some fixes in openssl signature process

static/mitgliedsantrag.php

@@ -106,8 +106,9 @@ $jwt_payload = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode(json_e
     'exp' => time()+30,
     'iat' => time()
 ))));
-$pkey = openssl_pkey_get_private(base64_decode(getenv('MITGLIEDSANTRAG_SHEETS_PKEY', true)));
-openssl_sign($jwt_header.'.'.$jwt_payload, $jwt_signature, $pkey);
+$pkey = openssl_pkey_get_private(base64_decode(getenv('MITGLIEDSANTRAG_SHEET_PKEY', true)));
+$jwt_signature = '';
+openssl_sign($jwt_header.'.'.$jwt_payload, $jwt_signature, $pkey, OPENSSL_ALGO_SHA256);
 openssl_free_key($pkey);
 $jwt_signature = str_replace(['+', '/', '='], ['-', '_', ''], $jwt_signature);
 $req_body = <<<EOF