This is hypothetical problem, so remarks about whether it is feasible in practice are are off topic.
I have been designing a documentation system for medical records where the patient owns his/her own data (instead of how it currently works in most (?) cases where the data is stored in a big database at a hospital or similar - an excellent target for both black hats and authorities).
For example, by getting a physical printed paper after each visit to a doctor with the notes and other details of the visit on. The objection I always get when I suggest this is that it would be a problem in maltreatment cases and similar if the patient could manipulate the documentation.
My solution to this - and this is where I would appreciate input - would look something like this: each paper the doctor gives the patient contains a digital signature (checksum) calculated with the doctors private encryption key (e.g., a QR-code) in its footer. This prevents the patient from manipulating the document undetected.
Next problem is the document chain: the solution in the previous paragraph does not prevent the patient from handing in paper 1, 2 and 4 but ignoring 3. To solve this, every paper also contains the previous documents digital signature in it's body. If the patient presents page 1, 2 and 4 they checksum for the previous document on 2 will match the checksum on 1 but the the checksum for the previous document on 4 won't match the checksum on 2.
Would this work?
One problem remains: what if the patient just presents paper 1, 2 and 3 but not 4? Or if the patient on its fifth visit to the doctor just show 1, 2 and 3 - meaning you get two documents numbered 4? Any ideas for solutions for these problems? A separate log document? How is it solved in current solutions?