615

I added some extra repositories with the Software Sources program. But when I reload the package database, I get an error like the following:

W: GPG error: http://ppa.launchpad.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F

I know I can fix it using apt-key in a terminal, according to the official Ubuntu documentation. But I would have liked to do it graphically. Is there a way to do this without using a terminal?

Wilf
  • 30,194
  • 17
  • 108
  • 164
Agmenor
  • 16,214
  • 1
    Related: http://askubuntu.com/q/127326/178596 – Wilf Jul 19 '15 at 20:46
  • 'A mean'? Curious what you meant by that. – Michael Scheper Sep 13 '16 at 16:17
  • 1
    You can check this SO thread for solution. Link to related site – Aniket Thakur Oct 06 '16 at 03:44
  • @MichaelScheper 'Is there a mean[s] to not to open a terminal?' =~ 'Is there a way to do it without a terminal?' – Wilf Jul 26 '17 at 00:26
  • @Wilf: Oh! I don't mean to nitpick grammar, but it did confuse me. From the reference I just checked, 'means' is a singular noun, and the one you meant. http://dictionary.cambridge.org/dictionary/english/means But if you and Agmentor are using some variant form of English where the grammar in the question is correct, I'd love to see a reference to it, just because I'm interested in that sort of thing. ☺ – Michael Scheper Jul 26 '17 at 17:35
  • For users that want to remove a repository, see this question (that should make this comment more on-topic, though I suppose evaluating grammar is as well here :) ) @MichaelScheper It is an unusual way of saying it, but I have learnt as part of English in the UK (this probably means my English is worse than if I was taught it properly [with nouns etc]! xD). The quote a means to end comes to mind, though the issue there is the end bit, but it is where means means a method or a way. – Wilf Jul 27 '17 at 18:39
  • @Wilf: The dictionary I linked to was a UK dictionary, and 'a means to end' entirely illustrates my point, which is that 'means' is singular. Therefore, 'mean' is not the right word. But you're right where you say this has gone way off topic, so I'll bow out of further discussion, and leave it to you to decide whether to edit the question. Cheers. – Michael Scheper Jul 28 '17 at 17:51
  • Here is a reliable answer to this question: https://askubuntu.com/a/15272/481928 – Greenish Nov 14 '19 at 21:09

15 Answers15

922

This answer was valid for Ubuntu 20.04 and previous versions. For Ubuntu 20.10 and later versions, see this answer on StackOverflow.

The short version is:

sudo mkdir -m 0755 -p /etc/apt/keyrings/

wget -O- https://example.com/EXAMPLE.gpg |
    gpg --dearmor |
    sudo tee /etc/apt/keyrings/EXAMPLE.gpg > /dev/null
    sudo chmod 644 /etc/apt/keyrings/EXAMPLE.gpg


echo "deb [signed-by=/etc/apt/keyrings/EXAMPLE.gpg] https://example.com/apt stable main" |
    sudo tee /etc/apt/sources.list.d/EXAMPLE.list
    sudo chmod 644 /etc/apt/sources.list.d/EXAMPLE.list


Optional (you can find the email address / ID using 'apt-key list')


sudo apt-key del support@example.com

Original answer:

Execute the following commands in terminal

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <PUBKEY>

where <PUBKEY> is your missing public key for repository, e.g. 8BAF9A6F.

Then update

sudo apt-get update

ALTERNATE METHOD:

sudo gpg --keyserver pgpkeys.mit.edu --recv-key  <PUBKEY>
sudo gpg -a --export <PUBKEY> | sudo apt-key add -
sudo apt-get update

Note that when you import a key like this using apt-key you are telling the system that you trust the key you're importing to sign software your system will be using. Do not do this unless you're sure the key is really the key of the package distributor.

terdon
  • 100,812
karthick87
  • 81,947
  • 1
    man how to reverse this command it make a lot of Ign and didn't work see this : http://img688.imageshack.us/img688/6885/igny.png – Black Block Feb 19 '12 at 13:29
  • 2
    @Naruto That's normal. It means that list hasn't changed on the server. – nanofarad Aug 10 '12 at 15:50
  • 16
    You can simply pass NO_PUBKEY value as keys parameter. for example GPG error[...]NO_PUBKEY 3766223989993A70 => sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3766223989993A70 – S.M.Mousavi Feb 19 '14 at 19:40
  • 34
    8BAF9A6F <-- where did you get that number? – Olivier Lalonde Mar 09 '14 at 12:49
  • 18
    The number 8BAF9... is what you see in the original error. It would be something like NO_PUBKEY 8BAF... – Alex Oct 10 '14 at 19:56
  • 14
    If someone tampered with data between me and the repository, and substituted stuff they'd signed, this would wind up with me just adding the key they used, more or less blindly. So what's the process to verify that the key is the right one? – mc0e May 20 '15 at 15:37
  • 2
    Ultimately you are trusting the keyserver (at keyserver.ubuntu.com in the first example) – Phil_1984_ Sep 01 '16 at 12:47
  • 2
    This is a great answer. Just note the the op was asking specifically for a graphical way to do this, not using the command line. – monotasker Sep 06 '16 at 14:27
  • 2
    @monotasker: Indeed. I wish I'd seen this answer first, because I prefer typing over wading through a GUI any day. But to be fair, the OP did ask for a graphical method, right at the end. – Michael Scheper Sep 13 '16 at 16:20
  • For the alternate method, you don't actually have to specify the keyserver, since gpg has a pool of them that it trusts. – jpaugh Jul 27 '17 at 19:39
  • 2
    @Phil_1984_, @jpaugh: No, key servers are never trusted when using PGP. Keys are generally verified via chains of signatures of the UIDs or via manual inspection, such as comparing key IDs or fingerprints. The latter is effectively what you are doing when you use apt-key --recv-key 3766223989993A70: you're telling apt-key that you trust the key with that key ID. If the keyserver tried to return a different key, apt-key would not accept it in place of 3766223989993A70. – cjs Aug 06 '17 at 02:45
  • Best solution for Ubuntu 16.04 server. – Ariful Haque Aug 25 '17 at 03:55
  • On a recent Debian Stretch I had to install the dirmngr package first. – mvw Feb 21 '18 at 09:18
  • 1
    Although OP asked for it graphically, I needed it for CLI and this resolved my issue. – dylanh724 Feb 27 '18 at 15:52
  • This still works in Ubuntu 16! – Bernhard Döbler Apr 25 '20 at 21:28
  • The key adding works on debian 10. I had to add several public keys. – Timo Apr 29 '21 at 07:10
  • 9
    State on 2022.08.28 on jammy: Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)). – s.k Aug 28 '22 at 08:39
  • 2
    Neither of these methods is working for me. I successfully add the key, but when I do sudo apt-get update again, I still get the same error. – Thomas Levesque Mar 23 '23 at 12:46
  • 1
    I confirm that this doesn't work in ubuntu 22.04... – Ricky Robinson Apr 14 '23 at 10:32
261

By far the simplest way to handle this now is with Y-PPA-Manager (which now integrates the launchpad-getkeys script with a graphical interface).

  1. To install it, first add the webupd8 repository for this program:

    sudo add-apt-repository ppa:webupd8team/y-ppa-manager

  2. Update your software list and install Y-PPA-Manager:

    sudo apt-get update
sudo apt-get install y-ppa-manager

  3. Run y-ppa-manager (i.e. type y-ppa-manager then press enter key).

  4. When the main y-ppa-manager window appears, click on "Advanced."

  5. From the list of advanced tasks, select "Try to import all missing GPG keys" and click OK.

    You're done! As the warning dialog says when you start the operation, it may take quite a while (about 2 minutes for me) depending on how many PPA's you have and the speed of your connection.

Community
  • 1
monotasker
  • 3,675
  • fyi, while adding the repo it outputs the link webupd8.org/2010/11/y-ppa-manager-easily-search-add-remove.html for more information. – Elijah Lynn Sep 03 '14 at 14:55
  • 43
    Not really useful in a webserver, as this installs X11. Don't use this method if you're on a server edition, check karthick87's answer! – goncalotomas Feb 11 '16 at 20:13
  • sudo apt-get update produces error: W: GPG error: http://ppa.launchpad.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 089EBE08314DF160 – Mitch Apr 03 '16 at 18:40
  • 2
    Does this allow to verify the keys which are imported, or are you simply blindly importing everything (and therefore trusting everyone who has a PPA)? – Paŭlo Ebermann Sep 06 '16 at 10:36
  • 3
    You're importing (and trusting) the keys for every PPA you've added to your system. The assumption is that you trust those PPA's and have checked them out before you added them via apt. – monotasker Sep 06 '16 at 14:25
  • 1
    Does anybody happen to know what the command is that y-ppa-manager uses for its 'Advanced>Try to import all missing GPG keys'? That is so super helpful, I would really like to make an alias of it so wouldn't have to launch y-ppa-manager if that's all I need to do. Thanks! :) – Ev- Dec 28 '16 at 01:26
  • 7
    This answer is easier by far, and actually requires fewer commands than this "graphical" answer. – jpaugh Jul 27 '17 at 19:37
  • 2
    But the question asked for a graphical method. – monotasker Jul 28 '17 at 22:30
  • y-ppa-manager fails to "open display" on my ubuntu 17.10 – Mobigital Jan 16 '18 at 21:34
  • Tha's wont works on most server , you were most mention this app needs GUI to work I waste 15 min installing it .this command from answer below is perfect apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <PUBKEY> – Salem F Feb 24 '19 at 22:17
  • 1
    You'll notice that the question specifies "Is there a way to do this without using a terminal?" – monotasker Feb 25 '19 at 14:21
  • @jpaugh not if you have multiple keys missing. – vikki Nov 20 '19 at 07:49
  • @vikki Actually, batch jobs is where the command-line really shines. You can do it like this: for pubkey in Key1 Key2 Key3 ... KeyN; do sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys "$pubkey"; done. In that case, key1...KeyN is a space-separated list of public key IDs that should be imported. (The dots themselves should not be included.) The more keys you need to import, the more convenient this is, because you can let it run and walk away from it while it finishes. – jpaugh Nov 20 '19 at 19:24
  • @jpaugh getting the keys is the task I was thinking of as arduous. Is there a command to list the missing ones? – vikki Nov 21 '19 at 13:32
  • No, I don't. It will depend on why you need them. (Or maybe how you lost them?) I've never added more than a few ppas at a time, and can't think of a different reason to need keys. – jpaugh Nov 21 '19 at 18:50
  • Error: retrieving gpg key timed out. – Giorgi Gvimradze Dec 14 '19 at 15:16
  • Your fix involves using apt-get update which won't work because keys are missing, makes no sense – Shardj May 13 '20 at 10:29
  • Don't, Do not install this, Err:8 http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu groovy Release 404 Not Found, – Seandex May 17 '20 at 07:50
95

It happens when you don't have a suitable public key for a repository.

To solve this problem use this command:

gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv 9BDB3D89CE49EC21

which retrieves the key from ubuntu key server. And then this:

gpg --export --armor 9BDB3D89CE49EC21 | sudo apt-key add -

which adds the key to apt trusted keys.

The solution can be found here & here & here.

Kevin Bowen
  • 19,615
  • 55
  • 79
  • 83
Pedram
  • 5,711
39

You need to get and import the key.

To get the key from a PPA, visit the PPA's Launchpad page. On every PPA page at Launchpad you will find this link (2), after clicking on 'Technical details about this PPA' (1):

image 1

Follow it and click on the key ID link (3):

image 2

Save the page, this is your key file.

Now it's time to import it:

  • Applications > Software Center,
  • Edit > Software sources...,
  • Enter your password,
  • Go to the Authentication tab and click on Import Key File..., finally
  • Select the saved key file and click on OK.
xiota
  • 4,849
htorque
  • 64,798
  • 1
    Don't lost your time, see the answer bellow. – Felipe Oct 17 '11 at 09:06
  • 5
    @FelipeMicaroniLalli, the question was how to add a pubkey using the GUI, not the terminal, so this answer was perfect. – Chris Woods Jul 30 '13 at 14:24
  • It's much easier and faster now to do this with y-ppa-manager (also a gui application). See my answer below. – monotasker Dec 04 '13 at 15:53
  • 1
    OK, but what if the repository is not an ubuntu ppa. E.g. Intel run their own repository for video hardware drivers at https://download.01.org – mc0e May 20 '15 at 15:39
  • Great step-by-step guide, thanks very much! really helpful for some one who failed to add key via apt-key. – Roy Ling Nov 10 '15 at 01:35
22

note: As of recent versions, it is no longer considered good practice to add PPA keys to the keyring. However, I will leave this answer but apt-key is now deprecated so it is recommended we follow different methods for now.

apt can only handle 40 keys in /etc/apt/trusted.gpg.d . 41 keys and you will get the GPG error "no public key found" even if you go through all the steps to add the missing key(s).

Check to see if there are any unused keys in this file from ppa(s) you no longer use. If all are in use, consider removing some ppa(s) along with the corresponding keyfiles in /etc/apt/trusted.gpg.d

Furthermore, using

sudo apt-key adv

Is considered a security risk and is not recommended as you are "undermining the whole security concept as this is not a secure way of recieving keys for various reasons (like: hkp is a plaintext protocol, short and even long keyids can be forged, …)". http://ubuntuforums.org/showthread.php?t=2195579

I believe the correct way to add missing keys (for example 1ABC2D34EF56GH78) is

gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv 1ABC2D34EF56GH78
gpg --export --armor 1ABC2D34EF56GH78 | sudo apt-key add -
Benjamin Loison
  • 184
mchid
  • 43,546
  • 8
  • 97
  • 150
  • 1
    I found it easier to just delete all keys from /etc/apt/trusted.gpg.d and then proceed to accepted answer http://askubuntu.com/a/386003/284664 – janot Feb 08 '15 at 18:22
  • @mchid Can you please quote a document/url that talks about this 41 keys limit ? – SebMa Mar 27 '19 at 02:54
  • @SebMa The link is posted in my answer and references a bug in Debian that was impacted by this limit. Here is an anchor to the actual post within the link which mentions this: https://ubuntuforums.org/showthread.php?t=2195579#post_message_12882784 I'm not sure if actual documentation exists on this but the number 40 may have been used because "40" translates to "a lot" in many different languages. – mchid Mar 27 '19 at 08:22
  • @SebMa However, the limit exists or did exist at the time of this answer and for some time after as well. I have personally experienced this 41 keys limit and have fixed it by deleting unused keys to add a new key when 40 keys already existed to avoid this error. – mchid Mar 27 '19 at 08:23
  • @SebMa Additionally, that is not to say that you will not encounter this error if you have <41 keys. You will also get this error when you have a missing key. So, first check to see if you have too many keys and then proceed to fix the problem by adding the key correctly. – mchid Mar 27 '19 at 08:32
  • @SebMa And if you want more, just google: 'gpg mailing list "40-keys"' there are many references in the results. – mchid Mar 27 '19 at 09:39
  • @mchid Thanks. One more thing, you said in your answer no to use sudo apt-key adv because hkp is a plaintext protocol, when then does your gpg --keyserver ... command contain this hkp url : hkp://keyserver.ubuntu.com:80 , is it not a plaintext url too ? – SebMa Mar 27 '19 at 13:41
  • @SebMa I didn't say that. The plaintext thing was only one thing mentioned in one of the posts. The alternate commands I use come from the Debian documentation. – mchid Mar 27 '19 at 15:10
  • @mchid Sorry, I didn't notice it came from the Debian documentation. Do know a more secure way to add a missing key ? – SebMa Mar 27 '19 at 15:17
  • 1
    @SebMa no https://wiki.debian.org/SecureApt – mchid Mar 27 '19 at 15:20
  • 3
    Warning: apt-key is deprecated – Daniel Andrzejewski Feb 15 '23 at 13:28
  • 2
    @DanielAndrzejewski Yes, thank you. I will have to update the answer later. In the meantime, you can follow these instructions as an alternative method of adding a key for a repository. Also, if you do use this other method, remember to delete the corresponding key from your keyring so that the key only applies to the single repository. The reason it is depreciated is because adding the key to your keyring applies the key to all repositories. Adding the key to a single repo in one of your sources.list files only applies to the single repository. – mchid Feb 17 '23 at 03:35
  • @DanielAndrzejewski Alternatively, if it's a PPA, you can simply delete the corresponding sources list file for the PPA in your /etc/apt/sources.list.d/ directory and then add the ppa again using the sudo add-apt-repository command. Adding the PPA again should automatically update the key to the newest version. The only problem with this is that it seems like it's vulnerable to the same security flaw (it adds the key to the global keyring). – mchid Feb 26 '23 at 07:58
  • 1
    @mchid my problem was related to docker-ce and containerd.io packages. Docker-ce was the latest but containerd.io package was version locked to some version not fully compatible with the latest docker-ce. When I removed versionlock and updated containerd.io package the problem got fixed. – Daniel Andrzejewski Mar 01 '23 at 15:02
  • @DanielAndrzejewski That's good. On a side note, it seems like we should be able to use apt-key to add the key and then simply move the key over to /etc/apt/keyrings to avoid the security issue and then manually link that path to the key file in the sources list file for the individual repository. Although, I have not tested this. – mchid Mar 02 '23 at 14:15
13

There is a tiny script packaged in the WebUpd8 PPA which I'll link as a single .deb download so you don't have to add the whole PPA - which automatically imports all missing GPG keys.

Download and install Launchpad-getkeys (ignore the ~natty in its version, it works with all Ubuntu versions from Karmic all the way to Oneiric). Once installed, open a terminal and type:

sudo launchpad-getkeys

If you're behind a proxy, things are a bit more complicated so see this for more info

Alin Andrei
  • 7,348
  • 1
    It is indeed the way I do now, since I saw this program presented on your website. Nevertheless, the aim of the question was to know how to do it in a graphical way. – Agmenor Jun 05 '11 at 22:34
  • The launchpad-getkeys script is now integrated into the program Y-PPA-manager. https://launchpad.net/~webupd8team/+archive/y-ppa-manager – monotasker Dec 04 '13 at 15:41
7

This error can also occur when the apt list file by the PPA points to a local keyring, like

deb [signed-by=/usr/share/keyrings/SOMETHING.gpg] https://download.something.org/something something/

And while that file may exist on your system (possibly downloaded with a prior command), it may be unreadable due to missing permissions. I just fixed this kind of error by running 

chmod 644 /usr/share/keyrings/*

after having fetched the keyring file. The underlying issue was the usage of sudo when I already was root user. Really weird as all of this is root anyway and there was no access permission failure message anywhere... but that fixed it

phil294
  • 589
  • 1
    This was also the reason why it wouldn't work for me. The GPG key instructions from Hashicorp do not work on my Ubuntu because the permissions were not set correctly. After chmod, apt finally could read the file. – Jodiug Jan 18 '23 at 12:26
  • I had a similar issue where the keyrings directory had incorrect permissions. I fixed it by running sudo chmod 755 /etc/apt/keyrings. – Minding Oct 29 '23 at 10:08
6

I faced the same issue while installing Heroku. The link below solved my problem -

http://naveenubuntu.blogspot.in/2011/08/fixing-gpg-keys-in-ubuntu.html

After fixing the NO_PUBKEY issue, the below issue remained

W: GPG error: xhttp://toolbelt.heroku.com ./ Release: The following signatures were invalid: BADSIG C927EBE00F1B0520 Heroku Release Engineering <release@heroku.com>

To fix it I executed the following commands in terminal: 

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

Source - Link to solve it

Community
  • 1
dennyac
  • 217
  • I'm still getting same error, GPG error: http://download.opensuse.org/repositories/home:/colomboem/xUbuntu_16.04 Release: The following signatures were invalid: – Itamar Katz Apr 13 '20 at 08:58
6

Make sure you have apt-transport-https installed:

dpkg -s apt-transport-https > /dev/null || bash -c "sudo apt-get update; 
sudo apt-get install apt-transport-https -y"

Add repository:

curl https://repo.skype.com/data/SKYPE-GPG-KEY | sudo apt-key add - 
echo "deb [arch=amd64] https://repo.skype.com/deb stable main" | sudo tee /etc/apt/sources.list.d/skype-stable.list

Install Skype for Linux:

sudo apt-get update 
sudo apt-get install skypeforlinux -y

Source: https://community.skype.com/t5/Linux/Skype-for-Linux-Beta-signatures-couldn-t-be-verified-because-the/td-p/4645756

Eduardo Cuomo
  • 332
5

More generally, the following method should work for every repository. First of all search, with eventual help of a search engine, for a text on the program provider's website looking like the following:

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.1 (GNU/Linux)
[...]
-----END PGP PUBLIC KEY BLOCK-----

Such a text is for example displayed on http://deb.opera.com. Copy the passage, paste it in an empty file that you create on your desktop. This results in the key file.

Then continue with the importation of the key:

  • Applications > Sofware Center
  • Edit > Sofware sources..., enter password
  • Authentication tab, click on 'Import Key File...'
  • Select the saved key file and click on 'Ok'.

You may now remove the previously created key file.

Agmenor
  • 16,214
2

Updated version (Ubuntu 22.04 LTS)

Because apt-key is deprecated now, and you want to use /etc/apt/trusted.gpg.d/, you can use

sudo gpg --keyserver pgpkeys.mit.edu --recv-key <PUBKEY>
sudo mkdir -p /etc/apt/keyrings/
sudo gpg -a --export <PUBKEY> /etc/apt/keyrings/<your-keyfile-name>.gpg
# now go to your /etc/apt/sources.list.d/<source definition list file>, and 
# add [signed-by=/etc/apt/keyrings/<your-keyfile-name>.gpg] between deb and url like this:
# deb <add here> https://...

<PUBKEY> is the 8 character fingerprint like 210976F2 and <target name> is a name of your choice by which you will know that key.

EDIT: Updated for more security, taken from a lengthy answer

smido
  • 155
  • https://askubuntu.com/a/1307181/887635 explains in detail why your answer is insecure and should not be applied. – iron9 Oct 04 '23 at 22:38
2

Good! I finally found the way!

I've tested all methods to fix GPG error NO_PUBKEY and nothing worked for me.

I've deleted the entire contents of the folder /etc/apt/trusted.gpg.d

cd /etc/apt/trusted.gpg.d
sudo rm -R *
sudo apt-get update

And I use the Y-PPA-Manager method because I'm too lazy to create all pubkey's manually (too many): http://www.unixmen.com/fix-w-gpg-error-no_pubkey-ubuntu/

run sudo apt-get update again and finally everything works great now! Thanks!

Based Source : post #17 on https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1263540

kellyfj
  • 105
  • 4
NeurOSick
  • 144
  • 8
0

2021 August. This is what worked for me.

cd /etc/apt/trusted.gpg.d
sudo rm -R *
sudo apt-get update

The last line will raise errors of missing keys.

What you'd then have to do is manually install each of the keys listed in the errors for example if the error is saying that your missing PUB_KEY is 9BDB3D89CE49EC21,

You can manually add the Key with the command sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9BDB3D89CE49EC21

Re-run sudo apt-get update

Repeat the process for the new key raised in the error

Say if the new key was 3BDB3D89CE49EC24, Just Manually add the Key with the command sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3BDB3D89CE49EC24

Re-run sudo apt-get update and repeat the process until all the errors are gone.

Then go back to the package site you were trying to install and repeat the installation process.

For my case, the error was coming while I tried installing Sublime Text Doing the above and returning to the Sublime installation guide here solved the issues.

Don't forget to upvote if this works for you. And it must do

NMukama
  • 356
0

It is always a good idea to check who is signing the repository by inspecting the offending file(s) in /etc/apt/sources.list.d For example, examining the mysql.list file, it shows where the key is stored

### THIS FILE IS AUTOMATICALLY CONFIGURED ###
# You may comment out entries below, but any other modifications may be lost.
# Use command 'dpkg-reconfigure mysql-apt-config' as root for modifications.
deb [signed-by=/usr/share/keyrings/mysql-apt-config.gpg] http://repo.mysql.com/apt/ubuntu/ jammy mysql-apt-config
deb [signed-by=/usr/share/keyrings/mysql-apt-config.gpg] http://repo.mysql.com/apt/ubuntu/ jammy mysql-8.0
deb [signed-by=/usr/share/keyrings/mysql-apt-config.gpg] http://repo.mysql.com/apt/ubuntu/ jammy mysql-tools
#deb [signed-by=/usr/share/keyrings/mysql-apt-config.gpg] http://repo.mysql.com/apt/ubuntu/ jammy mysql-tools-preview
deb-src [signed-by=/usr/share/keyrings/mysql-apt-config.gpg] http://repo.mysql.com/apt/ubuntu/ jammy mysql-8.0

As you can see, the key is stored in /usr/share/keyrings/mysql-apt-config.gp. At this point you can download the new offending key in the proper place

gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys [OFFENDING KEY] && rm /usr/share/keyrings/mysql-apt-config.gpg && gpg  --output /usr/share/keyrings/mysql-apt-config.gpg --export [OFFENDING KEY]

eventually leaving away the rm /usr/share/keyrings/mysql-apt-config.gpg part if you don't have the key

Christian Deligant
  • 11
  • 2
0

I had the same problem with DynDNS's Updater client.

Turns out it was just expired keys.

Reinstalling the software (downloading a new .deb from the website, then using Software Centre to reinstall) fixed the problem.

Error message for reference:

W: GPG error: http://cdn.dyn.com stable/ Release: The following signatures were invalid: KEYEXPIRED 141943.......
kos
  • 35,891
Cranky
  • 454
  • 5
  • 11