Secure key handling using the TPM

So there are things you can do about this. A fully untrusted kernel is a hugely difficult problem but a trusted but vulnerable one (meaning it's your kernel but someone could gain access via an exploit) is much easier because the more interception channels you shut down the less likely the exploit is to gain access.

However, the point about the TPM is that even a fully untrusted kernel can't gain access to the key you place in the TPM if you do it correctly. The handheld market is working on this (where you can root the system but can't get access to their credentials) but there's a huge amount of work that goes into "... do it correctly".