问腾讯云人脸比对 总是签名错误？

人脸对比接口https://cloud.tencent.com/document/product/867/44987

报错如下

"The provided credentials could not be validated. Please check your signature is correct."

<?php

header("X-TC-Action: no-cache");

header('X-TC-Timestamp: '.time().'');

header("X-TC-Version: 2020-03-03");

header("Authorization: Signature");

header("host: cvm.tencentcloudapi.com");

header("content-type:application/json");

load()->func('communication');

$SecretId='111';

$secretKey='2222';

$param['Action']="CompareFace";

$param['Timestamp']=time();

$param['Nonce']=rand();

$param['SecretId']=$SecretId;

$param['Version']='2020-03-03';

$param['UrlA']='https://up.enterdesk.com/edpic_360_360/3a/d1/66/3ad1668da63c67a9dc421238938dfb8c.jpg';

$param['UrlB']='https://up.enterdesk.com/edpic_360_360/3a/d1/66/3ad1668da63c67a9dc421238938dfb8c.jpg';

$param['QualityControl']='0';

ksort($param);

$url='https://iai.tencentcloudapi.com';

$signStr = "GETiai.tencentcloudapi.com/?";

foreach ( $param as $key => $value ) {

$signStr = $signStr . $key . "=" . $value . "&";

}

$aa = substr($signStr, 0, -1);

$signature = base64_encode(hash_hmac("sha1", $signStr, $secretKey, true));

$param['Signature']=$signature;

$data=ihttp_post($url, $param);

$this->result(0,'信息',json_decode($data['content'],TRUE));

?>

应该咋写 谁又完整代码 求copy