The Trusted Platform Module offers facilities for the secure generation of cryptographic keys, and limitation of their use, in addition to a hardware pseudo-random number generator. It also includes capabilities such as remote attestation and sealed storage. “Remote attestation” creates a nearly unforgeable hash key summary of the hardware and software configuration. The extent of the summary of the software is decided by the program encrypting the data. This allows a third party to verify that the software has not been changed. “Sealing” encrypts data in such a way that it may be decrypted only if the TPM releases the associated decryption key, which it only does for software that can provide the same password that was supplied when software “ownership” of the TPM was initially configured”Binding” encrypts data using the TPM endorsement key, a unique RSA key burned into the chip during its production, or another trusted key descended from it.
A Trusted Platform Module can be used 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. For example, it can be used to verify that a system seeking access is the expected system.
Generally, pushing the security down to the hardware level in conjunction with software provides more protection than a software-only solution that is more easily compromised by an attacker. 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.
