Trusted Computing

Trusted computing (TC) is a set of design techniques and operation principles to create a computing environment that the user can trust to behave as expected. This is important in general and vital for security applications. Among the various proposals to create a TC environment, the Trusted Computing Group (TCG) architecture is of specific interest nowadays because its hardware foundation – the trusted platformmodule (TPM)– is readily available in commodity computers and it provides several interesting features: attestation, sealing, and trusted signature. Attestation refers to integrity measures computed at boot time that can later be used to prove system integrity to a third party across a network. Sealing protects some data (typically application level cryptographic keys or configurations) in hardware so that it can be accessed only when the system is in a specific state (i.e., a specific set of software modules is running, from drivers up to applications). Trusted signature is performed directly by the hardware and is permitted only when the system is in a specific state. TC does not provide perfect protection for all possible attacks: it has been designed to counter software attacks and some hardware ones. Nonetheless it is an interesting tool to build secure systems, with special emphasis on the integrity of the operations.