Method and system for cryptographically authenticating a printed document by a trusted party

• US 6,907,528 B1
• Filed: 02/15/2000
• Issued: 06/14/2005
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Fujitsu Services Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Services Limited (Fujitsu Limited)
• Inventors: Bunn, Michael George
• Primary Examiner(s): Barrón, Jr., Gilberto
• Assistant Examiner(s): KIM, JUNG W
• Application Number:
  US09/504,150
• Time in Patent Office: 1,946 Days
• Field of Search: 713/168, 713/155, 713/156, 713/176, 713/179
• US Class Current: 713/179
• CPC Class Codes: G06Q 20/389 Keeping log of transactions for guaranteeing non-repudiation of a transaction
• CPC Class Codes: G07D 7/0043 using barcodes
• CPC Class Codes: G07D 7/0047 using checkcodes, e.g. coded numbers derived from serial number and denomination
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/125 Offline card verification

Abstract

A method for authenticating a printed document is described. A document producer sends information to be included in a document to an authentication authority. The authentication authority cryptographically generates an authentication code from this information, and sends the authentication code back to the document producer. The document producer then prints the document, including both the information and the authentication code, and a bar code representing the authentication code. A document checker scans in the bar code, and cryptographically checks the authentication code against the information in the document.

Claims

1. A method for producing and authenticating a printed test certificate compressing the following steps:

a) a test certificate producer performs a test and generates test information to be included in the test certificate;

b) the test certificate producer generates said test information, and also pre-printed information read from a blank test certificate, to an authentication authority;

c) the authentication authority checks whether the test certificate producer is authorized to perform the test and, if so, cryptographically generates an authentication code form said test information and said pre-printed information, and sends the authentication code back to the test certificate producer;

d) upon receipt of the authentication code from the authentication authority, the test certificate producer prints both said test information and said authentication code on the blank test certificate; and

e) upon presentation of the printed test certificate for authentication, a certificate checker cryptographically checks the authentication code against said test information and said pre-printed information in the printed test certificate to determine whether the printed test certificate is authentic.

2. A method according to claim 1 wherein said pre-printed information is contained in a pre-printed bar code.

3. A method according to claim 2 wherein the test certificate producer uses a combined printer and bar-code scanner to read said pre-printed bar code and also to print said printed test certificate.

4. A method according to claim 1 wherein said certificate checker performs the following steps:

a) entering said authentication code into a computer;

b) entering information in the printed certificate into the computer;

c) causing the computer to cryptographically generate a check code from said information; and

d) causing the computer to compare said check code with said authentication code and to generate a warning indication if said check code does not correspond with said authentication code.

5. A method according to claim 1 wherein said authentication authority cryptographically generates said authentication code using a secret key known to both the authentication authority and said certificate checker, but not known to said test certificate producer.

6. A method according to claim 1 wherein said authentication code is generated by performing a key-dependent one-way bash of said test information and said pre-printed information, using a secret key.

7. A method according to claim 1 wherein said authentication authority generates said authentication code using the private key of a public/private key pair, and wherein the certificate checker checks the authentication code using the public key of said public/private key pair.

8. A method according to claim 1 wherein communication between said test certificate producer and said authentication authority is protected by encryption.

10. A method according to claim 1 wherein said pre-printed information comprises a serial number.

9. A method for producing and authenticating a printed test certificate comprising the following steps:

a) a test certificate producer performs a test and sends information to be included in a test certificate to an authentication authority;

b) the authentication authority checks whether the test certificate producer is authorized to perform the test and, if so, cryptographically generates an authentication code from said information, and sends the authentication code back to the test certificate producer;

c) upon receipt of the authentication code from the authentication authority, the test certificate produce prints the test certificate, including both said information and said authentication code; and

d) upon presentation of the printed test certificate for authentication, a certificate checker cryptographically checks the authentication code against said information in the printed test certificate to determine whether the printed test certificate is authentic;

e) wherein the test certificate is printed on a blank test certificate which includes a pre-printed bar-coded serial number;

f) wherein the test certificate producer uses a combined printer and bar-code scanner to read said pre-printed bar-coded serial number from said black test certificate and sends said pre-printed bar-coded serial number to said authentication authority;

g) wherein said authenticaion authority uses said pre-printed bar-coded serial number in generating said authentication code;

h) and wherein the test certificate producer uses the combined printer and bar-code scanner to print said information and said authentication code on to said blank test certificate, to form said printed test certificate.