| 摘要 |
When software is initially loaded to RAM 20 , an engine 30 A is installed at the beginning of an otherwise empty area of RAM 20 . When the protected application is called, the engine first creates a series of steps (FIG. 3 D), including a CALL command to a protection block 38 . On reaching the call 36 , the protection block 38 is executed, to complete various security checks. If these are successful, step 2 is created and written over the call 36 so that execution of steps 2 and 3 can continue as normal. Consequently, the protected software (steps 1, 2 and 3 ) is not exposed to scrutiny unless the security checks have successfully been completed. |
