Software can use a Trusted Platform Module to authenticate hardware devices. Since each TPM chip has a unique and secret RSA key burned in as it is produced, it is capable of performing platform authentication.

Generally, pushing the security down to the hardware level in conjunction with software provides more protection than a software-only solution. However even where a TPM is used, a key is still vulnerable while a software application that has obtained it from the TPM is using it to perform encryption/decryption operations, as has been illustrated in the case of a cold boot attack.

via Trusted Platform Module – Wikipedia, the free encyclopedia.

“Trusted Platform Module (TPM) Specifications”. Trusted Computing Group.