Até onde eu sei, o Tails é baseado no Debian. Eu tentei instalar o Docker usando a instrução para o Debian. Mas não quer adicionar a chave
amnesia@amnesia:~$ sudo apt-key adv \
> --keyserver hkp://ha.pool.sks-keyservers.net:80 \
> --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
[sudo] password for amnesia:
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.JPiSwbg3oi --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyring /etc/apt/trusted.gpg.d/deb.torproject.org-keyring.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-security-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-jessie-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-squeeze-stable.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-automatic.gpg --keyring /etc/apt/trusted.gpg.d/debian-archive-wheezy-stable.gpg --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
gpg: запрашиваю ключ 2C52609D с hkp сервера ha.pool.sks-keyservers.net
gpgkeys: HTTP fetch error 6: Could not resolve host: ha.pool.sks-keyservers.net
gpg: не найдено данных формата OpenPGP.
gpg: Всего обработано: 0