ubuntu@ubuntu-XPS-15-9570 ~/Downloads sudo apt-get update
Get:1 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 InRelease
Ign:1 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 InRelease
Get:2 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 Release [574 B]
Get:2 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 Release [574 B]
Get:3 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 Release.gpg [833 B]
Get:3 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 Release.gpg [833 B]
Get:4 file:/var/cuda-repo-10-2-local-10.2.89-440.33.01 Packages [23.8 kB]
Hit:5 http://packages.microsoft.com/repos/code stable InRelease
Hit:6 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:7 http://packages.ros.org/ros/ubuntu bionic InRelease
Hit:8 http://kr.archive.ubuntu.com/ubuntu bionic InRelease
Get:9 http://kr.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:10 https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 InRelease [1,581 B]
Err:10 https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A4B469963BF863CC
Get:11 http://kr.archive.ubuntu.com/ubuntu bionic-backports InRelease [83.3 kB]
Get:12 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Reading package lists... Done
W: GPG error: https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A4B469963BF863CC
E: The repository 'https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64 InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A4B469963BF863CC
