the text lines appear as maximums and the blanks between lines, as minimums. It is easy then to identify the beginning and end of each line by a simple differential analysis.
  • each line is given by a maximum that goes from a small value to a large value and the end of each line passes from a high value to a small value. It is clear that one skilled in the art can easily implement an algorithm that performs the described identification.
  • the segmenter After identifying the lines of the text, the segmenter obtains a horizontal histogram for each line where the amount of black pixels per column in that line is now stored. This histogram can be used once again to identify the beginning and end of each word, using a procedure similar to that described in the previous paragraph. In this way, the segmenter produces a list of words by line, where each word is assigned a unique number (coordinate).
  • the positions of each word and the image are passed to the step identification stage 18.
  • This stage individually analyzes each word to obtain the most representative straight line segments (strokes) of each word. This is achieved, in particular, through tensor voting techniques (described in detail in "A Computational Framework for Segmentation and Grouping” by Medioni, Lee and Tang, Elsevier 2000); although the use of alternative techniques such as Hough transform (US Patent 3,069,654 "Method and Meansfor Recognizing Complex Patterns”), active contours (snakes in English, such as those described in the article “Snakes, Shapes, and Gradient Vector Flow “IEEE Transactions on Image Processing, 7 (3), p. 359-369, March 1998 by C.
  • the strokes identified in this way are stored in a list of strokes per word and are passed, together with the positions of each word, to the line alignment stage 19. At this stage, all occurrences of each word are found in the rest of the document To detect the occurrence of a word in the rest of the document, said word is placed on a target word to be tested. If it is possible to properly align the main lines of the original word with the target word, then there is an occurrence.
  • Zhang the ICP
  • Zhang the ICP in "Iterative Point Matching for Registration of Free-Form Curves and Surfaces"
  • the list of strokes of each word and the list of repetitions of each word are appended to the list of words by line in step 20 to generate a series of numbers that uniquely identify each document.
  • This series of numbers can be encoded by itself as a two-dimensional barcode (or some other form of binary image coding); but usually, it is compressed and the result is obtained a cyclic redundancy code (CRC) which is normally used as a signature. It is also possible to obtain the original signature CRC (uncompressed). The signature thus obtained can be as small as a 16-bit number. This number is finally printed as a normal or two-dimensional barcode on the printed image you wish to secure. All these methods (compression and CRC) are widely known and used.
  • step 20 may use the information from the main lines of some critical sections of the document (such as figures on a check) to generate the signature, or as an annex to the regular signature described in the previous paragraph. It is also possible to systematically insert the list of words by line, the list of lines by word (for the critical sections of the document) and the list of repetitions, according to the needs of each particular document or the user's instructions, to generate the signature. Additionally, the signature generated with any of the procedures described (the sequence of numbers that describe the words and their repetitions, the sequence of the main strokes of the words or the systematic combination of all of them), can be encrypted with the public key of the issuer of the document to give greater security to the document. The encrypted signature can then be processed normally (it is compressed and its CRC is obtained).
  • OCR optical character recognizers
  • the signature obtained by this method is sent together with the image to the signature and printing annexation stage 6.
  • This stage converts the signature to a small image (two-dimensional barcode, widely known and used technology) and appends it into some unused part of the original document (for example, at the edges of the page).
  • the modified image is printed to finally generate a secure document 7.
  • step 9 To verify the integrity of a document 8, it is scanned and converted into an image in step 9. This image is sent to a signature analysis stage 10 that simply reads and interprets the signature printed on the document.
  • This stage can be implemented with a two-dimensional barcode reader, the use of which is widespread.
  • step 10 the image is sent to the signature generation stage 11 (whose operation has already been explained above) to obtain the signature from the content of document 8.
  • Both signatures are compared in the certification stage 12.
  • the signatures will be different.
  • the certifier 12 responds by indicating that the document has been altered. Otherwise, an integrity certificate 13 is issued, indicating that the document is true to the original.
  • the method of generating the signature constitutes the novelty of the invention.
  • the novelty of the method is that, through computational vision algorithms, the textual content of the printed document is analyzed to generate a signature without using a character recognizer (OCR). That is, all the information necessary to verify the integrity of the document is found in the document itself, and the signature can be as small as a 16-bit number. Instead of recognizing individual characters, the form and position of the words in the text are used as a signature to ensure that the content has not been modified.
  • OCR character recognizer

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Signal Processing (AREA)
  • Editing Of Facsimile Originals (AREA)

Abstract

L'invention concerne un procédé permettant de générer des documents sécurisés. La nouveauté de l'invention réside dans le fait que le procédé permet de générer des signatures utilisées pour sécuriser lesdits documents. Ces signatures sont formées à partir du contenu textuel d'un document imprimé sans disposer nécessairement d'une transcription électronique dudit texte. Le procédé de l'invention est fondé sur la reconnaissance automatique de la forme des mots et sur la localisation des positions où ceux-ci se répètent, sans nécessairement connaître leur signification. Le procédé de l'invention permet que le document soit copié ou modifié par quelconque moyen sans altérer le message original contenu dans le document. Enfin, le procédé de l'invention permet de sécuriser des documents imprimés au moyen d'un papier commun.
PCT/MX2005/000089 2005-10-04 2005-10-04 Procede de generation d'une signature imprimee pour securiser le contenu de documents texte WO2007040380A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/MX2005/000089 WO2007040380A1 (fr) 2005-10-04 2005-10-04 Procede de generation d'une signature imprimee pour securiser le contenu de documents texte

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/MX2005/000089 WO2007040380A1 (fr) 2005-10-04 2005-10-04 Procede de generation d'une signature imprimee pour securiser le contenu de documents texte

Publications (1)

Publication Number Publication Date
WO2007040380A1 true WO2007040380A1 (fr) 2007-04-12

Family

ID=37906381

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/MX2005/000089 WO2007040380A1 (fr) 2005-10-04 2005-10-04 Procede de generation d'une signature imprimee pour securiser le contenu de documents texte

Country Status (1)

Country Link
WO (1) WO2007040380A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3200255A2 (fr) 2016-01-06 2017-08-02 Konica Minolta, Inc. Élément électroluminescent organique, procédé de fabrication d'éléments électroluminescents organiques, écran et dispositif d'éclairage

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641347A (en) * 1983-07-18 1987-02-03 Pitney Bowes Inc. System for printing encrypted messages with a character generator and bar-code representation
EP0702322A2 (fr) * 1994-09-12 1996-03-20 Adobe Systems Inc. Méthode et appareil pour identifier des mots décrits dans un document électronique portable
US6279828B1 (en) * 1999-03-01 2001-08-28 Shawwen Fann One dimensional bar coding for multibyte character
US20010047476A1 (en) * 2000-05-25 2001-11-29 Jonathan Yen Authenticatable graphical bar codes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641347A (en) * 1983-07-18 1987-02-03 Pitney Bowes Inc. System for printing encrypted messages with a character generator and bar-code representation
EP0702322A2 (fr) * 1994-09-12 1996-03-20 Adobe Systems Inc. Méthode et appareil pour identifier des mots décrits dans un document électronique portable
US6279828B1 (en) * 1999-03-01 2001-08-28 Shawwen Fann One dimensional bar coding for multibyte character
US20010047476A1 (en) * 2000-05-25 2001-11-29 Jonathan Yen Authenticatable graphical bar codes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3200255A2 (fr) 2016-01-06 2017-08-02 Konica Minolta, Inc. Élément électroluminescent organique, procédé de fabrication d'éléments électroluminescents organiques, écran et dispositif d'éclairage

Similar Documents

Publication Publication Date Title
ES2718528T3 (es) Código de barras bidimensional y procedimiento de autenticación de dicho código de barras
ES2758791T3 (es) Procedimiento y dispositivo de aseguramiento de documentos
KR100405828B1 (ko) 위변조의 방지가 가능한 문서를 제작하는 장치 및 방법,그리고 상기 문서를 인증하는 장치 및 방법
US8190901B2 (en) Layered security in digital watermarking
CN110073368B (zh) 用于认证插图的方法
ES2802448T3 (es) Dispositivo y proceso para proteger un documento digital, y proceso correspondiente para verificar la autenticidad de una copia impresa
WO2003087991A2 (fr) Systeme et procede d'authentification d'une piece par maintien de la forme tridimensionnelle
KR20110028311A (ko) 서류의 인쇄 플레이트를 식별하기 위한 방법 및 장치
WO2009149408A2 (fr) Procédé, système et support accessible par ordinateur pour authentification d’un papier à l’aide d’un motif de moucheture
EP2048867B1 (fr) Procédé et système de génération et de vérification d'un joint numérique sur un document analogue
HUE026760T2 (en) Secure element identification and authentication system and non-cloning properties
Tan et al. Print-Scan Resilient Text Image Watermarking Based on Stroke Direction Modulation for Chinese Document Authentication.
Richter et al. Forensic analysis and anonymisation of printed documents
Picard et al. Towards fraud-proof id documents using multiple data hiding technologies and biometrics
US20050206158A1 (en) Certificate issuing method and certificate verifying method
EP3069293A1 (fr) Système et procédé d'impression de code à barres caché et sécurisé
US20080164328A1 (en) Tamper detection of documents using encoded dots
WO2007040380A1 (fr) Procede de generation d'une signature imprimee pour securiser le contenu de documents texte
Mayer et al. Fundamentals and applications of hardcopy communication
Ahmad et al. Paper document authentication using print-scan resistant image hashing and public-key cryptography
US9361516B2 (en) Forensic verification utilizing halftone boundaries
RU2446464C2 (ru) Способ и система встраивания и извлечения скрытых данных в печатаемых документах
Sale et al. Graduation certificate verification model: a preliminary study
Hassan et al. A survey on techniques of detecting identity documents forgery
Gomez‐Krämer Verifying document integrity

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC OF 220708

122 Ep: pct application non-entry in european phase

Ref document number: 05803573

Country of ref document: EP

Kind code of ref document: A1