Electrical computers and digital processing systems: support – Digital data processing system initialization or configuration – Loading initialization program
Reexamination Certificate
1997-05-29
2001-03-27
Hayes, Gail (Department: 2131)
Electrical computers and digital processing systems: support
Digital data processing system initialization or configuration
Loading initialization program
C380S029000
Reexamination Certificate
active
06209090
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to apparatus and methods for providing secure time stamps to documents and transactions.
BACKGROUND OF THE INVENTION
A need has always existed for a method of establishing the age and authenticity of documents, particularly for legal and business purposes. For documents written on paper, methods currently exist for establishing the age of a document by analysis of the chemical composition of the paper and the ink. Further, handwriting analysis can be used to establish the authenticity of the document signatures. These methods, however, are not practical for widespread use and require a significant level of expertise to establish either the age or the authenticity of the document signatures.
Impartial third party notaries have been typically relied upon to establish both the age and authenticity of paper documents. With such an approach, there is no assurance against collusion or conspiracies to defraud involving a third party notary. Still, further, where a large volume of transactions or documents related thereto, such as with financial transactions, is involved, the task of third party notarization becomes too cumbersome and the ability to immediately notarize the document is not possible.
With the rapid qrowth of electronic documents and the movement toward a paperless society, there is an increasing need for establishing not only the integrity of an electronic document but the exact date and time, and, possibly, even the place at which a document was created or last modified.
Prior time stamp apparatus have used internal clock modules contained within a data processing system or the time stamp apparatus itself to generate the value of the day and time within a time stamp. For security purposes, this solution is unacceptable since such internal clocks are readily modifiable by the user to reset the date and time upon computer initialization or power loss. One such apparatus is disclosed in U.S. Pat. No. 5,136,643, issued to Fisher, entitled PUBLIC/KEY DATE TIME NOTARY FACILITY. The system disclosed in Fisher contains one or more digital clocks, the values of which are averaged and used as part of a notary time stamp value. Although the clock module in the Fisher apparatus has been designed to prevent physical tampering, the problem of continuous power to the clock is not solved, since even backup batteries lose power eventually. Further, since the internally generated clock signal is not a universally recognized, the authenticity of the time stamp is not universally recognized. United States Patent 5,189,700, issued to Blandford, entitled DEVICES TO SUPPLY AUTHENTICATED TIME AND TIME STAMP AND AUTHENTICATE DIGITAL DOCUMENTS, likewise discloses a device in which a resident real time clock provides the source of time for the time stamps. The apparatus disclosed in Blandford suffers from the same inherent problems as the Fisher patent, namely, the internally generated clock is not a universally recognized value for the time at any given instance. Hence, the credibility of the time stamps issued therefrom is similarly not universally recognized.
Accordingly, in light of the above deficiencies in previously attempted solutions, a need exists for a method and apparatus by which a highly accurate and universally accepted notary stamp may be applied to both paper and electronic documents and associated transactions, such a stamp being useful to both compute the age of a document, and, in the case of electronic documents, verify the authenticity and integrity of the document. A further need exists for a method of providing a “virtual seal” on computer files and records so that the exact date, time and place of the sealing may be later ascertained. Further, a need exists to determine whether modifications or subsequent edits to such sealed documents has occurred and, possibly, even a history of such modifications to the documents.
SUMMARY OF THE INVENTION
The above described deficiencies in prior devices and previously described needs are fulfilled by the present invention which contemplates a method and apparatus for generating a time stamp from a widely accepted, externally generated time signal. The time stamp further comprises a time stamp serial number generated through an irreversible process which may not be duplicated by the same generating apparatus. In addition, time stamp includes one or mcre check-sum values based on the contents of the time stamp and/or the document with which the time stamp is associated.
In one aspect of the invention, an apparatus for generating notary time stamps comprises means for obtaining a time signal generated external to the apparatus, the time signal comprising date and time information. The apparatus further comprises logic means for creating a unique, sequential time stamp identifier through an irreversible process. The apparatus further comprises means for forming the time stamp and for generating a check-sum value which may be based on the content of one or all of the parameters of the time stamp itself. In an illustrative embodiment, the external, signal comprises a time signal in Universal Time Code (UTC) format or a signal based on a Global Positioning Satellite (GPS) signal. The logic means for creating the sequential time stamp identifier comprises a programmable memory device having a plurality of cells, each of which may be written or “burned” only once, to irreversibly change the digital signature output from the memory device.
According to a second aspect of the invention, a method for generating time stamps to be associated with documents and data files comprises the steps of receiving a request for a time stamp, retrieving an external time signal including date and time information, irreversibly modifying the output signature of a write-once memory to generate a unique, sequential time stamp identifier, generating the notary time stamp from the date and time data and the time stamp identifier, and generating a check-sum value derived at least partially from the date and time data or time stamp identifier.
According to a third aspect of the invention, a notary time stamp for association with documents and data files comprises a source identifier uniquely identifying the source of the time stamp, a time stamp sequence identifier generated through an irreversible process by the source of the notary time stamp, time and date data obtained externally of the source of the notary time stamp, and a check-sum value derived from at least one of the source identifier, time stamp sequence identifier and day and time data.
According to yet a fourth aspect of the invention, an apparatus for verifying the authenticity of a time stamp is presented, the time stamp parameters including a source identifier, a time stamp sequence identifier, date and time data and a check-sum value. The apparatus for verifying the authenticity comprises means for reading the notary time stamp parameters and means responsive to the check-sum value for verifying the integrity of the parameters from which the check-sum value is derived.
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Aisenberg Sol
Freedman George
Hed A. Ze'ev
Pavelle Richard
Hayes Gail
Kudirka & Jobse LLP
Seal James
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