KGC_TEST/miracl/source/mrrand.c

111 lines
3.9 KiB
C

/***************************************************************************
*
Copyright 2013 CertiVox UK Ltd. *
*
This file is part of CertiVox MIRACL Crypto SDK. *
*
The CertiVox MIRACL Crypto SDK provides developers with an *
extensive and efficient set of cryptographic functions. *
For further information about its features and functionalities please *
refer to http://www.certivox.com *
*
* The CertiVox MIRACL Crypto SDK is free software: you can *
redistribute it and/or modify it under the terms of the *
GNU Affero General Public License as published by the *
Free Software Foundation, either version 3 of the License, *
or (at your option) any later version. *
*
* The CertiVox MIRACL Crypto SDK is distributed in the hope *
that it will be useful, but WITHOUT ANY WARRANTY; without even the *
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. *
See the GNU Affero General Public License for more details. *
*
* You should have received a copy of the GNU Affero General Public *
License along with CertiVox MIRACL Crypto SDK. *
If not, see <http://www.gnu.org/licenses/>. *
*
You can be released from the requirements of the license by purchasing *
a commercial license. Buying such a license is mandatory as soon as you *
develop commercial activities involving the CertiVox MIRACL Crypto SDK *
without disclosing the source code of your own applications, or shipping *
the CertiVox MIRACL Crypto SDK with a closed source product. *
*
***************************************************************************/
/*
* MIRACL random number routines
* mrrand.c
*/
#include "miracl.h"
#ifdef MR_FP
#include <math.h>
#endif
#ifndef MR_NO_RAND
void bigrand(_MIPD_ big w,big x)
{ /* generate a big random number 0<=x<w */
int m;
mr_small r;
#ifdef MR_FP
mr_small dres;
#endif
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
MR_IN(20)
/* decr(_MIPP_ w,2,w); */
m=0;
zero(mr_mip->w0);
do
{ /* create big rand piece by piece */
m++;
mr_mip->w0->len=m;
r=brand(_MIPPO_ );
if (mr_mip->base==0) mr_mip->w0->w[m-1]=r;
else mr_mip->w0->w[m-1]=MR_REMAIN(r,mr_mip->base);
} while (mr_compare(mr_mip->w0,w)<0);
mr_lzero(mr_mip->w0);
divide(_MIPP_ mr_mip->w0,w,w);
copy(mr_mip->w0,x);
/* incr(_MIPP_ x,2,x);
if (w!=x) incr(_MIPP_ w,2,w); */
MR_OUT
}
void bigdig(_MIPD_ int n,int b,big x)
{ /* generate random number n digits long *
* to "printable" base b */
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
MR_IN(19)
if (b<2 || b>256)
{
mr_berror(_MIPP_ MR_ERR_BASE_TOO_BIG);
MR_OUT
return;
}
do
{ /* repeat if x too small */
expint(_MIPP_ b,n,mr_mip->w1);
bigrand(_MIPP_ mr_mip->w1,x);
subdiv(_MIPP_ mr_mip->w1,b,mr_mip->w1);
} while (!mr_mip->ERNUM && mr_compare(x,mr_mip->w1)<0);
MR_OUT
}
#endif