Protecting mobile code against malicious hosts

US7421586B2 · kind B2 · utility

Assignee

• FRAUNHOFER-GESELSCHAFT · DE

Inventors

• Chenghui Luo · Johnston, US
• Jian Zhao · Rumford, US

Key dates

• Filing date: Sep 4, 2003
• Grant date: Sep 2, 2008
• Expiry date: Feb 21, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F21/125
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

Techniques for using a class loader to protect mobile code against a malicious host. The techniques include using the class loader to extend a class used by the mobile code such that a method is added to the code which authenticates the mobile code. When executed, the method provides a dynamic watermark that authenticates the code. The method may be encrypted until it is added to the code. One such method uses a static watermark in the code to determine whether the code has been modified.The techniques also include using a class loader to extend the class such that obfuscated symbolic names in the program that correspond to symbolic names defined by the class can be resolved. A way of doing this is to include a first association between the obfuscated symbolic names and encrypted forms of the corresponding symbolic names in the program and to make a second association between the encrypted forms of the corresponding symbolic names and information used to resolve the symbolic names defined in the class. The loader then uses the first and second associations to resolve the obfuscated names.The class extension techniques may be combined with obfuscation of names defined in the program…