Method for encrypting a program for subsequent execution by a microprocessor configured to decrypt and execute the encrypted program

A method for encrypting a program for subsequent execution by a microprocessor configured to decrypt and execute the encrypted program, the method comprising:

• receiving an object file specifying an unencrypted program that includes conventional branch instructions whose target address may only be determined at the time in which the microprocessor runs the program;
• analyzing the program to obtain chunk information, wherein the chunk information divides the program into a sequence of chunks, wherein each of the chunks comprises a sequence of instructions, wherein the chunk information further comprises encryption key data associated with each of the chunks, wherein the encryption key data associated with each of the chunks is distinct;
• replacing each of the conventional branch instructions with a branch and switch key instruction;
• and
• encrypting the program based on the chunk information.

A computer program product encoded in at least one non-transitory computer usable medium for use with a computing device, the computer program product comprising:

• computer usable program code embodied in said medium, for specifying a method for encrypting a program for subsequent execution by a microprocessor configured to decrypt and execute the encrypted program, the computer usable program code comprising:
• first program code for receiving an object file specifying an unencrypted program that includes conventional branch instructions whose target address may be determined prior to the time in which the microprocessor runs the program;
• second program code for analyzing the program to obtain chunk information, wherein the chunk information divides the program into a sequence of chunks, wherein each of the chunks comprises a sequence of instructions, wherein the chunk information further comprises encryption key data associated with each of the chunks, wherein the encryption key data associated with each of the chunks is distinct;
• third program code for replacing each of the conventional branch instructions that specifies a target address that is within a different chunk than the chunk in which the conventional branch instruction resides with a branch and switch key instruction;
• and
• fourth program code for encrypting the program based on the chunk information.