Abstract: Techniques are provided for automatically detecting homologies between documents based on structural characteristics. Various statistics relating to the COS structure of a PDF document are compiled. The statistics are input into a rolling hash function to generate a digital fingerprint of the document. Fingerprints from two similar documents will have small edit distances between them, and can therefore be classified similarly or provided as results to a fingerprint-based search. For example, an unclassified document may be classified in the same class as a representative document where the fingerprints of the two documents have a small edit distance between them. Since the structure of the document is used instead of the text content or renderings, it is possible to operate on encrypted documents. Further, representative elements of a particular class of documents can be selected for comparison against a target document for improved resolution of the results.

Abstract: Techniques are provided for automatically detecting homologies between documents based on structural characteristics. Various statistics relating to the COS structure of a PDF document are compiled. The statistics are input into a rolling hash function to generate a digital fingerprint of the document. Fingerprints from two similar documents will have small edit distances between them, and can therefore be classified similarly or provided as results to a fingerprint-based search. For example, an unclassified document may be classified in the same class as a representative document where the fingerprints of the two documents have a small edit distance between them. Since the structure of the document is used instead of the text content or renderings, it is possible to operate on encrypted documents. Further, representative elements of a particular class of documents can be selected for comparison against a target document for improved resolution of the results.

Abstract: A method and apparatus for reconnecting a security token without restarting an application that supports use of the security token. In some embodiments, the method establishes at least one session for an application with a security token that is used to authenticate application data associated with the application, creates dynamic session data including cryptographic information associated with the security token, detects an occurrence of the security token being disconnected and, upon detecting the occurrence, terminates all established sessions and deleting the cryptographic information from the dynamic session data.