243 lines
7.0 KiB
C
243 lines
7.0 KiB
C
/*
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* Example ECDHE with Curve25519 program
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdio.h>
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#include <stdlib.h>
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#define mbedtls_printf printf
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#define mbedtls_exit exit
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#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
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#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
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#endif /* MBEDTLS_PLATFORM_C */
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#if !defined(MBEDTLS_ECDH_C) || !defined(MBEDTLS_ECDH_LEGACY_CONTEXT) || \
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!defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
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!defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C)
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int main( void )
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{
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mbedtls_printf( "MBEDTLS_ECDH_C and/or MBEDTLS_ECDH_LEGACY_CONTEXT and/or "
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"MBEDTLS_ECP_DP_CURVE25519_ENABLED and/or "
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"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C "
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"not defined\n" );
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mbedtls_exit( 0 );
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}
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#else
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "mbedtls/ecdh.h"
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int main( int argc, char *argv[] )
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{
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int ret = 1;
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int exit_code = MBEDTLS_EXIT_FAILURE;
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mbedtls_ecdh_context ctx_cli, ctx_srv;
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mbedtls_entropy_context entropy;
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mbedtls_ctr_drbg_context ctr_drbg;
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unsigned char cli_to_srv[32], srv_to_cli[32];
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const char pers[] = "ecdh";
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((void) argc);
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((void) argv);
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mbedtls_ecdh_init( &ctx_cli );
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mbedtls_ecdh_init( &ctx_srv );
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mbedtls_ctr_drbg_init( &ctr_drbg );
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/*
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* Initialize random number generation
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*/
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mbedtls_printf( " . Seeding the random number generator..." );
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fflush( stdout );
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mbedtls_entropy_init( &entropy );
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if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
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(const unsigned char *) pers,
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sizeof pers ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* Client: initialize context and generate keypair
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*/
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mbedtls_printf( " . Setting up client context..." );
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fflush( stdout );
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ret = mbedtls_ecp_group_load( &ctx_cli.grp, MBEDTLS_ECP_DP_CURVE25519 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_ecdh_gen_public( &ctx_cli.grp, &ctx_cli.d, &ctx_cli.Q,
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mbedtls_ctr_drbg_random, &ctr_drbg );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_mpi_write_binary( &ctx_cli.Q.X, cli_to_srv, 32 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* Server: initialize context and generate keypair
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*/
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mbedtls_printf( " . Setting up server context..." );
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fflush( stdout );
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ret = mbedtls_ecp_group_load( &ctx_srv.grp, MBEDTLS_ECP_DP_CURVE25519 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_ecdh_gen_public( &ctx_srv.grp, &ctx_srv.d, &ctx_srv.Q,
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mbedtls_ctr_drbg_random, &ctr_drbg );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_mpi_write_binary( &ctx_srv.Q.X, srv_to_cli, 32 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* Server: read peer's key and generate shared secret
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*/
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mbedtls_printf( " . Server reading client key and computing secret..." );
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fflush( stdout );
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ret = mbedtls_mpi_lset( &ctx_srv.Qp.Z, 1 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_mpi_read_binary( &ctx_srv.Qp.X, cli_to_srv, 32 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_ecdh_compute_shared( &ctx_srv.grp, &ctx_srv.z,
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&ctx_srv.Qp, &ctx_srv.d,
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mbedtls_ctr_drbg_random, &ctr_drbg );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* Client: read peer's key and generate shared secret
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*/
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mbedtls_printf( " . Client reading server key and computing secret..." );
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fflush( stdout );
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ret = mbedtls_mpi_lset( &ctx_cli.Qp.Z, 1 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_mpi_read_binary( &ctx_cli.Qp.X, srv_to_cli, 32 );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret );
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goto exit;
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}
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ret = mbedtls_ecdh_compute_shared( &ctx_cli.grp, &ctx_cli.z,
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&ctx_cli.Qp, &ctx_cli.d,
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mbedtls_ctr_drbg_random, &ctr_drbg );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* Verification: are the computed secrets equal?
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*/
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mbedtls_printf( " . Checking if both computed secrets are equal..." );
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fflush( stdout );
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ret = mbedtls_mpi_cmp_mpi( &ctx_cli.z, &ctx_srv.z );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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exit_code = MBEDTLS_EXIT_SUCCESS;
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exit:
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#if defined(_WIN32)
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mbedtls_printf( " + Press Enter to exit this program.\n" );
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fflush( stdout ); getchar();
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#endif
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mbedtls_ecdh_free( &ctx_srv );
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mbedtls_ecdh_free( &ctx_cli );
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mbedtls_ctr_drbg_free( &ctr_drbg );
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mbedtls_entropy_free( &entropy );
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mbedtls_exit( exit_code );
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}
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#endif /* MBEDTLS_ECDH_C && MBEDTLS_ECP_DP_CURVE25519_ENABLED &&
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MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
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