Digital Logic Design Project Combinational Lock?

In this project you are required to design a 4 digits combination lock (not using arduino)  The project is such that it can be reconfigurable i.e. there should be an option that we can change the password of the lock at run time. Input to the system is from the hex keypad. Output of the system is ‘open’ and ‘close’ words displayed on a seven segment
I used registers,flip flops, mux ,comparator  but couldn't get the desired result

Show your working, and the design concept.