intel / intel/confidential-computing.sgx

Freshness on new SGX Processors?

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Last year Intel announced that their new 3rd gen Xeon Scalable Processor can support up to 1 TB of EPC. I always understood that the small EPC in SGX was due to the need for an on-chip Merkle tree that maintains freshness. This announcement by Intel was accompanied by an explanation saying that they have overcome this scaling issue by [removing the Merkle tree/MEE][1] and instead using AES-XTS. I have read a [few][2] [sources][3] [explaining][4] AES-XTS, but have not been able to confirm anywhere if it provides support for checking freshness. [Some sources ](https://heartever.github.io/files/scalable_sgx_public.pdf) even seem to imply that freshness is not guaranteed anymore, but this could be me reading into certain claims incorrectly. I was hoping to learn more from Intel/get an official source on this because I am having difficulty finding clear information on the subject. Thank you!

[1]: https://www.intel.com/content/www/us/en/support/articles/000059614/software/intel-security-products.html
[2]: https://en.wikipedia.org/wiki/Disk_encryption_theory
[3]: https://security.stackexchange.com/questions/101995/explanation-of-the-xts-encryption-mode
[4]: https://xilinx.github.io/Vitis_Libraries/security/2019.2/guide_L1/internals/xts.html

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