KALI error FIX: Cannot update Kali Linux due to invalid signatures. To fix the issue we had to get a fresh copy of the archive key for Kali repositories and import it into apt.

command-line.sh

KALI reports the following error message about PGP key on apt-get:

"The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository <devel@kali.org>"

To fix, execute the command:

      $ wget -q -O - https://archive.kali.org/archive-key.asc | apt-key add;