/* $OpenBSD: bn_mpi.c,v 1.6 2014/06/12 15:49:28 deraadt Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include
#include
#include "bn_lcl.h"
int
BN_bn2mpi(const BIGNUM *a, unsigned char *d)
{
int bits;
int num = 0;
int ext = 0;
long l;
bits = BN_num_bits(a);
num = (bits + 7) / 8;
if (bits > 0) {
ext = ((bits & 0x07) == 0);
}
if (d == NULL)
return (num + 4 + ext);
l = num + ext;
d[0] = (unsigned char)(l >> 24) & 0xff;
d[1] = (unsigned char)(l >> 16) & 0xff;
d[2] = (unsigned char)(l >> 8) & 0xff;
d[3] = (unsigned char)(l) & 0xff;
if (ext)
d[4] = 0;
num = BN_bn2bin(a, &(d[4 + ext]));
if (a->neg)
d[4] |= 0x80;
return (num + 4 + ext);
}
BIGNUM *
BN_mpi2bn(const unsigned char *d, int n, BIGNUM *a)
{
long len;
int neg = 0;
if (n < 4) {
BNerr(BN_F_BN_MPI2BN, BN_R_INVALID_LENGTH);
return (NULL);
}
len = ((long)d[0] << 24) | ((long)d[1] << 16) | ((int)d[2] << 8) |
(int)d[3];
if ((len + 4) != n) {
BNerr(BN_F_BN_MPI2BN, BN_R_ENCODING_ERROR);
return (NULL);
}
if (a == NULL)
a = BN_new();
if (a == NULL)
return (NULL);
if (len == 0) {
a->neg = 0;
a->top = 0;
return (a);
}
d += 4;
if ((*d) & 0x80)
neg = 1;
if (BN_bin2bn(d, (int)len, a) == NULL)
return (NULL);
a->neg = neg;
if (neg) {
BN_clear_bit(a, BN_num_bits(a) - 1);
}
bn_check_top(a);
return (a);
}