(PHP 4 >= 4.2.0, PHP 5)
openssl_pkey_export — Gets an exportable representation of a key into a string
$key
   , string &$out
   [, string $passphrase
   [, array $configargs
  ]] )
   openssl_pkey_export() exports
   key as a PEM encoded string and stores it into
   out (which is passed by reference).
  
Note: You need to have a valid openssl.cnf installed for this function to operate correctly. See the notes under the installation section for more information.
key
out
passphrase
       The key is optionally protected by passphrase.
      
configargs
       configargs can be used to fine-tune the export
       process by specifying and/or overriding options for the openssl
       configuration file.  See openssl_csr_new() for more
       information about configargs.
      
   Returns TRUE on success or FALSE on failure.