Part 2: Trust Mechanisms in a Trusted Platform

In this part, we document the set of mechanisms identified by the TCPA specification to turn an ordinary platform into a TP. We hope to provide a companion to the TCPA specification that will help you understand the specification's design. This part can be read independently from the rest of the book. To accomplish this goal, we must explain how the TCPA specification Trusted Platform Module (TPM) and Trusted platform Support Services (TSS) commands are used together to provide individual trust mechanisms. Each chapter in this part covers a category of TCPA mechanisms:

• Chapter 4 discusses access control—ownership, enabling, and authorization

• Chapter 5 deals with platform identification and certification

• Chapter 6 explains integrity and the boot process

• Chapter 7 covers protected data storage

• Chapter 8 discusses migration and maintenance mechanisms

• Chapter 9 describes the conventional cryptographic support provided by the TPM for the host platform, plus the features provided by the TPM to support hosting by the platform

The description of each chapter will mainly focus on TPM commands used for each type of trust mechanism, describing necessary TSS commands only when needed to explain the corresponding TPM commands.

Part 1 of this book describes general notions of TP mechanisms, but Part 2 is much more precise. For that purpose, we define here a vocabulary to be used throughout the rest of the book when referring to data or cryptographic keys handled by a TPM:

• TPM object: This term defines both cryptographic keys and data that will be handled by a TPM. They can be referred to as either TPM key objects or TPM data objects.

• TPM Protected Objects: This term refers to a TPM object whose secret information has been encrypted under the public portion of a TPM key object. We will differentiate between TPM protected data objects and TPM protected key objects.

• Parent TPM Object: This term identifies a particular role in a relationship between two TPM objects. It refers to a TPM key object whose public portion has been used to encrypt the secret information of another TPM object. A parent TPM object is always a TPM key object.

• Child TPM Object: This term identifies a particular role in a relationship between two TPM objects. It refers to a TPM protected object whose secret information has been encrypted under the public portion of a TPM key object.

Chapter 7 discusses these notions in greater detail and describes the TCPA Protected Storage mechanisms.