An Use Case that Requires Apart-from-Text Change Tracking

["Dennis E. Hamilton" <dennis.hamilton@acm.org>]

I am a strong adherent of the current ODF approach where the text body is resolved as the post-change form of a document when change-tracking is ignored.

And I have found an use case where the before-changes default is called for.

Essentially, it has to do with changes to signed documents which are protected or otherwise designed to be kept read-only (if the signature is to be preserved) but certain changes are allowed.  In this case, the markup (or entered values for fields) need to be kept in some sort of annex that can be projected onto the original without altering the digitally-signed form of the document.  (In fact, Microsoft Office does something like this when signature blocks are shown in the presentation of the document, but the document is not actually altered when the digital signature and the signature block are created.)

This case cascades.  In effect the changes can be signed (and the original text countersigned), and subsequent changes and or acceptance/rejection of changes leads to another appendage and there can be additional signings to prevent removal of this history if the signatures are to be preserved.

This situation is more interesting in the case of protected documents where that changes that are allowed are kept in an annex so that the protection of the document can be preserved by a digital signature on its original form.  This applies more to use of spreadsheets as turnaround documents, since the protection feature doesn't really prevent alteration of the protected parts, but having a digital signature on the original document will make it infeasible to hide the presence of alteration of the protected part.

It only occurred to me in the past week that this case is also meaningful for change-tracking too.

 - Dennis