Numeric KeyPad Login Form with replacing numbers during Login password entering

I want to create Numeric KeyPad Login Form with replacing numbers during Login password entering.

Numeric KeyPad Login Form opens as soon as my app start and ask to the User that please enter password.

Lets say user's password is 497356.

When user start entering his/her password by clicking number 4 via mouse then other numbers on Numeric KeyPad must be replaced their places randomly.

I have searched all web but there is no example about this issue.