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hal.structure.identifierUniversité Cheikh Anta Diop de Dakar [Sénégal] [UCAD]
dc.contributor.authorMAIGA, Abdoulaye
hal.structure.identifierLithe and fast algorithmic number theory [LFANT]
hal.structure.identifierInstitut de Mathématiques de Bordeaux [IMB]
hal.structure.identifierAnalyse cryptographique et arithmétique [CANARI]
dc.contributor.authorROBERT, Damien
dc.date.accessioned2024-04-04T02:41:05Z
dc.date.available2024-04-04T02:41:05Z
dc.date.created2022-03-01
dc.date.issued2022-03-16
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/191120
dc.description.abstractEnLet $p$ be a prime; using modular polynomial $\Phi_p$, T.~Satoh and al\cite{satoh2000canonical,harley2002,vercau} developed several algorithmsto compute the canonical lift of an ordinary elliptic curve $E$ over$\F_{p^n}$ with $j$-invariant not in $\F_{p^2}$. When $p$ is constant, thebest variant has a complexity $\Otilde(n m)$ to lift $E$ to $p$-adicprecision~$m$. As an application, lifting $E$ to precision $m=O(n)$ allowsto recover its cardinality in time $\Otilde(n^2)$. However, taking $p$ intoaccount the complexity is $\Otilde(p^2 n m)$, so Satoh's algorithm can onlybe applied to small~$p$.We propose in this paper two variants of these algorithms, which do notrely on the modular polynomial, for computing the canonical lift of anordinary curve. Our new method yield a complexity of $\Otilde(p n m)$ tolift at precision~$m$, and even $\Otilde(\sqrt{p} nm)$ when we are provideda rational point of $p$-torsion on the curve. This allows to extend Saoth'spoint counting algorithm to larger~$p$.
dc.description.sponsorshipCryptographie, isogenies et variété abéliennes surpuissantes - ANR-19-CE48-0008
dc.language.isoen
dc.subject.enCanonical lift of Elliptic curves
dc.subject.enIsogeny computation
dc.subject.enPoint counting
dc.title.enTowards computing canonical lifts of ordinary elliptic curves in medium characteristic
dc.typeDocument de travail - Pré-publication
dc.subject.halMathématiques [math]/Théorie des nombres [math.NT]
dc.subject.halInformatique [cs]
bordeaux.hal.laboratoriesInstitut de Mathématiques de Bordeaux (IMB) - UMR 5251*
bordeaux.institutionUniversité de Bordeaux
bordeaux.institutionBordeaux INP
bordeaux.institutionCNRS
hal.identifierhal-03702658
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-03702658v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.date=2022-03-16&rft.au=MAIGA,%20Abdoulaye&ROBERT,%20Damien&rft.genre=preprint


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