include/polarssl/dhm.h - third_party/github/ARMmbed/mbedtls - Git at Google

 /**
  * \file dhm.h
  *
  * \brief Diffie-Hellman-Merkle key exchange
  *
  *  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.
  */
 #ifndef POLARSSL_DHM_H
 #define POLARSSL_DHM_H

 #include "bignum.h"

 /*
  * DHM Error codes
  */
 #define POLARSSL_ERR_DHM_BAD_INPUT_DATA                    -0x3080  /**< Bad input parameters to function. */
 #define POLARSSL_ERR_DHM_READ_PARAMS_FAILED                -0x3100  /**< Reading of the DHM parameters failed. */
 #define POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED                -0x3180  /**< Making of the DHM parameters failed. */
 #define POLARSSL_ERR_DHM_READ_PUBLIC_FAILED                -0x3200  /**< Reading of the public values failed. */
 #define POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED                -0x3280  /**< Making of the public value failed. */
 #define POLARSSL_ERR_DHM_CALC_SECRET_FAILED                -0x3300  /**< Calculation of the DHM secret failed. */
 #define POLARSSL_ERR_DHM_INVALID_FORMAT                    -0x3380  /**< The ASN.1 data is not formatted correctly. */
 #define POLARSSL_ERR_DHM_MALLOC_FAILED                     -0x3400  /**< Allocation of memory failed. */
 #define POLARSSL_ERR_DHM_FILE_IO_ERROR                     -0x3480  /**< Read/write of file failed. */

 /**
  * RFC 2409 defines a number of standardized Diffie-Hellman groups
  * that can be used.
  * RFC 3526 defines a number of standardized Diffie-Hellman groups
  * for IKE.
  * RFC 5114 defines a number of standardized Diffie-Hellman groups
  * that can be used.
  *
  * Some are included here for convenience.
  *
  * Included are:
  *  RFC 2409 6.2.  1024-bit MODP Group (Second Oakley Group)
  *  RFC 3526 3.    2048-bit MODP Group
  *  RFC 3526 4.    3072-bit MODP Group
  *  RFC 5114 2.1.  1024-bit MODP Group with 160-bit Prime Order Subgroup
  *  RFC 5114 2.2.  2048-bit MODP Group with 224-bit Prime Order Subgroup
  */
 #define POLARSSL_DHM_RFC2409_MODP_1024_P               \
     "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
     "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
     "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
     "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
     "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" \
     "FFFFFFFFFFFFFFFF"

 #define POLARSSL_DHM_RFC2409_MODP_1024_G          "02"

 #define POLARSSL_DHM_RFC3526_MODP_2048_P               \
     "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
     "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
     "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
     "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
     "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" \
     "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" \
     "83655D23DCA3AD961C62F356208552BB9ED529077096966D" \
     "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" \
     "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" \
     "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" \
     "15728E5A8AACAA68FFFFFFFFFFFFFFFF"

 #define POLARSSL_DHM_RFC3526_MODP_2048_G          "02"

 #define POLARSSL_DHM_RFC3526_MODP_3072_P               \
     "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
     "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
     "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
     "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
     "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" \
     "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" \
     "83655D23DCA3AD961C62F356208552BB9ED529077096966D" \
     "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" \
     "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" \
     "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" \
     "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64" \
     "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7" \
     "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B" \
     "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C" \
     "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31" \
     "43DB5BFCE0FD108E4B82D120A93AD2CAFFFFFFFFFFFFFFFF"

 #define POLARSSL_DHM_RFC3526_MODP_3072_G          "02"

 #define POLARSSL_DHM_RFC5114_MODP_1024_P               \
     "B10B8F96A080E01DDE92DE5EAE5D54EC52C99FBCFB06A3C6" \
     "9A6A9DCA52D23B616073E28675A23D189838EF1E2EE652C0" \
     "13ECB4AEA906112324975C3CD49B83BFACCBDD7D90C4BD70" \
     "98488E9C219A73724EFFD6FAE5644738FAA31A4FF55BCCC0" \
     "A151AF5F0DC8B4BD45BF37DF365C1A65E68CFDA76D4DA708" \
     "DF1FB2BC2E4A4371"

 #define POLARSSL_DHM_RFC5114_MODP_1024_G               \
     "A4D1CBD5C3FD34126765A442EFB99905F8104DD258AC507F" \
     "D6406CFF14266D31266FEA1E5C41564B777E690F5504F213" \
     "160217B4B01B886A5E91547F9E2749F4D7FBD7D3B9A92EE1" \
     "909D0D2263F80A76A6A24C087A091F531DBF0A0169B6A28A" \
     "D662A4D18E73AFA32D779D5918D08BC8858F4DCEF97C2A24" \
     "855E6EEB22B3B2E5"

 #define POLARSSL_DHM_RFC5114_MODP_2048_P               \
     "AD107E1E9123A9D0D660FAA79559C51FA20D64E5683B9FD1" \
     "B54B1597B61D0A75E6FA141DF95A56DBAF9A3C407BA1DF15" \
     "EB3D688A309C180E1DE6B85A1274A0A66D3F8152AD6AC212" \
     "9037C9EDEFDA4DF8D91E8FEF55B7394B7AD5B7D0B6C12207" \
     "C9F98D11ED34DBF6C6BA0B2C8BBC27BE6A00E0A0B9C49708" \
     "B3BF8A317091883681286130BC8985DB1602E714415D9330" \
     "278273C7DE31EFDC7310F7121FD5A07415987D9ADC0A486D" \
     "CDF93ACC44328387315D75E198C641A480CD86A1B9E587E8" \
     "BE60E69CC928B2B9C52172E413042E9B23F10B0E16E79763" \
     "C9B53DCF4BA80A29E3FB73C16B8E75B97EF363E2FFA31F71" \
     "CF9DE5384E71B81C0AC4DFFE0C10E64F"

 #define POLARSSL_DHM_RFC5114_MODP_2048_G              \
     "AC4032EF4F2D9AE39DF30B5C8FFDAC506CDEBE7B89998CAF"\
     "74866A08CFE4FFE3A6824A4E10B9A6F0DD921F01A70C4AFA"\
     "AB739D7700C29F52C57DB17C620A8652BE5E9001A8D66AD7"\
     "C17669101999024AF4D027275AC1348BB8A762D0521BC98A"\
     "E247150422EA1ED409939D54DA7460CDB5F6C6B250717CBE"\
     "F180EB34118E98D119529A45D6F834566E3025E316A330EF"\
     "BB77A86F0C1AB15B051AE3D428C8F8ACB70A8137150B8EEB"\
     "10E183EDD19963DDD9E263E4770589EF6AA21E7F5F2FF381"\
     "B539CCE3409D13CD566AFBB48D6C019181E1BCFE94B30269"\
     "EDFE72FE9B6AA4BD7B5A0F1C71CFFF4C19C418E1F6EC0179"\
     "81BC087F2A7065B384B890D3191F2BFA"

 #ifdef __cplusplus
 extern "C" {
 #endif

 /**
  * \brief          DHM context structure
  */
 typedef struct
 {
     size_t len; /*!<  size(P) in chars  */
     mpi P;      /*!<  prime modulus     */
     mpi G;      /*!<  generator         */
     mpi X;      /*!<  secret value      */
     mpi GX;     /*!<  self = G^X mod P  */
     mpi GY;     /*!<  peer = G^Y mod P  */
     mpi K;      /*!<  key = GY^X mod P  */
     mpi RP;     /*!<  cached R^2 mod P  */
     mpi Vi;     /*!<  blinding value    */
     mpi Vf;     /*!<  un-blinding value */
     mpi pX;     /*!<  previous X        */
 }
 dhm_context;

 /**
  * \brief          Parse the ServerKeyExchange parameters
  *
  * \param ctx      DHM context
  * \param p        &(start of input buffer)
  * \param end      end of buffer
  *
  * \return         0 if successful, or an POLARSSL_ERR_DHM_XXX error code
  */
 int dhm_read_params( dhm_context *ctx,
                      unsigned char **p,
                      const unsigned char *end );

 /**
  * \brief          Setup and write the ServerKeyExchange parameters
  *
  * \param ctx      DHM context
  * \param x_size   private value size in bytes
  * \param output   destination buffer
  * \param olen     number of chars written
  * \param f_rng    RNG function
  * \param p_rng    RNG parameter
  *
  * \note           This function assumes that ctx->P and ctx->G
  *                 have already been properly set (for example
  *                 using mpi_read_string or mpi_read_binary).
  *
  * \return         0 if successful, or an POLARSSL_ERR_DHM_XXX error code
  */
 int dhm_make_params( dhm_context *ctx, int x_size,
                      unsigned char *output, size_t *olen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

 /**
  * \brief          Import the peer's public value G^Y
  *
  * \param ctx      DHM context
  * \param input    input buffer
  * \param ilen     size of buffer
  *
  * \return         0 if successful, or an POLARSSL_ERR_DHM_XXX error code
  */
 int dhm_read_public( dhm_context *ctx,
                      const unsigned char *input, size_t ilen );

 /**
  * \brief          Create own private value X and export G^X
  *
  * \param ctx      DHM context
  * \param x_size   private value size in bytes
  * \param output   destination buffer
  * \param olen     must be equal to ctx->P.len
  * \param f_rng    RNG function
  * \param p_rng    RNG parameter
  *
  * \return         0 if successful, or an POLARSSL_ERR_DHM_XXX error code
  */
 int dhm_make_public( dhm_context *ctx, int x_size,
                      unsigned char *output, size_t olen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

 /**
  * \brief          Derive and export the shared secret (G^Y)^X mod P
  *
  * \param ctx      DHM context
  * \param output   destination buffer
  * \param olen     number of chars written
  * \param f_rng    RNG function, for blinding purposes
  * \param p_rng    RNG parameter
  *
  * \return         0 if successful, or an POLARSSL_ERR_DHM_XXX error code
  *
  * \note           If non-NULL, f_rng is used to blind the input as
  *                 countermeasure against timing attacks. Blinding is
  *                 automatically used if and only if our secret value X is
  *                 re-used and costs nothing otherwise, so it is recommended
  *                 to always pass a non-NULL f_rng argument.
  */
 int dhm_calc_secret( dhm_context *ctx,
                      unsigned char *output, size_t *olen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

 /**
  * \brief          Free the components of a DHM key
  */
 void dhm_free( dhm_context *ctx );

 #if defined(POLARSSL_ASN1_PARSE_C)
 /** \ingroup x509_module */
 /**
  * \brief          Parse DHM parameters
  *
  * \param dhm      DHM context to be initialized
  * \param dhmin    input buffer
  * \param dhminlen size of the buffer
  *
  * \return         0 if successful, or a specific DHM or PEM error code
  */
 int dhm_parse_dhm( dhm_context *dhm, const unsigned char *dhmin,
                    size_t dhminlen );

 #if defined(POLARSSL_FS_IO)
 /** \ingroup x509_module */
 /**
  * \brief          Load and parse DHM parameters
  *
  * \param dhm      DHM context to be initialized
  * \param path     filename to read the DHM Parameters from
  *
  * \return         0 if successful, or a specific DHM or PEM error code
  */
 int dhm_parse_dhmfile( dhm_context *dhm, const char *path );
 #endif /* POLARSSL_FS_IO */
 #endif /* POLARSSL_ASN1_PARSE_C */

 /**
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
  */
 int dhm_self_test( int verbose );

 #ifdef __cplusplus
 }
 #endif

 #endif /* dhm.h */
	/**
	* \file dhm.h
	*
	* \brief Diffie-Hellman-Merkle key exchange
	*
	* 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.
	*/
	#ifndef POLARSSL_DHM_H
	#define POLARSSL_DHM_H

	#include "bignum.h"

	/*
	* DHM Error codes
	*/
	#define POLARSSL_ERR_DHM_BAD_INPUT_DATA -0x3080 /*< Bad input parameters to function. /
	#define POLARSSL_ERR_DHM_READ_PARAMS_FAILED -0x3100 /*< Reading of the DHM parameters failed. /
	#define POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED -0x3180 /*< Making of the DHM parameters failed. /
	#define POLARSSL_ERR_DHM_READ_PUBLIC_FAILED -0x3200 /*< Reading of the public values failed. /
	#define POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED -0x3280 /*< Making of the public value failed. /
	#define POLARSSL_ERR_DHM_CALC_SECRET_FAILED -0x3300 /*< Calculation of the DHM secret failed. /
	#define POLARSSL_ERR_DHM_INVALID_FORMAT -0x3380 /*< The ASN.1 data is not formatted correctly. /
	#define POLARSSL_ERR_DHM_MALLOC_FAILED -0x3400 /*< Allocation of memory failed. /
	#define POLARSSL_ERR_DHM_FILE_IO_ERROR -0x3480 /*< Read/write of file failed. /

	/**
	* RFC 2409 defines a number of standardized Diffie-Hellman groups
	* that can be used.
	* RFC 3526 defines a number of standardized Diffie-Hellman groups
	* for IKE.
	* RFC 5114 defines a number of standardized Diffie-Hellman groups
	* that can be used.
	*
	* Some are included here for convenience.
	*
	* Included are:
	* RFC 2409 6.2. 1024-bit MODP Group (Second Oakley Group)
	* RFC 3526 3. 2048-bit MODP Group
	* RFC 3526 4. 3072-bit MODP Group
	* RFC 5114 2.1. 1024-bit MODP Group with 160-bit Prime Order Subgroup
	* RFC 5114 2.2. 2048-bit MODP Group with 224-bit Prime Order Subgroup
	*/
	#define POLARSSL_DHM_RFC2409_MODP_1024_P \
	"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
	"29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
	"EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
	"E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
	"EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" \
	"FFFFFFFFFFFFFFFF"

	#define POLARSSL_DHM_RFC2409_MODP_1024_G "02"

	#define POLARSSL_DHM_RFC3526_MODP_2048_P \
	"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
	"29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
	"EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
	"E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
	"EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" \
	"C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" \
	"83655D23DCA3AD961C62F356208552BB9ED529077096966D" \
	"670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" \
	"E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" \
	"DE2BCBF6955817183995497CEA956AE515D2261898FA0510" \
	"15728E5A8AACAA68FFFFFFFFFFFFFFFF"

	#define POLARSSL_DHM_RFC3526_MODP_2048_G "02"

	#define POLARSSL_DHM_RFC3526_MODP_3072_P \
	"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" \
	"29024E088A67CC74020BBEA63B139B22514A08798E3404DD" \
	"EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" \
	"E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
	"EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" \
	"C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" \
	"83655D23DCA3AD961C62F356208552BB9ED529077096966D" \
	"670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" \
	"E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" \
	"DE2BCBF6955817183995497CEA956AE515D2261898FA0510" \
	"15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64" \
	"ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7" \
	"ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B" \
	"F12FFA06D98A0864D87602733EC86A64521F2B18177B200C" \
	"BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31" \
	"43DB5BFCE0FD108E4B82D120A93AD2CAFFFFFFFFFFFFFFFF"

	#define POLARSSL_DHM_RFC3526_MODP_3072_G "02"

	#define POLARSSL_DHM_RFC5114_MODP_1024_P \
	"B10B8F96A080E01DDE92DE5EAE5D54EC52C99FBCFB06A3C6" \
	"9A6A9DCA52D23B616073E28675A23D189838EF1E2EE652C0" \
	"13ECB4AEA906112324975C3CD49B83BFACCBDD7D90C4BD70" \
	"98488E9C219A73724EFFD6FAE5644738FAA31A4FF55BCCC0" \
	"A151AF5F0DC8B4BD45BF37DF365C1A65E68CFDA76D4DA708" \
	"DF1FB2BC2E4A4371"

	#define POLARSSL_DHM_RFC5114_MODP_1024_G \
	"A4D1CBD5C3FD34126765A442EFB99905F8104DD258AC507F" \
	"D6406CFF14266D31266FEA1E5C41564B777E690F5504F213" \
	"160217B4B01B886A5E91547F9E2749F4D7FBD7D3B9A92EE1" \
	"909D0D2263F80A76A6A24C087A091F531DBF0A0169B6A28A" \
	"D662A4D18E73AFA32D779D5918D08BC8858F4DCEF97C2A24" \
	"855E6EEB22B3B2E5"

	#define POLARSSL_DHM_RFC5114_MODP_2048_P \
	"AD107E1E9123A9D0D660FAA79559C51FA20D64E5683B9FD1" \
	"B54B1597B61D0A75E6FA141DF95A56DBAF9A3C407BA1DF15" \
	"EB3D688A309C180E1DE6B85A1274A0A66D3F8152AD6AC212" \
	"9037C9EDEFDA4DF8D91E8FEF55B7394B7AD5B7D0B6C12207" \
	"C9F98D11ED34DBF6C6BA0B2C8BBC27BE6A00E0A0B9C49708" \
	"B3BF8A317091883681286130BC8985DB1602E714415D9330" \
	"278273C7DE31EFDC7310F7121FD5A07415987D9ADC0A486D" \
	"CDF93ACC44328387315D75E198C641A480CD86A1B9E587E8" \
	"BE60E69CC928B2B9C52172E413042E9B23F10B0E16E79763" \
	"C9B53DCF4BA80A29E3FB73C16B8E75B97EF363E2FFA31F71" \
	"CF9DE5384E71B81C0AC4DFFE0C10E64F"

	#define POLARSSL_DHM_RFC5114_MODP_2048_G \
	"AC4032EF4F2D9AE39DF30B5C8FFDAC506CDEBE7B89998CAF"\
	"74866A08CFE4FFE3A6824A4E10B9A6F0DD921F01A70C4AFA"\
	"AB739D7700C29F52C57DB17C620A8652BE5E9001A8D66AD7"\
	"C17669101999024AF4D027275AC1348BB8A762D0521BC98A"\
	"E247150422EA1ED409939D54DA7460CDB5F6C6B250717CBE"\
	"F180EB34118E98D119529A45D6F834566E3025E316A330EF"\
	"BB77A86F0C1AB15B051AE3D428C8F8ACB70A8137150B8EEB"\
	"10E183EDD19963DDD9E263E4770589EF6AA21E7F5F2FF381"\
	"B539CCE3409D13CD566AFBB48D6C019181E1BCFE94B30269"\
	"EDFE72FE9B6AA4BD7B5A0F1C71CFFF4C19C418E1F6EC0179"\
	"81BC087F2A7065B384B890D3191F2BFA"

	#ifdef __cplusplus
	extern "C" {
	#endif

	/**
	* \brief DHM context structure
	*/
	typedef struct
	{
	size_t len; /!< size(P) in chars /
	mpi P; /!< prime modulus /
	mpi G; /!< generator /
	mpi X; /!< secret value /
	mpi GX; /!< self = G^X mod P /
	mpi GY; /!< peer = G^Y mod P /
	mpi K; /!< key = GY^X mod P /
	mpi RP; /!< cached R^2 mod P /
	mpi Vi; /!< blinding value /
	mpi Vf; /!< un-blinding value /
	mpi pX; /!< previous X /
	}
	dhm_context;

	/**
	* \brief Parse the ServerKeyExchange parameters
	*
	* \param ctx DHM context
	* \param p &(start of input buffer)
	* \param end end of buffer
	*
	* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
	*/
	int dhm_read_params( dhm_context *ctx,
	unsigned char **p,
	const unsigned char *end );

	/**
	* \brief Setup and write the ServerKeyExchange parameters
	*
	* \param ctx DHM context
	* \param x_size private value size in bytes
	* \param output destination buffer
	* \param olen number of chars written
	* \param f_rng RNG function
	* \param p_rng RNG parameter
	*
	* \note This function assumes that ctx->P and ctx->G
	* have already been properly set (for example
	* using mpi_read_string or mpi_read_binary).
	*
	* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
	*/
	int dhm_make_params( dhm_context *ctx, int x_size,
	unsigned char output, size_t olen,
	int (f_rng)(void , unsigned char *, size_t),
	void *p_rng );

	/**
	* \brief Import the peer's public value G^Y
	*
	* \param ctx DHM context
	* \param input input buffer
	* \param ilen size of buffer
	*
	* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
	*/
	int dhm_read_public( dhm_context *ctx,
	const unsigned char *input, size_t ilen );

	/**
	* \brief Create own private value X and export G^X
	*
	* \param ctx DHM context
	* \param x_size private value size in bytes
	* \param output destination buffer
	* \param olen must be equal to ctx->P.len
	* \param f_rng RNG function
	* \param p_rng RNG parameter
	*
	* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
	*/
	int dhm_make_public( dhm_context *ctx, int x_size,
	unsigned char *output, size_t olen,
	int (f_rng)(void , unsigned char *, size_t),
	void *p_rng );

	/**
	* \brief Derive and export the shared secret (G^Y)^X mod P
	*
	* \param ctx DHM context
	* \param output destination buffer
	* \param olen number of chars written
	* \param f_rng RNG function, for blinding purposes
	* \param p_rng RNG parameter
	*
	* \return 0 if successful, or an POLARSSL_ERR_DHM_XXX error code
	*
	* \note If non-NULL, f_rng is used to blind the input as
	* countermeasure against timing attacks. Blinding is
	* automatically used if and only if our secret value X is
	* re-used and costs nothing otherwise, so it is recommended
	* to always pass a non-NULL f_rng argument.
	*/
	int dhm_calc_secret( dhm_context *ctx,
	unsigned char output, size_t olen,
	int (f_rng)(void , unsigned char *, size_t),
	void *p_rng );

	/**
	* \brief Free the components of a DHM key
	*/
	void dhm_free( dhm_context *ctx );

	#if defined(POLARSSL_ASN1_PARSE_C)
	/** \ingroup x509_module */
	/**
	* \brief Parse DHM parameters
	*
	* \param dhm DHM context to be initialized
	* \param dhmin input buffer
	* \param dhminlen size of the buffer
	*
	* \return 0 if successful, or a specific DHM or PEM error code
	*/
	int dhm_parse_dhm( dhm_context dhm, const unsigned char dhmin,
	size_t dhminlen );

	#if defined(POLARSSL_FS_IO)
	/** \ingroup x509_module */
	/**
	* \brief Load and parse DHM parameters
	*
	* \param dhm DHM context to be initialized
	* \param path filename to read the DHM Parameters from
	*
	* \return 0 if successful, or a specific DHM or PEM error code
	*/
	int dhm_parse_dhmfile( dhm_context dhm, const char path );
	#endif /* POLARSSL_FS_IO */
	#endif /* POLARSSL_ASN1_PARSE_C */

	/**
	* \brief Checkup routine
	*
	* \return 0 if successful, or 1 if the test failed
	*/
	int dhm_self_test( int verbose );

	#ifdef __cplusplus
	}
	#endif

	#endif /* dhm.h */