  Distributed Virtual Private Networks (dVPNs) are new VPN solutions aiming to
solve the trust-privacy concern of a VPN's central authority by leveraging a
distributed architecture. In this paper, we first review the existing dVPN
ecosystem and debate on its privacy requirements. Then, we present VPN0, a dVPN
with strong privacy guarantees and minimal performance impact on its users.
VPN0 guarantees that a dVPN node only carries traffic it has "whitelisted",
without revealing its whitelist or knowing the traffic it tunnels. This is
achieved via three main innovations. First, an attestation mechanism which
leverages TLS to certify a user visit to a specific domain. Second, a zero
knowledge proof to certify that some incoming traffic is authorized, e.g.,
falls in a node's whitelist, without disclosing the target domain. Third, a
dynamic chain of VPN tunnels to both increase privacy and guarantee service
continuation while traffic certification is in place. The paper demonstrates
VPN0 functioning when integrated with several production systems, namely
BitTorrent DHT and ProtonVPN.
