fTPM: A Software-Only Implementation of a TPM Chip
summary
A firmware TPM 2.0 runs inside ARM TrustZone and ships on millions of devices, replacing a discrete TPM by combining eMMC RPMB storage and secure fuses to provide counters, authenticated storage and entropy; long TPM commands use cooperative checkpointing to avoid freezing the OS, and anti‑hammering survives boot dirty‑bit semantic changes to handle dark periods. Implementation is faster than discrete TPM chips for RSA‑2048 ops and is deployed in multiple Microsoft Surface and phone products.
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chapters (8)
- 0:00fTPM introduction
- 3:02fTPM contributions
- 4:04TPM and TrustZone background
- 11:28fTPM architecture
- 15:18TrustZone limitations in fTPM
- 19:09Design compromises
- 24:44fTPM vs discrete TPM
- 26:31Conclusion
