Personal computer with encrypted programs

摘要

A personal computer includes a microprocessor (27) operating under control of a read only store (31) and code stored in random access memory (32). The microprocessor receives programs in encrypted form and from a program imbedded encryption key identifier or identifiers determines which encryption key or keys to fetch the read only store and subsequently uses the fetched key or keys to decode (decrypt the received encoded/encrypted program to load decoded/ decrypted code into the random access memory for subsequent execution). One or more keys can be reserved for use with unencrypted programs.