That could be a good idea, adding an additional layer of security by checksumming against the filename itself. This would make it even harder for unauthorized users to gain access to specific files or directories without proper clearance.
Incorporating multiple layers of security, including timestamp, filename checksums, and other additional security requirements would make your proposed system even more robust and secure. However, it's important to balance this level of protection with ease of use for the end user so that they can access their data when needed without too much hassle or inconvenience.