So in a web app made using .NET core 2.1 and Jquery, sensitive information is stored in a cookie.

This is a security problem because that means all a user has to do is change the value of a cookie and be able to access restricted things.

​

in .NET core 2.1 and jquery, how can I create some sort of session variable or something that is hidden from the client?

or if that's not possible, is there another more secure method I can implement?

​

Any help would be appreciated.