微信退款结果回调解密,低版本以及7.1以上版本的使用方法

    /**
     * 退款解密
     * @param array $data
     * @return bool|string
     */
    public function decryption($data = array())
    {
        $encryption = base64_decode($data['req_info']);
        $key = md5($data['key']);
        $str = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $encryption, MCRYPT_MODE_ECB);
        $block = mcrypt_get_block_size('rijndael_128', 'ecb');
        $pad = ord($str[($len = strlen($str)) - 1]);
        $len = strlen($str);
        $pad = ord($str[$len - 1]);
        return substr($str, 0, strlen($str) - $pad);
    }

$data = [
    'req_info' => $xml['req_info'], // 退款回调xml中的req_info
    'key'      => $key,             // 商户的key
];
var_dump($work->decryption($data));

Function mcrypt_decrypt() is deprecated in ...

    /**
     * 退款解密(7.1+版本推荐使用)
     * @param array $data
     * @return bool|string
     */
    public function decryption($data = array())
    {
        $encryption = base64_decode($data['req_info']);
        $key = md5($data['key']);
        $return = openssl_decrypt($encryption , 'AES-256-ECB', $key, OPENSSL_RAW_DATA);
        return $return;
    }