9. A machine-readable storage device tangibly embodying a computer program product configured to cause data processing apparatus to perform operations comprising: identifying state dependent content in an electronic document, wherein the state dependent content is renderable to have a plurality of appearances; receiving an attestation corresponding to the state dependent content; associating the attestation with the electronic document; and digitally signing the electronic document to generate a signed electronic document including a digital signature corresponding to a user associated with the attestation.
9. A machine-readable storage device tangibly embodying a computer program product configured to cause data processing apparatus to perform operations comprising: identifying state dependent content in an electronic document, wherein the state dependent content is renderable to have a plurality of appearances; receiving an attestation corresponding to the state dependent content; associating the attestation with the electronic document; and digitally signing the electronic document to generate a signed electronic document including a digital signature corresponding to a user associated with the attestation. 15. The machine-readable storage device of claim 9 , further operable to cause data processing apparatus to perform operations comprising: associating with the electronic document one or more permissions specifying at least one modification that can be made to the electronic document without invalidating the digital signature.