Permission for a time interval

You write in Protocol Definitions that a use case could be to "give read permission to an asset for a time interval", but i don't see this being explained (or at least I don't understand) how it could work. Could you go little bit into detail with this one.
I am asking, because I would be interested in a way of revoking the asset access, either timely or manually.

Start with the Protocol Definitions section referenced in the issue and review how it describes giving read permission to an asset for a time interval. Document how timely and manual revocation would work, and consider the explanation complete when both revocation cases are clearly described.

Written by the indexing model from the issue text.