Ejecuté este comando en la Terminal:
sudo apt-get update
La actualización finaliza con el siguiente informe de error:
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com precise Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG 4C1CBC1B69B0E2F4 Launchpad PPA for Jonathan French
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/precise/Release
¿Qué significa esto y por qué está sucediendo?