On 11/12/2014 8:43 PM, Luigi Semenzato wrote: > > Forgive my curiosity,
Feel free to be curious. We're engineers! > but how would one use the PCR in this situation? > Just getting its value with TPM_PRCRead does not seem secure, because > the application would have to trust that the kernel is returning the actual > value stored in the TPM, and not making it up, which it might do > if it is compromised (by inserting code into the OS image). You are absolutely correct. A PCR read by itself is insufficient. Look at TPM_Quote, which provides an RSA digital signature over the PCR values. Of course, the next problem is trusting that the quote signing key is valid. Look at TPM_CertifyKey, which pushes the problem up one level, and TPM_ActivateIdentity, which proves that the quote signing key (or certifying key) was a TPM non-migratable key. It's rooted in the EK certificate, where the TPM manufacturer certifies that the part is an authentic TPM. Your out of band trust root is the TPM manufacturer's public key. ------------------------------------------------------------------------------ Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk _______________________________________________ TrouSerS-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/trousers-users
