Method of identifying a copied security document

• US 20080050004A1
• Filed: 09/28/2007
• Published: 02/28/2008
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Lapstun, Paul
• Granted Patent: US 7,461,778 B2
• Time in Patent Office: Days
• US Class Current: 382/135
• 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

,

at least part of a signature, the signature being a digital signature of at least part of the identity;

wherein the method includes;

in a sensing device;

sensing at least one coded data portion; and

,

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

the identity; and

,

at least one signature part;

in a processor;

determining, from the indicating data;

a determined identity; and

,

at least one determined signature part;

determining if the security document is a counterfeit document using the determined identity and the at least one determined signature part.

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

accessing a data store, using the determined identity, to determine a stored signature part;

comparing the stored signature part to the at least one determined signature part; and

,

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

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

generating, using the determined identity and a key, at least a generated signature part;

comparing the generated signature part to the at least one determined signature part; and

,

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

4. A method according to claim 1, wherein the entire signature is 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 the entire 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 entire signature;

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

comparing the generated identity to the determined identity; and

,

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

5. A method according to claim 1, wherein the signature is a digital signature of at least part of the identity and at least part of predetermined padding, the padding being at least one of:

a predetermined number; and

,

a random number.

6. A method according to claim 1, wherein the processor forms part of the sensing device.

7. A method according to claim 1, wherein the processor forms part of a computer system, and wherein the method includes, transferring the indicating data to the computer system via a communications system.

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

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

the identity of the security document; and

,

tracking information indicative of the location of the security document;

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

9. A method according to claim 1, wherein the coded data includes a plurality of layouts, each layout defining the position of a plurality of first symbols encoding the identity, and a plurality of second symbols defining at least part of the signature.

10. A method according to claim 1, wherein the sensing device stores data indicative of at least one of an identity of the sensing device and an identity of a user, and wherein the method includes, in the sensing device, generating the indicating data using the stored data.

11. A method according to claim 1, wherein the coded data is at least one of:

substantially invisible to an unaided human;

printed on the surface using at least one of;

an invisible ink; and

,

an infrared-absorptive ink;

provided substantially coincident with visible human-readable information.

12. A method according to claim 1, wherein at least one coded data portion encodes the entire signature.

13. A method according to claim 1, wherein the entire signature is formed from a plurality of signature parts, and wherein each coded data portion encodes a respective signature part.

14. A method according to claim 1, wherein at least some of the coded data portions encode at least one of:

a location of the respective coded data portion;

a position of the respective coded data portion on the surface;

a size of the coded data portions;

a size of a signature;

an identity of a signature part; and

,

units of indicated locations.

15. A method according to claim 1, wherein the coded data includes at least one of:

redundant data;

data allowing error correction;

Reed-Solomon data; and

,

Cyclic Redundancy Check (CRC) data.

16. A method according to claim 1, wherein the digital signature includes at least one of:

a random number associated with the identity;

a keyed hash of at least the identity;

a keyed hash of at least the identity produced using a private key, and verifiable using a corresponding public key;

cipher-text produced by encrypting at least the identity;

cipher-text produced by encrypting at least the identity and a random number;

cipher-text produced using a private key, and verifiable using a corresponding public key; and

,

cipher-text produced using RSA encryption.

17. A method according to claim 1, wherein the security document is at least one of:

a currency note;

a check;

a credit or debit card;

a redeemable ticket, voucher, or coupon;

a lottery ticket or instant win ticket; and

,

an identity card or document, such as a driver'"'"'s license or passport.

18. A method according to claim 1, wherein the identity is indicative of at least one of:

a currency note attribute including at least one of;

currency;

issue country;

denomination;

note side;

printing works; and

serial number;

a check attribute including at least one of;

currency;

issuing institution;

account number;

serial number;

expiry date;

check value; and

limit;

a card attribute including at least one of;

card type;

issuing institution;

account number;

issue date;

expiry date; and

limit.

19. 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.

20. 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 centre 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.