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

A technology of system components and update methods, applied in the direction of program loading/starting, program control devices, etc., can solve the problems of difficult to guarantee the security of smart cards, waste of storage space, time-consuming and other problems, so as to simplify the modification amount in the card and improve the update rate. Efficiency and security effect

Active Publication Date: 2011-11-16
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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

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Embodiment Construction

[0033] The present invention will be further described below based on the drawings and specific embodiments.

[0034] A card storage architecture based on an MMU mechanism, and a solution for upgrading Java Card system components using MMU. This solution requires a series of operations outside the card and inside the card. The outside of the card locates the modified position in the system binary target file by comparing the modification of the code, forming an update task list, and adopting a certain algorithm to optimize the list to reduce Update the number of items and the amount of communication; the modified code fragments are stored in the EEPROM in the card, and the method of modifying the TLB (Translation Lookaside Buffer) table is used to change the virtual address to physical address mapping, and the original virtual address is mapped to the modified After the storage location of the project, the code can be relocated to achieve the purpose of updating system compon...

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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, embedded system and binary code relocation technology, and mainly realizes a method for solving the dynamic update of Java Card system components based on a new MMU architecture. Background technique [0002] Java Card is a smart card that can run Java small applications. It has developed rapidly due to its multi-application support, good security features, object-oriented programming environment, and dynamic application downloads. It has developed rapidly in SIM / USIM applications, The application of identity authentication and finance is 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 applications on the card after the card is issued, realizing more flexibility. Application card. However, due to the storage characteristics of the current...

Claims

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Application Information

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IPC IPC(8): G06F9/445
Inventor 李莹曹晓殷中科邓水光吴健尹建伟
Owner ZHEJIANG UNIV
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