A method for preserving a digitally signed document (160) in a digital data preservation system (10). A secure preservation request (176) combines the document (160) with a preservation signature (174) that is generated using an identification mark (172) and the document's associated digital signature (168). Once the document (160) is authenticated by the digital preservation system vendor, both the document (160) and the identification mark (172) are recorded onto preservation media (210) in human-readable form.
Embodiments of the present invention relate to attesting a document that contains encoded data, such as a barcode or DataGlyph. When a document contains encoded data that is not in human-readable form, the document is checked to determine whether content in the encoded data appears somewhere in the document in human-readable form. Based on the amount of content that appears in the document, the document may be marked with a seal that attests to the amount of content in the encoded data that appears in human-readable form. The seal may be visually distinctive to facilitate easy recognition by a user or device.
