Proving age and integrity of website pages
Systems and methods are disclosed which enable the establishment of file dates and the absence of tampering, even for documents held in secrecy and those stored in uncontrolled environments, but which does not require trusting a timestamping authority or document archival service. A trusted timestamping authority (TTSA) may be used, but even if the TTSA loses credibility or a challenger refuses to acknowledge the validity of a timestamp, a date for an electronic document may still be established. Systems and methods are disclosed which enable detection of file duplication in large collections of documents, which can improve searching for documents within the large collection.
1. A computer implemented method of proving age and integrity of a published website page, the method executable by a processor, the method comprising:
receiving an integrity verification code (IVC) generator into a non-transitory computer readable medium, the IVC generator being executable by a processor;
receiving at least a portion of the page into a non-transitory computer readable medium;
with a processor, generating an IVC for the received portion of the page using the executable IVC generator;
submitting the IVC to a first document dating list (DDL) edition across a public computer network;
after closure of the first DDL edition, identifying a provable date of the first DDL edition;
with a processor, generating a database file that links an identification of the page with an identification of the closed DDL edition;
publishing the database to be accessible over the public computer network.
2. The method of claim 1 wherein receiving at least a portion of the page comprises receiving at least a portion of a hypertext mark-up language (html) document.
3. The method of claim 2 wherein generating an IVC for the page comprises generating a modified IVC using modification rules applied to html documents to exclude portions of the document.
4. The method of claim 1 wherein generating an IVC for the page comprises generating a modified IVC using modification rules applied to elements in the page that are not printably determinable.
5. The method of claim 1 further comprising:
inserting the provable date of the closed DDL edition into the database.
6. The method of claim 5 further comprising:
within the database, identifying the provable date of the closed DDL edition as the provable date of the website page.
7. The method of claim 1 further comprising:
inserting into the database a record index number that indicates a position, within the closed DDL, of a DDL record that comprises an IVC for the page.
8. The method of claim 1 wherein the IVCs are each 168 characters in length.
9. The method of claim 8 wherein the IVC for a file consists of the combination of a SHA-1 and a SHA-512 hash of the file.
10. The method of claim 1 wherein generating an IVC comprises generating a hash function message digest.
11. The method of claim 1 further comprising:
after alteration of the website page, generating a second IVC for the page; and
archiving the first and second IVCs in a revision history for the page.