The way of effective use of incremental with multiple thinning of test values for Fermat's factoring method

Yevhen Maksymenko


Among the modern methods of cryptographic information protection asymmetric algorithms is most widely used. A special place among them is occupied by RSA (Rivest-Shamir-Adleman) encryption algorithm, which recommended the use a number of international standards and recommendations. RSA cryptographic resistance is based on the difficulty of the task execution of multi-digit numbers factorization and is not an effective problem of compromising its software and hardware implementations. Currently the “fastest” ways of decomposition the big numbers into factors are methods of the general number field sieve (GNFS), the quadratic sieve (QS) algorithm and the elliptic curve factorization method (ECM). It is known that the basis of these methods are based on a number of fundamental relations of Fermat’s classical algorithm, proceeding from which it can be argued that the improvement of Fermat’s method can have an impact on reducing the computational complexity of modern factorization methods listed above. One of the ways to increase the efficiency of the improved Fermat's factoring method is a modification of existing or developing new algorithms of execution the algebraic operations with large numbers. Among these can be the operation of the modular division in procedures for advance sieving of test values X. A modified method of thinning test values in Fermat’s factoring algorithm is proposed, the main advantage of which is the refusal to perform complex arithmetic operations of modular division of large sequences and replacing them with the procedure of the modular division of small numbers.


RSA algorithm; factorization; Fermat's algorithm; the sieve method; thinning of test values.


D. Brown, “Breaking RSA May Be As Difficult As Factoring”, Journal of Cryptology, vol. 29, iss. 1, pp. 220-241, January 2016. doi: 10.1007/s00145-014-9192-y.

O.N. Vasilenko. Number-theoretic algorithms in cryptography. Moskow, Russia: MTsNMO, 2003.

Sh.T. Ishmukhametov. Factoring methods of integers. Kazan, Republic of Tatarstan: Kazan Federal University, 2011.

A.V. Korneiko, and A.V. ZHilin, “Analysis of the known methods for computing the factorization of large numbers”, Modelling Problems in Power Engineering, iss. 61, pp. 3-13, 2011.

D. Knut. Art of Computer Programming. Vol. 2. Москва, Moskow, Russia: Мir, 1979.

“RSA. Security Solutions to Address Cyber Threats”. [Online]. Available: Accessed on: Jan. 19, 2016.

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