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56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
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#include <tommath.h>
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#ifdef BN_MP_RAND_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library was designed directly after the MPI library by
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* Michael Fromberger but has been written from scratch with
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* additional optimizations in place.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
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*/
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/* makes a pseudo-random int of a given size */
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int
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mp_rand (mp_int * a, int digits)
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{
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int res;
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mp_digit d;
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mp_zero (a);
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if (digits <= 0) {
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return MP_OKAY;
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}
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/* first place a random non-zero digit */
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do {
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d = ((mp_digit) abs (rand ())) & MP_MASK;
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} while (d == 0);
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if ((res = mp_add_d (a, d, a)) != MP_OKAY) {
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return res;
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}
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while (--digits > 0) {
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if ((res = mp_lshd (a, 1)) != MP_OKAY) {
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return res;
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}
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if ((res = mp_add_d (a, ((mp_digit) abs (rand ())), a)) != MP_OKAY) {
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return res;
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}
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}
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return MP_OKAY;
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}
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#endif
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/* $Source: /cvs/libtom/libtommath/bn_mp_rand.c,v $ */
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/* $Revision: 1.3 $ */
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/* $Date: 2006/03/31 14:18:44 $ */
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