apt update fails / cannot install pkgs: key not working?

edit

That didn't work for me.

This command did:

sudo launchpad-getkeys

hi I am new to ros and trying to follow a ros2 installation tutorial form this YouTube video (https://www.youtube.com/watch?v=-AouI...) but i keep getting the same error constantly I have tried the solutions provided above but did not improve anything I am using ubuntu in a virtual machine on Mac.

parallels@ubuntu-linux-20-04-desktop:~$ sudo apt-key del 421C365BD9FF1F717815A3895523BAEEB01FA116 OK parallels@ubuntu-linux-20-04-desktop:~$ sudo -E apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654 Executing: /tmp/apt-key-gpghome.6cydgLlBka/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654 gpg: keyserver receive failed: No name parallels@ubuntu-linux-20-04-desktop:~$ sudo ntpdate time.windows.com sudo: ntpdate: command not found parallels@ubuntu-linux-20-04-desktop:~$ sudo -E apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654 Executing: /tmp/apt-key-gpghome.Ug3PX2PVGh/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654 gpg: keyserver receive failed: No name parallels@ubuntu-linux-20-04-desktop:~$ sudo apt clean && sudo apt update Get:1 http://packages.ros.org/ros/ubuntu focal InRelease [4,676 B]
Err:1 http://packages.ros.org/ros/ubuntu focal InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654 Hit:2 http://ports.ubuntu.com/ubuntu-ports focal InRelease Hit:3 http://ports.ubuntu.com/ubuntu-ports focal-updates InRelease Hit:4 http://ports.ubuntu.com/ubuntu-ports focal-backports InRelease Hit:5 http://ports.ubuntu.com/ubuntu-ports focal-security InRelease Reading package lists... Done W: GPG error: http://packages.ros.org/ros/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654 E: The repository 'http://packages.ros.org/ros/ubuntu focal InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. parallels@ubuntu-linux-20-04-desktop:~$

gvdhoorn has a fantastic answer. I'd just like to point to solution to a problem which can be caused on remote machines like a Raspberry Pi. I had renewed the keys and was surprised as I still received the error.

I checked the expiry date using the command sudo apt-key list | grep -A 1 expired and found that the key wasn't expired yet, still it showed as expired.

I later found the time of my system (Raspberry Pi) was wrong and showed year 2024.

A simple sync via internet (using a command like sudo ntpdate time.windows.com) fixed the date, and then the apt update and apt install commands ran perfectly!

The following solution worked for me on Ubuntu 16.04, trying to install the Clearpath Robotics ROS Kinetic Libraries.

Step 1 - Check the Sources List has Referenced to the ROS Packages Within your sources.list file, ensure you have deb http://packages.ros.org/ros/ubuntu xenial main.

You can view your sources.list file using the command below in the terminal:

sudo nano /etc/apt/sources.list

If it's not in there, create a new line with the ROS address as above, and then save and exit.

Step 2 - Do a sudo apt-get-update Bring in the new libraries by executing the following.

sudo apt-get update

At this point, my sudo apt-get update failed, this was because I was missing a ROS Package Key that needed to be added.

If you do get an error, it may look like this:

W: GPG error: http://packages.ros.org/ros/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654 W: The repository 'http://packages.ros.org/ros/ubuntu 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.

If so, proceed to step 3.

Step 3 - Adding your ROS Key In your terminal run the following command: sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

Step 4 - Run another sudo apt-get update

As the title suggests, run sudo apt-get update.

Step 5 - Install ROS Kinetic for the Husky

sudo apt-get install ros-kinetic-husky-desktop sudo apt-get install ros-kinetic-husky-simulator

This worked for me. Hope it works!

After adding the new key, when I execute sudo apt clean && sudo apt update I'm still getting the same error.