| /* |
| * Example ECDHE with Curve25519 program |
| * |
| * 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. |
| */ |
| |
| #if !defined(MBEDTLS_CONFIG_FILE) |
| #include "mbedtls/config.h" |
| #else |
| #include MBEDTLS_CONFIG_FILE |
| #endif |
| |
| #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_ECDH_C) || !defined(MBEDTLS_ECDH_LEGACY_CONTEXT) || \ |
| !defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \ |
| !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) |
| int main( void ) |
| { |
| mbedtls_printf( "MBEDTLS_ECDH_C and/or MBEDTLS_ECDH_LEGACY_CONTEXT and/or " |
| "MBEDTLS_ECP_DP_CURVE25519_ENABLED and/or " |
| "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C " |
| "not defined\n" ); |
| mbedtls_exit( 0 ); |
| } |
| #else |
| |
| #include "mbedtls/entropy.h" |
| #include "mbedtls/ctr_drbg.h" |
| #include "mbedtls/ecdh.h" |
| |
| |
| int main( int argc, char *argv[] ) |
| { |
| int ret = 1; |
| int exit_code = MBEDTLS_EXIT_FAILURE; |
| mbedtls_ecdh_context ctx_cli, ctx_srv; |
| mbedtls_entropy_context entropy; |
| mbedtls_ctr_drbg_context ctr_drbg; |
| unsigned char cli_to_srv[32], srv_to_cli[32]; |
| const char pers[] = "ecdh"; |
| ((void) argc); |
| ((void) argv); |
| |
| mbedtls_ecdh_init( &ctx_cli ); |
| mbedtls_ecdh_init( &ctx_srv ); |
| mbedtls_ctr_drbg_init( &ctr_drbg ); |
| |
| /* |
| * Initialize random number generation |
| */ |
| mbedtls_printf( " . Seeding the random number generator..." ); |
| fflush( stdout ); |
| |
| mbedtls_entropy_init( &entropy ); |
| if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, |
| (const unsigned char *) pers, |
| sizeof pers ) ) != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| /* |
| * Client: inialize context and generate keypair |
| */ |
| mbedtls_printf( " . Setting up client context..." ); |
| fflush( stdout ); |
| |
| ret = mbedtls_ecp_group_load( &ctx_cli.grp, MBEDTLS_ECP_DP_CURVE25519 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_ecdh_gen_public( &ctx_cli.grp, &ctx_cli.d, &ctx_cli.Q, |
| mbedtls_ctr_drbg_random, &ctr_drbg ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_mpi_write_binary( &ctx_cli.Q.X, cli_to_srv, 32 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| /* |
| * Server: initialize context and generate keypair |
| */ |
| mbedtls_printf( " . Setting up server context..." ); |
| fflush( stdout ); |
| |
| ret = mbedtls_ecp_group_load( &ctx_srv.grp, MBEDTLS_ECP_DP_CURVE25519 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecp_group_load returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_ecdh_gen_public( &ctx_srv.grp, &ctx_srv.d, &ctx_srv.Q, |
| mbedtls_ctr_drbg_random, &ctr_drbg ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecdh_gen_public returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_mpi_write_binary( &ctx_srv.Q.X, srv_to_cli, 32 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_write_binary returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| /* |
| * Server: read peer's key and generate shared secret |
| */ |
| mbedtls_printf( " . Server reading client key and computing secret..." ); |
| fflush( stdout ); |
| |
| ret = mbedtls_mpi_lset( &ctx_srv.Qp.Z, 1 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_mpi_read_binary( &ctx_srv.Qp.X, cli_to_srv, 32 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_ecdh_compute_shared( &ctx_srv.grp, &ctx_srv.z, |
| &ctx_srv.Qp, &ctx_srv.d, |
| mbedtls_ctr_drbg_random, &ctr_drbg ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| /* |
| * Client: read peer's key and generate shared secret |
| */ |
| mbedtls_printf( " . Client reading server key and computing secret..." ); |
| fflush( stdout ); |
| |
| ret = mbedtls_mpi_lset( &ctx_cli.Qp.Z, 1 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_lset returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_mpi_read_binary( &ctx_cli.Qp.X, srv_to_cli, 32 ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_mpi_read_binary returned %d\n", ret ); |
| goto exit; |
| } |
| |
| ret = mbedtls_ecdh_compute_shared( &ctx_cli.grp, &ctx_cli.z, |
| &ctx_cli.Qp, &ctx_cli.d, |
| mbedtls_ctr_drbg_random, &ctr_drbg ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| /* |
| * Verification: are the computed secrets equal? |
| */ |
| mbedtls_printf( " . Checking if both computed secrets are equal..." ); |
| fflush( stdout ); |
| |
| ret = mbedtls_mpi_cmp_mpi( &ctx_cli.z, &ctx_srv.z ); |
| if( ret != 0 ) |
| { |
| mbedtls_printf( " failed\n ! mbedtls_ecdh_compute_shared returned %d\n", ret ); |
| goto exit; |
| } |
| |
| mbedtls_printf( " ok\n" ); |
| |
| exit_code = MBEDTLS_EXIT_SUCCESS; |
| |
| exit: |
| |
| #if defined(_WIN32) |
| mbedtls_printf( " + Press Enter to exit this program.\n" ); |
| fflush( stdout ); getchar(); |
| #endif |
| |
| mbedtls_ecdh_free( &ctx_srv ); |
| mbedtls_ecdh_free( &ctx_cli ); |
| mbedtls_ctr_drbg_free( &ctr_drbg ); |
| mbedtls_entropy_free( &entropy ); |
| |
| mbedtls_exit( exit_code ); |
| } |
| #endif /* MBEDTLS_ECDH_C && MBEDTLS_ECP_DP_CURVE25519_ENABLED && |
| MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */ |