Patent ID: 7870396

Claim:
A portable recorded storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function for protecting a target function, the function comprising: generating an inserted function, having a function name identical to the function name of the target function, that includes code for a process relating to protection of the target function and a call instruction for calling the target function after the process, the inserted function including a reserved area and first relocation information for having a linker execute a process to write an address of the target function to an operand for the call instruction; and generating a protected executable code on the basis of an object code, in which the function name of a function definition of the target function has been changed to a second function name, and the inserted function; the process generating the protected executable code including having the linker link the inserted function and the object code, in which the function name of the function definition of the target function has been changed to the second function name, and generating the protected executable code by inserting a decryption code into the reserved area of an executable code output by the linker and encrypting the target function within the executable code.