iOS dialer App like original iPhone's

I need a fake app of original Phone app of iPhone. When you press numbers in dialpad it should show the numbers, which entered by me in settings Instead of real pressed numbers. So there is green icon built in app in iphone. Where you add contacts, call numbers and etc right? So, i need the same visual but fake app. Which will have hidden settings, where i want enter number of digits and which digits will appear when somebody will press to any buttons. Forexample, i will set 4 digit number and it is 1234. But when somebody will press buttons of 7420 it will write in screen 1234. Pressing 7will show 1, press 4 will show 2, press 2 will show 3, press 0 will show 4. Other functions stays as original app. Colors, contacts, calling list and etc.