I have an entity called 'History' where all users need to be able to search on the 'ChangedBy' attribute of the entity. I can't seem to be able to grant read or write access on these attributes. Is there a way to do so? I know I can add my own attribute to do track this, but I'm hoping there's an easier way, as this is one of many entities I would have to do this for.
You can't change the permissions on the changedby "field".
This is really an association (not a field) to the System.User entity.
When a user is not able to view the user, due to security restrictions the user will not be able to query the records. Therefore I think you'll have to implement your own field to perform the queries on.