the TPM contents are unreadable, even to a skilled attacker Depends how "skilled". Nation-state level? Most definitely not. "IC break" services in China? Maybe

the TPM contents are unreadable, even to a skilled attacker Depends how "skilled". Nation-state level? Most definitely not. "IC break" services in China? Maybe. AFAIK TPMs are based on similar secure-processor designs as the chips in payment cards and other smartcards, and even those with enough determination and $$$, or the right equipment, will get you through. Here's an old but quite thorough discussion of the techniques involved: https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-630.pdf https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-630.pdf