WARNING: The following packages cannot be authenticated! $ sudo apt-get install gstreamer1.0-pulseaudio Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libdirac-encoder0 libopencore-amrnb0 libopencore-amrwb0 libsvga1 libvo-aacenc0 libvo-amrwbenc0 Use 'apt-get autoremove' to remove them. The following NEW packages will be installed: gstreamer1.0-pulseaudio 0 upgraded, 1 newly installed, 0 to remove and 1 not upgraded. Need to get 57.6 kB of archives. After this operation, 220 kB of additional disk space will be used. WARNING: The following packages cannot be authenticated! gstreamer1.0-pulseaudio Install these packages without verification [y/N]?
To solve that:
$ sudo apt-key update $ sudo apt-get update
$ sudo apt-key list $ sudo apt-key remove FBB75451 $ sudo apt-key list