We're a global platform that runs an intra-fleet WireGuard mesh, so we have authenticated addressing between nodes; we layer a couple dozen lines of BPF C on top of that to extend the authentication model to customer address prefixes. So, effectively, we're using WireGuard as an identity. In fact: we do so explicitly for peering connections to other services.

So yeah, it's a model that can work. It's straightforward for us because we have a lot of granular control over what can get addressed where. It might be trickier if your network model is chaotic.

I too am interested in this.

I long for the day where Kubernetes services, virtual machines, dedicated servers and developer machines can all securely talk to eachother in some kind of service mesh, where security and firewalls can be implemented with "tags".

Tailscale seems to be pretty much this, but while it seems great for the dev/user facing side of things (developer machine connectivity), it doesn't seem like it's suited for the service to service communication side? It would be nice to have one unified connectivity solution with identity based security rather than e.g Consul Connect for services, Tailscale / Wireguard for dev machine connectivity, etc.

>I long for the day where Kubernetes services, virtual machines, dedicated servers and developer machines can all securely talk to eachother in some kind of service mesh, where security and firewalls can be implemented with "tags".

That's exactly what Scalable Group Tags (SGTs) are -

https://tools.ietf.org/id/draft-smith-kandula-sxp-07.html

Cisco implements this as a part of TrustSec

One of the methods that Cilium (which implements this eBPF-based service mesh idea) uses to implementation authentication between workloads is Wireguard. It does exactly what you describe above.

In addition it can also be used to enforce based on service specific keys/certificates as well.

Isn't the Wireguard implementation in Cilium between nodes only, not workloads (pods)?

It can do both. It can authenticate and encrypt all traffic between nodes which then also encrypts all traffic between the pods running on those pods. This is great because it also covers pod to node and all control plane traffic. The encryption can also use specific keys for different services to authenticate and encrypt pod to pod individually.

You'd be adding a whole new layer of what would effectively be dynamic routing. It's doable, but it's not a trivial amount of effort. Especially if you want everything to be transparent and automagic.

There's earlier projects like CJDNS which provide pubkey-addressed networking, but they're limited in usability as they route based on a DHT.

Ziti (Apache) provides bootstrapped* identity based security (and programmable, least privilege overlays).

Disclosure: founder of company which sells SaaS on top of Ziti FOSS.

* https://ziti.dev/blog/bootstrapping-trust-part-5-bootstrappi...