#include <openssl/conf.h>
#include <openssl/evp.h>
#include <openssl/err.h>


#include <string.h>

int main(int arc, char *argv[])
{
  /* Set up the key and iv. Do I need to say to not hard code these in a
   * real application? :-)
   */

  /* A 256 bit key */
  unsigned char *key = "01234567890123456789012345678901";

  /* A 128 bit IV */
  unsigned char *iv = "01234567890123456";

  /* Message to be encrypted */
  unsigned char *plaintext =
    "The quick brown fox jumps over the lazy dog";

  /* Buffer for ciphertext. Ensure the buffer is long enough for the
   * ciphertext which may be longer than the plaintext, dependant on the
   * algorithm and mode
   */
  unsigned char ciphertext[128];

  /* Buffer for the decrypted text */
  unsigned char decryptedtext[128];

  int decryptedtext_len, ciphertext_len;

 /* Initialise the library */
  ERR_load_crypto_strings();
  OpenSSL_add_all_algorithms();
  OPENSSL_config(NULL);

  /* Encrypt the plaintext */
  ciphertext_len = encrypt(plaintext, strlen(plaintext), key, iv,ciphertext);

  /* Do something useful with the ciphertext here */
  printf("Ciphertext is:n");
  BIO_dump_fp(stdout, ciphertext, ciphertext_len);

  /* Decrypt the ciphertext */
  decryptedtext_len = decrypt(ciphertext, ciphertext_len, key, iv,decryptedtext);

  /* Add a NULL terminator. We are expecting printable text */
  decryptedtext[decryptedtext_len] = '';

  /* Show the decrypted text */
  printf("Decrypted text is:n");
  printf("%sn", decryptedtext);

  /* Clean up */
  EVP_cleanup();
  ERR_free_strings();

  return 0;
}

||=== Build: Release in CryptoProject (compiler: GNU GCC Compiler) ===|
obj/Release/main.o||In function `main':|
main.c:(.text.startup+0x46)||undefined reference to `encrypt'|
main.c:(.text.startup+0x81)||undefined reference to `decrypt'|
||=== Build failed: 2 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|