openssl_free_key預計參數1是資源

Question

我有這樣的代碼：

openssl_pkcs12_read($p12buf, $p12cert, $decPass); 
openssl_pkey_export($p12cert['pkey'], $pemkey); 
openssl_sign($toSign, $signature, $pemkey, OPENSSL_ALGO_SHA1); 
openssl_free_key($pemkey); 

我得到這樣的警告：

Warning (2): openssl_free_key() expects parameter 1 to be resource, string given 

我怎麼能擺脫它還是什麼，我做錯了什麼？

Answer 1

openssl_free_key需要openssl_pkey_get_private或openssl_pkey_get_public

$key = openssl_pkey_get_private($keyFile, $passphrase); 
openssl_free_key($key);