5. The method of claim 1 , further comprising forming a blurred feature-based representation of the document by modifying the feature-based vector based on the reconstructed feature-based vector.
6. The method of claim 5 , wherein the step of modifying the feature-based vector comprises: obtaining a first attribute value from the feature-based vector; obtaining a second attribute value corresponding to the first attribute from the reconstructed feature-based vector; and computing a third attribute value as the corresponding attribute value of the blurred feature-based representation of the document based on the first and second attribute values.