问无法在Kali Linux上得到更新

EN

当我尝试apt-get update时，它说：

获取:1 http://archive-3.kali.org/kali Kali滚动InRelease错误:1 http://archive-3.kali.org/kali Kali滚动InRelease以下签名无效: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux devel@kali.org阅读包列表.Done : GPG错误：http://archive-3.kali.org/kali Kali滚动InRelease:下列签名无效: EXPKEYSIG ED444FF07D8D0BF6 kali Linux devel@kali.org E:存储库'http://http.kali.org/kali kali滚动InRelease‘未签名。N:无法安全地从这样的存储库进行更新，因此默认情况下是禁用的。N:有关存储库创建和用户配置的详细信息，请参见apt安全(8)手册。

我的/etc/apt/source.list看起来是这样的：

deb http://http.kali.org/kali kali-rolling main contrib non-free
# For source package access, uncomment the following line
# deb-src http://http.kali.org/kali kali-rolling main contrib non-free
# deb cdrom:[Debian GNU/Linux 2017.3 _Kali-rolling_ - Official Snapshot amd64 L$

#deb cdrom:[Debian GNU/Linux 2017.3 _Kali-rolling_ - Official Snapshot amd64 LI$

我该怎么办？谢谢!