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Selective data encryption using style sheet processing

  • US 6,931,532 B1
  • Filed: 10/21/1999
  • Issued: 08/16/2005
  • Est. Priority Date: 10/21/1999
  • Status: Expired due to Fees
First Claim
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1. A computer program product embodied on computer readable media readable by a computing system in a computing environment, for enforcing security policy using style sheet processing, comprising:

  • computer-readable program code for obtaining an input document;

    computer-readable program code for obtaining a Document Type Definition (DTD) that defines elements of said input document, wherein;

    (1) an attribute of at least one element defined in said DTD references one of a plurality of stored policy enforcement objects;

    (2) more than one of said references may reference a single stored policy enforcement object; and

    (3) each of said stored policy enforcement objects specifies a visibility policy for said referencing element or elements, said visibility policy identifying an encryption requirement for all elements having that visibility policy and a community whose members are authorized to view those elements;

    computer-readable program code for applying one or more style sheets to said input document, thereby adding markup notation to each element of said input document for which said element definition in said DTD references one of said stored policy enforcement objects specifying a visibility policy with a non-null encryption requirement, resulting in creation of an interim transient document that indicates elements of said input document which are to be encrypted; and

    computer-readable program code for creating an output document in which each element of said interim transient document for which markup notation has been added is encrypted in a manner that enables each community member that is authorized to view that element to use key distribution material associated with the output document to decrypt the encrypted element, and that precludes decryption of the encrypted element by unauthorized community members.

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