Thus spake "Scott A Crosby" <crosby@qwes.math.cmu.edu>
Rolling off the top of my head, I think its doable. The general trick is to make it hard to forge packets with arbitrary addresses (by using authentication).
No, the trick is for a distributed algorithm to generate a non-trivial number of unique values for a (short) fixed-length field.
Assume each host has an public and private key pair by some conventional algorithm (RSA, or other). The private key is never disclosed. ... A variant of this could be made where just the network is assigned with this scheme, the host isn't. IE, hosts are assigned addresses of:
k_public || hostaddr
For instance, let's say IP had started with a constant 24-bit network field (no Class A or B), or 16M possible networks. My rough count shows we have 97 /8's usefully allocated, or 776M hosts assuming 50% efficiency. We'd need 6.4M /24 networks to cover this many hosts, out of a possible 16M networks. I dare you to find any hash that can reliably give 38% of all possible values without a collision. Once you've done that, perhaps you can enhance BGP to handle 800M routes :)
Which isn't robust against malicious hosts in the same network, but thats fixable with a heirarchial scheme.
The odds of k_private being disclosed grow exponentially with the number of hosts per network. Interesting idea though. Perhaps someone will write an i-d on autonomous numbering for IPv6. S