Patent ID: 8522354

Claim:
An apparatus providing for a secure execution environment, comprising: a microprocessor, configured to execute non-secure application programs and a secure application program, wherein said secure application program comprises instructions from a host architecture instruction set, and wherein said microprocessor encrypts said secure application program using a processor unique key to store an encrypted version of said secure application program in a secure non-volatile memory that is coupled to said microprocessor via a private bus, and wherein said non-secure application programs are accessed from a system memory via a system bus and said secure application program is accessed from said secure non-volatile memory, said microprocessor comprising: a secure real time clock, configured to provide a persistent time, wherein said secure real time clock is only visible and accessible by said secure application program when said microprocessor is executing in a secure mode; and an external crystal, coupled to said secure real time clock within said microprocessor, configured to cause an oscillator within said secure real time clock to generate an oscillating output voltage that is proportional to the frequency of said external crystal.