International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: CacheQuote: Efficiently Recovering Long-term Secrets of SGX EPID via Cache Attacks

Fergus Dall , University of Adelaide
Gabrielle De Micheli , University of Pennsylvania
Thomas Eisenbarth , University of Lübeck; Worcester Polytechnic Institute
Daniel Genkin , University of Pennsylvania; University of Maryland
Nadia Heninger , University of Pennsylvania
Ahmad Moghimi , Worcester Polytechnic Institute
Yuval Yarom , University of Adelaide; Data61
DOI: 10.13154/tches.v2018.i2.171-191
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Abstract: Intel Software Guard Extensions (SGX) allows users to perform secure computation on platforms that run untrusted software. To validate that the computation is correctly initialized and that it executes on trusted hardware, SGX supports attestation providers that can vouch for the user’s computation. Communication with these attestation providers is based on the Extended Privacy ID (EPID) protocol, which not only validates the computation but is also designed to maintain the user’s privacy. In particular, EPID is designed to ensure that the attestation provider is unable to identify the host on which the computation executes. In this work we investigate the security of the Intel implementation of the EPID protocol. We identify an implementation weakness that leaks information via a cache side channel. We show that a malicious attestation provider can use the leaked information to break the unlinkability guarantees of EPID. We analyze the leaked information using a lattice-based approach for solving the hidden number problem, which we adapt to the zero-knowledge proof in the EPID scheme, extending prior attacks on signature schemes.
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  title={CacheQuote: Efficiently Recovering Long-term Secrets of SGX EPID via Cache Attacks},
  journal={Transactions on Cryptographic Hardware and Embedded Systems},
  publisher={Ruhr-Universität Bochum},
  volume={2018, Issue 2},
  author={Fergus Dall and Gabrielle De Micheli and Thomas Eisenbarth and Daniel Genkin and Nadia Heninger and Ahmad Moghimi and Yuval Yarom},