Computing isogenies between Montgomery curves using the action of (0, 0)
Computing isogenies between Montgomery curves using the action of (0, 0)
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使用 (0, 0) 的作用计算蒙哥马利曲线之间的同源性
DOI:
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发表时间:
2018
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通讯作者:
Joost Renes
中科院分区:
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作者:
Joost Renes
A recent paper by Costello and Hisil at Asiacrypt’17 presents efficient formulas for computing isogenies with odd-degree cyclic kernels on Montgomery curves. We provide a constructive proof of a generalization of this theorem which shows the connection between the shape of the isogeny and the simple action of the point ((0,0)). This generalization removes the restriction of a cyclic kernel and allows for any separable isogeny whose kernel does not contain ((0,0)). As a particular case, we provide efficient formulas for 2-isogenies between Montgomery curves and show that these formulas can be used in isogeny-based cryptosystems without expensive square root computations and without knowledge of a special point of order 8. We also consider elliptic curves in triangular form containing an explicit point of order 3.