Associating a Signing key with a Software Component of a Computing Platform

A method of operatively associating a signing key with a predetermined software component of a computing platform;

• the computing platform including a trusted device and being arranged on start-up to first load a set of software components with each component being measured prior to loading and a corresponding integrity metric recorded in registers of the trusted device, said predetermined component being the last to be loaded component of said set;
• the method comprising:
• generating a signing key;
• storing a key-related item in secure persistent storage, the key-related item being one of said signing key and authorisation data for its use;
• and
• using the trusted device to enable the predetermined component to obtain the key-related item, this enabling occurring only during a particular period of platform start-up when the current register values correspond to values present immediately following recording of the integrity metric of the predetermined component;
• and
• changing the register values after the predetermined component has obtained the key-related item and prior to the loading of any further software component.

A system comprising a computing platform including a trusted device with registers for storing integrity metrics, the computer platform being arranged on start-up to first load a set of software components with each component being measured prior to loading and a corresponding integrity metric recorded in the trusted-device registers;

• the system including:
• a key generator for generating a signing key,
• a certificate authority for generating certificate evidence, comprising at least one certificate signed by the certificate authority, indicative that the signing key is operatively associated with a component of said set;
• and
• secure persistent storage for storing a key-related item, the key-related item being one of said signing key and authorisation data for its use;
• the trusted device being arranged to enable a component of said set, herein the “key-associated component”, to obtain the key-related item, this enabling occurring only during a particular period of platform start-up when the current register values correspond to values only present prior to loading of software components additional to those of said set.