我一直试图在我的 Dell 7559 Ubuntu 14.04.5 上安装 NVIDIA 驱动程序，但收效甚微。附加驱动程序菜单不应用推荐的驱动程序（恢复为 X.org），我无法从 PPA 下载驱动程序，ppa:graphics-drivers/ppa因为某些软件包无法通过身份验证。
跑步sudo ubuntu-drivers autoinstall：
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
libfdk-aac0
Use 'apt-get autoremove' to remove it.
The following extra packages will be installed:
bbswitch-dkms libcuda1-387 nvidia-opencl-icd-387 nvidia-prime
nvidia-settings ocl-icd-libopencl1 screen-resolution-extra
Suggested packages:
bumblebee opencl-icd
The following NEW packages will be installed:
bbswitch-dkms libcuda1-387 nvidia-387 nvidia-opencl-icd-387 nvidia-prime
nvidia-settings ocl-icd-libopencl1 screen-resolution-extra
0 upgraded, 8 newly installed, 0 to remove and 1 not upgraded.
Need to get 82,1 MB/82,1 MB of archives.
After this operation, 374 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
ocl-icd-libopencl1 bbswitch-dkms screen-resolution-extra
E: There are problems and -y was used without --force-yes
我确实运行sudo apt-key update并sudo apt-get update尝试解决身份验证问题，但没有成功。
有没有解决的办法？