debian或者Ubuntu在使用apt-get update出现GPG erro

问题：debian 9.x stretch

• GPG error: http://mirrors.aliyun.com/debian-archive/debian stretch-backports InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9

解决方法：
有可能是授权或证书失效
执行如下命令：apt install debian-keyring debian-archive-keyring 然后执行apt-get update

root@local:/var/www/html# apt install debian-keyring debian-archive-keyring
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  debian-keyring
The following packages will be upgraded:
  debian-archive-keyring
1 upgraded, 1 newly installed, 0 to remove and 33 not upgraded.
Need to get 33.3 MB of archives.
After this operation, 35.0 MB of additional disk space will be used.
Get:1 http://mirrors.aliyun.com/debian-archive/debian stretch/main arm64 debian-archive-keyring all 2017.5+deb9u1 [73.9 kB]
10% [Waiting for headers]
10% [Waiting for headers]
Get:2 http://mirrors.aliyun.com/debian-archive/debian stretch/main arm64 debian-keyring all 2017.05.28 [33.2 MB]
Fetched 33.3 MB in 35s (949 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
(Reading database ... 28767 files and directories currently installed.)
Preparing to unpack .../debian-archive-keyring_2017.5+deb9u1_all.deb ...
Unpacking debian-archive-keyring (2017.5+deb9u1) over (2017.5) ...
Setting up debian-archive-keyring (2017.5+deb9u1) ..............................]
Removing obsolete conffile /etc/apt/trusted.gpg.d/debian-archive-wheezy-automatic.gpg ...ess: [ 36%] [######################........................................]
Removing obsolete conffile /etc/apt/trusted.gpg.d/debian-archive-wheezy-stable.gpg ...
Selecting previously unselected package debian-keyring.
(Reading database ... 28768 files and directories currently installed.).........]
Preparing to unpack .../debian-keyring_2017.05.28_all.deb ...
Unpacking debian-keyring (2017.05.28) ...
Setting up debian-keyring (2017.05.28) ...#########.............................]
root@local:/var/www/html# apt-get update
Ign:1 http://mirrors.aliyun.com/debian-archive/debian stretch InRelease
Get:2 http://mirrors.aliyun.com/debian-archive/debian stretch-backports InRelease [78.5 kB]
Hit:3 http://mirrors.aliyun.com/debian-archive/debian stretch Release
Fetched 78.5 kB in 0s (190 kB/s)
Reading package lists... Done


root@local:/var/www/html# apt update
Ign:1 http://mirrors.aliyun.com/debian-archive/debian stretch InRelease
Hit:2 http://mirrors.aliyun.com/debian-archive/debian stretch-backports InRelease
Hit:3 http://mirrors.aliyun.com/debian-archive/debian stretch Release
Reading package lists... Done
Building dependency tree
Reading state information... Done
33 packages can be upgraded. Run 'apt list --upgradable' to see them.