Constructing Cycles in Isogeny Graphs of Supersingular Elliptic Curves

Autor: Xiao Guanju, Luo Lixia, Deng Yingpu
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Mathematical Cryptology, Vol 15, Iss 1, Pp 454-464 (2021)
Druh dokumentu: article
ISSN: 1862-2976
1862-2984
DOI: 10.1515/jmc-2020-0029
Popis: Loops and cycles play an important role in computing endomorphism rings of supersingular elliptic curves and related cryptosystems. For a supersingular elliptic curve E defined over 𝔽p2, if an imaginary quadratic order O can be embedded in End(E) and a prime L splits into two principal ideals in O, we construct loops or cycles in the supersingular L-isogeny graph at the vertices which are next to j(E) in the supersingular ℓ-isogeny graph where ℓ is a prime different from L. Next, we discuss the lengths of these cycles especially for j(E) = 1728 and 0. Finally, we also determine an upper bound on primes p for which there are unexpected 2-cycles if ℓ doesn’t split in O.
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