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