Php openSsl_encrypt ...

Question

developers. I would want to have some info about open_ssl_encrypt with public and private keys.

I have a project and i must encrypt data from *PDF file than to decrypt it when it needed to be.

i have use the following example to generate a private and public key.

$pkGenerate = openssl_pkey_new(array(
'private_key_bits' => 2048,
'private_key_type' => OPENSSL_KEYTYPE_RSA

));

openssl_pkey_export($pkGenerate,$pkGeneratePrivate); // NOTE: second argument is passed by reference
$pkGenerateDetails = openssl_pkey_get_details($pkGenerate);
$pkGeneratePublic = $pkGenerateDetails['key'];
openssl_pkey_free($pkGenerate);
$pkImport = openssl_pkey_get_private($pkGeneratePrivate); // import
$pkImportDetails = openssl_pkey_get_details($pkImport); // same as getting the public key in previous
$pkImportPublic = $pkImportDetails['key'];
openssl_pkey_free($pkImport); // clean up
echo "
".$pkGeneratePrivate
     ."
".$pkGeneratePublic
     ."
".$pkImportPublic
     ."
".'Public keys are         '.(strcmp($pkGeneratePublic,$pkImportPublic)?'different':'identical').'.';

So in my mind, i think i must generate a private key, and encrypt the data with it, than the data can only be decrypted by the public key witch is a part of the private key.Correct me if i am wrong..

next step i do.

openssl_private_decrypt ( $loadedPDF ,  $decryptedPDF , $pkGeneratePrivate );
echo $pkGeneratePrivate;

But nothings happend, can someone help me with my issue, thank you for spending your time with my problems,

Best Regrats!