System and methods for generating trusted and authenticatable time stamps for electronic documents
First Claim
1. A time stamp certifying the existence of a digital document at a time, the time stamp comprising:
- an identification of an issuing clock certified through a chain of at least one signed certificates to be synchronized with an accepted standard source of time, wherein each of the signed certificates certifies that two clocks are synchronized;
an identification of the time, wherein the identification of the time is provided by the issuing clock;
a document identifier based upon which the identity of the digital document can be verified; and
a cryptographic signature of a set of data comprising;
the identification of the issuing clock, the identification of the time, and the document identifier.
1 Assignment
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Accused Products
Abstract
A trusted time infrastructure system provides time stamps for electronic documents from a local source. The system comprises a trusted master clock, a trusted local clock, and a network operations center. The trusted master clock and network operations center are located within secure environments controlled by a trusted third party. The trusted local clock may be located in an insecure environment. The trusted master clock is certified to be synchronized with an accepted time standard, such as a national time server. The trusted local clock, which issues time stamps, is certified to be synchronized with the trusted master clock. Time stamps and certifications are signed by the issuing device using public key cryptography to enable subsequent authentication. The network operations center logs clock certifications and responds to requests for authentication of time stamps.
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Citations
29 Claims
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1. A time stamp certifying the existence of a digital document at a time, the time stamp comprising:
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an identification of an issuing clock certified through a chain of at least one signed certificates to be synchronized with an accepted standard source of time, wherein each of the signed certificates certifies that two clocks are synchronized;
an identification of the time, wherein the identification of the time is provided by the issuing clock;
a document identifier based upon which the identity of the digital document can be verified; and
a cryptographic signature of a set of data comprising;
the identification of the issuing clock, the identification of the time, and the document identifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of creating an authenticatable time stamp certifying the existence of a digital document at a time, the method comprising:
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providing an identification of a trusted source of time certified through a chain of at least one signed certificates to be synchronized with an accepted standard source of time, wherein each of the signed certificates certifies that two clocks are synchronized;
providing an identification of the time, wherein the identification of the time is provided by the trusted source of time;
providing a document identifier based upon which the identity of the digital document can be verified; and
generating a cryptographic signature by cryptographically signing a set of data comprising;
the identification of the trusted source of time, the identification of the time, and the document identifier. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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- 21. A trusted clock configured to provide time, the trusted clock certified through a chain of at least one cryptographically signed certificates to be synchronized with an accepted standard, wherein each of the signed certificates certifies that two clocks have been determined to be synchronized.
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25. A certificate certifying that two clocks are synchronized, the certificate comprising:
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an identification of a first clock;
an identification of a second clock;
an identification of a time at which the first clock and the second clock have been determined to be synchronized; and
a first cryptographic signature of a first set of data comprising;
the identification of the first clock, the identification of the second clock, and the identification of the time.
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Specification