/* 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>

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);
	}

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 */

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;
	}