Program execution device

摘要

A program execution device capable of protecting a program against unauthorized analysis and alteration is provided. The program execution device includes an execution unit, a first protection unit, and a second protection unit. The execution unit executes a first program and a second program, and is connected with an external device that is capable of controlling the execution. The first protection unit disconnects the execution unit from the external device while the execution unit is executing the first program. The second protection unit protects the first program while the execution unit is executing the second program.

主权项

1. An encrypted digital content playback device comprising:
a program execution unit configured to execute a program while switching between a first mode indicating an operating state in a first security level and a second mode indicating an operating state in a second security level lower than the first security level; and an external device disconnection unit configured to disconnect the program execution unit from an external device when the program is executed in the first mode, wherein a first secure program is executed in the first mode, a second secure program is different from the first secure program and runs in the second security level, an application program starts the second secure program according to a digital content playback instruction from a user, the first secure program obtains a content key for decrypting encrypted digital content according to an instruction from the second secure program after the external device disconnection unit disconnects the program execution unit from the external device, and the second secure program causes digital content to be played back using a buffer.