Method of identifying a copied security document

• US 7,461,778 B2
• Filed: 09/28/2007
• Issued: 12/09/2008
• Est. Priority Date: 05/18/2004
• Status: Expired due to Fees

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Lapstun, Paul
• Primary Examiner(s): Koyama; Kumiko C
• Application Number:
  US11/863,255
• Publication Number:
  US 20080050004A1
• Time in Patent Office: 438 Days
• Field of Search: 235/379, 235/380, 235/493, 235/494, 235/375, 382/115, 382/116, 382/135, 382/37, 382/137
• US Class Current: 235/379
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G06Q 20/105 involving programming of a portable memory device, e.g. IC cards, "electronic purses"
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes
• CPC Class Codes: G06Q 20/3674 involving authentication
• CPC Class Codes: G06Q 30/018 Certifying business or products
• CPC Class Codes: G06Q 30/0185 Product, service or business identity fraud
• CPC Class Codes: G06Q 40/08 Insurance
• CPC Class Codes: G06Q 40/12 Accounting
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A method of determining a counterfeit security document which includes a number of coded data portions indicative of an identity of the security document; and at least part of a digital signature of at least part of the identity. The method includes using a sensing device to sense at least one coded data portion and generate indicating data. The indicating data is used by a processor to obtain a determined identity and at least one determined signature part, which are then used to determine if the security document is a counterfeit document.

Claims

1. A method of determining a counterfeit security document, the security document having disposed thereon or therein coded data including a number of coded data portions, each coded data portion being indicative of:

an identity of the security document; and

a part of a signature, the signature being a digital signature of at least a part of the identity and comprising a plurality of signature parts;

wherein the method includes the steps of;

in a sensing device;

sensing one of the coded data portions; and

generating, using the sensed coded data portion, indicating data indicative of;

the identity;

the part of the signature; and

a signature part identifier;

in a processor;

determining, a determined signature using the identity;

determining a determined signature part using the determined signature and the signature part identifier; and

,

determining if the security document is a counterfeit document by comparing the determined signature part and the part of the signature.

2. A method according to claim 1, wherein the determined signature is determined by:

accessing a data store.

3. A method according to claim 1, wherein the determined signature is determined by:

generating, using the identity and a key.

4. A method according to claim 1, wherein all parts of the signature are encoded within a plurality of coded data portions, and wherein the method includes:

in the sensing device;

sensing a number of coded data portions to thereby determine all parts of the signature; and

generating the indicating data using the sensed coded data portions; and

in the processor;

determining, from the indicating data, a plurality of determined signature parts representing the signature;

generating, using the plurality of determined signature parts and a key, a generated identity;

comparing the generated identity to the identity generated from the sensed coded data portion; and

authenticating the security document using the result of the comparison to thereby determine if the document is a counterfeit.

5. A method according to claim 1, wherein the method includes, in the processor:

accessing, using the identity, tracking data indicative of, for each of a number of existing security documents;

the identity of each security document; and

tracking information indicative of the location of each security document; and

determining, using the tracking information, if the security document is a duplicate of one of the existing security documents.

6. A method according to claim 1, wherein the coded data is arranged in accordance with at least one layout having n-fold rotational symmetry, where n is at least two, the layout including n identical sub-layouts rotated 1/n revolutions apart about a centre of rotation, at least one sub-layout including rotation-indicating data that distinguishes that sub-layout from each other sub-layout.

7. A method according to claim 1, wherein the coded data is arranged in accordance with at least one layout having n-fold rotational symmetry, where n is at least two, the layout encoding orientation-indicating data comprising a sequence of an integer multiple m of n symbols, where m is one or more, each encoded symbol being distributed at n locations about a center of rotational symmetry of the layout such that decoding the symbols at each of the n orientations of the layout produces n representations of the orientation-indicating data, each representation comprising a different cyclic shift of the orientation-indicating data and being indicative of the degree of rotation of the layout.