[Debian] Apt-get : NO_PUBKEY / GPG error

vim /etc/apt/source.list deb http://archive.canonical.com/ubuntu lucid partner Ubuntu kaynaklarını kullanmak isterken aşağıdaki hatayı aldım. W: GPG error: http://archive.canonical.com lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF455D05B5 Çözüm bir keyring servera keyinizi tanımlamanız gerekmektedir. root@husonet:~# gpg --keyserver pgpkeys.mit.edu --recv-key 40976EAF455D05B5 gpg: requesting key 437D05B5 from hkp server pgpkeys.mit.edu gpg: key 437D05B5: "Ubuntu Archive Automatic Signing Key " not changed gpg: Total number processed: 1 gpg: unchanged: 1 root@husonet:~# gpg -a --export 40976EAF455D05B5 | apt-key add - OK