library/pk_wrap.c - security/mbedtls - Rivoreo Source Code Repositories

 /*
  *  Public Key abstraction layer: wrapper functions
  *
  *  Copyright (C) 2006-2013, Brainspark B.V.
  *
  *  This file is part of PolarSSL (http://www.polarssl.org)
  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
  *
  *  All rights reserved.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */

 #include "polarssl/config.h"

 #if defined(POLARSSL_PK_C)

 #include "polarssl/pk_wrap.h"

 /* Even if RSA not activated, for the sake of RSA-alt */
 #include "polarssl/rsa.h"

 #if defined(POLARSSL_ECP_C)
 #include "polarssl/ecp.h"
 #endif

 #if defined(POLARSSL_ECDSA_C)
 #include "polarssl/ecdsa.h"
 #endif

 #if defined(POLARSSL_MEMORY_C)
 #include "polarssl/memory.h"
 #else
 #include <stdlib.h>
 #define polarssl_malloc     malloc
 #define polarssl_free       free
 #endif

 /* Used by RSA-alt too */
 static int rsa_can_do( pk_type_t type )
 {
     return( type == POLARSSL_PK_RSA );
 }

 #if defined(POLARSSL_RSA_C)
 static size_t rsa_get_size( const void *ctx )
 {
     return( 8 * ((const rsa_context *) ctx)->len );
 }

 static int rsa_verify_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    const unsigned char *sig, size_t sig_len )
 {
     if( sig_len != ((rsa_context *) ctx)->len )
         return( POLARSSL_ERR_RSA_VERIFY_FAILED );

     return( rsa_pkcs1_verify( (rsa_context *) ctx, NULL, NULL,
                 RSA_PUBLIC, md_alg, (unsigned int) hash_len, hash, sig ) );
 }

 static int rsa_sign_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     *sig_len = ((rsa_context *) ctx)->len;

     return( rsa_pkcs1_sign( (rsa_context *) ctx, f_rng, p_rng, RSA_PRIVATE,
                 md_alg, (unsigned int) hash_len, hash, sig ) );
 }

 static int rsa_decrypt_wrap( void *ctx,
                     const unsigned char *input, size_t ilen,
                     unsigned char *output, size_t *olen, size_t osize,
                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     if( ilen != ((rsa_context *) ctx)->len )
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

     return( rsa_pkcs1_decrypt( (rsa_context *) ctx, f_rng, p_rng,
                 RSA_PRIVATE, olen, input, output, osize ) );
 }

 static int rsa_encrypt_wrap( void *ctx,
                     const unsigned char *input, size_t ilen,
                     unsigned char *output, size_t *olen, size_t osize,
                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     ((void) osize);

     *olen = ((rsa_context *) ctx)->len;

     return( rsa_pkcs1_encrypt( (rsa_context *) ctx,
                 f_rng, p_rng, RSA_PUBLIC, ilen, input, output ) );
 }

 static void *rsa_alloc_wrap( void )
 {
     void *ctx = polarssl_malloc( sizeof( rsa_context ) );

     if( ctx != NULL )
         rsa_init( (rsa_context *) ctx, 0, 0 );

     return ctx;
 }

 static void rsa_free_wrap( void *ctx )
 {
     rsa_free( (rsa_context *) ctx );
     polarssl_free( ctx );
 }

 static void rsa_debug( const void *ctx, pk_debug_item *items )
 {
     items->type = POLARSSL_PK_DEBUG_MPI;
     items->name = "rsa.N";
     items->value = &( ((rsa_context *) ctx)->N );

     items++;

     items->type = POLARSSL_PK_DEBUG_MPI;
     items->name = "rsa.E";
     items->value = &( ((rsa_context *) ctx)->E );
 }

 const pk_info_t rsa_info = {
     POLARSSL_PK_RSA,
     "RSA",
     rsa_get_size,
     rsa_can_do,
     rsa_verify_wrap,
     rsa_sign_wrap,
     rsa_decrypt_wrap,
     rsa_encrypt_wrap,
     rsa_alloc_wrap,
     rsa_free_wrap,
     rsa_debug,
 };
 #endif /* POLARSSL_RSA_C */

 #if defined(POLARSSL_ECP_C)
 /*
  * Generic EC key
  */
 static int eckey_can_do( pk_type_t type )
 {
     return( type == POLARSSL_PK_ECKEY ||
             type == POLARSSL_PK_ECKEY_DH ||
             type == POLARSSL_PK_ECDSA );
 }

 static size_t eckey_get_size( const void *ctx )
 {
     return( ((ecp_keypair *) ctx)->grp.pbits );
 }

 #if defined(POLARSSL_ECDSA_C)
 /* Forward declarations */
 static int ecdsa_verify_wrap( void *ctx, md_type_t md_alg,
                        const unsigned char *hash, size_t hash_len,
                        const unsigned char *sig, size_t sig_len );

 static int ecdsa_sign_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );

 static int eckey_verify_wrap( void *ctx, md_type_t md_alg,
                        const unsigned char *hash, size_t hash_len,
                        const unsigned char *sig, size_t sig_len )
 {
     int ret;
     ecdsa_context ecdsa;

     ecdsa_init( &ecdsa );

     if( ( ret = ecdsa_from_keypair( &ecdsa, ctx ) ) == 0 )
         ret = ecdsa_verify_wrap( &ecdsa, md_alg, hash, hash_len, sig, sig_len );

     ecdsa_free( &ecdsa );

     return( ret );
 }

 static int eckey_sign_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     int ret;
     ecdsa_context ecdsa;

     ecdsa_init( &ecdsa );

     if( ( ret = ecdsa_from_keypair( &ecdsa, ctx ) ) == 0 )
         ret = ecdsa_sign_wrap( &ecdsa, md_alg, hash, hash_len, sig, sig_len,
                                f_rng, p_rng );

     ecdsa_free( &ecdsa );

     return( ret );
 }

 #endif /* POLARSSL_ECDSA_C */

 static void *eckey_alloc_wrap( void )
 {
     void *ctx = polarssl_malloc( sizeof( ecp_keypair ) );

     if( ctx != NULL )
         ecp_keypair_init( ctx );

     return( ctx );
 }

 static void eckey_free_wrap( void *ctx )
 {
     ecp_keypair_free( (ecp_keypair *) ctx );
     polarssl_free( ctx );
 }

 static void eckey_debug( const void *ctx, pk_debug_item *items )
 {
     items->type = POLARSSL_PK_DEBUG_ECP;
     items->name = "eckey.Q";
     items->value = &( ((ecp_keypair *) ctx)->Q );
 }

 const pk_info_t eckey_info = {
     POLARSSL_PK_ECKEY,
     "EC",
     eckey_get_size,
     eckey_can_do,
 #if defined(POLARSSL_ECDSA_C)
     eckey_verify_wrap,
     eckey_sign_wrap,
 #else
     NULL,
     NULL,
 #endif
     NULL,
     NULL,
     eckey_alloc_wrap,
     eckey_free_wrap,
     eckey_debug,
 };

 /*
  * EC key resticted to ECDH
  */
 static int eckeydh_can_do( pk_type_t type )
 {
     return( type == POLARSSL_PK_ECKEY ||
             type == POLARSSL_PK_ECKEY_DH );
 }

 const pk_info_t eckeydh_info = {
     POLARSSL_PK_ECKEY_DH,
     "EC_DH",
     eckey_get_size,         /* Same underlying key structure */
     eckeydh_can_do,
     NULL,
     NULL,
     NULL,
     NULL,
     eckey_alloc_wrap,       /* Same underlying key structure */
     eckey_free_wrap,        /* Same underlying key structure */
     eckey_debug,            /* Same underlying key structure */
 };
 #endif /* POLARSSL_ECP_C */

 #if defined(POLARSSL_ECDSA_C)
 static int ecdsa_can_do( pk_type_t type )
 {
     return( type == POLARSSL_PK_ECDSA );
 }

 static int ecdsa_verify_wrap( void *ctx, md_type_t md_alg,
                        const unsigned char *hash, size_t hash_len,
                        const unsigned char *sig, size_t sig_len )
 {
     ((void) md_alg);

     return( ecdsa_read_signature( (ecdsa_context *) ctx,
                 hash, hash_len, sig, sig_len ) );
 }

 static int ecdsa_sign_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     ((void) md_alg);

     return( ecdsa_write_signature( (ecdsa_context *) ctx,
                 hash, hash_len, sig, sig_len, f_rng, p_rng ) );
 }

 static void *ecdsa_alloc_wrap( void )
 {
     void *ctx = polarssl_malloc( sizeof( ecdsa_context ) );

     if( ctx != NULL )
         ecdsa_init( (ecdsa_context *) ctx );

     return( ctx );
 }

 static void ecdsa_free_wrap( void *ctx )
 {
     ecdsa_free( (ecdsa_context *) ctx );
     polarssl_free( ctx );
 }

 const pk_info_t ecdsa_info = {
     POLARSSL_PK_ECDSA,
     "ECDSA",
     eckey_get_size,     /* Compatible key structures */
     ecdsa_can_do,
     ecdsa_verify_wrap,
     ecdsa_sign_wrap,
     NULL,
     NULL,
     ecdsa_alloc_wrap,
     ecdsa_free_wrap,
     eckey_debug,        /* Compatible key structures */
 };
 #endif /* POLARSSL_ECDSA_C */

 /*
  * Support for alternative RSA-private implementations
  */

 static size_t rsa_alt_get_size( const void *ctx )
 {
     const rsa_alt_context *rsa_alt = (const rsa_alt_context *) ctx;

     return( rsa_alt->key_len_func( rsa_alt->key ) );
 }

 static int rsa_alt_sign_wrap( void *ctx, md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     rsa_alt_context *rsa_alt = (rsa_alt_context *) ctx;

     *sig_len = rsa_alt->key_len_func( rsa_alt->key );

     return( rsa_alt->sign_func( rsa_alt->key, f_rng, p_rng, RSA_PRIVATE,
                 md_alg, (unsigned int) hash_len, hash, sig ) );
 }

 static int rsa_alt_decrypt_wrap( void *ctx,
                     const unsigned char *input, size_t ilen,
                     unsigned char *output, size_t *olen, size_t osize,
                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
     rsa_alt_context *rsa_alt = (rsa_alt_context *) ctx;

     ((void) f_rng);
     ((void) p_rng);

     if( ilen != rsa_alt->key_len_func( rsa_alt->key ) )
         return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

     return( rsa_alt->decrypt_func( rsa_alt->key,
                 RSA_PRIVATE, olen, input, output, osize ) );
 }

 static void *rsa_alt_alloc_wrap( void )
 {
     void *ctx = polarssl_malloc( sizeof( rsa_alt_context ) );

     if( ctx != NULL )
         memset( ctx, 0, sizeof( rsa_alt_context ) );

     return ctx;
 }

 static void rsa_alt_free_wrap( void *ctx )
 {
     polarssl_free( ctx );
 }

 const pk_info_t rsa_alt_info = {
     POLARSSL_PK_RSA_ALT,
     "RSA-alt",
     rsa_alt_get_size,
     rsa_can_do,
     NULL,
     rsa_alt_sign_wrap,
     rsa_alt_decrypt_wrap,
     NULL,
     rsa_alt_alloc_wrap,
     rsa_alt_free_wrap,
     NULL,
 };

 #endif /* POLARSSL_PK_C */
	/*
	* Public Key abstraction layer: wrapper functions
	*
	* Copyright (C) 2006-2013, Brainspark B.V.
	*
	* This file is part of PolarSSL (http://www.polarssl.org)
	* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
	*
	* All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	*/

	#include "polarssl/config.h"

	#if defined(POLARSSL_PK_C)

	#include "polarssl/pk_wrap.h"

	/* Even if RSA not activated, for the sake of RSA-alt */
	#include "polarssl/rsa.h"

	#if defined(POLARSSL_ECP_C)
	#include "polarssl/ecp.h"
	#endif

	#if defined(POLARSSL_ECDSA_C)
	#include "polarssl/ecdsa.h"
	#endif

	#if defined(POLARSSL_MEMORY_C)
	#include "polarssl/memory.h"
	#else
	#include <stdlib.h>
	#define polarssl_malloc malloc
	#define polarssl_free free
	#endif

	/* Used by RSA-alt too */
	static int rsa_can_do( pk_type_t type )
	{
	return( type == POLARSSL_PK_RSA );
	}

	#if defined(POLARSSL_RSA_C)
	static size_t rsa_get_size( const void *ctx )
	{
	return( 8 * ((const rsa_context *) ctx)->len );
	}

	static int rsa_verify_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	const unsigned char *sig, size_t sig_len )
	{
	if( sig_len != ((rsa_context *) ctx)->len )
	return( POLARSSL_ERR_RSA_VERIFY_FAILED );

	return( rsa_pkcs1_verify( (rsa_context *) ctx, NULL, NULL,
	RSA_PUBLIC, md_alg, (unsigned int) hash_len, hash, sig ) );
	}

	static int rsa_sign_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	unsigned char sig, size_t sig_len,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	sig_len = ((rsa_context ) ctx)->len;

	return( rsa_pkcs1_sign( (rsa_context *) ctx, f_rng, p_rng, RSA_PRIVATE,
	md_alg, (unsigned int) hash_len, hash, sig ) );
	}

	static int rsa_decrypt_wrap( void *ctx,
	const unsigned char *input, size_t ilen,
	unsigned char output, size_t olen, size_t osize,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	if( ilen != ((rsa_context *) ctx)->len )
	return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

	return( rsa_pkcs1_decrypt( (rsa_context *) ctx, f_rng, p_rng,
	RSA_PRIVATE, olen, input, output, osize ) );
	}

	static int rsa_encrypt_wrap( void *ctx,
	const unsigned char *input, size_t ilen,
	unsigned char output, size_t olen, size_t osize,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	((void) osize);

	olen = ((rsa_context ) ctx)->len;

	return( rsa_pkcs1_encrypt( (rsa_context *) ctx,
	f_rng, p_rng, RSA_PUBLIC, ilen, input, output ) );
	}

	static void *rsa_alloc_wrap( void )
	{
	void *ctx = polarssl_malloc( sizeof( rsa_context ) );

	if( ctx != NULL )
	rsa_init( (rsa_context *) ctx, 0, 0 );

	return ctx;
	}

	static void rsa_free_wrap( void *ctx )
	{
	rsa_free( (rsa_context *) ctx );
	polarssl_free( ctx );
	}

	static void rsa_debug( const void ctx, pk_debug_item items )
	{
	items->type = POLARSSL_PK_DEBUG_MPI;
	items->name = "rsa.N";
	items->value = &( ((rsa_context *) ctx)->N );

	items++;

	items->type = POLARSSL_PK_DEBUG_MPI;
	items->name = "rsa.E";
	items->value = &( ((rsa_context *) ctx)->E );
	}

	const pk_info_t rsa_info = {
	POLARSSL_PK_RSA,
	"RSA",
	rsa_get_size,
	rsa_can_do,
	rsa_verify_wrap,
	rsa_sign_wrap,
	rsa_decrypt_wrap,
	rsa_encrypt_wrap,
	rsa_alloc_wrap,
	rsa_free_wrap,
	rsa_debug,
	};
	#endif /* POLARSSL_RSA_C */

	#if defined(POLARSSL_ECP_C)
	/*
	* Generic EC key
	*/
	static int eckey_can_do( pk_type_t type )
	{
	return( type == POLARSSL_PK_ECKEY \|\|
	type == POLARSSL_PK_ECKEY_DH \|\|
	type == POLARSSL_PK_ECDSA );
	}

	static size_t eckey_get_size( const void *ctx )
	{
	return( ((ecp_keypair *) ctx)->grp.pbits );
	}

	#if defined(POLARSSL_ECDSA_C)
	/* Forward declarations */
	static int ecdsa_verify_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	const unsigned char *sig, size_t sig_len );

	static int ecdsa_sign_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	unsigned char sig, size_t sig_len,
	int (f_rng)(void , unsigned char , size_t), void p_rng );

	static int eckey_verify_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	const unsigned char *sig, size_t sig_len )
	{
	int ret;
	ecdsa_context ecdsa;

	ecdsa_init( &ecdsa );

	if( ( ret = ecdsa_from_keypair( &ecdsa, ctx ) ) == 0 )
	ret = ecdsa_verify_wrap( &ecdsa, md_alg, hash, hash_len, sig, sig_len );

	ecdsa_free( &ecdsa );

	return( ret );
	}

	static int eckey_sign_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	unsigned char sig, size_t sig_len,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	int ret;
	ecdsa_context ecdsa;

	ecdsa_init( &ecdsa );

	if( ( ret = ecdsa_from_keypair( &ecdsa, ctx ) ) == 0 )
	ret = ecdsa_sign_wrap( &ecdsa, md_alg, hash, hash_len, sig, sig_len,
	f_rng, p_rng );

	ecdsa_free( &ecdsa );

	return( ret );
	}

	#endif /* POLARSSL_ECDSA_C */

	static void *eckey_alloc_wrap( void )
	{
	void *ctx = polarssl_malloc( sizeof( ecp_keypair ) );

	if( ctx != NULL )
	ecp_keypair_init( ctx );

	return( ctx );
	}

	static void eckey_free_wrap( void *ctx )
	{
	ecp_keypair_free( (ecp_keypair *) ctx );
	polarssl_free( ctx );
	}

	static void eckey_debug( const void ctx, pk_debug_item items )
	{
	items->type = POLARSSL_PK_DEBUG_ECP;
	items->name = "eckey.Q";
	items->value = &( ((ecp_keypair *) ctx)->Q );
	}

	const pk_info_t eckey_info = {
	POLARSSL_PK_ECKEY,
	"EC",
	eckey_get_size,
	eckey_can_do,
	#if defined(POLARSSL_ECDSA_C)
	eckey_verify_wrap,
	eckey_sign_wrap,
	#else
	NULL,
	NULL,
	#endif
	NULL,
	NULL,
	eckey_alloc_wrap,
	eckey_free_wrap,
	eckey_debug,
	};

	/*
	* EC key resticted to ECDH
	*/
	static int eckeydh_can_do( pk_type_t type )
	{
	return( type == POLARSSL_PK_ECKEY \|\|
	type == POLARSSL_PK_ECKEY_DH );
	}

	const pk_info_t eckeydh_info = {
	POLARSSL_PK_ECKEY_DH,
	"EC_DH",
	eckey_get_size, /* Same underlying key structure */
	eckeydh_can_do,
	NULL,
	NULL,
	NULL,
	NULL,
	eckey_alloc_wrap, /* Same underlying key structure */
	eckey_free_wrap, /* Same underlying key structure */
	eckey_debug, /* Same underlying key structure */
	};
	#endif /* POLARSSL_ECP_C */

	#if defined(POLARSSL_ECDSA_C)
	static int ecdsa_can_do( pk_type_t type )
	{
	return( type == POLARSSL_PK_ECDSA );
	}

	static int ecdsa_verify_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	const unsigned char *sig, size_t sig_len )
	{
	((void) md_alg);

	return( ecdsa_read_signature( (ecdsa_context *) ctx,
	hash, hash_len, sig, sig_len ) );
	}

	static int ecdsa_sign_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	unsigned char sig, size_t sig_len,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	((void) md_alg);

	return( ecdsa_write_signature( (ecdsa_context *) ctx,
	hash, hash_len, sig, sig_len, f_rng, p_rng ) );
	}

	static void *ecdsa_alloc_wrap( void )
	{
	void *ctx = polarssl_malloc( sizeof( ecdsa_context ) );

	if( ctx != NULL )
	ecdsa_init( (ecdsa_context *) ctx );

	return( ctx );
	}

	static void ecdsa_free_wrap( void *ctx )
	{
	ecdsa_free( (ecdsa_context *) ctx );
	polarssl_free( ctx );
	}

	const pk_info_t ecdsa_info = {
	POLARSSL_PK_ECDSA,
	"ECDSA",
	eckey_get_size, /* Compatible key structures */
	ecdsa_can_do,
	ecdsa_verify_wrap,
	ecdsa_sign_wrap,
	NULL,
	NULL,
	ecdsa_alloc_wrap,
	ecdsa_free_wrap,
	eckey_debug, /* Compatible key structures */
	};
	#endif /* POLARSSL_ECDSA_C */

	/*
	* Support for alternative RSA-private implementations
	*/

	static size_t rsa_alt_get_size( const void *ctx )
	{
	const rsa_alt_context rsa_alt = (const rsa_alt_context ) ctx;

	return( rsa_alt->key_len_func( rsa_alt->key ) );
	}

	static int rsa_alt_sign_wrap( void *ctx, md_type_t md_alg,
	const unsigned char *hash, size_t hash_len,
	unsigned char sig, size_t sig_len,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	rsa_alt_context rsa_alt = (rsa_alt_context ) ctx;

	*sig_len = rsa_alt->key_len_func( rsa_alt->key );

	return( rsa_alt->sign_func( rsa_alt->key, f_rng, p_rng, RSA_PRIVATE,
	md_alg, (unsigned int) hash_len, hash, sig ) );
	}

	static int rsa_alt_decrypt_wrap( void *ctx,
	const unsigned char *input, size_t ilen,
	unsigned char output, size_t olen, size_t osize,
	int (f_rng)(void , unsigned char , size_t), void p_rng )
	{
	rsa_alt_context rsa_alt = (rsa_alt_context ) ctx;

	((void) f_rng);
	((void) p_rng);

	if( ilen != rsa_alt->key_len_func( rsa_alt->key ) )
	return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

	return( rsa_alt->decrypt_func( rsa_alt->key,
	RSA_PRIVATE, olen, input, output, osize ) );
	}

	static void *rsa_alt_alloc_wrap( void )
	{
	void *ctx = polarssl_malloc( sizeof( rsa_alt_context ) );

	if( ctx != NULL )
	memset( ctx, 0, sizeof( rsa_alt_context ) );

	return ctx;
	}

	static void rsa_alt_free_wrap( void *ctx )
	{
	polarssl_free( ctx );
	}

	const pk_info_t rsa_alt_info = {
	POLARSSL_PK_RSA_ALT,
	"RSA-alt",
	rsa_alt_get_size,
	rsa_can_do,
	NULL,
	rsa_alt_sign_wrap,
	rsa_alt_decrypt_wrap,
	NULL,
	rsa_alt_alloc_wrap,
	rsa_alt_free_wrap,
	NULL,
	};

	#endif /* POLARSSL_PK_C */