Method for updating Java Card system component based on memory management unit (MMU) framework

Abstract

The invention discloses a method for updating a Java Card system component based on a memory management unit (MMU) framework. The method comprises card outside operation and card inside operation and is characterized by comprising the following steps of: 1) providing a code modified item list by comparing a modified engineering code and an original engineering code; 2) searching virtual address entries and binary lengths of items in a target file from the code modified item list, and providing a system component updating task list; 3) combining the items, of which virtual addresses are close, in the system component updating task list to generate a card inside MMU modified information sheet and code actual binary modified information sheet; 4) transmitting code modified data, writing updated code data into a card inside electrically erasable programmable read-only memory (EEPROM) and performing system call on a new address of the updated code data in the card inside EEPROM after the new address serving as a parameter is processed; and 5) authenticating the updated code data by a card inside operating system, if the updated code data passes through the authentication, modifying a translation lookaside buffer (TLB) initialization table of an MMU and restarting the card inside operating system for initialization.

Description

technical field [0001] The invention relates to Java Card technology, an embedded system and a binary code relocation technology, and mainly realizes a method for solving dynamic updating of Java Card system components based on a new MMU architecture. Background technique [0002] Java Card is a smart card that can run Java applets. It has developed rapidly due to its advantages of multi-application support, good security features, object-oriented programming environment, and dynamic download of applications. It is widely used in SIM / USIM applications, Applications in identity authentication and financial fields are becoming more and more extensive. Java Card is an embedded system that runs a java runtime environment on a smart card with extremely limited resources. Its biggest advantage is that it can dynamically download and update the application program on the card after the card is issued, realizing flexible multiple application card. However, due to the storage chara...

AI Technical Summary

Problems solved by technology

[0004] For the dynamic update of Java, Alessandro proposed a technology based on class renaming and code rewriting to realize the dynamic update of Java classes, using a tool called DUSC to dynamically switch classes at runtime, but this method is very time-consuming and The storage space is seriously wasted, and it is not suitable for the Java Card environment with extremely limited computing and storage resources; another JVM that supports online updates is JVOLVE, which uses related tools to find the list of classes that need to be updated, and then dynamically loads classes and uses JIT Technology compiles it to replace existing classes, and finally uses a modified garbage collector to change the original object reference to a new object reference

Because the Java Card platform does not support class dynamic loading and JIT mechanism, this method must be modified. Agnes C. Noubissi proposed a similar method and used it on the Java Card platform to obtain the update list through corresponding tools outside the card. , the card uses software to find all classes that need to be replaced, creates new classes and instances by passing in data, and modifies all references to the original instances to achieve dynamic updates. It uses pure software methods to implement search, replace, and update operations. The efficiency is relatively low, and the security issues that smart cards depend on are difficult to be guaranteed

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