Re: [tor-dev] Proposition: Applying an AONT to Prop224 addresses?

[Alec Muffett <alec.muffett@xxxxxxxxx>]

We could leave the version field outside the AONT, though, but commit to

changing the paramaters of the AONT (in particular, the domain
separation constant?) if we change the version number, so that an
adversary changing the version number to "2" would just cause the client
to throw an error (before version 2 exists) or be an invalid address
(after version 2 exists)?

To add an aside from a discussion with Teor: the entire "version" field could be reduced to a single - probably "zero" - bit, in a manner perhaps similar to the distinctions between Class-A, Class-B, Class-C... addresses in old IPv4.

Thus: if the first bit in the address is zero, then there is no version, and we are at version 0 of the format

If the first bit is one, we are using v1+ of the format and all bets are off, except that the obvious thing then to do is count the number of 1-bits (up to some limit) and declare that to be version number.  Once we're up to 3 or 4 or 7 or 8 one-bits, then shift version encoding totally.

Teor will correct me if I misquote him, but the advantage here was:

a) the version number is 1 bit, ie: small, for the forseeable / if we get it right

b) in pursuit of smallness, we could maybe dump the hash in favour of a AONT + eyeballs, which would give back a bunch of extra bits 

result: shorter addresses, happier users.

 

--

http://dropsafe.crypticide.com/aboutalecm

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