I am looking for something like hash tree in a sense that leaves node can be verified to be part of the tree but the tree has to be able to built top down (from top node to leaves).
I'm not sure exactly what I am looking for, but here's the application:
- Suppose there are users of a certain type of data storage.
- User can create new data and edit or remove any data they created.
- User can also create user accounts and also manipulate data of all users created by them (unlimited levels of user).
When a user creates something in the data storage I plan to store something along with the file created so I can verify which user can modify which file and I want to do it with fixed length metadata and with fixed or at least faster than linear verification time (compared to maximum levels of user).
Is this possible? How? Is there any other existing solutions for this application?