How to convert json checked checkbox data to a list?

How would I convert a json string that contains checkbox values to a list?

For example, I have the following json string : {"User1":"Checked","User2":"","User3":"Checked"}

I want to pull a list from the above data, and assign it to a variable. The list should of course, only output the checked elements as such :

User1 User3

and ignore the unchecked items.

Is this possible?