What are some use cases this can be applied to?
IP addresses (normal, unicast ones) like 1.2.3.4 and a9c::890 are meant to reach a computer somewhere on the Internet, through any number of routers. Routers are meant to forward IP packets until they reach their goal.
Try it with your neighbor's computer, it's not going to work. Did he enable DMZ or port forwarding? Alright, that works when your neighbor is home. Now try it when your neighbor is at work. His IP address changed, so there goes the reachability. This seems like "duh, obviously," and you're right. But I just want to perform the fundamental action of connecting two computers.
I personally used Tor to solve this problem: run a hidden service on one, connect to the .onion address on the other (you can configure ssh to work with .onion addresses).
This public key system would solve the problem in a much better way, without going through Tor. Not that Tor is bad, it's just not meant for this. Connecting the two machines directly without thinking about the intermediary network is what I wanted.
Second, snow does not change whether an application is centralized or not. It's the application which is centralized, not the address. Your host's address can be "1.2.3.4" or "abcdefghijklmnop", this does not change how the application works at all.
Third, snow is just a tunnel. Any tunnel would "fix" an application the same way by simply translating addresses and encapsulating communication.
This is basically just onion routing, but snow doesn't really exist to be an onion router. The real purpose of snow appears to be that the author wanted to use the features of IPv6 (secure connections and the ability to address and connect to a host behind a network firewall) without having to actually use IPv6 in his application, and doing all this on top of an IPv6-only network. This is what sets it apart from every other NAT-tunnel. The public key stuff is a red herring.
Applications tend to assume that IP addresses are globally unique. ISPs depend a lot on each other to handle routing properly. Occasionally we see a route leak when someone screws up. Sometimes it even happens deliberately. And it's entirely possible that malicious routes are announced on a regular basis to conduct clandestine MITM attacks. Technical solutions for automatically determining which ASNs should be allowed to announce an IP prefix remain problematic. And BCP 38 - while it helps to deal with DoS attacks and certain security issues - also breaks some very useful approaches to deploying high performance/scale applications.
The internet is currently far more centralized than most people like to admit. The reality is that both DNS and IP are handled by delegation from a central authority. For instance, proof of IP address ownership remains outside the scope of the protocols. Network connectivity still remains based on trust relationships. That is fundamentally incompatible with a decentralized and ad-hoc approach to networked applications.
There are many network operators who have been shown untrustworthy. The design of the internet hasn't quite caught up yet.
And it really has nothing to do with centralization or decentralization. It's peer to peer. Your peers can be anywhere and you can send and receive anything, out of order, connectionless. This is fantastic for decentralized distributed networking.
Applications can 'assume' anything they want; that's the application, not the addressing protocol. Everyone who has read RFC1918 knows IP addresses are not unique.
And there is no way to ensure a route doesn't have a malicious actor. It's been shown time and again with networks like Tor that it doesn't matter what layers of security or obfuscation or decentralization you add. A bad actor on a route will be able to identify or mess with your traffic. Your application is the deciding factor in the security of the connection.
DNS and IP are not handled for everyone by a central authority. Both are independent protocols which can be used across the internet without a central authority's authorization. Of course IP addresses are more closely guarded, but like you mentioned before, advertising an invalid range of addresses works all the time. And DNS is not even needed to use the internet! Public domain registration using specific TLDs does have centralized control bodies, of course, but that's necessary to prevent conflict.
The internet is a web of trust. That will never, ever change. The reason it will never change is we all want something for free.
If you wanted, you could pay for and bury fiber-optic cable from your home to every place on planet earth that you want to make a network connection to. Then you wouldn't have to trust anyone, and when someone taps into your fiber or cuts the connection, you could (hopefully) determine that your connection is no longer "safe" or "reliable". But this is not very practical.
The internet fixes this by allowing any network to help any other network get around common network problems. We help each other because it is mutually beneficial. When that mutual assistance breaks down you get problems like the Comcast-Netflix debacle. No internet protocol or addressing scheme will route around a monopoly on the network. The only "decentralized" solution is a bunch of people on a wireless mesh network and a satellite link, which will still result in Netflix not being practically usable.
But please, keep believing that an addressing scheme will somehow keep you from having to trust a foreign network. Good luck getting House of Cards to stream.
Isn't this a similar concept to Tor addresses without the onion routing being part of it?
The problem with SSL is that it needs certificates. You need a domain name and a certificate if you want to run anything over SSL in a resonable manner.
If address == identity then those requirements vanish because learning about the address already provides you all the information you need to establish a secure connection.
It democratizes authenticated connections.
It's interesting, and it may be useful. But for securing what we currently do with IP it's useless.
You would still have the problem of name resolution. However since the address would be the public key, once you had resolved the address the identity of the other party would be assured. Assuming that an attacker cannot feasibly generate an equivalent public key, you remove key exchange+authentication as an attack surface.
Key management could be a downside. If you want to update your key you have changed your address, which would look like a name-resolution poisoning attack. There are feasible ways around this but none are ideal (particularly if your key was compromised, mechanisms like signed forwarding records would become extremely hazardous). It would probably have to rely on name-resolution mechanisms similar to those used by current IP addresses.
Would you bake the private key into the container or set it at runtime? If you set it at runtime how will two containers in different places know who to talk to?
Perhaps you generate the keys at build time and add the public keys to the partner containers, then at run time you inject the private key into the container via an env var. Now you have to securely manage and transport private keys and you've got two problems.
There must be other things I'm not considering.
And, of course, whatever system is running the container can step into it and read the private keys (or any malicious containers running on the host that are able to break out of the container). But we can just avoid that by saying they are our own hardware.