GnuPG from PHP - Where is the include ??

Please advise - I'guess it is not a build in and looking for the GnuPG PHP include as all the GnuPG functions are now considered undefined. See below. Thanks Eli // GnuPG from PHP - Where is the include ?? // http://www.gnupg.org/gph/en/manual.html // http://www.gnupg.org/documentation/howtos.en.html // GnuPG allows to encrypt and sign your data and communication, // features a versatile key management system as well as access // modules for all kinds of public key directories. // echo "GNU Encrypt with agreed secret key between sides."; $secret_key = "8660281B6051D071D94B5B230549F9DC851566DC"; // Only shared parties know this $the_secret_content = "this is a very secret XML keep the secret key in the server and client well hidden from 4rd parties"; // Only shared parties know this echo "Secret Key between Parties: [$secret_key] <br>"; echo "The sensitive content to keep safe <br>

     from 3rd parties: <b> $the_secret_content </b><br>";

//Creating the encryption content

                    $res = gnupg_init();

gnupg_addencryptkey($res, $secret_key); $enc = gnupg_encrypt($res, $the_secret_content); echo "This is the sensitive content encrypted by strong shared secret key:[".$enc."] <br>"; echo "Secret Key between Parties: [$secret_key] <br>";

                     $res = gnupg_init();

gnupg_adddecryptkey($res,$secret_key); $plain = gnupg_decrypt($res, $enc); echo "This is the sensitive content decrypted by recieving party <br>

     that has the shared secret key:[".$plain."] <br>";

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