How to fix gpf key on ubuntu ?

sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 313D312748A22A95; gpg --export --armor 313D312748A22A95 | sudo apt-key add -



gpg –keyserver keyserver.ubuntu.com –recv 3E5C1192

gpg –export –armor 3E5C1192 | sudo apt-key add -

sudo apt-get update





sudo apt-get update -o Acquire::http::No-Cache=True

sudo aptitude update -o Acquire::http::No-Cache=True

sudo apt-get -o Acquire::http::No-Cache=True -o Acquire::BrokenProxy=True update

sudo aptitude update -o Acquire::http::No-Cache=True -o Acquire::BrokenProxy=True



sudo bash

apt-get clean

cd /var/lib/apt

mv lists lists.old

mkdir -p lists/partial

apt-get clean

apt-get update