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Algorithms for Inversion Mod pk

delete2020-06-01
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Çetin Kaya Koç *
DOI:10.1109/TC.2020.2970411delete
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Abstract

Abstract

En 中文
This article describes and analyzes all existing algorithms for computing x = a(-1) omod pk THORN for a prime p, and also introduces a new algorithm based on the exact solution of linear equations using p-adic expansions. The algorithm starts with the initial value c = a(-1) omod pTHORN and iteratively computes the digits of the inverse x = a(-1) omod pk THORN in base p. The mod 2 version of the algorithm is more efficient than all existing algorithms for small values of k. Moreover, it stands out as being the only one that works for any p, any k, and digit-by-digit. While the new algorithm is asymptotically worse off, it requires the minimal number of arithmetic operations (just a single addition) per step, as compared to all existing algorithms.
Keywords:
Number-theoretic algorithms
computer arithmetic
multiplicative inverse

Journal

IEEE Transactions on Computers cover
IEEE Transactions on Computers
IF:
3.8
Papers:
5.3K
Citations:
9.8K

Organization

I
Istinye University
Scholars:
1.1K
Papers: 1.3K
Citations: 1.9K