Dynamic Data Web Site

I have control tables in my database which have columns to track when and who
created/modified record(s) for a table.

CreateDate DateTime Default: getDate()
ModifiedDate DateTime Default: getDate()
CreatedBy varchar(15) Foreign Key
ModifiedBy varchar(15) Foreign Key

Would like to create login functionality for user and store UserID in
Session Variables. How can I hide the columns mentioned above for each table
so the user cannot set value but rather the system enters it behind the
scene?

Thanks

Manny