Using an enclose latch (or enclosed latch) is an excellent way to increase the security of your hard tonneau cover and prevent thieves from easily opening it. Here's how an enclosed latch can help, and a few additional tips to maximize its effectiveness:

Benefits of an Enclose Latch:

Hidden Mechanism: Enclose latches are often designed to be hidden or less accessible, making it harder for thieves to figure out how to open the tonneau cover. If the latch mechanism is concealed or integrated into the tommeau cover design, it adds an extra layer of difficulty for anyone trying to tamper with it.
Increased Resistance to Tampering: These latches are often built to resist common breaking and prying tools. Some are even designed to be pick-resistant, further reducing the risk of unauthorized access.
Secure Locking: An enclosed latch usually provides a more secure, tightly sealed closure that requires a key or specific tool to open, making it less likely for someone to be able to simply slide it open or force it without significant effort.

https://teamztruckbedcovers.ca/blogs/news/provent-hard-tonneau-covers-being-opened-by-thieves