解決ubuntu下error occurred during the signature verification

解決ubuntu下error occurred during the signature verification 在ubuntu 下想安裝一個軟體（我使用的是163的源），卻被告知 file size mismatch. 於是更新了package list: sudo apt-get update... ... W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: http://security.ubuntu.com lucid-security Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com> W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: http://us.archive.ubuntu.com lucid Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com> W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: http://us.archive.ubuntu.com lucid-updates Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com> 即使執行： sudo apt-get clean sudo apt-get update 還是會有相同的錯誤。 有瞭解決方案： sudo apt-get clean  cd /var/lib/apt  sudo mv lists lists.old  sudo mkdir -p lists/partial  sudo apt-get clean  sudo apt-get update