ESP-IDF on Eclipse IDE error with external Library - c

Question

I am using esp-idf v4.1.1 with different compilers, I have used Visual Studio Code and Eclipse IDE with Espressif tool installed.
My intention is that I want to use an external library that, at the moment, only has a function that does a SHA256 hash for which the openssl sha library (<openssl/sha.h>) is used.
The problem is that I include the library as a component to my project and I call it from the main but I get the following error when building the project.
(https://i.stack.imgur.com/3EECj.png)
If I try it in the Eclipse IDE I get more information about the error and I get "undefined reference to SHA256_INIT()" as for the rest of the functions.
See main.c, dual.c and dual.h code:
main.c:
#include <stdio.h>
#include "dual.h"
void app_main(void)
{
printf("Empezamos");
char * data = "hola";
char * e = generateHashSHA256(data);
printf("%s",e);
}
Dual.c:
#include <stdio.h>
#include "dual.h"
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
#include <stdbool.h>
#include <limits.h>
#include <openssl/sha.h>
char * generateHashSHA256(char *data){
SHA256_CTX ctx;
u_int8_t results[SHA256_DIGEST_LENGTH];
int n;
n = strlen(data);
SHA256_Init(&ctx);
SHA256_Update(&ctx, (u_int8_t *)data, n);
SHA256_Final(results, &ctx);
char *newString;
newString = malloc(sizeof(char)*SHA256_DIGEST_LENGTH*2);
memset(newString, 0, sizeof(char)*SHA256_DIGEST_LENGTH*2);
for(n=0;n<SHA256_DIGEST_LENGTH;n++)
{
printf(newString, "%s%02x", newString, results[n]);
}
return newString;
}
And Dual.h:
char * generateHashSHA256(char *data);
and CMake files:
CMake of component Dual:
idf_component_register(SRCS "dual.c"
INCLUDE_DIRS "include"
)
CMake of main folder:
idf_component_register(SRCS "main.c"
INCLUDE_DIRS ".")
CMake of project folder:
cmake_minimum_required(VERSION 3.5)
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
project(template-app)
I compiled the library from the terminal with "gcc -o name main.c -lssl -lcrypto" and it works correctly but when compiling it in an esp-idf project nothing...
Please HELP!
I have tried everything, I have included the openssl libraries in all the esp-idf directories, I have put the paths in the CMake... etc.