/* crypto/bn/bn_blind.c */

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

  * Copyright (c) 1998-2005 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

  *    openssl-core@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).

  *

  */

 /* 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 <stdio.h>

 #include "cryptlib.h"

 #include "bn_lcl.h"

 #define BN_BLINDING_COUNTER	32

 struct bn_blinding_st

 	{

 	BIGNUM *A;

 	BIGNUM *Ai;

 	BIGNUM *e;

 	BIGNUM *mod; /* just a reference */

 	unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b;

 				  * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */

 	unsigned int  counter;

 	unsigned long flags;

 	BN_MONT_CTX *m_ctx;

 	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,

 			  const BIGNUM *m, BN_CTX *ctx,

 			  BN_MONT_CTX *m_ctx);

 	};

 EXPORT_C BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)

 	{

 	BN_BLINDING *ret=NULL;

 	bn_check_top(mod);

 	if ((ret=(BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL)

 		{

 		BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);

 		return(NULL);

 		}

 	memset(ret,0,sizeof(BN_BLINDING));

 	if (A != NULL)

 		{

 		if ((ret->A  = BN_dup(A))  == NULL) goto err;

 		}

 	if (Ai != NULL)

 		{

 		if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;

 		}

 	ret->mod = mod;

 	/* save a copy of mod in the BN_BLINDING structure */

 	if ((ret->mod = BN_dup(mod)) == NULL) goto err;

 	if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)

 		BN_set_flags(ret->mod, BN_FLG_CONSTTIME);

 	ret->counter = BN_BLINDING_COUNTER;

 	return(ret);

 err:

 	if (ret != NULL) BN_BLINDING_free(ret);

 	return(NULL);

 	}

 EXPORT_C void BN_BLINDING_free(BN_BLINDING *r)

 	{

 	if(r == NULL)

 	    return;

 	if (r->A  != NULL) BN_free(r->A );

 	if (r->Ai != NULL) BN_free(r->Ai);

 	if (r->e  != NULL) BN_free(r->e );

 	if (r->mod != NULL) BN_free(r->mod); 

 	OPENSSL_free(r);

 	}

 EXPORT_C int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)

 	{

 	int ret=0;

 	if ((b->A == NULL) || (b->Ai == NULL))

 		{

 		BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);

 		goto err;

 		}

 	if (--(b->counter) == 0 && b->e != NULL &&

 		!(b->flags & BN_BLINDING_NO_RECREATE))

 		{

 		/* re-create blinding parameters */

 		if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))

 			goto err;

 		}

 	else if (!(b->flags & BN_BLINDING_NO_UPDATE))

 		{

 		if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;

 		if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;

 		}

 	ret=1;

 err:

 	if (b->counter == 0)

 		b->counter = BN_BLINDING_COUNTER;

 	return(ret);

 	}

 EXPORT_C int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)

 	{

 	return BN_BLINDING_convert_ex(n, NULL, b, ctx);

 	}

 EXPORT_C int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)

 	{

 	int ret = 1;

 	bn_check_top(n);

 	if ((b->A == NULL) || (b->Ai == NULL))

 		{

 		BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);

 		return(0);

 		}

 	if (r != NULL)

 		{

 		if (!BN_copy(r, b->Ai)) ret=0;

 		}

 	if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;

 	return ret;

 	}

 EXPORT_C int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)

 	{

 	return BN_BLINDING_invert_ex(n, NULL, b, ctx);

 	}

 EXPORT_C int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)

 	{

 	int ret;

 	bn_check_top(n);

 	if ((b->A == NULL) || (b->Ai == NULL))

 		{

 		BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);

 		return(0);

 		}

 	if (r != NULL)

 		ret = BN_mod_mul(n, n, r, b->mod, ctx);

 	else

 		ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);

 	if (ret >= 0)

 		{

 		if (!BN_BLINDING_update(b,ctx))

 			return(0);

 		}

 	bn_check_top(n);

 	return(ret);

 	}

 EXPORT_C unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)

 	{

 	return b->thread_id;

 	}

 EXPORT_C void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)

 	{

 	b->thread_id = n;

 	}

 EXPORT_C unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)

 	{

 	return b->flags;

 	}

 EXPORT_C void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)

 	{

 	b->flags = flags;

 	}

 EXPORT_C BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,

 	const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,

 	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,

 			  const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),

 	BN_MONT_CTX *m_ctx)

 {

 	int    retry_counter = 32;

 	BN_BLINDING *ret = NULL;

 	if (b == NULL)

 		ret = BN_BLINDING_new(NULL, NULL, m);

 	else

 		ret = b;

 	if (ret == NULL)

 		goto err;

 	if (ret->A  == NULL && (ret->A  = BN_new()) == NULL)

 		goto err;

 	if (ret->Ai == NULL && (ret->Ai	= BN_new()) == NULL)

 		goto err;

 	if (e != NULL)

 		{

 		if (ret->e != NULL)

 			BN_free(ret->e);

 		ret->e = BN_dup(e);

 		}

 	if (ret->e == NULL)

 		goto err;

 	if (bn_mod_exp != NULL)

 		ret->bn_mod_exp = bn_mod_exp;

 	if (m_ctx != NULL)

 		ret->m_ctx = m_ctx;

 	do {

 		if (!BN_rand_range(ret->A, ret->mod)) goto err;

 		if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)

 			{

 			/* this should almost never happen for good RSA keys */

 			unsigned long error = ERR_peek_last_error();

 			if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)

 				{

 				if (retry_counter-- == 0)

 				{

 					BNerr(BN_F_BN_BLINDING_CREATE_PARAM,

 						BN_R_TOO_MANY_ITERATIONS);

 					goto err;

 				}

 				ERR_clear_error();

 				}

 			else

 				goto err;

 			}

 		else

 			break;

 	} while (1);

 	if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)

 		{

 		if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))

 			goto err;

 		}

 	else

 		{

 		if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))

 			goto err;

 		}

 	return ret;

 err:

 	if (b == NULL && ret != NULL)

 		{

 		BN_BLINDING_free(ret);

 		ret = NULL;

 		}

 	return ret;

 }