加密移动代码的密钥管理方案

针对加密保护移动代码存在的密钥管理困难、影响程序升级的问题,提出了基于Shamir的门限分存算法的密钥管理方案,并在JavaTM上实现.该方案使不同的Java字节码文件产生不同的密钥,避免了对程序升级的影响;利用门限算法将密钥分成多个伪随机性因子,通过置乱和异或的方法,将因子均匀地分布到加密的代码中,使攻击者难以直接发现密钥因子;在加密代码还原时,随机地提取因子恢复密钥,重复使用相同因子的概率很小.该方案避免了对程序升级的影响,同时能有效干扰攻击者对密钥生成过程的跟踪,在很大程度上增加了攻击者破解密钥的难度;而且通过性能测试看出,没有增加原Java程序的运行负担.

Key Management Method of Encrypting Mobile Code

The difficulty of key management and the influence to the upgrade of the code are the main problems when use encryption to protect the mobile codes. A security key management using Shamir Threshold algorithm implemented on JavaTM was proposed. Produced different key according to different Java bytecode file; then broke up the key into many pseudo-random genes and evenly diffused the genes into the encrypted file using scramble algorithm and exclusive OR operation; using random genes to recover the key at the program running. It could avoid the influence to the upgrade, and effectively disturbed the attacker to track the process of producing the key, increased the difficulty to find the key. At the same time, it did not bring much burden to the original program from the efficiency test.