Design of secure short message protocol is also expatiated, which focuses on structurizing the user data field of short message, to implement system access, bearing of three security services and other interactive functions. On implement of system's modules, a guiding ideology of object oriented and reusability is adopted, algorithm library is organized with abstract factory pattern, three security services are coupling with algorithm library by bridge pattern, in order to make modules perform high cohesion and loose coupling, consequently, reusability and expansibility of program are improved. At last, security and capability of the system are evaluated with methods of qualitative analysis and quantitative analysis; ways to enhance system's performance are also discussedThe main research results of this article are as follows: a solution including three security services to settle short message security threatens; discussing on algorithm set which includes ECC, AES, HASH, describing implement of the three security services by using the algorithm set; design and implement of secure short message protocol; modularizing design and coupling research between modules with guiding ideology of object oriented and reusability; put forward an design of short message engine which is used for encapsulation operations of short message. Among them, idea of application layer access based on protocol and modules reusability design are more representative of original creation.
