131 lines
4.3 KiB
C
131 lines
4.3 KiB
C
/* crypto/bn/bn_mpi.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 "cryptlib.h"
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#include "bn_lcl.h"
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int BN_bn2mpi(const BIGNUM *a, unsigned char *d)
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{
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int bits;
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int num=0;
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int ext=0;
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long l;
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bits=BN_num_bits(a);
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num=(bits+7)/8;
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if (bits > 0)
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{
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ext=((bits & 0x07) == 0);
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}
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if (d == NULL)
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return(num+4+ext);
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l=num+ext;
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d[0]=(unsigned char)(l>>24)&0xff;
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d[1]=(unsigned char)(l>>16)&0xff;
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d[2]=(unsigned char)(l>> 8)&0xff;
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d[3]=(unsigned char)(l )&0xff;
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if (ext) d[4]=0;
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num=BN_bn2bin(a,&(d[4+ext]));
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if (a->neg)
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d[4]|=0x80;
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return(num+4+ext);
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}
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BIGNUM *BN_mpi2bn(const unsigned char *d, int n, BIGNUM *a)
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{
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long len;
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int neg=0;
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if (n < 4)
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{
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BNerr(BN_F_BN_MPI2BN,BN_R_INVALID_LENGTH);
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return(NULL);
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}
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len=((long)d[0]<<24)|((long)d[1]<<16)|((int)d[2]<<8)|(int)d[3];
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if ((len+4) != n)
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{
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BNerr(BN_F_BN_MPI2BN,BN_R_ENCODING_ERROR);
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return(NULL);
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}
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if (a == NULL) a=BN_new();
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if (a == NULL) return(NULL);
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if (len == 0)
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{
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a->neg=0;
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a->top=0;
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return(a);
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}
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d+=4;
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if ((*d) & 0x80)
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neg=1;
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if (BN_bin2bn(d,(int)len,a) == NULL)
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return(NULL);
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a->neg=neg;
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if (neg)
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{
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BN_clear_bit(a,BN_num_bits(a)-1);
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}
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bn_check_top(a);
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return(a);
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}
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