SHA-1 Hash Problem with i2d_Pubkey()

[Raj Singh]

Hi!

I was to send SHA1 hash of my public to some peer.
For that i have written a function:

EVP_PKEY * ReadPublicKey(const char *certfile)
{
  FILE *fp = fopen (certfile, "r");
  X509 *x509;
  EVP_PKEY *pkey;

  if (!fp)
     return NULL;

  x509 = PEM_read_X509(fp, NULL, 0, NULL);

  if (x509 == NULL)
  {
     ERR_print_errors_fp (stderr);
     return NULL;
  }

  fclose (fp);

  pkey=X509_extract_key(x509);

  X509_free(x509);

  if (pkey == NULL)
     ERR_print_errors_fp (stderr);
  return pkey;
}



Then, I am extracting the public key in a buffer:

pubKey = ReadPublicKey(PUBFILE);

   if(!pubKey)
   {
       fprintf(stderr,"Error: can't load public key");
       exit(1);
   }

issuer_pubkey_len = i2d_PUBKEY(pubKey, NULL);
issuer_pubkey = malloc(issuer_pubkey_len);
i2d_PUBKEY(pubKey, &issuer_pubkey);
memory_dump("issuer_pubkey", issuer_pubkey, issuer_pubkey_len);

The problem, is issuer_pubkey buffer is different each time, I run the my
application using same code.

To debug the problem, i created a separate test code, just reading the
issuer cert in .pem format and reading the pubkey in buffer, the buffer is
same each time i run test code as expected.
How come pubkey in a buffer can be different each time in my application ?
Is this some -lcrypto linking problem ?
I have also debugged for memory corruption. It is not present.

Please provide some pointers.
Thanks for the help in advance.

Best Regards,
Raj