Public/key date-time notary facility

• US 5,136,643 A
• Filed: 12/20/1990
• Issued: 08/04/1992
• 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:
  US07/633,259
• Time in Patent Office: 593 Days
• Field of Search: 380/23, 380/51, 380/52, 380/25, 380/30
• US Class Current: 713/178
• 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 7/12 Card verification
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• 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 crytographic 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., on 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:

a clock module for generating clock signals indicative of time;

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

a digital storage device, said storage device storing a private key associated with the notarization device, said private key having a corresponding device public key; and

a digital processor device for performing a digital signature operation on said clock signals and said digital input value using said private key corresponding to the device public key for generating a notarization time stamp, whereby a holder of said device public key may verify that said notarized time stamp is authentic.

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

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

4. A device according to claim 3, 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.

5. A device according to claim 3, 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.

6. A device according to claim 1, wherein said input value represents at least one digital message.

7. A device according to claim 1, wherein said digital input value is a hash value.

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

receiving a digital message to be date/time notarized by a 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;

performing a digital signature operation on said digital message, and said clock signals, using said private key, whereby a notarized time stamp is generated by said notarization device; and

generating a digital time stamp notarization packet including said notarized time stamp and digital data identifying said device public key.

9. A method according to claim 8, wherein said device public key is certified by a trusted authority and wherein said notarization packet includes at least a notarized time stamp and a digital certificate by the trusted authority certifying the device'"'"'s public key.

10. A method according to claim 8, further including the steps of:

generating a relatively unpredictable value, and

crating said notarized time stamp using said unpredictable value.

11. A method according to claim 8, wherein said receiving step includes the step of receiving said digital message from a data processing system.

12. A method according to claim 8, further including the steps of initializing said notarization device;

and

storing an indication in said notarization device that the initialization has been completed.