Problem with gpg jitsi-key.gpg.key

any Body have idea about the Problem here:

i have Problem with jitsi after i Download wget
i want to check if the key is valid or not but every time i try to enter gpg jitsi-key.gpg.key it give me this Message ( -bash: gpg: Command not found.)
i try many Things like gpg --search-keys but same result ( -bash: gpg: Command not found.)

apt-get install gnupg

thanks a lot it works