



01152nas a2200157   4500008004100000245007900041210006900120260001400189520065900203100001900862700001400881700001900895700002200914700002000936856003800956       2022                        eng d00aPost-Quantum Security of the (Tweakable) FX Construction, and Applications0 aPostQuantum Security of the Tweakable FX Construction and Applic  c8/29/20223 a<p>The FX construction provides a way to increase the effective key length of a block cipher E. We prove security of a tweakable version of the FX construction in the post-quantum setting, i.e., against a quantum attacker given only classical access to the secretly keyed construction while retaining quantum access to E, a setting that seems to be the most relevant one for real-world applications. We then use our results to prove post-quantum security&mdash;in the same model&mdash;of the (plain) FX construction, Elephant (a finalist of NIST&#39;s lightweight cryptography standardization effort), and Chaskey (an ISO-standardized lightweight MAC</p>1 aAlagic, Gorjan1 aBai, Chen1 aKatz, Jonathan1 aMajenz, Christian1 aStruck, Patrick  uhttps://eprint.iacr.org/2022/1097