Application Execution Device and Application Execution Device Application Execution Method

• US 20070271446A1
• Filed: 07/14/2005
• Published: 11/22/2007
• Est. Priority Date: 07/16/2004
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Nakamura, Tomonori
• Application Number:
  US11/632,418
• Publication Number:
  US 20070271446A1
• Time in Patent Office: Days
• US Class Current: 712/226
• CPC Class Codes: G06F 21/14 against software analysis or reverse engineering, e.g. by obfuscation
• CPC Class Codes: G06F 21/53 by executing in a restricted environment, e.g. sandbox or secure virtual machine
• CPC Class Codes: G06F 21/54 by adding security routines or objects to programs

Abstract

The conventional application protection technique complicates an application to make it difficult to analyze the application. However, with such a complication method, the complicate program can be analyzed sooner or later by taking a lot of time no matter how the degree of the complication is high. Also, it is impossible to protect the application from unauthorized copying. The meta-information managing unit that is to be executed in the secure execution unit stores the meta-information of the application in an area that can not be accessed by a debugger. When the meta-information is required by the normal execution unit to execute the application, a result of predetermined calculation using the meta-information is notified to the normal execution unit. In this way, the meta-information of the application can be kept secret.

Claims

1. An application execution device that executes each of classes included in an acquired application, comprising:

a meta-information storing unit operable to store meta-information included in a class file;

an instruction sequence storing unit operable to store an instruction sequence included in the class file;

an instruction execution unit operable (i) to execute an instruction if the instruction does not refer to any information, and (ii) if the instruction refers to first information, to submit a request and execute the instruction using second information provided in response to the request; and

a meta-information execution unit operable to generate the second information based on the meta-information in response to the request, and provide the instruction execution unit with the second information, wherein

only the meta-information execution unit is capable of reading the meta-information stored in the meta-information storing unit, and the meta-information execution unit accepts only a request from the instruction execution unit.

2. The application execution device of claim 1, wherein

the meta-information storing unit stores a constant pool describing an index, a constant pool type and a value, and a class structure information describing an item and a value,

the instruction sequence storing unit stores a bytecode of a method defined in the class file, and

if the instruction execution unit executes an instruction included in a bytecode that designates the index of the constant pool as the first information, the meta-information execution unit generates the second information with reference to the constant pool and the class structure information, in accordance with a type of the instruction.

3. The application execution device of claim 2, wherein

if the bytecode to be executed by the instruction execution unit represents a generation of a new object, the meta-information execution unit searches for a constant pool type corresponding to the designated index from the constant pool, and generates a memory size with reference to the class structure information.

4. The application execution device of claim 2, wherein

if the bytecode to be executed by the instruction execution unit represents a call of the method, the meta-information execution unit searches for a constant pool type corresponding to the designated index from the constant pool, and generates an address of the method with reference to the class structure information.

5. The application execution device of claim 2, wherein

if the bytecode to be executed by the instruction execution unit represents a reference to a field of an object, the meta-information execution unit searches for a constant pool type corresponding to the designated index from the constant pool, and generates an address of the field with reference to the class structure information.

6. The application execution device of claim 1, wherein

the acquired application is encrypted, and

the application execution device further comprises

a decryption unit operable to decrypt the encrypted application, store decrypted instruction sequence in the instruction sequence storing unit, and store decrypted meta-information in the meta-information storing unit.

7. The application execution device of claim 6, wherein

the decryption unit uses a decryption key to decrypt the application, the decryption key being stored in a key storing unit that does not accept a direct access from outside.

8. The application execution device of claim 1, wherein

the application is a Java™

application.

9. An application execution method used by an application execution device that executes each of classes included in an acquired application, the method comprising:

a meta-information storing step of storing meta-information included in a class file;

an instruction sequence storing step of storing an instruction sequence included in the class file;

an instruction execution step of (i) executing an instruction if the instruction does not refer to any information, and (ii) if the instruction refers to first information, submitting a request and executing the instruction using second information provided in response to the request; and

a meta-information execution step of generating the second information based on the meta-information in response to the request, and providing the instruction execution step with the second information, wherein.

only the meta-information execution step is capable of reading the meta-information stored by the meta-information storing step, and the meta-information execution step accepts only a request from the instruction execution step.