programs/pkey/key_app_writer.c - platform/external/mbedtls - Git at Google

 /*
  *  Key writing application
  *
  *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  *  not use this file except in compliance with the License.
  *  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */

 #include "mbedtls/build_info.h"

 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
 #include <stdlib.h>
 #define mbedtls_printf          printf
 #define mbedtls_exit            exit
 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
 #endif /* MBEDTLS_PLATFORM_C */

 #if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_PK_WRITE_C) && \
     defined(MBEDTLS_FS_IO) && \
     defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
 #include "mbedtls/error.h"
 #include "mbedtls/pk.h"
 #include "mbedtls/error.h"

 #include "mbedtls/entropy.h"
 #include "mbedtls/ctr_drbg.h"

 #include <stdio.h>
 #include <string.h>
 #endif

 #if defined(MBEDTLS_PEM_WRITE_C)
 #define USAGE_OUT \
     "    output_file=%%s      default: keyfile.pem\n"   \
     "    output_format=pem|der default: pem\n"
 #else
 #define USAGE_OUT \
     "    output_file=%%s      default: keyfile.der\n"   \
     "    output_format=der     default: der\n"
 #endif

 #if defined(MBEDTLS_PEM_WRITE_C)
 #define DFL_OUTPUT_FILENAME     "keyfile.pem"
 #define DFL_OUTPUT_FORMAT       OUTPUT_FORMAT_PEM
 #else
 #define DFL_OUTPUT_FILENAME     "keyfile.der"
 #define DFL_OUTPUT_FORMAT       OUTPUT_FORMAT_DER
 #endif

 #define DFL_MODE                MODE_NONE
 #define DFL_FILENAME            "keyfile.key"
 #define DFL_DEBUG_LEVEL         0
 #define DFL_OUTPUT_MODE         OUTPUT_MODE_NONE

 #define MODE_NONE               0
 #define MODE_PRIVATE            1
 #define MODE_PUBLIC             2

 #define OUTPUT_MODE_NONE               0
 #define OUTPUT_MODE_PRIVATE            1
 #define OUTPUT_MODE_PUBLIC             2

 #define OUTPUT_FORMAT_PEM              0
 #define OUTPUT_FORMAT_DER              1

 #define USAGE \
     "\n usage: key_app_writer param=<>...\n"            \
     "\n acceptable parameters:\n"                       \
     "    mode=private|public default: none\n"           \
     "    filename=%%s         default: keyfile.key\n"   \
     "    output_mode=private|public default: none\n"    \
     USAGE_OUT                                           \
     "\n"

 #if !defined(MBEDTLS_PK_PARSE_C) || \
     !defined(MBEDTLS_PK_WRITE_C) || \
     !defined(MBEDTLS_FS_IO)      || \
     !defined(MBEDTLS_ENTROPY_C)  || \
     !defined(MBEDTLS_CTR_DRBG_C)
 int main( void )
 {
     mbedtls_printf( "MBEDTLS_PK_PARSE_C and/or MBEDTLS_PK_WRITE_C and/or "
                     "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
                     "MBEDTLS_FS_IO not defined.\n" );
     mbedtls_exit( 0 );
 }
 #else


 /*
  * global options
  */
 struct options
 {
     int mode;                   /* the mode to run the application in   */
     const char *filename;       /* filename of the key file             */
     int output_mode;            /* the output mode to use               */
     const char *output_file;    /* where to store the constructed key file  */
     int output_format;          /* the output format to use             */
 } opt;

 static int write_public_key( mbedtls_pk_context *key, const char *output_file )
 {
     int ret;
     FILE *f;
     unsigned char output_buf[16000];
     unsigned char *c = output_buf;
     size_t len = 0;

     memset(output_buf, 0, 16000);

 #if defined(MBEDTLS_PEM_WRITE_C)
     if( opt.output_format == OUTPUT_FORMAT_PEM )
     {
         if( ( ret = mbedtls_pk_write_pubkey_pem( key, output_buf, 16000 ) ) != 0 )
             return( ret );

         len = strlen( (char *) output_buf );
     }
     else
 #endif
     {
         if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf, 16000 ) ) < 0 )
             return( ret );

         len = ret;
         c = output_buf + sizeof(output_buf) - len;
     }

     if( ( f = fopen( output_file, "w" ) ) == NULL )
         return( -1 );

     if( fwrite( c, 1, len, f ) != len )
     {
         fclose( f );
         return( -1 );
     }

     fclose( f );

     return( 0 );
 }

 static int write_private_key( mbedtls_pk_context *key, const char *output_file )
 {
     int ret;
     FILE *f;
     unsigned char output_buf[16000];
     unsigned char *c = output_buf;
     size_t len = 0;

     memset(output_buf, 0, 16000);

 #if defined(MBEDTLS_PEM_WRITE_C)
     if( opt.output_format == OUTPUT_FORMAT_PEM )
     {
         if( ( ret = mbedtls_pk_write_key_pem( key, output_buf, 16000 ) ) != 0 )
             return( ret );

         len = strlen( (char *) output_buf );
     }
     else
 #endif
     {
         if( ( ret = mbedtls_pk_write_key_der( key, output_buf, 16000 ) ) < 0 )
             return( ret );

         len = ret;
         c = output_buf + sizeof(output_buf) - len;
     }

     if( ( f = fopen( output_file, "w" ) ) == NULL )
         return( -1 );

     if( fwrite( c, 1, len, f ) != len )
     {
         fclose( f );
         return( -1 );
     }

     fclose( f );

     return( 0 );
 }

 int main( int argc, char *argv[] )
 {
     int ret = 1;
     int exit_code = MBEDTLS_EXIT_FAILURE;
     char buf[1024];
     int i;
     char *p, *q;

     const char *pers = "pkey/key_app";
     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;

     mbedtls_pk_context key;
     mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;

     /*
      * Set to sane values
      */
     mbedtls_entropy_init( &entropy );
     mbedtls_ctr_drbg_init( &ctr_drbg );

     mbedtls_pk_init( &key );
     memset( buf, 0, sizeof( buf ) );

     mbedtls_mpi_init( &N ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q );
     mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
     mbedtls_mpi_init( &DQ ); mbedtls_mpi_init( &QP );

     if( argc == 0 )
     {
     usage:
         mbedtls_printf( USAGE );
         goto exit;
     }

     opt.mode                = DFL_MODE;
     opt.filename            = DFL_FILENAME;
     opt.output_mode         = DFL_OUTPUT_MODE;
     opt.output_file         = DFL_OUTPUT_FILENAME;
     opt.output_format       = DFL_OUTPUT_FORMAT;

     for( i = 1; i < argc; i++ )
     {
         p = argv[i];
         if( ( q = strchr( p, '=' ) ) == NULL )
             goto usage;
         *q++ = '\0';

         if( strcmp( p, "mode" ) == 0 )
         {
             if( strcmp( q, "private" ) == 0 )
                 opt.mode = MODE_PRIVATE;
             else if( strcmp( q, "public" ) == 0 )
                 opt.mode = MODE_PUBLIC;
             else
                 goto usage;
         }
         else if( strcmp( p, "output_mode" ) == 0 )
         {
             if( strcmp( q, "private" ) == 0 )
                 opt.output_mode = OUTPUT_MODE_PRIVATE;
             else if( strcmp( q, "public" ) == 0 )
                 opt.output_mode = OUTPUT_MODE_PUBLIC;
             else
                 goto usage;
         }
         else if( strcmp( p, "output_format" ) == 0 )
         {
 #if defined(MBEDTLS_PEM_WRITE_C)
             if( strcmp( q, "pem" ) == 0 )
                 opt.output_format = OUTPUT_FORMAT_PEM;
             else
 #endif
             if( strcmp( q, "der" ) == 0 )
                 opt.output_format = OUTPUT_FORMAT_DER;
             else
                 goto usage;
         }
         else if( strcmp( p, "filename" ) == 0 )
             opt.filename = q;
         else if( strcmp( p, "output_file" ) == 0 )
             opt.output_file = q;
         else
             goto usage;
     }

     if( opt.mode == MODE_NONE && opt.output_mode != OUTPUT_MODE_NONE )
     {
         mbedtls_printf( "\nCannot output a key without reading one.\n");
         goto exit;
     }

     if( opt.mode == MODE_PUBLIC && opt.output_mode == OUTPUT_MODE_PRIVATE )
     {
         mbedtls_printf( "\nCannot output a private key from a public key.\n");
         goto exit;
     }

     if( opt.mode == MODE_PRIVATE )
     {
         /*
          * 1.1. Load the key
          */
         mbedtls_printf( "\n  . Loading the private key ..." );
         fflush( stdout );

         if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
                                    (const unsigned char *) pers,
                                    strlen( pers ) ) ) != 0 )
         {
             mbedtls_printf( " failed\n  !  mbedtls_ctr_drbg_seed returned -0x%04x\n", (unsigned int) -ret );
             goto exit;
         }

         ret = mbedtls_pk_parse_keyfile( &key, opt.filename, NULL,
                                         mbedtls_ctr_drbg_random, &ctr_drbg );
         if( ret != 0 )
         {
             mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
             mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
             goto exit;
         }

         mbedtls_printf( " ok\n" );

         /*
          * 1.2 Print the key
          */
         mbedtls_printf( "  . Key information    ...\n" );

 #if defined(MBEDTLS_RSA_C)
         if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_RSA )
         {
             mbedtls_rsa_context *rsa = mbedtls_pk_rsa( key );

             if( ( ret = mbedtls_rsa_export    ( rsa, &N, &P, &Q, &D, &E ) ) != 0 ||
                 ( ret = mbedtls_rsa_export_crt( rsa, &DP, &DQ, &QP ) )      != 0 )
             {
                 mbedtls_printf( " failed\n  ! could not export RSA parameters\n\n" );
                 goto exit;
             }

             mbedtls_mpi_write_file( "N:  ",  &N,  16, NULL );
             mbedtls_mpi_write_file( "E:  ",  &E,  16, NULL );
             mbedtls_mpi_write_file( "D:  ",  &D,  16, NULL );
             mbedtls_mpi_write_file( "P:  ",  &P,  16, NULL );
             mbedtls_mpi_write_file( "Q:  ",  &Q,  16, NULL );
             mbedtls_mpi_write_file( "DP: ",  &DP, 16, NULL );
             mbedtls_mpi_write_file( "DQ:  ", &DQ, 16, NULL );
             mbedtls_mpi_write_file( "QP:  ", &QP, 16, NULL );
         }
         else
 #endif
 #if defined(MBEDTLS_ECP_C)
         if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_ECKEY )
         {
             mbedtls_ecp_keypair *ecp = mbedtls_pk_ec( key );
             mbedtls_mpi_write_file( "Q(X): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), 16, NULL );
             mbedtls_mpi_write_file( "Q(Y): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Y), 16, NULL );
             mbedtls_mpi_write_file( "Q(Z): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Z), 16, NULL );
             mbedtls_mpi_write_file( "D   : ", &ecp->MBEDTLS_PRIVATE(d)  , 16, NULL );
         }
         else
 #endif
             mbedtls_printf("key type not supported yet\n");

     }
     else if( opt.mode == MODE_PUBLIC )
     {
         /*
          * 1.1. Load the key
          */
         mbedtls_printf( "\n  . Loading the public key ..." );
         fflush( stdout );

         ret = mbedtls_pk_parse_public_keyfile( &key, opt.filename );

         if( ret != 0 )
         {
             mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
             mbedtls_printf( " failed\n  !  mbedtls_pk_parse_public_key returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
             goto exit;
         }

         mbedtls_printf( " ok\n" );

         /*
          * 1.2 Print the key
          */
         mbedtls_printf( "  . Key information    ...\n" );

 #if defined(MBEDTLS_RSA_C)
         if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_RSA )
         {
             mbedtls_rsa_context *rsa = mbedtls_pk_rsa( key );

             if( ( ret = mbedtls_rsa_export( rsa, &N, NULL, NULL,
                                             NULL, &E ) ) != 0 )
             {
                 mbedtls_printf( " failed\n  ! could not export RSA parameters\n\n" );
                 goto exit;
             }
             mbedtls_mpi_write_file( "N: ", &N, 16, NULL );
             mbedtls_mpi_write_file( "E: ", &E, 16, NULL );
         }
         else
 #endif
 #if defined(MBEDTLS_ECP_C)
         if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_ECKEY )
         {
             mbedtls_ecp_keypair *ecp = mbedtls_pk_ec( key );
             mbedtls_mpi_write_file( "Q(X): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), 16, NULL );
             mbedtls_mpi_write_file( "Q(Y): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Y), 16, NULL );
             mbedtls_mpi_write_file( "Q(Z): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Z), 16, NULL );
         }
         else
 #endif
             mbedtls_printf("key type not supported yet\n");
     }
     else
         goto usage;

     if( opt.output_mode == OUTPUT_MODE_PUBLIC )
     {
         write_public_key( &key, opt.output_file );
     }
     if( opt.output_mode == OUTPUT_MODE_PRIVATE )
     {
         write_private_key( &key, opt.output_file );
     }

     exit_code = MBEDTLS_EXIT_SUCCESS;

 exit:

     if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
 #ifdef MBEDTLS_ERROR_C
         mbedtls_strerror( ret, buf, sizeof( buf ) );
         mbedtls_printf( " - %s\n", buf );
 #else
         mbedtls_printf("\n");
 #endif
     }

     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
     mbedtls_mpi_free( &D ); mbedtls_mpi_free( &E ); mbedtls_mpi_free( &DP );
     mbedtls_mpi_free( &DQ ); mbedtls_mpi_free( &QP );

     mbedtls_pk_free( &key );

     mbedtls_ctr_drbg_free( &ctr_drbg );
     mbedtls_entropy_free( &entropy );

 #if defined(_WIN32)
     mbedtls_printf( "  + Press Enter to exit this program.\n" );
     fflush( stdout ); getchar();
 #endif

     mbedtls_exit( exit_code );
 }
 #endif /* MBEDTLS_PK_PARSE_C && MBEDTLS_PK_WRITE_C && MBEDTLS_FS_IO &&
           MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
	/*
	* Key writing application
	*
	* Copyright The Mbed TLS Contributors
	* SPDX-License-Identifier: Apache-2.0
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may
	* not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "mbedtls/build_info.h"

	#if defined(MBEDTLS_PLATFORM_C)
	#include "mbedtls/platform.h"
	#else
	#include <stdio.h>
	#include <stdlib.h>
	#define mbedtls_printf printf
	#define mbedtls_exit exit
	#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
	#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
	#endif /* MBEDTLS_PLATFORM_C */

	#if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_PK_WRITE_C) && \
	defined(MBEDTLS_FS_IO) && \
	defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
	#include "mbedtls/error.h"
	#include "mbedtls/pk.h"
	#include "mbedtls/error.h"

	#include "mbedtls/entropy.h"
	#include "mbedtls/ctr_drbg.h"

	#include <stdio.h>
	#include <string.h>
	#endif

	#if defined(MBEDTLS_PEM_WRITE_C)
	#define USAGE_OUT \
	" output_file=%%s default: keyfile.pem\n" \
	" output_format=pem\|der default: pem\n"
	#else
	#define USAGE_OUT \
	" output_file=%%s default: keyfile.der\n" \
	" output_format=der default: der\n"
	#endif

	#if defined(MBEDTLS_PEM_WRITE_C)
	#define DFL_OUTPUT_FILENAME "keyfile.pem"
	#define DFL_OUTPUT_FORMAT OUTPUT_FORMAT_PEM
	#else
	#define DFL_OUTPUT_FILENAME "keyfile.der"
	#define DFL_OUTPUT_FORMAT OUTPUT_FORMAT_DER
	#endif

	#define DFL_MODE MODE_NONE
	#define DFL_FILENAME "keyfile.key"
	#define DFL_DEBUG_LEVEL 0
	#define DFL_OUTPUT_MODE OUTPUT_MODE_NONE

	#define MODE_NONE 0
	#define MODE_PRIVATE 1
	#define MODE_PUBLIC 2

	#define OUTPUT_MODE_NONE 0
	#define OUTPUT_MODE_PRIVATE 1
	#define OUTPUT_MODE_PUBLIC 2

	#define OUTPUT_FORMAT_PEM 0
	#define OUTPUT_FORMAT_DER 1

	#define USAGE \
	"\n usage: key_app_writer param=<>...\n" \
	"\n acceptable parameters:\n" \
	" mode=private\|public default: none\n" \
	" filename=%%s default: keyfile.key\n" \
	" output_mode=private\|public default: none\n" \
	USAGE_OUT \
	"\n"

	#if !defined(MBEDTLS_PK_PARSE_C) \|\| \
	!defined(MBEDTLS_PK_WRITE_C) \|\| \
	!defined(MBEDTLS_FS_IO) \|\| \
	!defined(MBEDTLS_ENTROPY_C) \|\| \
	!defined(MBEDTLS_CTR_DRBG_C)
	int main( void )
	{
	mbedtls_printf( "MBEDTLS_PK_PARSE_C and/or MBEDTLS_PK_WRITE_C and/or "
	"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
	"MBEDTLS_FS_IO not defined.\n" );
	mbedtls_exit( 0 );
	}
	#else


	/*
	* global options
	*/
	struct options
	{
	int mode; /* the mode to run the application in */
	const char filename; / filename of the key file */
	int output_mode; /* the output mode to use */
	const char output_file; / where to store the constructed key file */
	int output_format; /* the output format to use */
	} opt;

	static int write_public_key( mbedtls_pk_context key, const char output_file )
	{
	int ret;
	FILE *f;
	unsigned char output_buf[16000];
	unsigned char *c = output_buf;
	size_t len = 0;

	memset(output_buf, 0, 16000);

	#if defined(MBEDTLS_PEM_WRITE_C)
	if( opt.output_format == OUTPUT_FORMAT_PEM )
	{
	if( ( ret = mbedtls_pk_write_pubkey_pem( key, output_buf, 16000 ) ) != 0 )
	return( ret );

	len = strlen( (char *) output_buf );
	}
	else
	#endif
	{
	if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf, 16000 ) ) < 0 )
	return( ret );

	len = ret;
	c = output_buf + sizeof(output_buf) - len;
	}

	if( ( f = fopen( output_file, "w" ) ) == NULL )
	return( -1 );

	if( fwrite( c, 1, len, f ) != len )
	{
	fclose( f );
	return( -1 );
	}

	fclose( f );

	return( 0 );
	}

	static int write_private_key( mbedtls_pk_context key, const char output_file )
	{
	int ret;
	FILE *f;
	unsigned char output_buf[16000];
	unsigned char *c = output_buf;
	size_t len = 0;

	memset(output_buf, 0, 16000);

	#if defined(MBEDTLS_PEM_WRITE_C)
	if( opt.output_format == OUTPUT_FORMAT_PEM )
	{
	if( ( ret = mbedtls_pk_write_key_pem( key, output_buf, 16000 ) ) != 0 )
	return( ret );

	len = strlen( (char *) output_buf );
	}
	else
	#endif
	{
	if( ( ret = mbedtls_pk_write_key_der( key, output_buf, 16000 ) ) < 0 )
	return( ret );

	len = ret;
	c = output_buf + sizeof(output_buf) - len;
	}

	if( ( f = fopen( output_file, "w" ) ) == NULL )
	return( -1 );

	if( fwrite( c, 1, len, f ) != len )
	{
	fclose( f );
	return( -1 );
	}

	fclose( f );

	return( 0 );
	}

	int main( int argc, char *argv[] )
	{
	int ret = 1;
	int exit_code = MBEDTLS_EXIT_FAILURE;
	char buf[1024];
	int i;
	char p, q;

	const char *pers = "pkey/key_app";
	mbedtls_entropy_context entropy;
	mbedtls_ctr_drbg_context ctr_drbg;

	mbedtls_pk_context key;
	mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;

	/*
	* Set to sane values
	*/
	mbedtls_entropy_init( &entropy );
	mbedtls_ctr_drbg_init( &ctr_drbg );

	mbedtls_pk_init( &key );
	memset( buf, 0, sizeof( buf ) );

	mbedtls_mpi_init( &N ); mbedtls_mpi_init( &P ); mbedtls_mpi_init( &Q );
	mbedtls_mpi_init( &D ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &DP );
	mbedtls_mpi_init( &DQ ); mbedtls_mpi_init( &QP );

	if( argc == 0 )
	{
	usage:
	mbedtls_printf( USAGE );
	goto exit;
	}

	opt.mode = DFL_MODE;
	opt.filename = DFL_FILENAME;
	opt.output_mode = DFL_OUTPUT_MODE;
	opt.output_file = DFL_OUTPUT_FILENAME;
	opt.output_format = DFL_OUTPUT_FORMAT;

	for( i = 1; i < argc; i++ )
	{
	p = argv[i];
	if( ( q = strchr( p, '=' ) ) == NULL )
	goto usage;
	*q++ = '\0';

	if( strcmp( p, "mode" ) == 0 )
	{
	if( strcmp( q, "private" ) == 0 )
	opt.mode = MODE_PRIVATE;
	else if( strcmp( q, "public" ) == 0 )
	opt.mode = MODE_PUBLIC;
	else
	goto usage;
	}
	else if( strcmp( p, "output_mode" ) == 0 )
	{
	if( strcmp( q, "private" ) == 0 )
	opt.output_mode = OUTPUT_MODE_PRIVATE;
	else if( strcmp( q, "public" ) == 0 )
	opt.output_mode = OUTPUT_MODE_PUBLIC;
	else
	goto usage;
	}
	else if( strcmp( p, "output_format" ) == 0 )
	{
	#if defined(MBEDTLS_PEM_WRITE_C)
	if( strcmp( q, "pem" ) == 0 )
	opt.output_format = OUTPUT_FORMAT_PEM;
	else
	#endif
	if( strcmp( q, "der" ) == 0 )
	opt.output_format = OUTPUT_FORMAT_DER;
	else
	goto usage;
	}
	else if( strcmp( p, "filename" ) == 0 )
	opt.filename = q;
	else if( strcmp( p, "output_file" ) == 0 )
	opt.output_file = q;
	else
	goto usage;
	}

	if( opt.mode == MODE_NONE && opt.output_mode != OUTPUT_MODE_NONE )
	{
	mbedtls_printf( "\nCannot output a key without reading one.\n");
	goto exit;
	}

	if( opt.mode == MODE_PUBLIC && opt.output_mode == OUTPUT_MODE_PRIVATE )
	{
	mbedtls_printf( "\nCannot output a private key from a public key.\n");
	goto exit;
	}

	if( opt.mode == MODE_PRIVATE )
	{
	/*
	* 1.1. Load the key
	*/
	mbedtls_printf( "\n . Loading the private key ..." );
	fflush( stdout );

	if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
	(const unsigned char *) pers,
	strlen( pers ) ) ) != 0 )
	{
	mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned -0x%04x\n", (unsigned int) -ret );
	goto exit;
	}

	ret = mbedtls_pk_parse_keyfile( &key, opt.filename, NULL,
	mbedtls_ctr_drbg_random, &ctr_drbg );
	if( ret != 0 )
	{
	mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
	mbedtls_printf( " failed\n ! mbedtls_pk_parse_keyfile returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
	goto exit;
	}

	mbedtls_printf( " ok\n" );

	/*
	* 1.2 Print the key
	*/
	mbedtls_printf( " . Key information ...\n" );

	#if defined(MBEDTLS_RSA_C)
	if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_RSA )
	{
	mbedtls_rsa_context *rsa = mbedtls_pk_rsa( key );

	if( ( ret = mbedtls_rsa_export ( rsa, &N, &P, &Q, &D, &E ) ) != 0 \|\|
	( ret = mbedtls_rsa_export_crt( rsa, &DP, &DQ, &QP ) ) != 0 )
	{
	mbedtls_printf( " failed\n ! could not export RSA parameters\n\n" );
	goto exit;
	}

	mbedtls_mpi_write_file( "N: ", &N, 16, NULL );
	mbedtls_mpi_write_file( "E: ", &E, 16, NULL );
	mbedtls_mpi_write_file( "D: ", &D, 16, NULL );
	mbedtls_mpi_write_file( "P: ", &P, 16, NULL );
	mbedtls_mpi_write_file( "Q: ", &Q, 16, NULL );
	mbedtls_mpi_write_file( "DP: ", &DP, 16, NULL );
	mbedtls_mpi_write_file( "DQ: ", &DQ, 16, NULL );
	mbedtls_mpi_write_file( "QP: ", &QP, 16, NULL );
	}
	else
	#endif
	#if defined(MBEDTLS_ECP_C)
	if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_ECKEY )
	{
	mbedtls_ecp_keypair *ecp = mbedtls_pk_ec( key );
	mbedtls_mpi_write_file( "Q(X): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), 16, NULL );
	mbedtls_mpi_write_file( "Q(Y): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Y), 16, NULL );
	mbedtls_mpi_write_file( "Q(Z): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Z), 16, NULL );
	mbedtls_mpi_write_file( "D : ", &ecp->MBEDTLS_PRIVATE(d) , 16, NULL );
	}
	else
	#endif
	mbedtls_printf("key type not supported yet\n");

	}
	else if( opt.mode == MODE_PUBLIC )
	{
	/*
	* 1.1. Load the key
	*/
	mbedtls_printf( "\n . Loading the public key ..." );
	fflush( stdout );

	ret = mbedtls_pk_parse_public_keyfile( &key, opt.filename );

	if( ret != 0 )
	{
	mbedtls_strerror( ret, (char *) buf, sizeof(buf) );
	mbedtls_printf( " failed\n ! mbedtls_pk_parse_public_key returned -0x%04x - %s\n\n", (unsigned int) -ret, buf );
	goto exit;
	}

	mbedtls_printf( " ok\n" );

	/*
	* 1.2 Print the key
	*/
	mbedtls_printf( " . Key information ...\n" );

	#if defined(MBEDTLS_RSA_C)
	if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_RSA )
	{
	mbedtls_rsa_context *rsa = mbedtls_pk_rsa( key );

	if( ( ret = mbedtls_rsa_export( rsa, &N, NULL, NULL,
	NULL, &E ) ) != 0 )
	{
	mbedtls_printf( " failed\n ! could not export RSA parameters\n\n" );
	goto exit;
	}
	mbedtls_mpi_write_file( "N: ", &N, 16, NULL );
	mbedtls_mpi_write_file( "E: ", &E, 16, NULL );
	}
	else
	#endif
	#if defined(MBEDTLS_ECP_C)
	if( mbedtls_pk_get_type( &key ) == MBEDTLS_PK_ECKEY )
	{
	mbedtls_ecp_keypair *ecp = mbedtls_pk_ec( key );
	mbedtls_mpi_write_file( "Q(X): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X), 16, NULL );
	mbedtls_mpi_write_file( "Q(Y): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Y), 16, NULL );
	mbedtls_mpi_write_file( "Q(Z): ", &ecp->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Z), 16, NULL );
	}
	else
	#endif
	mbedtls_printf("key type not supported yet\n");
	}
	else
	goto usage;

	if( opt.output_mode == OUTPUT_MODE_PUBLIC )
	{
	write_public_key( &key, opt.output_file );
	}
	if( opt.output_mode == OUTPUT_MODE_PRIVATE )
	{
	write_private_key( &key, opt.output_file );
	}

	exit_code = MBEDTLS_EXIT_SUCCESS;

	exit:

	if( exit_code != MBEDTLS_EXIT_SUCCESS )
	{
	#ifdef MBEDTLS_ERROR_C
	mbedtls_strerror( ret, buf, sizeof( buf ) );
	mbedtls_printf( " - %s\n", buf );
	#else
	mbedtls_printf("\n");
	#endif
	}

	mbedtls_mpi_free( &N ); mbedtls_mpi_free( &P ); mbedtls_mpi_free( &Q );
	mbedtls_mpi_free( &D ); mbedtls_mpi_free( &E ); mbedtls_mpi_free( &DP );
	mbedtls_mpi_free( &DQ ); mbedtls_mpi_free( &QP );

	mbedtls_pk_free( &key );

	mbedtls_ctr_drbg_free( &ctr_drbg );
	mbedtls_entropy_free( &entropy );

	#if defined(_WIN32)
	mbedtls_printf( " + Press Enter to exit this program.\n" );
	fflush( stdout ); getchar();
	#endif

	mbedtls_exit( exit_code );
	}
	#endif /* MBEDTLS_PK_PARSE_C && MBEDTLS_PK_WRITE_C && MBEDTLS_FS_IO &&
	MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */