Re: [bitcoin-dev] Bitcoin-NG whitepaper.

From: Ittay <ittay.eyal@cornell•edu>
To: odinn <odinn.cyberguerrilla@riseup•net>
Cc: odinn via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org>,
	Ittay Eyal <ittay.eyal@cornell•edu>,
	Bob McElrath <bob@mcelrath•org>
Subject: Re: [bitcoin-dev] Bitcoin-NG whitepaper.
Date: Thu, 15 Oct 2015 11:12:23 -0400	[thread overview]
Message-ID: <CABT1wWnH8TeMkwwrjqvgOWYbYtLE-CneDwNpf7Py06_EvhOJRQ@mail.gmail.com> (raw)
In-Reply-To: <561F6852.8060001@riseup.net>

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Hi Odinn,

I guess to answer we should separate pure-NG from
the hypothetical overlay-NG that runs on top of Bitcoin.
For pure NG one still has to set a transaction bandwidth
limit due to bandwidth and storage limitations of
the individual clients. This rate can be arbitrarily high
with NG without compromising protocol security.

With overlay NG you cannot run above Bitcoin's
bandwidth because all clients must agree on the ledger,
so different clients cannot run at different rates. You
could do two things:
1. Significantly reduce observed latency (time to first
confirmation). Users get better confidence as more
miners adopt NG.
2. Increase the bandwidth once everyone is on
board.

As for privacy - I don't see why NG would change things.
Such privacy schemes are only concerned with the
transaction DAG. NG does not touch this structure. Am
I missing something?

Thanks,
Ittay

On Thu, Oct 15, 2015 at 4:48 AM, odinn <odinn.cyberguerrilla@riseup•net>
wrote:

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> So, there could not be, for example, a user decision to activate it?
> (versus not activate it)?  I'm wondering if something about this can
> be boiled down to allowing the user to make a choice on the matter
> (turn it on and off).  In Bitcoin-NG, the protocol as follows (as
> described in a general overview of it): every 10 minutes, NG elects a
> 'leader,' who then vets future transactions as soon as they happen. NG
> approach supposedly can run as fast as the network will allow.
>
> If this is the case, and if NG functions without major hiccup,
> shouldn't a user (of Core, for example) be able to be given the option
> to choose between:
>
> (a) being limited by the blocksize and block interval, or
> (b) running out as fast as the network will allow (NG)?
>
> The other questions I had pertained to privacy.  How would this scheme
> affect users who would be trying to do things like stealth or
> confidential transactions?
>
> Matt Corallo:
> > Huh? No... This is not a Bitcoin Core issue, it is a Bitcoin
> > protocol one and should be discussed here, not on github. I really
> > appreciate Ittay and Emin's efforts in this space and their
> > willingness to work with the Bitcoin community on it! It seems it
> > still needs some tuning, but seems like if the pool-mining issues
> > were resolved it could make block relay times irrelevant, at
> > least.
> >
> > Matt
> >
> > On October 14, 2015 3:21:19 PM PDT, odinn via bitcoin-dev
> > <bitcoin-dev@lists•linuxfoundation.org> wrote: This (Bitcoin-NG in
> > concept) could be done as a (issue and pull request process) to
> > Bitcoin Core itself, amirite?  It seems like it would provide an
> > interesting issue to open and have healthy discussion on both
> > mailing list and github, adding the caveat that it would be at the
> > user's option.  Thus if something like Bitcoin-NG did come to be it
> > would be something more like a feature that the user could
> > activate / deactivate from within Core.  I assume it would be
> > default off, but with the option to utilize.  Code would thus be
> > available to others as well.  I am not saying yea or nay on it,
> > just that it seems like this could be done.
> >
> > Some notes:
> >
> > Once a node generates a key block it becomes the leader.  As a
> > leader, the node is allowed to generate  microblocks  at  a  set
> > rate smaller  than  a  prede >ned  maximum.  A  microblock in
> > Bitcoin-NG contains  ledger  entries  and  a  header.   The  header
> > contains the  reference  to the  previous  block,  the  current
> > GMT  time,  a cryptographic  hash  of  its  ledger  entries,  and
> > a cryptographic signature  of  the  header.   The  signature  uses
> > the  private  key that  matches  the public key in the latest key
> > block in the chain. For a microblock to be valid, all its entries
> > must be valid according to the specification of the state machine,
> > and the signature has to be valid.  However, the microblocks, it is
> > said, don't affect the weight of the chain, because they do not
> > contain proof of work.  It is assumed by the authors of this model
> > that this situation is critical for maintaining incentives here.
> >
> > The questions that then begin to emerge to me are how is this
> > information managed and protected?  The headers, thus containing
> > reference(s) to previous block(s), current GMT time(s),
> > cryptographic hash(es) of ledger entries, and cryptographic
> > signature(s) of the headers, so forth, and other information.  Can
> > the Bitcoin-NG scheme be designed or implemented in a manner which
> > supports Stealth sends, Confidential Transactions, or similar
> > privacy measures?  Or is this something which cannot be answered at
> > this time?
> >
> > Emin Gün Sirer via bitcoin-dev:
> >>>>> So it seems to me that all I need to do is figure out who
> >>>>> the current
> >>>> leader is,
> >>>>> and DDoS him off the network to shut Bitcoin-NG down.
> >>>>
> >>>> Good point. If NG is layered on top of Bitcoin, we'd retain
> >>>> all of Bitcoin as is. This would confer all the benefits of
> >>>> Bitcoin's retrospective blocks, as well as add the ability to
> >>>> mint microblocks with low latency in between. And despite the
> >>>> phrase "the leader," the actual leader in NG is a key, not a
> >>>> specific node. That makes it possible to deter DDoS attacks
> >>>> by dynamically migrating where in the network the leader is
> >>>> operating in response to an attack. Finally, DDoS attacks
> >>>> against miners are already possible, but they seem rare, and
> >>>> I suspect it's at least partly because of the success of Matt
> >>>> Corallo's high speed bitcoin relay network. Similar defenses
> >>>> can apply here.
> >>>>
> >>>> - egs
> >>>>
> >>>>
> >>>>
> >>>> On Wed, Oct 14, 2015 at 2:20 PM, Bob McElrath
> >>>> <bob@mcelrath•org> wrote:
> >>>>
> >>>>> So it seems to me that all I need to do is figure out who
> >>>>> the current leader is, and DDoS him off the network to
> >>>>> shut Bitcoin-NG down.
> >>>>>
> >>>>> This is a significant advantage to bitcoin's ex-post-facto
> >>>>> blocks: no one knows where the next one will come from.
> >>>>> The only way to shut the network down is to shut all nodes
> >>>>> down.
> >>>>>
> >>>>> Emin Gün Sirer via bitcoin-dev
> >>>>> [bitcoin-dev@lists•linuxfoundation.org] wrote:
> >>>>>> Hi everyone,
> >>>>>>
> >>>>>> We just released the whitepaper describing Bitcoin-NG, a
> >>>>>> new technique
> >>>>> for
> >>>>>> addressing some of the scalability challenges faced by
> >>>>>> Bitcoin.
> >>>>> Surprisingly,
> >>>>>> Bitcoin-NG can simultaneously increase throughput while
> >>>>>> reducing
> >>>>> latency, and
> >>>>>> do so without impacting Bitcoin's open architecture or
> >>>>>> changing its trust model. This post illustrates the core
> >>>>>> technique:
> >>>>>> http://hackingdistributed.com/2015/10/14/bitcoin-ng/
> >>>>>> while the whitepaper has all the nitty gritty details:
> >>>>>> http://arxiv.org/abs/1510.02037
> >>>>>>
> >>>>>> Fitting NG on top of the current Bitcoin blockchain is
> >>>>>> future work that
> >>>>> we
> >>>>>> think is quite possible. NG is compatible with both
> >>>>>> Bitcoin as is, as
> >>>>> well as
> >>>>>> Blockstream-like sidechains, and we currently are not
> >>>>>> planning to compete commercially with either technology
> >>>>>> -- we see NG as being complementary
> >>>>> to both
> >>>>>> efforts. This is pure science, published and shared with
> >>>>>> the community to advance the state of blockchains and to
> >>>>>> help them reach throughputs and latencies required of
> >>>>>> cutting edge fintech applications. Perhaps it can
> >>>>> be
> >>>>>> adopted, or perhaps it can provide the spark of
> >>>>>> inspiration for someone
> >>>>> else to
> >>>>>> come up with even better solutions.
> >>>>>>
> >>>>>> We would be delighted to hear your feedback. - Ittay Eyal
> >>>>>> and E. Gün Sirer.
> >>>>>>
> >>>>>> !DSPAM:561e98cd301391127216946!
> >>>>>
> >>>>>> _______________________________________________
> >>>>>> bitcoin-dev mailing list
> >>>>>> bitcoin-dev@lists•linuxfoundation.org
> >>>>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> !DSPAM:561e98cd301391127216946!
> >>>>>
> >>>>> -- Cheers, Bob McElrath
> >>>>>
> >>>>> "For every complex problem, there is a solution that is
> >>>>> simple, neat, and wrong." -- H. L. Mencken
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________ bitcoin-dev
> >>>> mailing list bitcoin-dev@lists•linuxfoundation.org
> >>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> >>>>
> >
> >>>>
> >> _______________________________________________ bitcoin-dev
> >> mailing list bitcoin-dev@lists•linuxfoundation.org
> >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> >
> >
>
> - --
> http://abis.io ~
> "a protocol concept to enable decentralization
> and expansion of a giving economy, and a new social good"
> https://keybase.io/odinn
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