Re: Ripple

On 11/14/2013 04:30 PM, Andrew Miller wrote:
> 2. But this doesn't work for public/anonymous networks.

Why doesn't it work for public/anonymous networks? Link? This is Web of
Trust stuff we're talking about, isn't it (chained trust metrics)?

> 3. Ripple, on the other hand, takes yet another approach. There's no
> global administrator, but nor is there a well-understood public
> competition. Instead, individual users are supposed to configure
> their clients to identify particular servers they have determined
> they trust.

Isn't this a good thing? If you allow anyone to pick who they trust, you
force cooperation in the system, don't you? The idea being that for the
system to be useful, people need to coordinate and thus won't pick
participants with whom they entirely disagree with.

> Here's where it gets really murky, and I can't figure out any set of
> assumptions that actually lead to robust functioning of the network.
> What if users entirely disagree with which servers they trust?

Why would someone deliberately do this? If you have to pick from 32
servers, why would you pick from 32 servers that are in a completely
different trust set? It would be incredibly difficult to do that in a
dependency chain based system, wouldn't it?

> Are they on two different networks or the same one?

No idea.

> If an individual doesn't do their due diligence, and carelessly
> approves bad servers, are they individually affected or does it
> affect the overall network?

I'd expect that in the worst case, the overall network suffers. However,
the likelihood of this is in the 51% attack against the Bitcoin network
category, isn't it?

> I really wish more people were looking into this rather than ignoring
> it, because I suspect it's not sound (although I haven't come up with
> a super clear explanation why not), and if the underlying assumptions
> aren't sound then does it matter if the frontend UI is great?

Well, yeah, if the algorithm is broken then no UI in the world is going
to save it. However, I don't think you've explained quite why Ripple's
consensus algorithm is broken. Why is allowing individuals to pick whom
they trust a bad thing (when the number of servers is large enough)?

> Unfortunately the only set of assumptions I can think of that lead
> to this actually working is where every one essentially picks the
> same default list, and the servers on that list are actually
> trustworthy.

I think the problem surfaces when a group of servers create a trust set
that has no intersection with another set of servers. With that said,
why would anyone do this? What's the attack?

> This is the "centralized" option, where the default list determines
> who participates, and no user has any incentive to deviate from the
> default list, either by adding some newcomer they individually trust
> or by removing default servers they don't trust.

I thought that only a subset of the list needs to be trusted for Ripple
to function, and all trust sets that all servers choose have to overlap
by at least a small degree. Is that not true?

-- manu

-- 
Manu Sporny (skype: msporny, twitter: manusporny, G+: +Manu Sporny)
Founder/CEO - Digital Bazaar, Inc.
blog: Meritora - Web payments commercial launch
http://blog.meritora.com/launch/

Received on Sunday, 17 November 2013 20:51:24 UTC