[ << ] | [ < ] | [ Up ] | [ > ] | [ >> ] | [Top] | [Contents] | [Index] | [ ? ] |

### 15.4.2 Modular Powering

Modular powering is implemented using a *2^k*-ary sliding window
algorithm, as per “Handbook of Applied Cryptography” algorithm 14.85
(see section References). *k* is chosen according to the size of the
exponent. Larger exponents use larger values of *k*, the choice being
made to minimize the average number of multiplications that must supplement
the squaring.

The modular multiplies and squarings use either a simple division or the REDC method by Montgomery (see section References). REDC is a little faster, essentially saving N single limb divisions in a fashion similar to an exact remainder (see section Exact Remainder).

This document was generated on *March 31, 2014* using *texi2html 5.0*.