System and method for authenticating documents

• US 8,090,950 B2
• Filed: 04/08/2004
• Issued: 01/03/2012
• Est. Priority Date: 04/11/2003
• Status: Expired due to Fees

• Current Assignee: Nextenders PVT Limited
• Original Assignee: Nextenders PVT Limited
• Inventors: Shevade, Ravindra Waman
• Primary Examiner(s): Arani, Taghi
• Assistant Examiner(s): Rahman, Mahfuzur
• Application Number:
  US10/553,067
• Publication Number:
  US 20080028439A1
• Time in Patent Office: 2,826 Days
• Field of Search: 713/176
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

A data processing system for distributing and authenticating documents from a plurality of parties to a recipient data processing apparatus is disclosed. The system comprises a plurality of document distribution devices each configured to generate an original hash value from the content of a file containing a document to be distributed. A recipient data processing apparatus is configured to generate an original super hash value from the plurality of the original hash values, and to distribute the original super hash value to each of the document distribution devices. The system provides assurance that distributed documents have not been tampered with during communication, by an unscrupulous distributing party, or by an unscrupulous recipient by only submitting a hash value of the document to be distributed. The hash value provides for assurance at the eventual recipient of the document that no changes to the document have been made.

Claims

1. A data processing system for distributing and authenticating documents, the data processing system comprising

a plurality of document distribution devices each configured to generate an original hash value based on an electronic file containing a document to be distributed, wherein the document distribution devices collectively generate a plurality of original hash values;

and

a data communications network configured to communicate each of the original hash values to the recipient data processing apparatus before a predetermined event, the recipient data processing apparatus comprising a processor configured to generate hash values, the recipient data processing apparatus configured to;

receive the original hash values from each of the plurality of document distribution devices via the data communication network,

generate an original super hash value from the plurality of the original hash values received, and

communicate the original super hash to the plurality of document distribution devices,

wherein after the predetermined event, the plurality of document distribution devices are configured to;

communicate each of the electronic files to the recipient data processing apparatus,

wherein the recipient data processing apparatus is further configured to;

generate a comparative hash value based on the electronic file containing the document received from each of the document distribution devices,

generate a comparative super hash value from each of the comparative hash values,

communicate the comparative super hash value to each of the document distribution devices, and

determine whether or not each of the documents of the electronic files received from the document distribution devices have changed from a comparison of at least one of the original hash values and the comparative hash values, and the comparative super hash value and the original super hash value.

2. The data processing system according to claim 1, wherein the recipient data processing apparatus is configured to identify a document which has changed by comparing each original hash value with the corresponding comparative hash value, and, if the comparative hash value is not the same as the original hash value, to determine that the corresponding document has changed.

3. The data processing system according to claim 1, wherein the original hash value generated by a document distribution device is encrypted using a private key associated with the document distribution device.

4. The data processing system according to claim 2, wherein the super hash value to be communicated to the document distribution devices is encrypted using a private key associated with the recipient data processing apparatus.

5. The data processing system according to claim 1, wherein the electronic file containing the document to be distributed is encrypted using a public key associated with the recipient data processing apparatus prior to being communicated to the recipient data processing apparatus.

6. The data processing system according to claim 1, wherein the predetermined event includes expiration of a time limit on a particular date.

7. The data processing system as claimed in claim 1, wherein the electronic file is created by an application program.

8. The data processing system as claimed in claim 7, wherein the electronic file is communicated as part of an e-mail.

9. The data processing system as claimed in claim 7, wherein the electronic file is communicated on a portable data storage medium to the recipient data processing device via a postal service.

10. The data processing system as claimed in claim 9, wherein the original hash value is represented as a bar code, the bar code being arranged in association with the portable data storage medium, and wherein the recipient data processing apparatus includes a storage medium reader configured to reproduce the electronic file from the portable data storage medium, and a bar code reader for reproducing the original hash value from the bar code associated with the portable data storage medium, the electronic file representing the document being stored in association with the hash value in a data store.

11. The data processing system as claimed in claim 7, wherein the document is generated from an on-line browser, and wherein the data communications network includes one of an intranet and the Internet.

12. A recipient data processing device configured to authenticate documents received from a plurality of document distribution devices via a data communications network, the recipient data processing device comprising:

a communications interface configured to receive a plurality of original hash values from the document distribution devices via the data communication network before a predetermined event, wherein the hash values are each generated based on an electronic file containing one of the documents; and

a data processing apparatus comprising a processor configured to generate an original super hash value from the plurality of the received original hash values, and communicate the original super hash value to each of the document distribution devices, wherein the data processing apparatus is configured to operate in combination with the communications interface to;

receive, after the predetermined event, a plurality of electronic files from the document distribution devices, each of the electronic files containing one of the documents,

generate a comparative hash value based on the electronic file received from each of the document distribution devices,

generate, using the processor, a comparative super hash value from each of the comparative hash values,

communicate the comparative super hash value to the document distribution devices, and

determine whether or not each of the documents of the electronic files received from the document distribution devices have changed based on a comparison of at least one of the original hash values and the comparative hash values, and the comparative super hash value and the original super hash value.

13. The recipient data processing apparatus as claimed in claim 12, wherein the data processing apparatus is configured to identify a document which has changed by comparing each original hash value with the corresponding comparative hash value, and if the comparative hash value is not the same as the original hash value, determine that the corresponding document has changed.

14. The recipient data processing apparatus as claimed in claim 12, wherein the original hash values received from the document distribution devices are encrypted using a private key associated with each document distribution device, and wherein the recipient data processing apparatus comprises

an encryption processor configured to decrypt the original hash values using a public key associated with the document distribution device.

15. The recipient data processing apparatus according to claim 14, wherein the encryption processor is configured to encrypt the original super hash value and the comparative super hash to be communicated to the document distribution devices in encrypted form.

16. The recipient data processing apparatus according to claim 12, wherein the encryption processor is configured to decrypt the electronic file representing the distributed document using a public key associated with the document distribution devices.

17. The recipient data processing apparatus according to claim 12, comprising a data storage medium reader configured to reproduce the electronic file from the portable data storage medium, and a bar code reader for reproducing the original hash value from the bar code associated with the portable data storage medium, the electronic file representing the document being stored in association with the hash value in a data store.

18. The recipient data processing apparatus as claimed in claim 12, wherein the communications interface includes an on-line browser facility for generating the document, and wherein the data communications network includes one of an intranet and the Internet.

19. A computer-implemented method for distributing documents, the computer-implemented method comprising:

generating a plurality of original hash values, each original hash value based on one of a plurality of electronic files, each file representing a document to be distributed;

communicating the original hash values to the recipient data processing apparatus before a predetermined event via a data communications network;

generating, at the recipient data processing apparatus, an original super hash value based on the plurality of the original hash values;

communicating the original super hash value to a plurality of document distribution devices; and

, after the predetermined event,

communicating, from the plurality of document distribution devices, each of the electronic files representing a document to the recipient data processing apparatus;

generating, at the recipient data processing apparatus, a comparative hash value based on the electronic files representing the documents received from the document distribution devices;

generating a comparative super hash value from each of the comparative hash values; and

determining whether or not each of the documents of the electronic files received from the document distribution devices have changed based on a comparison of at least one of the original hash values and the comparative hash values, and the comparative super hash value and the original super hash value.

20. The data processing method according to claim 19, further comprising:

identifying a document which has changed by comparing each original hash value with the corresponding comparative hash value, and if the comparative hash value is not the same as the original hash value, determining that the corresponding document has changed.

21. The method as claimed in claim 20, further comprising:

receiving, from the recipient data processing apparatus, an original super-hash value generated by the recipient data processing apparatus from a combination of the original hash value communicated by the data processing apparatus and a hash value generated by at least one other document distribution device; and

receiving a comparative super hash value generated by the recipient data processing apparatus from the electronic document received from the document distribution apparatus and at least one other electronic document received from the at least one other document distribution device.

22. A method of authenticating documents received from a plurality of document distribution devices via a data communications network, the method comprising:

receiving a plurality of original hash values from the document distribution devices, before a predetermined event, via the data communication network, each original hash value based on one of a plurality of electronic files, each file containing a document to be distributed;

generating an original super hash value from the plurality of the original hash values received;

communicating the original super hash value to each of the document distribution devices;

receiving, after the predetermined event, a plurality of electronic files from the document distribution devices, each received electronic file;

generating a comparative hash value based on the received electronic file;

generating a comparative super hash value from each of the comparative hash values;

communicating the comparative super hash value to the document distribution devices; and

determining whether or not each of the documents of the received electronic files from the document distribution devices have changed based on a comparison of at least one of the original hash values, and the comparative hash value and the comparative super hash value and the original super hash value.

23. A non-transitory computer readable medium having a program for executing a method of authenticating documents received from a plurality of document distribution devices via a data communications network, the method comprising:

receiving a plurality of original hash values from the document distribution devices, before a predetermined event, via the data communication network, each original hash value based on one of a plurality of electronic files, each electronic file containing a document to be distributed;

generating an original super hash value from the plurality of the original hash values received;

communicating the original super hash value to each of the document distribution devices;

receiving, after the predetermined event, the plurality of electronic files from the document distribution devices;

generating a comparative hash value based on the received electronic files;

generating a comparative super hash value from each of the comparative hash values;

communicating the comparative super hash value to the document distribution devices; and

determining whether or not each of the documents of the received electronic files from the document distribution devices have changed based on a comparison of at least one of the original hash values, and the comparative hash value and the comparative super hash value and the original super hash value.

24. A data processing apparatus for distributing documents from a plurality of document distribution devices to a recipient data processing apparatus, the data processing apparatus comprising:

means for generating, for each of the plurality of document distribution devices, a plurality of original hash values each original hash value based on one of a plurality of electronic files, each file representing a document to be distributed;

means for communicating the original hash values to the recipient data processing apparatus, before a predetermined event, via a data communications network;

means for generating, at the recipient data processing apparatus, an original super hash value based on the plurality of original hash values;

means for communicating the original super hash to the plurality of document distribution devices;

means for communicating, after the predetermined event, from the plurality of document distribution devices, each of the electronic files representing a document to the recipient data processing apparatus;

means for generating, after the predetermined event, at the recipient data processing apparatus, a comparative hash value based on the electronic files representing the documents received from the document distribution devices;

means for generating, after the predetermined event, a comparative super hash value from each of the comparative hash values; and

means for determining whether or not each of the documents of the electronic files received from the document distribution devices have changed based on a comparison of at least one of the original hash values and the comparative hash values, and the comparative super hash value and the original super hash value.