An Integrity Protection Model for the Keys of Trusted Platform Module

The trusted computing group (TCG) has set down and issued trusted platform module (TPM) specification, and the security of the trusted computing system relies on the security of TPM. In this paper, the relationship between the keys inside TPM and TPM users has been established by analyzing the access control mechanism of TPM. The fact that a malignant user of a child key can break the integrity of the parent key has been found. Without changes of the physical TPM structure, a security model of protecting the integrity of the inner key of TPM has been set up. This model introduces BIBA in addition to the original access control mechanism of the inner keys of TPM. Both the integrity security constraint and the access control mechanism have been implemented to enhance the security of the trusted computing system.