Abstract

. There is a well known shortcut for modular multiplication modulo a Mersenne number, performing modular reduction without integer division. We generalize this technique to a larger class of primes, and discuss parameter choices which are particularly well suited for machine implementation. Keywords: modular arithmetic, elliptic curves. Introduction It has long been known that certain integers are particularly well suited for modular reduction. The best known examples (e.g., [1]) are the Mersenne numbers m = 2 k \Gamma 1. In this case, the integers (mod m) are represented as k-bit integers. When performing modular multiplication, one carries out an integer multiplication followed by a modular reduction. One thus has the problem of reducing modulo m a 2k-bit number. Modular reduction is usually done by integer division, but this is unnecessary in the Mersenne case. Let n ! m 2 be the integer to be reduced (mod m). Let T be the integer represented by the k most significant bits o...

Citations

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