更新linux时候提示“由于没有公钥，无法验证下列签名".

本文链接：https://blog.csdn.net/loovejava/article/details/21837935

新安装的Ubuntu在使用sudo apt-get update更新源码的时候出现如下错误：

W: GPG 错误：http://ppa.launchpad.net precise Release: 由于没有公钥，无法验证下列签名： NO_PUBKEY 3EE66BD3F599ACE3
W: GPG 错误：http://ppa.launchpad.net precise Release: 由于没有公钥，无法验证下列签名： NO_PUBKEY 6AF0E1940624A220
W: 无法下载 bzip2:/var/lib/apt/lists/partial/mirrors.163.com_ubuntu_dists_precise_main_binary-i386_Packages  Hash 校验和不符

W: 无法下载 bzip2:/var/lib/apt/lists/partial/mirrors.163.com_ubuntu_dists_precise-security_main_binary-i386_Packages  Hash 校验和不符

W: 无法下载 bzip2:/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-amd64_Packages  Hash 校验和不符

W: 无法下载 bzip2:/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-i386_Packages  Hash 校验和不符

E: Some index files failed to download. They have been ignored, or old ones used instead.

解决方法很简单，下载导入公钥就行，下载导入key的命令如下：

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6AF0E1940624A220 #此处6AF0E1940624A220需要是错误提示的key

此时继续更新发现没有公钥错误提示，但是还是效验存在问题，此时需要打开软件源的界面，将其他软件选项中的Canpnical合作伙伴/独立等四个选项取消勾选，再执行sudo apt-get update

此时发现可以顺利更新了。

sanbo@ubuntu:~/dev$ sudo apt-get update

搞定收工！

另外送上一个163源，更新的速度挺不错，品种也挺全的:

# deb cdrom:[Ubuntu 12.04.1 LTS _Precise Pangolin_ - Release i386 (20120817.3)]/ precise main restricted
       
    # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
    # newer versions of the distribution.
    deb http://mirrors.163.com/ubuntu/ precise main restricted
    deb-src http://mirrors.163.com/ubuntu/ precise main restricted
       
    ## Major bug fix updates produced after the final release of the
    ## distribution.
    deb http://mirrors.163.com/ubuntu/ precise-updates main restricted
    deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted
       
    ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
    ## team. Also, please note that software in universe WILL NOT receive any
    ## review or updates from the Ubuntu security team.
    deb http://mirrors.163.com/ubuntu/ precise universe
    deb-src http://mirrors.163.com/ubuntu/ precise universe
    deb http://mirrors.163.com/ubuntu/ precise-updates universe
    deb-src http://mirrors.163.com/ubuntu/ precise-updates universe
       
    ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
    ## team, and may not be under a free licence. Please satisfy yourself as to
    ## your rights to use the software. Also, please note that software in
    ## multiverse WILL NOT receive any review or updates from the Ubuntu
    ## security team.
    deb http://mirrors.163.com/ubuntu/ precise multiverse
    deb-src http://mirrors.163.com/ubuntu/ precise multiverse
    deb http://mirrors.163.com/ubuntu/ precise-updates multiverse
    deb-src http://mirrors.163.com/ubuntu/ precise-updates multiverse
       
    ## N.B. software from this repository may not have been tested as
    ## extensively as that contained in the main release, although it includes
    ## newer versions of some applications which may provide useful features.
    ## Also, please note that software in backports WILL NOT receive any review
    ## or updates from the Ubuntu security team.
       
    deb http://mirrors.163.com/ubuntu/ precise-security main restricted
    deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted
    deb http://mirrors.163.com/ubuntu/ precise-security universe
    deb-src http://mirrors.163.com/ubuntu/ precise-security universe
    deb http://mirrors.163.com/ubuntu/ precise-security multiverse
    deb-src http://mirrors.163.com/ubuntu/ precise-security multiverse
       
    ## Uncomment the following two lines to add software from Canonical's
    ## 'partner' repository.
    ## This software is not part of Ubuntu, but is offered by Canonical and the
    ## respective vendors as a service to Ubuntu users.
    deb http://archive.canonical.com/ubuntu precise partner
    deb-src http://archive.canonical.com/ubuntu precise partner
       
    ## This software is not part of Ubuntu, but is offered by third-party
    ## developers who want to ship their latest software.
    deb http://extras.ubuntu.com/ubuntu precise main
    deb-src http://extras.ubuntu.com/ubuntu precise main
       
    # codeblock
    deb http://ppa.launchpad.net/pasgui/ppa/ubuntu precise main
    deb-src http://ppa.launchpad.net/pasgui/ppa/ubuntu precise main
       
    # ubuntu tweak
    deb http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main
    deb-src http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main

==============================================偶尔时刻还是有各种问题，归纳如下================================================

【缺少公钥】

现象：

sudo apt-get update
    W: GPG error: http://apt.tt-solutions.com dapper Release: 由于没有公钥，下列签名无法进行验证： NO_PUBKEY 06EA41DE4F6C1E86

解决方法：

gpg --keyserver subkeys.pgp.net --recv 4F6C1E86
    gpg --export --armor 4F6C1E86 | sudo apt-key add -

说明：
若缺少其他公钥，则将命令中两处4F6C1E86改为NO_PUBKEY
06EA41DE4F6C1E86中最后8位即可！

如果是Ubuntu PPA的则按照如下方法处理：

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

【签名错解决办法】

情况一.概率出现的问题，这次有，可能下次就没了，可忽略

By simply waiting. This happens at times during archive updates.

情况二.使用如下方法更新：

$ sudo apt-get update -o Acquire::http::No-Cache=True
    或者
    $ sudo apt-get update -o Acquire::BrokenProxy=true

情况三.
现象：

In a particular case this was caused by a broken file and could get fixed using rescue boot and "fsck -fy /" (http://forum.ubuntuusers.de/goto?post=89197 - german)

解决办法：

fsck -fy /

情况四：

现象：

The fix is just to back up sources.list, delete everything in it and run "apt-get update". After the update replace sources.list with the backup and run "apt-get update" again. You should not get the error then.

解决办法：

备份sources.list，然后把sources.list中的东西删空，运行"apt-get update"，然后再用刚刚的备份将"apt-get update"复原，再运行"apt-get update"。

情况五.主旨就是清理缓存

sudo bash
     
    apt-get clean
    cd /var/lib/apt
    mv lists lists.old
    mkdir -p lists/partial
    apt-get clean
    apt-get update

情况六.缓存代理服务器导致的问题：

如下内容添加到/etc/apt/apt.conf.d/10broken_proxy文件里试试看。

Acquire::http::No-Cache "true";
    Acquire::http::Max-Age "0";

情况七

sudo apt-get install medibuntu-keyring
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版权声明：本文为CSDN博主「sanbo_xyz」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/loovejava/article/details/21837935