Efficient removal of divisors in the k-ary algorithm

The k-ary algorithm is one of the most efficient methods for finding the greatest common divisor (GCD). To find GCD of u and v, we performed the k-ary reduction t = |au + bv|/k, where 0 < a, |b| ≤ [√ k]: au + bv = 0(mod k). The reduction step is used when and have almost the same size. Otherwis...

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Main Author: R.R. Enikeev
Format: Article
Language:English
Published: Kazan Federal University 2019-09-01
Series:Учёные записки Казанского университета. Серия Физико-математические науки
Subjects:
Online Access:https://kpfu.ru/uz-eng-phm-2019-3-6.html
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author R.R. Enikeev
author_facet R.R. Enikeev
author_sort R.R. Enikeev
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description The k-ary algorithm is one of the most efficient methods for finding the greatest common divisor (GCD). To find GCD of u and v, we performed the k-ary reduction t = |au + bv|/k, where 0 < a, |b| ≤ [√ k]: au + bv = 0(mod k). The reduction step is used when and have almost the same size. Otherwise, we appled the dmod operation |u – cv|/2L, where c = uv–1mod 2L, L = L(u) – L(v), L(a) is a function returning the binary length of a. We considered that k-ary algorithm works with multi-precision integers and k = 22W, where W is the word size. We accelerated this method by minimizing the number of divisors removal operations. We combined this procedure with a division operation by 2iW and described its fast implementation. We proposed a new way to compute coefficients that allows to get rid of divisors removal before the reduction step and to produce that operation before dmod operation in 1/3 of the cases. The proposed method accelerates the main loop of the k-ary algorithm by 3–16%. The results obtained are important in many algorithms in cryptography.
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spelling doaj.art-46a44dd5dd0d43e0b882e8006f6549082023-01-03T03:14:41ZengKazan Federal UniversityУчёные записки Казанского университета. Серия Физико-математические науки2541-77462500-21982019-09-01161339340410.26907/2541-7746.2019.3.393-404Efficient removal of divisors in the k-ary algorithmR.R. Enikeev0Kazan Federal University, Kazan, 420008 RussiaThe k-ary algorithm is one of the most efficient methods for finding the greatest common divisor (GCD). To find GCD of u and v, we performed the k-ary reduction t = |au + bv|/k, where 0 < a, |b| ≤ [√ k]: au + bv = 0(mod k). The reduction step is used when and have almost the same size. Otherwise, we appled the dmod operation |u – cv|/2L, where c = uv–1mod 2L, L = L(u) – L(v), L(a) is a function returning the binary length of a. We considered that k-ary algorithm works with multi-precision integers and k = 22W, where W is the word size. We accelerated this method by minimizing the number of divisors removal operations. We combined this procedure with a division operation by 2iW and described its fast implementation. We proposed a new way to compute coefficients that allows to get rid of divisors removal before the reduction step and to produce that operation before dmod operation in 1/3 of the cases. The proposed method accelerates the main loop of the k-ary algorithm by 3–16%. The results obtained are important in many algorithms in cryptography.https://kpfu.ru/uz-eng-phm-2019-3-6.htmlgreatest common divisork-ary algorithmfactors removalmulti-precision integers
spellingShingle R.R. Enikeev
Efficient removal of divisors in the k-ary algorithm
Учёные записки Казанского университета. Серия Физико-математические науки
greatest common divisor
k-ary algorithm
factors removal
multi-precision integers
title Efficient removal of divisors in the k-ary algorithm
title_full Efficient removal of divisors in the k-ary algorithm
title_fullStr Efficient removal of divisors in the k-ary algorithm
title_full_unstemmed Efficient removal of divisors in the k-ary algorithm
title_short Efficient removal of divisors in the k-ary algorithm
title_sort efficient removal of divisors in the k ary algorithm
topic greatest common divisor
k-ary algorithm
factors removal
multi-precision integers
url https://kpfu.ru/uz-eng-phm-2019-3-6.html
work_keys_str_mv AT rrenikeev efficientremovalofdivisorsinthekaryalgorithm