apt-get upgrade时出现的问题
源存放的路径：
etc/apt/sources.list
deb http://mirrors.he.vobile:81 wheezy main contrib non-free
deb http://security.debian.org wheezy/updates main contrib non-free
当拿到机器时需要upgrade源：apt-get upgrade
今天在upgrade时出现了以下错误：
apt-get update
Ign http://packages.ops.vobile.org debian/ Release.gpg
Ign http://packages.ops.vobile.org debian/ Release
Ign http://packages.ops.vobile.org debian/ Packages/DiffIndex
Hit http://packages.ops.vobile.org debian/ Packages
Ign http://packages.ops.vobile.org debian/ Translation-en_US
Ign http://packages.ops.vobile.org debian/ Translation-en
Hit http://mirrors.he.vobile wheezy Release.gpg
Hit http://mirrors.he.vobile wheezy Release
Hit http://mirrors.he.vobile wheezy/main amd64 Packages
Hit http://mirrors.he.vobile wheezy/contrib amd64 Packages
Hit http://mirrors.he.vobile wheezy/non-free amd64 Packages
Hit http://mirrors.he.vobile wheezy/main i386 Packages
Hit http://mirrors.he.vobile wheezy/contrib i386 Packages
Hit http://mirrors.he.vobile wheezy/non-free i386 Packages
Hit http://mirrors.he.vobile wheezy/contrib Translation-en
Hit http://mirrors.he.vobile wheezy/main Translation-en
Hit http://mirrors.he.vobile wheezy/non-free Translation-en
Hit http://security.debian.org wheezy/updates Release.gpg
Hit http://security.debian.org wheezy/updates Release
Hit http://security.debian.org wheezy/updates/main amd64 Packages
Hit http://security.debian.org wheezy/updates/contrib amd64 Packages
Hit http://security.debian.org wheezy/updates/non-free amd64 Packages
Hit http://security.debian.org wheezy/updates/main i386 Packages
Hit http://security.debian.org wheezy/updates/contrib i386 Packages
Hit http://security.debian.org wheezy/updates/non-free i386 Packages
Hit http://security.debian.org wheezy/updates/contrib Translation-en
Hit http://security.debian.org wheezy/updates/main Translation-en
Hit http://security.debian.org wheezy/updates/non-free Translation-en
Reading package lists... Done
W: There is no public key available for the following key IDs:
7638D0442B90D010
W: There is no public key available for the following key IDs:
9D6D8F6BC857C906
有3种解决方法：
According to There is no public key available for the following key ID, this will fix it:
sudo aptitude install debian-keyring debian-archive-keyring
2.
$ sudo apt-get install debian-archive-keyring $ sudo apt-key update
This is better than other approaches because it does not install "debian-keyring", which is big and 99% of the time unnecessary.
3.
the other answers will work, or not, depending on whether or not the key '7638D0442B90D010' is present in the packages they indicate.
if you need a key, you have to get that key, and where to find it, it's in a key server (very probably any key server will do):
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 7638D0442B90D010
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9D6D8F6BC857C906
之后再执行apt-get update
就可以了，我使用的是第三种方法，前面2种还没试，是google出来的～