keytest.c

The example 'C' program keytest.c demonstrates how to load a private SSL key to perform actions such as digital signing of certificates or other data, using the OpenSSL library functions.

/* ------------------------------------------------------------------------ *
 * file:        keytest.c                                                   *
 * purpose:     tests loading of a private key for certificate signing      *
 * author:      02/23/2004 Frank4DD                                         * 
 * ------------------------------------------------------------------------ */

#include <stdio.h>
#include <string.h>
#include <openssl/x509v3.h>
#include <openssl/objects.h>
#include <openssl/pem.h>
#include <openssl/evp.h>


int main() {

   EVP_PKEY *ca_pkey;
   FILE *fp;
   char pass[] = "testpass";


   /* ---------------------------------------------------------- *
    * This function call is essential to make many PEM and other *
    * openssl functions work. It is not well documented.         *
    ------------------------------------------------------------ */
   OpenSSL_add_all_algorithms();

   ca_pkey = EVP_PKEY_new();

   fp = fopen ("cakey.pem", "r");

   PEM_read_PrivateKey( fp, &ca_pkey, NULL, pass);

   fclose(fp);

   PEM_write_PrivateKey(stdout,ca_pkey,NULL,NULL,0,0,NULL);

   exit(0);
}

Compile the test program with:

> gcc -lssl -lcrypto keytest.c -o keytest

The program expects a keyfile called ca_key.pem in the same directory it is run. If the key loading is successful, i.e. the passphrase is correct, the following output is produced for an unencrypted key (of course not a "real" one :-) ) With an incorrect passphrase, the key wont be loaded and the pointer is NULL.

tests loading of a private key for certificate signing

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