
Protocol for Asynchronous, Reliable, Secure and Efficient Consensus [pdf] - Mindphreaker
http://docs.maidsafe.net/Whitepapers/pdf/PARSEC.pdf
======
robotrout
Blockchains have been getting the lions share of attention for several years.
PARSEC enabled networks, SAFE (MAIDSAFE) in particular, could change that.
Blockchains have been battling energy usage, centralization and speed for
awhile. Non-blockchain consensus should really open a lot of doors to allow
decentralized, trustless, non-censorable solutions.

It will be interesting to see what other networks besides SAFE adopt this
consensus mechanism.

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coolspot
Without proof-of-work, what protects consenus from the sybil attack?

As I understood, after quick scan of the paper, consensus is achieved by
simple majority vote.

So if I setup 10,000 docker containers running malicious nodes, I could take
over the network and forge any blocks I want.

What I am missing?

~~~
SJMH
They mention 1/3 of the nodes. How much of a weakness is this?

~~~
saurik
How does that prevent me from pretending to be any number of nodes I want;
including, but by no means limited to, over 1/3 of the nodes? (Maybe you
should first do a quick search to learn what a Sybil attack actually is?) They
can shore this up by having some kind of Sybil attack prevention elsewhere,
but given their statements about proof-of-work here it seems unlikely they
would, for example, add proof-of-work elsewhere. It might be, based on
skimming some blog post I found if theirs, that the goal of this is to help
them shore up a proof-of-stake algorithm to deal with byzantine failures? That
would be interesting, but is a more involved scheme then than just this part,
and I actually don't think that is what they are doing either (as the
connection in that blog post is mostly me reaching for something that works,
not a direct connection made by the authors).

~~~
pdx
For SAFE Network, this is handled, I believe. Other networks that implement
PARSEC will need to address it in some similar way.

In the case of SAFE, you can generate as many nodes as you want, but they must
be valid nodes (doing the work that the network asks of them) for a long time
before being promoted to a status that allows them to participate in consensus
of a section. Any misbehavior on their part results in demotion or failure to
be promoted. So each node would need to be a legitimate contributor to the
network, with all that that entails, before being promoted to a status where
their later misbehavior would matter. You would be creating real nodes, that
used real bandwidth and real CPU resources and did real work that benefits the
network, in order to infiltrate your evil nodes into the network. So, not an
insubstantial cost to you.

Your nodes will be assigned into sections randomly, so it will be very
difficult for you to manage to get multiple nodes with voting status, into a
single section, and staggeringly difficult to get enough such that your nodes
constitute 1/3rd of that section. Of course, exactly how difficult depends on
network size (number of sections).

Finally, even once a node is assigned into a particular section, it will be
reassigned to another random section at some interval, further decreasing your
ability to take over a particular section.

~~~
hobofan
> Finally, even once a node is assigned into a particular section, it will be
> reassigned to another random section at some interval, further decreasing
> your ability to take over a particular section.

Doesn't that on the flipside also mean that given enough time your malicious
nodes will end up in the same section, allowing for a take over of that
section?

~~~
ktorn
As the network grows it becomes increasingly harder to do so, especially since
you need to add increasing amounts of resources (bandwidth, disk space, and
some cpu, for the proof-of-resource) to your attack.

This is not too dissimilar to what happens with CPU-only PoW consensus
networks. Easy to attack in the beginning but less so as the network grows.

It will be interesting to see how the SAFE network will be bootstrapped. I'm
sure there will be a significant number of malicious players waiting in line
to disrupt it early on.

If it works, and I believe it can, IMHO this network will be one of the most
important developments in decentralised systems in the past decade.

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hobofan
Nice! I found Hashgraph very interesting, but their patent stance made it a
no-go for any serious DLT project. Glad that there is now a similar project
without the attached patent! Let's just hope that it's not so similar that it
falls under the original one.

Still need to dig deeper into it, and would love to hear other peoples'
evaluations, but at a first glance, PARSEC could actually be a serious player
in the DLT game.

~~~
DrTiaJolie
Boom! Nailed it. As much as I love the hashgraph tech, it is not pure both
with respect to the patent AND the few dozen 'overseers' (or whatever they
will be called) that they will have in place. They really need to have an
opensource concept. I warned the Swirlds team that their tech will be knocked
off--patent or no patent--so they better get big dominance fast!!

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SafeNigel
A good point from the forum. “Now PARSEC won’t be used in SAFE to let the
entire network communicate and come into global consensus like for example
Bitcoin does, instead PARSEC will be used by many small sections of the
network to reach “local” consensus for the corresponding section of the
network. The obvious attack vector here is to join one section with many nodes
of your own to hijack that particular section. The idea is to make this attack
infeasible by having the network occasionally relocate nodes (when they
age/rank up), so an attacker doesn’t have control over in what sections of the
network its nodes are located. If this idea works as well in practice as it
does in theory, attacking a section is about as hard as attacking the entire
network (all the sections).”

So proof-of-work is inherently resistant to sybil attacks while PARSEC on its
own isn’t, so to tell the story properly the random but deterministic
relocating of nodes needs to be included.

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avastmick
I always felt that blockchain is a precursor technology like "Web 2.0", which
laid the technical foundations (of Web APIs and micro-services) that enabled
the explosion of mobile apps that followed.

If smarter people than me can mathematically verify the PARSEC algorithm as
valid, it may lead the way for a radical change to the way information is
propagated, secured and validated.

~~~
Mindphreaker
Yes, I'm also looking forward to what the crypto engineering community has to
say about this algo after it has been peer-reviewed more often. If it holds
the promises then it will would be VERY huge.

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Jabbawa
No noises from the big names in crypto yet. I guess many are carefully going
through it and preparing their questions and concerns. Peer-review can't come
quickly enough. I can't wait to see how the world responds to this. Have
MaidSafe really managed to pull this off?! I mean, WOW, if they have! Fingers
crossed.

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SafeNigel
Interesting to see PARSEC mentioned in this topical piece.
[https://news.bitcoin.com/proof-of-work-coins-on-high-
alert-f...](https://news.bitcoin.com/proof-of-work-coins-on-high-alert-
following-spate-of-51-attacks/)

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Cshelton
Medium article that goes with the release:
[https://medium.com/safenetwork/parsec-a-paradigm-shift-
for-a...](https://medium.com/safenetwork/parsec-a-paradigm-shift-for-
asynchronous-and-permissionless-consensus-e312d721f9d8)

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equalunique
Refreshing to see a maidsafe submission here on HN.

