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V. Gunupudi and S. R. Tate.
"Timing-Accurate TPM Simulation for What-If Explorations in Trusted Computing," in the
Proceedings of the 2010 International Symposium on Performance Evaluation of Computer and Telecommunication Systems,
2010, pp. 171-178.
The addition of security-oriented hardware devices
such as Trusted Platform Modules (TPMs) to computing systems,
as promoted by the Trusted Computing Group, leads to many
interesting possibilities. Many interesting research questions are
of the form “What if the TPM could do x?”, but since the
functionality of these chips is necessarily fixed it is difficult to
explore these questions experimentally and evaluate the performance
of proposed solutions. In this paper, we develop a timing
model for TPMs which we can instantiate based on experiments
with existing TPMs. We perform experiments that validate this
model, building “performance profiles” for TPMs from different
manufacturers. Our validation process shows that our timing
model is very accurate (errors less than 20ms and typically less
than 1%) for all but one of the TPMs tested. While the accuracy
for the remaining TPM is less than ideal, approaching 25% error,
we were able to hand-tune this model so that errors in estimated
time were reduced to less than 16%.
In this paper we also describe our work incorporating these
performance profiles into an existing software-based TPM simulator.
This modified simulator then allows us to add new
functionality with performance that accurately reflects the time
such functionality would require if implemented in actual devices.
As an example application of this, we describe results of our
experiments with implementing random oracles on TPMs, using
enhanced functionality not available on existing TPMs.