Patent ID: 7412519
Filing Date: 2008-08-12
Classification: H04L

Abstract:
1. A method for using a partially encrypted document, comprising: issuing a document usage request for using the partially encrypted document in a session; authenticating the partially encrypted document; receiving authorization to use the partially encrypted document; receiving a session key for the session; receiving a proxy key that delegates decryption to the session; rendering a non-encrypted portion of the partially encrypted document; performing a proxy transformation on the partially rendered, partially encrypted document using the proxy key, wherein rendering a portion of the partially encrypted document and performing proxy transformation on the rendered portion of the partially encrypted document comprises a combination of performing partial rendering transformations and performing partial decryption transformations; and decrypting the proxy transformed, partially rendered, partially encrypted document using the session key, wherein the proxy key and the session key are used to decrypt the partially encrypted document as part of the session rendering process only, thereby assuring that only rendered images of the decrypted document are available to an end user.