Patent ID: 8484555

Claim:
An electronic document control apparatus for editing an electronic document, which has been imparted with a policy for permitting page layout editing or for permitting background rendering of a content in addition to page layout editing, and in which a digital signature has been applied to the content, the apparatus comprising a central processing unit comprising: a first verification unit configured to verify that the content to which the digital signature has been applied has not been altered; a second verification unit configured to verify that a referential target of a new page generated afresh in editing of the electronic document is a signature area to which a digital signature has been applied; a third verification unit configured to, if the electronic document has been imparted with a policy for permitting page layout editing, verify that the referential target of a new page generated afresh in editing of the electronic document does not include anything other than the content to which the digital signature has been applied, and if the electronic document has been imparted with a policy for permitting page layout editing and background rendering of the content, verify that the referential target of a new page generated afresh in editing of the electronic document does not include anything other than the content and a background object of the content; and a determination unit configured to determine, based on at least one result of said first, second and third verification units, whether the edited electronic document has been altered, wherein said determination unit determines that the edited electronic document has not been altered if verification is achieved by said first, second and third verification units, and said determination unit determines that the edited electronic document has been altered if verification is not achieved by any one of said first, second and third verification units.