provided is an air interface security method . in the process of protocol transmission , the method executes : 1 ) a short - range coupling device sending a security parameter request message to a short - range card ; 2 ) after receiving the security parameter request message , the short - range card conduct security parameter feedback on the short - range coupling device ; and 3 ) the short - range coupling device and the short - range card establish a security link according to a security parameter . provided are a short - range coupling device , a short - range card , etc . for achieving the method . by introducing a security mechanism , the present invention provides a security protection capability for an air interface , can provide identity authentication for a short - range coupling device and a short - range card to ensure the validity and authenticity of the identities of both sides in the communications , and at the same time , will not bring additional hardware overhead to the short - range coupling device and the short - range card .