Developing api system and sci system of a Payment gateway

I have a website [login to view URL] Its an payment processor,same as paypal.I need two works. Number one: The sci or api system is not very secured,its just a simple.I want someone to make it like a perfect money or egopay or okpay api/sci system.I want someone to develop its built in sci system to make it more secured with hash or extra field such as store (key/password). Number Two:I need 1 more layer for sending money.I mean if someone want to send money,then he also need to put master key to send [login to view URL] then even he need to also put master key for login into [login to view URL] also need to be added on sign up page in user field.