Mobile banking system with cryptographic expansion device

Claims a gateway device and a performing, so for preventing client and device for authorization to gateway device and method of mainframe network. The gateway device without respond is plugged with the output to the gateway equipment via client message. On the top, gateway device is responded is formed as a client information sequence of confirm, the preset the sequence of confirm is knew a gateway device and after the receiver client device. Wherein the gateway device to respond is a random client message, and client device for authorization of guess for pre-twisted patching bar by the client information sequence very low correctly, therefore of the lowered evaluating malicious provide for invention provides the mainframe network by using interface scanning method for risk.