Public/key date-time notary facility

• US 5,001,752 A
• Filed: 10/13/1989
• Issued: 03/19/1991
• Est. Priority Date: 10/13/1989
• Status: Expired due to Term

• Current Assignee: Addison M. Fischer
• Original Assignee: Addison M. Fischer
• Inventors: Fischer, Addison M.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): CAIN, DAVID C
• Application Number:
  US07/421,104
• Time in Patent Office: 522 Days
• Field of Search: 380/23, 380/51, 380/52, 380/25, 380/30
• US Class Current: 713/178
• CPC Class Codes: G06F 21/87 by means of encapsulation, e.g. for integrated circuits
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps

Abstract

A time notarization apparatus and method is disclosed which uses a secure, microprocessor based hardware platform which performs public key cryptographic operations to obtain trusted time stamping with a minimum of intervention by third parties. The hardware platform is encapsulated in a secure fashion so that the device'"'"'s timestamping mechanism may not be readily tampered with or altered. The hardware platform includes at least one digital clock and a stable, secure storage device to record the private half of a public/private key pair. Coupled to both the digital clock and the storage device is a data processing device which performs public key signature operations in a secure and tamper-proof manner. Only the processing device has access to the secure storage device and its associated private key. The hardware platform also includes input/output means which receives a digital message which is to be digitally signed and timestamped and which outputs the resulting timestamped signature generated by the device. The hardware platform also includes a power source, (e.g., an on-board battery) to ensure the accuracy of the device'"'"'s digital clock and the security of storage data prior to installation or in case of a power failure.

Claims

1. A digital time notarization device for enabling a user to digitally notarize digital information without regard to any particular recipient of said digital information comprising:

platform means for supporting components;

clock means for generating clock signals indicative of time;

input means for receiving a digital input value to be notarized;

storage means for storing a private key created for said device having a corresponding device public key where said device public key has been certified by a trusted authority, said storage means being secured such that said private key is not accessible to said user; and

processor means for operating on said clock signals and said digital input value using said private key corresponding to the public key certified by said trusted authority for generating a notarized time stamp, said input means, storage means and processor means being supported by said platform means, whereby a holder of said device public key certified by said trusted authority may verify that said notarized time stamp is authentic without any further information regarding said notarization device.

2. A device according to claim 1, further comprising random number generator means, coupled to said processor means for generating a relatively unpredictable output value, said processor means creating said notarized time stamp using said unpredictable output value.

3. A device according to claim 2, wherein said random number generator means includes a noise generating diode.

4. A device according to claim 2, wherein said random number generator means comprises a random number generating subroutine executed by said processor means.

5. A device according to claim 1, wherein said clock means includes a plurality of digital clocks.

6. A device according to claim 5, further including averaging means coupled to receive the outputs of said plurality of digital clocks for generating a time output signal which is the average of the outputs of said plurality of digital clocks.

7. A device according to claim 5, further including threshold detecting means for generating an error signal if the difference between the outputs of said plurality of clocks exceeds a predetermined threshold.

8. A device according to claim 1, further including means for rendering said device effectively tamper-proof.

9. A device according to claim 8, further including means for encapsulating said clock means and said processor means on said platforms means such that said clock means and said processor means can not be readily tampered with.

10. A device according to claim 8, further including switch means coupled to said processor means, said processor means including means responsive to a change of state of said switch means for preventing said device from operating properly.

11. A device according to claim 1, wherein said processor means comprises computational means for performing a public key digital signature operation on said input value and said clock signals.

12. A device according to claim 1, further including power supply means, disposed on said platform means for supplying power to components disposed on said platform means.

13. A device according to claim 1, wherein said input value represents at least one digital message, said input means being coupled to said processor means, for receiving said input value, and for supplying said input value to said processor means, whereby said device may be coupled to a communications system for receiving a digital message to be time stamped and for transmitting a time stamped notarized digital document to said communications system.

14. A device according to claim 1, wherein said processor means includes means for generating a public key/private key pair.

15. A device according to claim 1, wherein said processor means includes flag means for storing an indication that the notarization initialization has been completed.

16. A digital time notarization system comprising:

data processing means for performing data processing related tasks;

a digital time notarization device coupled to said data processing means, said notarization device including;

platform means for supporting digital components;

input means, disposed on said platform means, for receiving from said data processing means an input value to be time notarized;

storage means, disposed on said platform means, for storing a private key created for said notarization device, said private key having a corresponding device public key, said device public key having been certified by a trusted authority;

clock means, disposed on said platform means, for generating clock signals indicative of time; and

processor means, disposed on said platform means, for operating on said clock signals and said input value using said private key and for generating a notarized time stamp.

17. A system according to claim 16, wherein said data processing means includes a personal computer.

18. A system according to claim 16, wherein said data processing means includes a plurality of ports and said platform means is coupled to one of said ports.

19. A system according to claim 16, wherein said data processing means includes a telecommunications system for coupling digital messages to be time stamped to said device and for receiving time stamped signatures from said device.

20. A system according to claim 16, further comprising random number generator means, coupled to said processor means for generating a relatively unpredictable output value, said processor means creating said notarized time stamp using said unpredictable output value.

21. A system according to claim 16, wherein said clock means includes a plurality of digital clocks.

22. A system according to claim 21, further including averaging means coupled to receive the outputs of said plurality of digital clocks for generating a time of day output signal which is the average of the outputs of said plurality of digital clocks.

23. A system according to claim 21, further including threshold detecting means for generating an error signal if the difference between the outputs of said plurality of clocks exceeds a predetermined threshold.

24. A system according to claim 16, further including means for encapsulating said clock means and said processor means on said platforms means such that said clock means and said processor means can not be feasibly tampered with.

25. A system according to claim 16, wherein said processor means comprises computational means for performing a public key digital signature operation using said input value and said clock signals.

26. A system according to claim 16, further including power supply means, disposed on said platform means for supplying power to components disposed on said platform means.

27. A system according to claim 16 further including origination means for transmitting a digital message to be time stamped to said data processing means, said data processing means including means for transmitting a digital time stamped notarization proof set.

28. A system according to claim 16, further including means for generating a proof set which includes at least a notarized time stamp and the digital certificate by the manufacturer of the device of the device'"'"'s public key.

29. A system according to claim 28, wherein the manufacturer'"'"'s certificate includes the public key of the device and it'"'"'s signature by the manufacturer'"'"'s public key.

30. A method of digitally time notarizing a digital message comprising the steps of:

receiving a digital message to be date/time notarized by a special purpose digital notarization device;

generating clock signals indicative of time within said device;

accessing a private key created for said device and stored in a tamper proof storage device in said notarization device, said private key having a corresponding device public key, said device public key having been certified by a trusted authority; and

operating on said digital message, and said clock signals, using said private key, whereby a notarized time stamp is generated by said notarization device.

31. A method according to claim 30, further including the steps of

generating a relatively unpredictable value, and

creating said notarized time stamp using said unpredictable value.

32. A method according to claim 30, further including the step of encapsulating components on said device such that the components can not be readily tampered with.

33. A method according to claim 30, wherein said receiving step includes receiving said digital value from a data processing system.

34. A method according to claim 30, further including the step of generating a public key/private key pair within a processor in said special purpose device.

35. A method according to claim 30, further including the step of initializing said special purpose device prior to said receiving step and

storing an indication within said special purpose device that the initialization has been completed.

36. A method according to claim 30 further including the step of generating a digital time stamped notarization proof set.

37. A method according to claim 30, wherein said trusted authority is the manufacturer of the device and further including the step of generating a proof set which includes at least a notarized time stamp and the digital certificate by the manufacturer of the device of the device'"'"'s public key.

38. A method according to claim 30, further including the step of initializing said device by:

initializing a clock module within the device generating a public/private key pair, and

loading the private key in a storage device within said device.

39. A method according to claim 38, wherein said initializing step further includes the step of digitally verifying the device initialization by a witness.

40. A method according to claim 39, wherein said verifying step includes the step of generating a digital certificate for said device.