I have been playing lately with isogeny computation functions that Sage provides, but I noticed that they kind of get stuck (computations does not finish in reasonable time) when using _largish_ values, which doesn't seem to happen when using Magma's isogeny computation functions.
For example, this <https://ask.sagemath.org/question/41214/isogeny-computation-for-larger-numbers-doesnt-finish/> is one case where the computations doesn't seem to finish in a reasonable time, but a simple search reveals other cases too, such as this <https://ask.sagemath.org/question/40675/isogeny-computation-does-not-finish-in-sage/>, and this <https://ask.sagemath.org/question/41236/even-degree-large-isogeny-computation/> . With the introduction of SIDH, isogeny-based crypto has gained a lot of attention, and people have started to play around with these functions more, though, it can get a bit annoying when these functions don't give results in a reasonable time for large numbers, which Magma seems to be comfortable in handling. Do you have any idea why they don't give answers for _largish_ isogeny degrees? Also, is there a way to do chaining of low degree isogenies so they work in reasonable time? Shortly, how can one compute in Sage in a _reasonable_ time isogeny of degree $3^239$ and $2^372$ in this field and elliptic curve: p = 10354717741769305252977768237866805321427389645549071170116189679054678940682478846502882896561066713624553211618840202385203911976522554393044160468771151816976706840078913334358399730952774926980235086850991501872665651576831 Fp = GF(p) R.<x> = PolynomialRing(Fp) # The quadratic extension via x^2 + 1 since p = 3 mod 4 Fp2.<j> = Fp.extension(x^2 + 1) E = EllipticCurve(Fp2, [1,0]) The exact values can be found here <https://ask.sagemath.org/question/41236/even-degree-large-isogeny-computation/>. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
