Merge "Updated the description on Root of Trust Binding."

 * derive a key that is used to encrypt the private/secret key material.

 *

 * The root of trust consists of a bitstring that must be derived from the public key used by

 * Verified Boot to verify the signature on the boot image and from the lock state of the

 * device.  If the public key is changed to allow a different system image to be used or if the

 * lock state is changed, then all of the IKeyMintDevice-protected keys created by the previous

 * system state must be unusable, unless the previous state is restored.  The goal is to increase

 * the value of the software-enforced key access controls by making it impossible for an attacker-

 * installed operating system to use IKeyMintDevice keys.

 * Verified Boot to verify the signature on the boot image, from the lock state and from the

 * Verified Boot state of the device.  If the public key is changed to allow a different system

 * image to be used or if the lock state is changed, then all of the IKeyMintDevice-protected keys

 * created by the previous system state must be unusable, unless the previous state is restored.

 * The goal is to increase the value of the software-enforced key access controls by making it

 * impossible for an attacker-installed operating system to use IKeyMintDevice keys.

 *

 * == Version Binding ==

 *