The security of Kyber's FO-transform

ePrint Report: The security of Kyber's FO-transform

Manuel Barbosa, Andreas Hülsing

In this short note we give another direct proof for the variant of the FO transform used by Kyber in the QROM. At PKC'23 Maram & Xagawa gave the first direct proof which does not require the indirection via FO with explicit rejection, thereby avoiding either a non-tight bound, or the necessity to analyze the failure probability in a new setting. However, on the downside their proof produces a …

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