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hal.structure.identifierDGA CELAR
hal.structure.identifierInstitut de Recherche Mathématique de Rennes [IRMAR]
dc.contributor.authorLUBICZ, David
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.accessioned2024-04-04T02:40:50Z
dc.date.available2024-04-04T02:40:50Z
dc.date.issued2023
dc.date.conference2022-08-08
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/191095
dc.description.abstractEnLet (A, L , Θn) be a dimension g abelian variety together with a level n theta structure over a field k of odd characteristic, we denote by (θ Θ L i) (Z/nZ) g ∈ Γ(A, L) the associated standard basis. For ℓ a positive integer relatively prime to n and the characteristic of k, we study change of level algorithms which allow to compute level ℓn theta functions (θ Θ L ℓ i (x)) i∈(Z/ℓnZ) g from the knowledge of level n theta functions (θ Θ L i (x)) (Z/nZ) g or conversely. The classical duplication formulas is an example of change of level algorithm to go from level n to level 2n. The main result of this paper states that there exists an algorithm to go from level n to level ℓn in O(n g ℓ 2g log(ℓ)) operations in k. We deduce an algorithm to compute an isogeny f : A → B from the knowledge of (A, L , Θn) and K ⊂ A[ℓ] isotropic for the Weil pairing which computes f (x) for x ∈ A(k) in O((nℓ) g log(ℓ)) operations in k. We remark that this isogeny computation algorithm is of quasi-linear complexity in the size of K.
dc.description.sponsorshipCryptographie, isogenies et variété abéliennes surpuissantes - ANR-19-CE48-0008
dc.description.sponsorshipCentre de Mathématiques Henri Lebesgue : fondements, interactions, applications et Formation - ANR-11-LABX-0020
dc.language.isoen
dc.rights.urihttp://creativecommons.org/licenses/by/
dc.source.titleResearch in Number Theory
dc.subject.enIsogenies
dc.subject.enabelian varieties
dc.subject.encomputational algebraic geometry
dc.title.enFast change of level and applications to isogenies
dc.typeCommunication dans un congrès
dc.identifier.doi10.1007/s40993-022-00407-9
dc.subject.halInformatique [cs]/Calcul formel [cs.SC]
dc.subject.halMathématiques [math]/Théorie des nombres [math.NT]
bordeaux.pagearticle n°7
bordeaux.volume9
bordeaux.hal.laboratoriesInstitut de Mathématiques de Bordeaux (IMB) - UMR 5251*
bordeaux.issue1
bordeaux.institutionUniversité de Bordeaux
bordeaux.institutionBordeaux INP
bordeaux.institutionCNRS
bordeaux.conference.titleANTS 2022 - Fifteenth Algorithmic Number Theory Symposium
bordeaux.countryGB
bordeaux.title.proceedingResearch in Number Theory
bordeaux.conference.cityBristol
bordeaux.peerReviewedoui
hal.identifierhal-03738315
hal.version1
hal.invitednon
hal.proceedingsoui
hal.conference.end2022-08-12
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-03738315v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.btitle=Research%20in%20Number%20Theory&rft.date=2023&rft.volume=9&rft.issue=1&rft.spage=article%20n%C2%B07&rft.epage=article%20n%C2%B07&rft.au=LUBICZ,%20David&ROBERT,%20Damien&rft.genre=unknown


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