160 lines
4.7 KiB
C
160 lines
4.7 KiB
C
/* crypto/bn/bn_sqr.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include <stdio.h>
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#include <string.h>
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#include "bn_lcl.h"
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/* r must not be a */
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/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
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int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx)
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{
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int max,al;
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int ret = 0;
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BIGNUM *tmp,*rr;
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#ifdef BN_COUNT
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printf("BN_sqr %d * %d\n",a->top,a->top);
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#endif
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bn_check_top(a);
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al=a->top;
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if (al <= 0)
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{
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r->top=0;
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return(1);
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}
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BN_CTX_start(ctx);
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rr=(a != r) ? r : BN_CTX_get(ctx);
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tmp=BN_CTX_get(ctx);
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if (tmp == NULL) goto err;
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max=(al+al);
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if (bn_wexpand(rr,max+1) == NULL) goto err;
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r->neg=0;
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if (al == 4)
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{
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#ifndef BN_SQR_COMBA
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BN_ULONG t[8];
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bn_sqr_normal(rr->d,a->d,4,t);
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#else
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bn_sqr_comba4(rr->d,a->d);
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#endif
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}
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else if (al == 8)
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{
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#ifndef BN_SQR_COMBA
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BN_ULONG t[16];
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bn_sqr_normal(rr->d,a->d,8,t);
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#else
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bn_sqr_comba8(rr->d,a->d);
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#endif
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}
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else
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{
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if (bn_wexpand(tmp,max) == NULL) goto err;
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bn_sqr_normal(rr->d,a->d,al,tmp->d);
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}
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rr->top=max;
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if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
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if (rr != r) BN_copy(r,rr);
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ret = 1;
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err:
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BN_CTX_end(ctx);
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return(ret);
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}
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/* tmp must have 2*n words */
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void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
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{
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int i,j,max;
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BN_ULONG *ap,*rp;
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max=n*2;
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ap=a;
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rp=r;
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rp[0]=rp[max-1]=0;
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rp++;
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j=n;
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if (--j > 0)
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{
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ap++;
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rp[j]=bn_mul_words(rp,ap,j,ap[-1]);
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rp+=2;
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}
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for (i=n-2; i>0; i--)
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{
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j--;
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ap++;
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rp[j]=bn_mul_add_words(rp,ap,j,ap[-1]);
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rp+=2;
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}
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bn_add_words(r,r,r,max);
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/* There will not be a carry */
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bn_sqr_words(tmp,a,n);
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bn_add_words(r,r,tmp,max);
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}
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