I would like to update all of my programs, but something wrong.

$ sudo apt update && sudo apt full-upgrade
[sudo] password for racztamaska:           
Hit:1 http://gb.archive.ubuntu.com/ubuntu xenial InRelease
Hit:2 http://ppa.launchpad.net/elementary-os/stable/ubuntu xenial InRelease
Ign:3 http://dl.google.com/linux/chrome/deb stable InRelease                        
Hit:4 http://ppa.launchpad.net/elementary-os/os-patches/ubuntu xenial InRelease     
Get:5 http://gb.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]         
Hit:6 http://dl.google.com/linux/chrome/deb stable Release                          
Hit:7 http://packages.elementary.io/appcenter xenial InRelease                      
Get:8 http://gb.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]       
Get:9 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]        
Get:10 https://repo.skype.com/deb stable InRelease [4,487 B]  
Err:10 https://repo.skype.com/deb stable InRelease             
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1F3045A5DF7587C3
Reading package lists... Done 
W: GPG error: https://repo.skype.com/deb stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1F3045A5DF7587C3
E: The repository 'https://repo.skype.com/deb stable 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.

What is the problem? What is public_key?

Please, help me.

Thank you


  • Hi Guys I have a dangerous problem ı need my pc because ı cant login on my elementary os.I see a solving in this site it says "press ctrl + alt + f2 and write this command : (sudo service lightdm restart)" ı used this method and I wrote this code succesfuly after Terminal is asked my pc password but ıt Couldnt see my press on the keys.Help me please THANK YOU SO MUCH....
    – user12868
    Nov 29 '17 at 19:19

Per the Debian Wiki:

Public key cryptography is based on pairs of keys, a public key and a private key. The public key is given out to the world; the private key must be kept a secret. Anyone possessing the public key can encrypt a message so that it can only be read by someone possessing the private key. It's also possible to use a private key to sign a file, not encrypt it. If a private key is used to sign a file, then anyone who has the public key can check that the file was signed by that key. Anyone who doesn't have the private key can't forge such a signature.

To solve the error messages shown by the Terminal and install Skype, you need to add Skype's public key which can be done by running:

curl https://repo.skype.com/data/SKYPE-GPG-KEY | sudo apt-key add - 

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.