Staged measured boot sequence of a computer

A method, comprising:

• decrypting a memory location of a memory to obtain an initial secret value using a secret device key that is derived from a first boot configuration register;
• receiving a signed measured value of a boot loader image;
• encrypting the initial secret value using the signed measured value;
• storing the initial secret value in a second boot configuration register and extending the second boot configuration register with a measurement of an operating system image;
• and
• using the second boot configuration register to decrypt an encryption key stored in the memory.

A system, comprising:

• a first boot configuration register within a secure module of the system;
• a second boot configuration register within the secure module of the system;
• one or more memories for storing a boot loader image and an operating system image;
• a boot Read Only Memory (ROM) for storing executable instructions for measuring the boot loader image to generate a first measured value and for extending the first boot configuration register using the first measured value;
• and
• a processor for executing the boot loader image for measuring the operating system image to generate a second measured value and for extending the second boot configuration register using the second measured value, wherein the processor is further configured to use the second boot configuration register to decrypt an encryption key stored in the one or more memories.

One or more computer-readable media, which are non-transitory, comprising computer-executable instructions that, when executed, cause a computing system to perform a method comprising:

• decrypting a memory location to obtain an initial secret value using a secret device key that is derived from a first boot configuration register;
• receiving a signed measured value of a boot loader image;
• encrypting the initial secret value using the signed measured value;
• storing the initial secret value in a second boot configuration register and extending the second boot configuration register with a measurement of an operating system image;
• and
• using the second boot configuration register to decrypt an encryption key stored in a memory.