Methods of securely changing the root key of a chip and related electronic devices and chips

摘要

Disclosed are methods and apparatus for changing a security key on a computer chip that has a CPU, a first OTPROM (OTPROM1) storing a root key of the chip or derivative thereof (RKPUB1), and a second OTPROM (OTPROM2) on which the chip manufacturer stores nothing. A ROM of the chip stores a first software program (SW1). A device manufacturer can take that chip and interface it to a mass memory of a memory block of an electronic device, then execute a second software program (SW2) that is stored on the mass memory only if SW2 is authenticated by SW1 using the RKPUB1. Then a new root key of the chip or derivative thereof (RKPUB2) is provided (via SW2 or a USB connection for example) which is stored to the OTPROM2 via a security service portion of SW1. Thereafter RKPUB2 can be used to authenticate SW2.