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发表于 2023-8-16 13:19:28
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| 本帖最后由 nyy 于 2023-8-16 13:21 编辑 
 https://members.loria.fr/PZimmermann/papers/ecm-entry.pdf
 
 THE ELLIPTIC CURVE METHOD
 PAUL ZIMMERMANN
 The Elliptic Curve Method (ECM for short) was invented in 1985 by H. W. Lenstra,
 Jr. [5]. It is suited to find small — say 9 to 30 digits — prime factors of large numbers.
 Among the different factorization algorithms whose complexity mainly depends on the size
 of the factor searched for (trial division, Pollard rho, Pollard p − 1, Williams p + 1), it is
 asymptotically the best method known. ECM can be viewed as a generalization of Pollard’s
 p − 1 method, just like ECPP generalizes the n − 1 primality test. ECM relies on Hasse’s
 theorem: if p is prime, then an elliptic curve over Z/pZ has group order p + 1 − t with
 |t| ≤ 2
 √p, where t depends on the curve. If p + 1 − t is a smooth number, then ECM will
 — most probably — succeed and reveal the unknown factor p.
 Since 1985, many improvements have been proposed to ECM. Lenstra’s original algorithm
 had no second phase. Brent proposes in [2] a “birthday paradox” second phase, and further
 more technical refinements. In [7], Montgomery presents different variants of phase two of
 ECM and Pollard p − 1, and introduces a parameterization with homogeneous coordinates,
 which avoids inversions modulo n, with only 6 and 5 modular multiplications per addition
 and duplication on E, respectively. It is also possible to choose elliptic curves with a group
 order divisible by 12 or 16 [7, 8, 1].
 Phase one of ECM works as follow
 
 这儿有介绍
 
 
 来自链接
 http://www.fermatsearch.org/links.html
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