ecdh.h

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/*
 *  Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
 *  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.
 *
 *  This file is part of Mbed TLS (https://tls.mbed.org)
 */

#ifndef MBEDTLS_ECDH_H
#define MBEDTLS_ECDH_H

#include "ecp.h"

/*
 * Use a backward compatible ECDH context.
 *
 * This flag is always enabled for now and future versions might add a
 * configuration option that conditionally undefines this flag.
 * The configuration option in question may have a different name.
 *
 * Features undefining this flag, must have a warning in their description in
 * config.h stating that the feature breaks backward compatibility.
 */
#define MBEDTLS_ECDH_LEGACY_CONTEXT

#ifdef __cplusplus
extern "C" {
#endif

typedef enum
{
    MBEDTLS_ECDH_OURS,   
    MBEDTLS_ECDH_THEIRS, 
} mbedtls_ecdh_side;

#if !defined(MBEDTLS_ECDH_LEGACY_CONTEXT)

typedef enum
{
    MBEDTLS_ECDH_VARIANT_NONE = 0,   
    MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0,
} mbedtls_ecdh_variant;

typedef struct mbedtls_ecdh_context_mbed
{
    mbedtls_ecp_group grp;   
    mbedtls_mpi d;           
    mbedtls_ecp_point Q;     
    mbedtls_ecp_point Qp;    
    mbedtls_mpi z;           
#if defined(MBEDTLS_ECP_RESTARTABLE)
    mbedtls_ecp_restart_ctx rs; 
#endif
} mbedtls_ecdh_context_mbed;
#endif

typedef struct mbedtls_ecdh_context
{
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
    mbedtls_ecp_group grp;   
    mbedtls_mpi d;           
    mbedtls_ecp_point Q;     
    mbedtls_ecp_point Qp;    
    mbedtls_mpi z;           
    int point_format;        
    mbedtls_ecp_point Vi;    
    mbedtls_ecp_point Vf;    
    mbedtls_mpi _d;          
#if defined(MBEDTLS_ECP_RESTARTABLE)
    int restart_enabled;        
    mbedtls_ecp_restart_ctx rs; 
#endif /* MBEDTLS_ECP_RESTARTABLE */
#else
    uint8_t point_format;       
    mbedtls_ecp_group_id grp_id;
    mbedtls_ecdh_variant var;   
    union
    {
        mbedtls_ecdh_context_mbed   mbed_ecdh;
    } ctx;                      
#if defined(MBEDTLS_ECP_RESTARTABLE)
    uint8_t restart_enabled;    
#endif /* MBEDTLS_ECP_RESTARTABLE */
#endif /* MBEDTLS_ECDH_LEGACY_CONTEXT */
}
mbedtls_ecdh_context;

int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
                     int (*f_rng)(void *, unsigned char *, size_t),
                     void *p_rng );

int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
                         const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
                         int (*f_rng)(void *, unsigned char *, size_t),
                         void *p_rng );

void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx );

int mbedtls_ecdh_setup( mbedtls_ecdh_context *ctx,
                        mbedtls_ecp_group_id grp_id );

void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx );

int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
                      unsigned char *buf, size_t blen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx,
                              const unsigned char **buf,
                              const unsigned char *end );

int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx,
                             const mbedtls_ecp_keypair *key,
                             mbedtls_ecdh_side side );

int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
                      unsigned char *buf, size_t blen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx,
                              const unsigned char *buf, size_t blen );

int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
                      unsigned char *buf, size_t blen,
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng );

#if defined(MBEDTLS_ECP_RESTARTABLE)

void mbedtls_ecdh_enable_restart( mbedtls_ecdh_context *ctx );
#endif /* MBEDTLS_ECP_RESTARTABLE */

#ifdef __cplusplus
}
#endif

#endif /* ecdh.h */