A proper standard for redacted documents would be a format where the author provides a list of ((text, position), signature) entries and the redactor is free to

A proper standard for redacted documents would be a format where the author provides a list of ((text, position), signature) entries and the redactor is free to remove elements of this list when redistributing it. (edit: to show the deletions, the author would have to provide a singed background shape as well where the text entries is cut out already)