There is no public key available for the following key ID

Solutions:-1 Try this as root: Code: # gpg --recv-keys 4D270D06F42584E6 # gpg --export 4D270D06F42584E6 | apt-key add - That should download the key from a public keyserver and then the second command adds it to apt. You may need to specify a keyserver if the default doesn't work. There are several public ones available.   Solution:-2 Code: # apt-get install debian-keyring debian-archive-keyring # apt-key update