Ubuntu 16.04 軟件更新問題

現象：使用Software updater軟件，輸入管理員口令後，彈出提示窗口

sudo apt-get update 

提示以下錯誤

W: GPG error: http://archive.ubuntukylin.com:10006/ubuntukylin xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8D5A09DC9B929006
W: The repository 'http://archive.ubuntukylin.com:10006/ubuntukylin xenial InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: There is no public key available for the following key IDs:
8D5A09DC9B929006  

解決辦法：http://askubuntu.com/questions/578292/software-update-this-requires-installing-packages-from-unauthenticated-sources

sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 8D5A09DC9B929006

http://www.ubuntukylin.com/ukylin/forum.php?mod=viewthread&tid=25629