Apparatus and method for enhancing the security of negotiable documents

• US 6,549,624 B1
• Filed: 05/04/2000
• Issued: 04/15/2003
• Est. Priority Date: 03/01/1996
• Status: Expired due to Term

• Current Assignee: Advanced Software Design Corporation (Advanced Software Design|Calin A. Sandru)
• Original Assignee: Calin A. Sandru
• Inventors: Sandru, Calin A.
• Primary Examiner(s): Barron, Gilberto
• Assistant Examiner(s): CALLAHAN, PAUL E
• Application Number:
  US09/564,955
• Time in Patent Office: 1,076 Days
• Field of Search: 380/51, 380/259, 380/59, 380/282, 380/246, 705/62, 705/408, 283/73, 283/74, 283/17, 283/58, 283/59
• US Class Current: 380/51
• CPC Class Codes: G06Q 20/04 Payment circuits
• CPC Class Codes: G06Q 20/042 characterized in that the payment protocol involves at least one cheque
• CPC Class Codes: G07D 7/0047 using checkcodes, e.g. coded numbers derived from serial number and denomination
• CPC Class Codes: G09C 5/00 Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

The invention relates to an apparatus and method for enhancing the security of selected information associated with a negotiable document, such as the monetary value of a cheque. In the invention, one or more security features are printed or applied onto the cheque. One such security feature is an encrypted control code. The preferred embodiment employs a secret key cryptographic scheme to encrypt the monetary value and thereby generate a first control code which is printed on the cheque. When the cheque is presented for payment, a validator, such as bank or cheque clearing house, employs a verification system having a copy of the encryption key to read the monetary value from the cheque and re-encrypt it according to said scheme to generate a second control code. The cheque is not honored if the first and second control codes are not identical. Another security feature is a security image, composed, for instance, from a foreground image of the monetary value superimposed over a background motif image. The security image has a number of hidden attributes, such as the relative aspect ratios, absolute and relative dimensions of the underlying foreground and background images, that are preselected and used when printing the security image. When the cheque is presented for payment a teller can visually inspect the security image for compliance with certain of the preselected attributes. The preferred validation system can also electronically scan the security image for the hidden attributes.

Claims

1. A process for enhancing the security of a cheque, comprising:

selecting private and public encryption keys associated with one of a cheque payor and cheque validator;

selecting information found on the cheque wherein the selected information varies for each instantiation of the cheque presented by the same payor;

encrypting a combination of the selected information and one of the private and public keys with a practicably secure cryptographic scheme to thereby generate a control code;

printing the selected information and the control code on the cheque;

reading the selected information from the cheque;

decrypting the control code using the other of the private and public encryption keys to thereby obtain decrypted information; and

the cheque validator refusing to honour the cheque if the selected information found on the cheque does not match the decrypted information.

2. A process according to claim 1, wherein the step of printing includes printing machine-readable characters corresponding to the control code on the cheque.

3. A process according to claim 2, wherein the selected information includes a monetary value of the cheque.

4. A process according to claim 2, wherein the selected information includes payee of the cheque.

5. A process according to claim 2, wherein the encryption scheme is a public key encryption scheme.

6. A process according to claim 5, wherein the public key encryption scheme is an RSA scheme.

7. A system for enhancing the protection of selected information found on a cheque from forgery, wherein the selected information varies for each instantiation of the cheque presented by the same payor, comprising:

first and second computational-capable devices, the first device employing one of a private key and a public key, the second device employing the other of the private and public keys;

the first device encrypting a combination of the selected information and one of the private and public encryption keys with a practicably secure cryptographic scheme to thereby generate a control code;

a printer for printing the control code on the cheque;

a scanner for reading the selected information and the control code from the cheque;

the second device decrypting the control code to thereby generate decrypted information; and

circuitry for comparing the selected information and the decrypted information and generating a signal in response to the equality thereof.

8. A system according to claim 7, wherein the selected information includes a monetary value of the cheque.

9. A system according to claim 7, wherein the selected information includes a payee of the cheque.

10. A process for enhancing the security of a cheque, comprising:

selecting private and public encryption keys associated with one of a cheque payor and cheque validator;

selecting information found on the cheque wherein the selected information varies for each instantiation of the cheque presented by the same payor;

encrypting a combination of the selected information and the private key with a digital signature encryption scheme to thereby generate a digital signature;

printing the selected information and the digital signature on the cheque;

reading the selected information from the cheque;

verifying the authenticity of the digital signature based on the public key and the read selected information; and

the cheque validator refusing to honour the cheque if the digital signature is not authenticated.