/* rsa_x931.c */

/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL

 * project 2005.

 */

/* ====================================================================

 * Copyright (c) 2005 The OpenSSL Project.  All rights reserved.

 *

 * 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 above 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 acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    licensing@OpenSSL.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED 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 OpenSSL PROJECT OR

 * ITS 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.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com).

 *

 */

#include <stdio.h>

#include "cryptlib.h"

#include <openssl/bn.h>

#include <openssl/rsa.h>

#include <openssl/rand.h>

#include <openssl/objects.h>

EXPORT_C int RSA_padding_add_X931(unsigned char *to, int tlen,

	     const unsigned char *from, int flen)

	{

	int j;

	unsigned char *p;

	/* Absolute minimum amount of padding is 1 header nibble, 1 padding

	 * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.

	 */

	j = tlen - flen - 2;

	if (j < 0)

		{

		RSAerr(RSA_F_RSA_PADDING_ADD_X931,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);

		return -1;

		}

	p=(unsigned char *)to;

	/* If no padding start and end nibbles are in one byte */

	if (j == 0)

		*p++ = 0x6A;

	else

		{

		*p++ = 0x6B;

		if (j > 1)

			{

			memset(p, 0xBB, j - 1);

			p += j - 1;

			}

		*p++ = 0xBA;

		}

	memcpy(p,from,(unsigned int)flen);

	p += flen;

	*p = 0xCC;

	return(1);

	}

EXPORT_C int RSA_padding_check_X931(unsigned char *to, int tlen,

	     const unsigned char *from, int flen, int num)

	{

	int i = 0,j;

	const unsigned char *p;

	p=from;

	if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B)))

		{

		RSAerr(RSA_F_RSA_PADDING_CHECK_X931,RSA_R_INVALID_HEADER);

		return -1;

		}

	if (*p++ == 0x6B)

		{

		j=flen-3;

		for (i = 0; i < j; i++)

			{

			unsigned char c = *p++;

			if (c == 0xBA)

				break;

			if (c != 0xBB)

				{

				RSAerr(RSA_F_RSA_PADDING_CHECK_X931,

					RSA_R_INVALID_PADDING);

				return -1;

				}

			}

		j -= i;

		if (i == 0)

			{

			RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);

			return -1;

			}

		}

	else j = flen - 2;

	if (p[j] != 0xCC)

		{

		RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_TRAILER);

		return -1;

		}

	memcpy(to,p,(unsigned int)j);

	return(j);

	}

/* Translate between X931 hash ids and NIDs */

EXPORT_C int RSA_X931_hash_id(int nid)

	{

	switch (nid)

		{

		case NID_sha1:

		return 0x33;

		case NID_sha256:

		return 0x34;

		case NID_sha384:

		return 0x36;

		case NID_sha512:

		return 0x35;

		}

	return -1;

	}