An apparatus providing for a secure execution environment, including a secure non-volatile memory and a microprocessor. The secure non-volatile memory stores a secure application program. The secure application program is encrypted according to a cryptographic algorithm. The microprocessor is coupled to the secure non-volatile memory via a private bus and to a system memory via a system bus. The microprocessor executes non-secure application programs and the secure application program. The non-secure application programs are accessed from the system memory via the system bus. Transactions over the private bus are isolated from the system bus and corresponding system bus resources within the microprocessor. The microprocessor has a cryptographic unit, disposed within execution logic. The cryptographic unit is configured to encrypt the secure application program for storage in the secure non-volatile memory, and is configured to decrypt the secure application program for execution by the microprocessor.