#include <stdio.h>
#include <string.h>
#include <openssl/bio.h>
#include <openssl/asn1.h>
#include <openssl/err.h>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/objects.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>


BIO *bio_out;

int main(int argc, char* argv[])
{
        BIO *bio_crt=NULL,*bio_key=NULL;
        char crtfile[]="D:\\dev\\openssl\\verify\\crt.pem";
        char pvkfile[]="D:\\dev\\openssl\\verify\\crt_pvk.pem";
        X509 *x=NULL;
        EVP_PKEY *pkey=NULL;
        int i=0;


        OpenSSL_add_all_digests();
        OpenSSL_add_all_algorithms(); // !! IMPORTANT
        ERR_load_crypto_strings();

        bio_out=BIO_new_fp(stdout,BIO_NOCLOSE);
        if ((bio_crt=BIO_new(BIO_s_file())) == NULL){
                ERR_print_errors(bio_out);
                goto end;
        }

        if(BIO_read_filename(bio_crt,crtfile)<=0){
                BIO_printf(bio_out,"%s@%i unable to load certificate\n",__FILE__,__LINE__);
                goto end;
        }

        x=PEM_read_bio_X509(bio_crt,NULL,0,NULL);
        if (x == NULL){
                BIO_printf(bio_out,"%s@%i unable to open certificate\n",__FILE__,__LINE__);
                goto end;
        }
        //X509_print(bio_out,x);

        bio_key=BIO_new(BIO_s_file());
        if (BIO_read_filename(bio_key,pvkfile) <= 0){
                BIO_printf(bio_out,"%s@%i unable to load private key\n",__FILE__,__LINE__);
                goto end;
        }              


        pkey=PEM_read_bio_PrivateKey(bio_key,NULL,0,"test");
        if(pkey==NULL){
                BIO_printf(bio_out,"%s@%i unable to open private key\n",__FILE__,__LINE__);
                ERR_print_errors(bio_out);
                goto end;
        }


        //int nid=OBJ_obj2nid(x->sig_alg->algorithm);
        //BIO_printf(bio_out,"algo:%s\n",OBJ_nid2ln(nid));

        i=X509_check_private_key(x,pkey);
        BIO_printf(bio_out,"%s@%i i==%i\n",__FILE__,__LINE__,i);

        if (i < 0){
                BIO_printf(bio_out,"Signature verification problems....\n");
        }

        if (i == 0){
                BIO_printf(bio_out,"Signature did not match the certificate\n");
                ERR_print_errors(bio_out);
        }

end:
        BIO_free_all(bio_out);
        BIO_free(bio_crt);
        BIO_free_all(bio_key);
        if (pkey != NULL)
                EVP_PKEY_free(pkey);
        return 0;
}
 

#include <stdio.h>
#include <string.h>
#include <openssl/bio.h>
#include <openssl/asn1.h>
#include <openssl/err.h>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/objects.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>


BIO *bio_out;

int main(int argc, char* argv[])
{
        BIO *bio_crt=NULL,*bio_key=NULL;
        char crtfile[]="D:\\dev\\openssl\\verify\\Debug\\crt.pem";
        char pubfile[]="D:\\dev\\openssl\\verify\\Debug\\crt_pub.pem";
        X509 *x=NULL;
        EVP_PKEY *pkey=NULL;
        int i=0;

        OpenSSL_add_all_digests();
        OpenSSL_add_all_algorithms(); // !! IMPORTANT
        ERR_load_crypto_strings();

        bio_out=BIO_new_fp(stdout,BIO_NOCLOSE);
        if ((bio_crt=BIO_new(BIO_s_file())) == NULL){
                ERR_print_errors(bio_out);
                goto end;
        }

        if(BIO_read_filename(bio_crt,crtfile)<=0){
                BIO_printf(bio_out,"%s@%i unable to load certificate\n",__FILE__,__LINE__);
                goto end;
        }

        x=PEM_read_bio_X509(bio_crt,NULL,0,NULL);
        if (x == NULL){
                BIO_printf(bio_out,"%s@%i unable to open certificate\n",__FILE__,__LINE__);
                goto end;
        }

        bio_key=BIO_new(BIO_s_file());
        if (BIO_read_filename(bio_key,pubfile) <= 0){   
                BIO_printf(bio_out,"%s@%i unable to load public key\n",__FILE__,__LINE__);
                goto end;
        }              

        pkey = PEM_read_bio_PUBKEY(bio_key, NULL, NULL, NULL);
        if(pkey==NULL){
                BIO_printf(bio_out,"%s@%i unable to open public key\n",__FILE__,__LINE__);
                ERR_print_errors(bio_out);
                goto end;
        }

        i=X509_check_private_key(x,pkey);
        BIO_printf(bio_out,"%s@%i i==%i\n",__FILE__,__LINE__,i);

        if (i < 0){
                BIO_printf(bio_out,"Signature verification problems....\n");
        }

        if (i == 0){
                BIO_printf(bio_out,"Signature did not match the certificate\n");
                ERR_print_errors(bio_out);
        }



end:
        BIO_free_all(bio_out);
        BIO_free(bio_crt);
        BIO_free_all(bio_key);
        if (pkey != NULL)
                EVP_PKEY_free(pkey);

        return 0;
}