SHA256上的PHP密码输出

我正在php上创建一个注册页面，我设法按计划完成了所有工作，现在每次有人注册时我都会生成新文件。但是，我希望密码显示在输出的SHA256上，而不是纯文本。我已经尝试了在其他问题上看到的几个功能，但我没能做到。这是我的代码，我希望你能帮助我：

$file = scandir($this->path_accounts);
$UID = count($file)+999998;
$Data  = '<?xml version="1.0" encoding="utf-8"?>'.EL;
$Data .= "<Account>".EL;
$Data .= '  <section name="Informations">'.EL;
$Data .= '    <entry name="AccountID">'.$this->username.'</entry>'.EL;
$Data .= '    <entry name="Password">'.$this->+password."</entry>".EL;
$Data .= '    <entry name="RealName">'.$this->realname."</entry>".EL;
$Data .= '    <entry name="Email">'.$this->email."</entry>".EL;
$Data .= '    <entry name="Question">'.$this->question."</entry>".EL;
$Data .= '    <entry name="Answer">'.$this->answer."</entry>".EL;
$Data .= '    <entry name="Creation">Mon, 21 Dec 2015 19:24:17 GMT</entry>'.EL;
$Data .= "  </section>".EL;
$Data .= "</Account>".EL;
file_put_contents($this->fullpath, $Data);
if(file_exists($this->fullpath)):
    echo $this->message('Thank you for registering.');
else: