Subject: Re: [Bitcoin-development] bitcoin DNS addresses

From: Matt Corallo <[email-masked]>
Date: Tue, 26 Jul 2011 15:23:39 +0200

On Mon, 2011-07-25 at 20:35 -0700, Rick Wesson wrote:
> Matt,
> 
> I started from the premise that I can't remember a bitcoin address but
> I can/do remember email addresses which, as an identity are easy
> labels for humans to remember. The IPv4 address is the metaphor I
> consider. As someone who actually worked on parts of DNSSEC I do
> believe in it -- and that it offers reasonable security for
> transactions.

> Remember MITM attacks on DNS for a transaction are for the sender
> against the merchant, and it is only the wallet ID that would be
> available. These identifiers are something people use "like" an
> identity in that they are frequently shared in public spaces.
> 
Yes, DNSSEC is great if you are running your own recursive name server.
However, that is probably something like 0.01% of the people out there.
If this were to be made secure, one would have to implement a full
recursive nameserver inside of Bitcoin with the root trust anchors
hardcoded in.  This seems like way overkill to do name->address mapping.
(My attack scenario here is coffee shop wifi with the default DNS
resolvers being somewhere at the ISP and a ARP (or other) MITM attack
intercepting and playing with your DNS queries).
Additionally, HTTPS mapping offers some advantages such as ease of
offering up different to different people by eg. IP address (could be
done by setting DNS TTL to 0 and assuming all users will be using a
built-in resolver, but its still not guaranteed that other clients would
use a built-in resolver and then the IP of the resolver is not the same
as the IP of the Bitcoin node).  
Not that DNS is a terrible idea, but there are clear advantages for
using HTTPS (or similar) mapping over DNS and I see no clear advantage
for using DNS over HTTPS (aside from the "that is what it is designed
for" argument, which I would claim is an invalid argument as you have to
consider the technology, not its intent).
> Also, a DNS mapping does not prevent or deny anyone from leveraging
> HTTP(S) for simular mapping. My point is that DNS is designed for name
> to thing mapping and its done a decent job. What I like about the DNS
> is that it is frequently leveraged as a proxy for identity and http
> URIs are not. Where https://wesson.us/ricks-bitcoin-address doesn't
> feel like and identity (to me) and rick.wesson.us does.
> 
> My point is about usability and user experience. Bitcoin if used in
> the DNS might make DNSSEC more popular which IMHO is a good thing.
Hold on there, Bitcoin is still tiny, I highly, highly doubt it will
make a difference to DNSSEC adoption.