177 lines
5.3 KiB
C
177 lines
5.3 KiB
C
/**
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* \file ecdh.h
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*
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* \brief Elliptic curve Diffie-Hellman
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*
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* Copyright (C) 2006-2013, Brainspark B.V.
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*
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* This file is part of PolarSSL (http://www.polarssl.org)
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* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef POLARSSL_ECDH_H
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#define POLARSSL_ECDH_H
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#include "polarssl/ecp.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* \brief ECDH context structure
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*/
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typedef struct
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{
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ecp_group grp; /*!< ellipitic curve used */
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mpi d; /*!< our secret value */
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ecp_point Q; /*!< our public value */
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ecp_point Qp; /*!< peer's public value */
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mpi z; /*!< shared secret */
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int point_format; /*!< format for point export */
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}
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ecdh_context;
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/**
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* \brief Generate a public key
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*
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* \param grp ECP group
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* \param d Destination MPI (secret exponent)
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* \param Q Destination point (public key)
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* \param f_rng RNG function
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* \param p_rng RNG parameter
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*
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* \return 0 if successful,
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* or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code
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*/
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int ecdh_gen_public( const ecp_group *grp, mpi *d, ecp_point *Q,
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int (*f_rng)(void *, unsigned char *, size_t),
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void *p_rng );
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/**
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* \brief Compute shared secret
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*
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* \param grp ECP group
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* \param z Destination MPI (shared secret)
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* \param Q Public key from other party
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* \param d Our secret exponent
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*
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* \return 0 if successful,
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* or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code
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*/
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int ecdh_compute_shared( const ecp_group *grp, mpi *z,
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const ecp_point *Q, const mpi *d );
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/**
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* \brief Initialize context
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*
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* \param ctx Context to initialize
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*/
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void ecdh_init( ecdh_context *ctx );
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/**
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* \brief Free context
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*
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* \param ctx Context to free
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*/
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void ecdh_free( ecdh_context *ctx );
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/**
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* \brief Setup and write the ServerKeyExhange parameters
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*
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* \param ctx ECDH context
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* \param buf destination buffer
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* \param olen number of chars written
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* \param f_rng RNG function
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* \param p_rng RNG parameter
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*
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* \note This function assumes that ctx->grp has already been
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* properly set (for example using ecp_use_known_dp).
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*
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* \return 0 if successful, or an POLARSSL_ERR_ECP_XXX error code
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*/
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int ecdh_make_params( ecdh_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int (*f_rng)(void *, unsigned char *, size_t),
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void *p_rng );
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/**
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* \brief Parse the ServerKeyExhange parameters
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*
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* \param ctx ECDH context
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* \param buf $(start of input buffer)
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* \param end one past end of buffer
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*
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* \return 0 if successful, or an POLARSSL_ERR_ECP_XXX error code
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*/
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int ecdh_read_params( ecdh_context *ctx,
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const unsigned char **buf, const unsigned char *end );
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/**
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* \brief Setup and export the client's public value
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*
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* \param ctx ECDH context
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* \param olen number of bytes actually written
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* \param buf destination buffer
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* \param blen size of destination buffer
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*
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* \return 0 if successful, or an POLARSSL_ERR_ECP_XXX error code
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*/
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int ecdh_make_public( ecdh_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int (*f_rng)(void *, unsigned char *, size_t),
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void *p_rng );
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/**
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* \brief Parse and import the client's public value
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*
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* \param ctx ECDH context
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* \param buf start of input buffer
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* \param blen length of input buffer
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*
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* \return 0 if successful, or an POLARSSL_ERR_ECP_XXX error code
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*/
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int ecdh_read_public( ecdh_context *ctx,
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const unsigned char *buf, size_t blen );
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/**
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* \brief Derive and export the shared secret
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*
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* \param ctx ECDH context
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* \param olen number of bytes written
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* \param buf destination buffer
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* \param blen buffer length
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*
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* \return 0 if successful, or an POLARSSL_ERR_ECP_XXX error code
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*/
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int ecdh_calc_secret( ecdh_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen );
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/**
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* \brief Checkup routine
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*
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* \return 0 if successful, or 1 if the test failed
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*/
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int ecdh_self_test( int verbose );
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#ifdef __cplusplus
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}
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#endif
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#endif
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