text: /* crypto/rsa/rsa_lib.c */
  /* 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.]
   */
  
  #define OPENSSL_FIPSAPI
  
  #include <stdio.h>
  #include <openssl/crypto.h>
  #include "cryptlib.h"
  #include <openssl/lhash.h>
  #include <openssl/bn.h>
  #include <openssl/rsa.h>
  #include <openssl/rand.h>
  
  int RSA_size(const RSA *r)
  	{
  	return(BN_num_bytes(r->n));
  	}
  
  int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
  	     RSA *rsa, int padding)
  	{
  	return(rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
  	}
  
  int RSA_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
  	     RSA *rsa, int padding)
  	{
  	return(rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
  	}
  
  int RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to,
  	     RSA *rsa, int padding)
  	{
  	return(rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
  	}
  
  int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
  	     RSA *rsa, int padding)
  	{
  	return(rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
  	}
  
  int RSA_flags(const RSA *r)
  	{
  	return((r == NULL)?0:r->meth->flags);
  	}
  
  void RSA_blinding_off(RSA *rsa)
  	{
  	if (rsa->blinding != NULL)
  		{
  		BN_BLINDING_free(rsa->blinding);
  		rsa->blinding=NULL;
  		}
  	rsa->flags &= ~RSA_FLAG_BLINDING;
  	rsa->flags |= RSA_FLAG_NO_BLINDING;
  	}
  
  int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
  	{
  	int ret=0;
  
  	if (rsa->blinding != NULL)
  		RSA_blinding_off(rsa);
  
  	rsa->blinding = RSA_setup_blinding(rsa, ctx);
  	if (rsa->blinding == NULL)
  		goto err;
  
  	rsa->flags |= RSA_FLAG_BLINDING;
  	rsa->flags &= ~RSA_FLAG_NO_BLINDING;
  	ret=1;
  err:
  	return(ret);
  	}
  
  static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
  	const BIGNUM *q, BN_CTX *ctx)
  {
  	BIGNUM *ret = NULL, *r0, *r1, *r2;
  
  	if (d == NULL || p == NULL || q == NULL)
  		return NULL;
  
  	BN_CTX_start(ctx);
  	r0 = BN_CTX_get(ctx);
  	r1 = BN_CTX_get(ctx);
  	r2 = BN_CTX_get(ctx);
  	if (r2 == NULL)
  		goto err;
  
  	if (!BN_sub(r1, p, BN_value_one())) goto err;
  	if (!BN_sub(r2, q, BN_value_one())) goto err;
  	if (!BN_mul(r0, r1, r2, ctx)) goto err;
  
  	ret = BN_mod_inverse(NULL, d, r0, ctx);
  err:
  	BN_CTX_end(ctx);
  	return ret;
  }
  
  BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
  {
  	BIGNUM local_n;
  	BIGNUM *e,*n;
  	BN_CTX *ctx;
  	BN_BLINDING *ret = NULL;
  
  	if (in_ctx == NULL)
  		{
  		if ((ctx = BN_CTX_new()) == NULL) return 0;
  		}
  	else
  		ctx = in_ctx;
  
  	BN_CTX_start(ctx);
  	e  = BN_CTX_get(ctx);
  	if (e == NULL)
  		{
  		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
  		goto err;
  		}
  
  	if (rsa->e == NULL)
  		{
  		e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
  		if (e == NULL)
  			{
  			RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
  			goto err;
  			}
  		}
  	else
  		e = rsa->e;
  
  	
  	if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
  		{
  		/* if PRNG is not properly seeded, resort to secret
  		 * exponent as unpredictable seed */
  		RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
  		}
  
  	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
  		{
  		/* Set BN_FLG_CONSTTIME flag */
  		n = &local_n;
  		BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
  		}
  	else
  		n = rsa->n;
  
  	ret = BN_BLINDING_create_param(NULL, e, n, ctx,
  			rsa->meth->bn_mod_exp, rsa->_method_mod_n);
  	if (ret == NULL)
  		{
  		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
  		goto err;
  		}
  	CRYPTO_THREADID_current(BN_BLINDING_thread_id(ret));
  err:
  	BN_CTX_end(ctx);
  	if (in_ctx == NULL)
  		BN_CTX_free(ctx);
  	if(rsa->e == NULL)
  		BN_free(e);
  
  	return ret;
  }
  