A secure system for executing program code in an insecure environment while making it impossible, or at least impractical, to determine how to copy the program code and associated data is provided. A program memory contains encrypted program data and security circuitry contained within an integrated circuit is provided for decrypting the program data as it is needed by a processor. A portion of the processing steps which would be done by the processor in an insecure system is performed in this secure system within the secure circuitry using portions of the decrypted program data which are not provided to the processor. Program data is parsed it out based on a proper request to the security chip from the processor. A key value stored in volatile memory is used in the decrypting process and the volatile memory is positioned on the integrated circuit such that its contents are lost before a chip peel provides access to the volatile memory.