Abstract: A system includes an associated tamperproof circuit that contains a cryptography unit and one or more keys. The system receives software having one or more portions of code that have been digitally signed prior to receipt of the code by the system. The cryptography unit and one of the keys contained in the tamperproof circuit are used to decrypt a signature file for a portion of the code. The validity of the portion of code is determined by using the decrypted signature file, and if the portion of code is invalid, operation of the system is prevented. One or more portions of the code received by the system, such as a communications protocol, may also be encrypted prior to receipt of the code by the system. The system obtains a key from a remote server via a secure communications channel and uses the key and the cryptography unit contained in the tamperproof circuit to decrypt the communications protocol.

Abstract: A system includes an associated tamperproof circuit that contains a cryptography unit and one or more keys. The system receives software having one or more portions of code that have been digitally signed prior to receipt of the code by the system. The cryptography unit and one of the keys contained in the tamperproof circuit are used to decrypt a signature file for a portion of the code. The validity of the portion of code is determined by using the decrypted signature file, and if the portion of code is invalid, operation of the system is prevented. One or more portions of the code received by the system, such as a communications protocol, may also be encrypted prior to receipt of the code by the system. The system obtains a key from a remote server via a secure communications channel and uses the key and the cryptography unit contained in the tamperproof circuit to decrypt the communications protocol.