| 摘要 |
A personal computer (PC), and methods (560) for proving dates of digital data files, which are accessed, created, modified, received, or transmitted by the PC includes a trusted time source in a tamperproof environment, a first subsystem for saving the file at a moment in time (610), a second subsystem for retrieving from the trusted time source a date and a time corresponding to the moment in time (620), a third subsystem for appending the date and the time retrieved from the trusted time source to the saved file (630), a fourth subsystem for signing the saved file with the date and the time retrieved from the trusted time source appended thereto (640), a fifth subsystem means for hashing the signed file to produce a digest (650), a sixth subsystem for signing the digest with a key (670) to produce a certificate (660), a seventh subsystem for appending the certificate to the saved file (680), and an eighth subsystem for saving the file with the certificate appended thereto (690). The trusted time source is a real time clock, which is not resettable, is independent of any system clock of the PC, and is installed locally relative to the PC.
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