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Possible Duplicate:
How do I fix the GPG error “NO_PUBKEY”?

after sudo apt-get update I get this error:

W: GPG error: all Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3C962022012520A0
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marked as duplicate by Jorge Castro, Mik, fossfreedom Dec 10 '12 at 17:38

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Hi! I tried, but no success, look: .... $sudo apt-key adv --keyserver --recv-keys 3C962022012520A0 Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver --recv-keys 3C962022012520A0 gpg: requesting key 012520A0 from hkp server ?: Connection refused gpgkeys: HTTP fetch error 7: couldn't connect: Connection refused gpg: no valid Open – Oleksa Feb 16 '11 at 14:30
The website appears to be either down or misconfigured, I can't get to it either. – Jorge Castro Feb 16 '11 at 14:30
up vote 107 down vote accepted

Run the following in your terminal,

 sudo apt-key adv --keyserver --recv-keys 3C962022012520A0 
 sudo apt-get update

References: How do I fix the GPG error "NO_PUBKEY"?

You need to replace the key (3C962022...) with the one that is displayed in the error message in the terminal.

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When you add a third-party repository, you should also add its key to your system. The public key is a string which identifies that certain repository. You can find some more information on this and how to add the key here.

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