254 lines
7 KiB
C
254 lines
7 KiB
C
/*
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* Example ECDSA program
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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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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* This file is part of mbed TLS (https://tls.mbed.org)
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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_ECDSA_C) && \
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defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_CTR_DRBG_C)
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "mbedtls/ecdsa.h"
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#include "mbedtls/sha256.h"
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#include <string.h>
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#endif
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/*
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* Uncomment to show key and signature details
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*/
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#define VERBOSE
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/*
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* Uncomment to force use of a specific curve
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*/
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#define ECPARAMS MBEDTLS_ECP_DP_SECP192R1
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#if !defined(ECPARAMS)
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#define ECPARAMS mbedtls_ecp_curve_list()->grp_id
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#endif
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#if !defined(MBEDTLS_ECDSA_C) || !defined(MBEDTLS_SHA256_C) || \
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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_ECDSA_C and/or MBEDTLS_SHA256_C and/or "
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"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C not defined\n");
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mbedtls_exit( 0 );
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}
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#else
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#if defined(VERBOSE)
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static void dump_buf( const char *title, unsigned char *buf, size_t len )
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{
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size_t i;
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mbedtls_printf( "%s", title );
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for( i = 0; i < len; i++ )
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mbedtls_printf("%c%c", "0123456789ABCDEF" [buf[i] / 16],
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"0123456789ABCDEF" [buf[i] % 16] );
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mbedtls_printf( "\n" );
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}
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static void dump_pubkey( const char *title, mbedtls_ecdsa_context *key )
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{
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unsigned char buf[300];
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size_t len;
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if( mbedtls_ecp_point_write_binary( &key->grp, &key->Q,
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MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof buf ) != 0 )
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{
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mbedtls_printf("internal error\n");
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return;
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}
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dump_buf( title, buf, len );
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}
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#else
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#define dump_buf( a, b, c )
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#define dump_pubkey( a, b )
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#endif
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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_ecdsa_context ctx_sign, ctx_verify;
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mbedtls_entropy_context entropy;
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mbedtls_ctr_drbg_context ctr_drbg;
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unsigned char message[100];
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unsigned char hash[32];
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unsigned char sig[MBEDTLS_ECDSA_MAX_LEN];
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size_t sig_len;
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const char *pers = "ecdsa";
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((void) argv);
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mbedtls_ecdsa_init( &ctx_sign );
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mbedtls_ecdsa_init( &ctx_verify );
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mbedtls_ctr_drbg_init( &ctr_drbg );
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memset( sig, 0, sizeof( sig ) );
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memset( message, 0x25, sizeof( message ) );
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if( argc != 1 )
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{
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mbedtls_printf( "usage: ecdsa\n" );
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#if defined(_WIN32)
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mbedtls_printf( "\n" );
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#endif
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goto exit;
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}
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/*
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* Generate a key pair for signing
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*/
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mbedtls_printf( "\n . 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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strlen( 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 . Generating key pair..." );
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fflush( stdout );
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if( ( ret = mbedtls_ecdsa_genkey( &ctx_sign, ECPARAMS,
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mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdsa_genkey returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok (key size: %d bits)\n", (int) ctx_sign.grp.pbits );
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dump_pubkey( " + Public key: ", &ctx_sign );
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/*
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* Compute message hash
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*/
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mbedtls_printf( " . Computing message hash..." );
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fflush( stdout );
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if( ( ret = mbedtls_sha256_ret( message, sizeof( message ), hash, 0 ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_sha256_ret 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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dump_buf( " + Hash: ", hash, sizeof( hash ) );
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/*
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* Sign message hash
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*/
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mbedtls_printf( " . Signing message hash..." );
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fflush( stdout );
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if( ( ret = mbedtls_ecdsa_write_signature( &ctx_sign, MBEDTLS_MD_SHA256,
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hash, sizeof( hash ),
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sig, &sig_len,
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mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdsa_write_signature returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok (signature length = %u)\n", (unsigned int) sig_len );
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dump_buf( " + Signature: ", sig, sig_len );
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/*
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* Transfer public information to verifying context
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*
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* We could use the same context for verification and signatures, but we
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* chose to use a new one in order to make it clear that the verifying
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* context only needs the public key (Q), and not the private key (d).
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*/
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mbedtls_printf( " . Preparing verification context..." );
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fflush( stdout );
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if( ( ret = mbedtls_ecp_group_copy( &ctx_verify.grp, &ctx_sign.grp ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecp_group_copy returned %d\n", ret );
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goto exit;
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}
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if( ( ret = mbedtls_ecp_copy( &ctx_verify.Q, &ctx_sign.Q ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecp_copy returned %d\n", ret );
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goto exit;
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}
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/*
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* Verify signature
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*/
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mbedtls_printf( " ok\n . Verifying signature..." );
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fflush( stdout );
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if( ( ret = mbedtls_ecdsa_read_signature( &ctx_verify,
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hash, sizeof( hash ),
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sig, sig_len ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ecdsa_read_signature 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_ecdsa_free( &ctx_verify );
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mbedtls_ecdsa_free( &ctx_sign );
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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_ECDSA_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
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ECPARAMS */
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