VirusTotal Api用法不明确

Question

我扫描了文件夹中的文件（$ cfile故意包含了虚假内容）

$api_key = getenv('VT_API_KEY') ? getenv('VT_API_KEY') :$this->_key;
$cfile = 'asdasdas';

$post = array('apikey' => $api_key,'file'=> $cfile);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://www.virustotal.com/vtapi/v2/file/scan');
curl_setopt($ch, CURLOPT_POST, True);
curl_setopt($ch, CURLOPT_VERBOSE, 1); // remove this if your not debugging
curl_setopt($ch, CURLOPT_ENCODING, 'gzip,deflate'); // please compress data
curl_setopt($ch, CURLOPT_USERAGENT, "gzip, My php curl client");
curl_setopt($ch, CURLOPT_RETURNTRANSFER ,True);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

$result=curl_exec ($ch);

使用类似的东西可获得良好的结果

stdClass Object
(
[scan_id] => ffd8f48291484e1373573bfedf591cdf38565fcc9fc89a4a1d0f16a98da4d4ec-1573916013
[sha1] => d8cc708a1760020e00e1da0e83dc1f7b25e5a5ab
[resource] => ffd8f48291484e1373573bfedf591cdf38565fcc9fc89a4a1d0f16a98da4d4ec
[response_code] => 1
[sha256] => ffd8f48291484e1373573bfedf591cdf38565fcc9fc89a4a1d0f16a98da4d4ec
[permalink] => https://www.virustotal.com/file/ffd8f48291484e1373573bfedf591cdf38565fcc9fc89a4a1d0f16a98da4d4ec/analysis/1573916013/
[md5] => 7ae6fa4e9595a6e9d7987b4cd66f5b7f
[verbose_msg] => Scan request successfully queued, come back later for the report
 )

为什么我将文件设置错误并获得良好的结果？