Secure computing device having boot read only memory verification of program code

The technical field of this invention is secure computing systems, especially computer systems that may execute after manufacture field provided programs secured to prevent the user from unauthorized use of selected computer services. The computer system may also be functionally reprogrammable in a secure manner. A secure computing system stores a program, preferably the real time operating system, that is encrypted with a private key. A boot ROM on the same integrated circuit as the data processor and inaccessible from outside includes an initialization program and a public key corresponding to the private key. On initialization the boot ROM decrypts at least a verification portion of the program. This enables verification or non-verification of the security of the program. The boot ROM may store additional public keys for verification of application programs following verification of the real time operating system. Alternatively, these additional public keys may be stored in the nonvolatile memory. On verification of the security of the program, normal operation is enabled. On non-verification, system could be disabled, or that application program could be disabled. The system could notify the system vendor of the security violation using the modem of the secure computing system. This technique is applicable to downloaded programs could be applied to after sale acquired application programs. On downloading the after acquired program they decrypted using an additional public key.