Fix: Potential side-channel in Kyber's Ciphertext::compress functions#3874
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FAlbertDev merged 1 commit intorandombit:masterfrom Feb 16, 2024
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reneme
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Jan 4, 2024
Replace the divisions by KyberConstants::Q with a divisionless alternative.
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This was referenced Feb 16, 2024
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This is a follow-up to #3846 and relates to the KyberSlash side channel. It also fixes the
Ciphertext::compressmethod's potential division side channel.To remove the critical division operation, we enforce the optimization most compilers perform to replace the division by multiplication and various shifts (see godbolt).