Research On Storage Management Of UCard Based On High Address Constraint

Currently, because of their security, portability and mobility, smart cards have been widely used, and have achieved good economic and social benefits. Since more and more different applications, the amount has increased dramatically, so every customer will hold more and more cards, this will affect the portability deeply. So many companies developed multi-application smart cards. But they all based on one COS, all applications'security is depended on one operating system. Once any application is attacked, other applications'security will be affected.UCard (Universal Card), a smart card with new architecture, was brought forward for this situation. It overcomes the weaknesses of secrecy and security that exist in the model of multi-application smart card. Its basic idea is to contain several COSes (Chip Operating System) in one card, with new hardware and software technology. Memory management module is an important component of UCard, and it directly related to the data structure of the file,memory speed,storage space utilization rate,the practical application and so on.By analyzing the UCard simulation system, because of its fixed storage allocation method, it has some disadvantages, for example, it wasted storage resources and can't contain large COS etc. So a method of space_sensitive storage allocation is proposed to solve this problem, it carried out by restricting high address. To guarantee the security among COSes, a kind of hardware supported is required, and we called that Dynamic Address Controller. Then we analyzed the reasons why it can carry out physical separation between COSes by restricting high address. And the improved architecture of UCard is given. The UCard based on high address constraint meets the ISO-7816 agreement. When a COS operations, the UCard is like a common smart card totally.Finally, the main modules of the UCard based on high address constraint are designed and implemented, including the processor module, the memory modules, and the dynamic address controller module. And then the security and efficiency of the UCard based on high address constraint is analyzed.