Ubuntu GPG error 非官方源无公钥

Today I use sudo apt-get update and it comes this error.

 

W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0E309B718DA8F7C3

It means some sources are not official so that is no key.

 

 

due to a missing GPG key do the following to correct the problem

gpg --keyserver subkeys.pgp.net --recv 0E309B718DA8F7C3




Replace the key number “7D2C7A23BF810CD5″ with the one included in your error message

gpg --export --armor 0E309B718DA8F7C3 | sudo apt-key add -

After that, the key will be added to a list and the error will not reappear.