smart contracts -- possible use case? yes or no?

smart contracts -- possible use case? yes or no?
2013-09-28 20:15 ` rob.golding
  
From: Melvin Carvalho @ 2013-09-27 23:41 UTC (permalink / raw)
  To: Bitcoin Dev

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We all love bitcoin's ability to transfer value in real time across borders.

But the regulatory environment in many geographical regions in uncertain.
Do we need to pay capital gains?   Do we need to pay a sales taxs etc. etc.

At this point bitcoin is small enough for this to not be a huge issue, but
one day that may change (maybe we hope!).

So my idea is to voluntarily pre empt legislation by giving donations to
govt (aka taxation) for bitcoin service providers.

However, there is something of a problem with voluntary donations.  Most
people are not satisfied with the way they are spent.  In the UK a recent
survey said that only 18% of people thought that tax money was wisely
spent.  This is bad for govt., bad for people, and bad for the trusted
relationship.

Can we fix it?  Maybe we smart contract and voluntary donations it's
possible!

So let's say I run a business and I make 1 million euros.  I wish to donate
10% of my profits to society.  But let's say I dont want that money to go
to wars of aggression, but rather, to the fire de[department.

So we set up a smart contract that is only "cashable" if the money goes to
the right place (verified by an oracle).

At this point everyone wins.  The business person is happy to make a
contribution.  The govt. is happy that it gets more revenue.  The fire
dept. is happy that it has revenue to do its work.  And everything has gone
to the right place in a kind of democratic way.

Over time if it takes off, this could provide revenue for many essential
services that are needed by people, in a way that allows more democratic
freedom of choice.

So my question is whether it may be possible to use smart contracts to
achieve a better democracy that is good for people, good for govt, and good
for innovation?  My hope is that the answer is ...

"Yes We Can"

:)

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 permalink raw reply	[|nested]
2013-09-27 23:41 [Bitcoin-development] smart contracts -- possible use case? yes or no? Melvin Carvalho

  2013-09-29  2:28   ` Neil Fincham
  
From: rob.golding @ 2013-09-28 20:15 UTC (permalink / raw)
  To: bitcoin-development

> But the regulatory environment in many geographical regions in
> uncertain.   Do we need to pay capital gains?   Do we need to pay a
> sales taxs etc. etc.

In most regions it's not only 'simple' but trivial - BTC is just 
'another currency' and accounted for exactly the same way - it doens't 
matter if you sell your hose for GBP, USD, EUR, BTC or sacks of Pig 
Dung, you still have a GBP tax issue ...

> So my idea is to voluntarily pre empt legislation by giving donations
> to govt (aka taxation) for bitcoin service providers. 

You want to volunteer to pay tax ? I'd suggest stronger medication ...

> However, there is something of a problem with voluntary donations. 
> Most people are not satisfied with the way they are spent.

80% of 'donations' end up spent on 'adminsitration' and not what they 
were donated for, this is a 'greed' issue not a 'currency' issue.

> In the UK
> a recent survey said that only 18% of people thought that tax money
> was wisely spent.

Tax isn't voluntary or a donation. The 18% who think UK tax is well 
spent are the 18% of the population who get the tax money, not the 82% 
that pay it ;)

> Can we fix it?

First we kill all the politicians ...

> So let's say I run a business and I make 1 million euros.  I wish to
> donate 10% of my profits to society.  But let's say I dont want that
> money to go to wars of aggression, but rather, to the fire
> de[department. 

So give it to the FD - what you do with your post-tax profits are up to 
you ;)

> At this point everyone wins.  The business person is happy to make a
> contribution.  The govt. is happy that it gets more revenue.  The
> fire dept. is happy that it has revenue to do its work.  And
> everything has gone to the right place in a kind of democratic way.

Where does gov't come into this ? I think you're confusing 'tax' which 
you have zero control over and 'donations' which you already have 100% 
control over.

Rob



 permalink raw reply	[|nested]
2013-09-28 20:15 ` rob.golding

  2013-09-29  8:32     ` Gavin Andresen
  2013-09-29  9:46     ` Melvin Carvalho
  
From: Neil Fincham @ 2013-09-29  2:28 UTC (permalink / raw)
  To: rob.golding;  bitcoin-development

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I subscribe to this list so I can keep up-to date with bitcoin development,
can we keep philosophy and tax evasion out of it?

Neil


On 29 September 2013 09:15, <rob.golding@astutium•com> wrote:

> > But the regulatory environment in many geographical regions in
> > uncertain.   Do we need to pay capital gains?   Do we need to pay a
> > sales taxs etc. etc.
>
> In most regions it's not only 'simple' but trivial - BTC is just
> 'another currency' and accounted for exactly the same way - it doens't
> matter if you sell your hose for GBP, USD, EUR, BTC or sacks of Pig
> Dung, you still have a GBP tax issue ...
>
> > So my idea is to voluntarily pre empt legislation by giving donations
> > to govt (aka taxation) for bitcoin service providers.
>
> You want to volunteer to pay tax ? I'd suggest stronger medication ...
>
> > However, there is something of a problem with voluntary donations.
> > Most people are not satisfied with the way they are spent.
>
> 80% of 'donations' end up spent on 'adminsitration' and not what they
> were donated for, this is a 'greed' issue not a 'currency' issue.
>
> > In the UK
> > a recent survey said that only 18% of people thought that tax money
> > was wisely spent.
>
> Tax isn't voluntary or a donation. The 18% who think UK tax is well
> spent are the 18% of the population who get the tax money, not the 82%
> that pay it ;)
>
> > Can we fix it?
>
> First we kill all the politicians ...
>
> > So let's say I run a business and I make 1 million euros.  I wish to
> > donate 10% of my profits to society.  But let's say I dont want that
> > money to go to wars of aggression, but rather, to the fire
> > de[department.
>
> So give it to the FD - what you do with your post-tax profits are up to
> you ;)
>
> > At this point everyone wins.  The business person is happy to make a
> > contribution.  The govt. is happy that it gets more revenue.  The
> > fire dept. is happy that it has revenue to do its work.  And
> > everything has gone to the right place in a kind of democratic way.
>
> Where does gov't come into this ? I think you're confusing 'tax' which
> you have zero control over and 'donations' which you already have 100%
> control over.
>
> Rob
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
> from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>

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 permalink raw reply	[|nested]
2013-09-29  2:28   ` Neil Fincham

  2013-09-29  9:37       ` Adam Back
  2013-09-29  9:44       ` [Bitcoin-development] smart contracts -- possible use case? yes or no? Melvin Carvalho
  2013-09-29  9:46     ` Melvin Carvalho
  
From: Gavin Andresen @ 2013-09-29  8:32 UTC (permalink / raw)
  To: Neil Fincham;  Bitcoin Dev

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On Sun, Sep 29, 2013 at 12:28 PM, Neil Fincham <neil@asdf•co.nz> wrote:

> I subscribe to this list so I can keep up-to date with bitcoin
> development, can we keep philosophy and tax evasion out of it?
>

Yes, that's off-topic for this mailing list. Lets stick to technical issues
that we can solve by writing code.

-- 
--
Gavin Andresen

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 permalink raw reply	[|nested]
2013-09-29  8:32     ` Gavin Andresen

  2013-09-29 17:49         ` Mark Friedenbach
  2013-09-29  9:44       ` [Bitcoin-development] smart contracts -- possible use case? yes or no? Melvin Carvalho
  
From: Adam Back @ 2013-09-29  9:37 UTC (permalink / raw)
  To: Gavin Andresen;  Bitcoin Dev

There are some policy decision points in the protocol (and code) that may
become centralized risks or choke points that undermine the p2p nature.  So
the extent that those can be argued to have in principle have a technical
fix, it could be quite interesting to research the necessary technology
(advanced crypto, byzantine networking argument etc) that could address
them.  eg payee/payer blacklisting by a large group of miners and "committed
transaction" proposal to address it.

However even for that type of thing I think bitcoin-dev would probably
rather focus eg on something that has reached the stage of having a BIP.  Eg
it might be better to discuss early stage or speculative ideas on
bitcointalk.org technical thread.

https://bitcointalk.org/index.php?board=6.0

taxation in particular there are examples where even the political sphere
accepts significantly anonymous taxation.  eg for europeans with certain
types of investment in a swiss bank, the swiss bank sends however many
million as a single payment across all users per european country to their
passport home country (minus 25% cut for the swiss government).  Perhaps
such things could be possible for bitcoin.  Again I think bitcoin talk would
be a good place for such a discussion if that was the OP question
indirectly.

Adam

On Sun, Sep 29, 2013 at 06:32:10PM +1000, Gavin Andresen wrote:
>   On Sun, Sep 29, 2013 at 12:28 PM, Neil Fincham <[1]neil@asdf•co.nz>
>   wrote:
>
>   I subscribe to this list so I can keep up-to date with bitcoin
>   development, can we keep philosophy and tax evasion out of it?
>
>   Yes, that's off-topic for this mailing list. Lets stick to technical
>   issues that we can solve by writing code.
>   --
>   --
>   Gavin Andresen
>
>References
>
>   1. mailto:neil@asdf•co.nz

>------------------------------------------------------------------------------
>October Webinars: Code for Performance
>Free Intel webinars can help you accelerate application performance.
>Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from
>the latest Intel processors and coprocessors. See abstracts and register >
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>_______________________________________________
>Bitcoin-development mailing list
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>https://lists.sourceforge.net/lists/listinfo/bitcoin-development




 permalink raw reply	[|nested]
2013-09-29  8:32     ` Gavin Andresen
  2013-09-29  9:37       ` Adam Back

  
From: Melvin Carvalho @ 2013-09-29  9:44 UTC (permalink / raw)
  To: Gavin Andresen;  Bitcoin Dev

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On 29 September 2013 10:32, Gavin Andresen <gavinandresen@gmail•com> wrote:

> On Sun, Sep 29, 2013 at 12:28 PM, Neil Fincham <neil@asdf•co.nz> wrote:
>
>> I subscribe to this list so I can keep up-to date with bitcoin
>> development, can we keep philosophy and tax evasion out of it?
>>
>
> Yes, that's off-topic for this mailing list. Lets stick to technical
> issues that we can solve by writing code.
>

Hi Gavin, apologies if my post came across as off-topic.  My aim was to
present a use case, and ask whether or not it was technically feasible
using smart contracts.


>
> --
> --
> Gavin Andresen
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
> from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>
>

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 permalink raw reply	[|nested]
2013-09-29  2:28   ` Neil Fincham
  2013-09-29  8:32     ` Gavin Andresen

  2013-09-29 11:33       ` Mike Hearn
  
From: Melvin Carvalho @ 2013-09-29  9:46 UTC (permalink / raw)
  To: Neil Fincham;  Bitcoin Dev

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On 29 September 2013 04:28, Neil Fincham <neil@asdf•co.nz> wrote:

> I subscribe to this list so I can keep up-to date with bitcoin
> development, can we keep philosophy and tax evasion out of it?
>

Hi Neil, perhaps I didnt present the use case clearly.  It was not about
evasion, it was about voluntary donations going to the correct place, being
verified by an oracle.  I dont wish to stray off topic, so I'll leave it at
that.


>
> Neil
>
>
> On 29 September 2013 09:15, <rob.golding@astutium•com> wrote:
>
>> > But the regulatory environment in many geographical regions in
>> > uncertain.   Do we need to pay capital gains?   Do we need to pay a
>> > sales taxs etc. etc.
>>
>> In most regions it's not only 'simple' but trivial - BTC is just
>> 'another currency' and accounted for exactly the same way - it doens't
>> matter if you sell your hose for GBP, USD, EUR, BTC or sacks of Pig
>> Dung, you still have a GBP tax issue ...
>>
>> > So my idea is to voluntarily pre empt legislation by giving donations
>> > to govt (aka taxation) for bitcoin service providers.
>>
>> You want to volunteer to pay tax ? I'd suggest stronger medication ...
>>
>> > However, there is something of a problem with voluntary donations.
>> > Most people are not satisfied with the way they are spent.
>>
>> 80% of 'donations' end up spent on 'adminsitration' and not what they
>> were donated for, this is a 'greed' issue not a 'currency' issue.
>>
>> > In the UK
>> > a recent survey said that only 18% of people thought that tax money
>> > was wisely spent.
>>
>> Tax isn't voluntary or a donation. The 18% who think UK tax is well
>> spent are the 18% of the population who get the tax money, not the 82%
>> that pay it ;)
>>
>> > Can we fix it?
>>
>> First we kill all the politicians ...
>>
>> > So let's say I run a business and I make 1 million euros.  I wish to
>> > donate 10% of my profits to society.  But let's say I dont want that
>> > money to go to wars of aggression, but rather, to the fire
>> > de[department.
>>
>> So give it to the FD - what you do with your post-tax profits are up to
>> you ;)
>>
>> > At this point everyone wins.  The business person is happy to make a
>> > contribution.  The govt. is happy that it gets more revenue.  The
>> > fire dept. is happy that it has revenue to do its work.  And
>> > everything has gone to the right place in a kind of democratic way.
>>
>> Where does gov't come into this ? I think you're confusing 'tax' which
>> you have zero control over and 'donations' which you already have 100%
>> control over.
>>
>> Rob
>>
>>
>> ------------------------------------------------------------------------------
>> October Webinars: Code for Performance
>> Free Intel webinars can help you accelerate application performance.
>> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
>> from
>> the latest Intel processors and coprocessors. See abstracts and register >
>>
>> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
>> _______________________________________________
>> Bitcoin-development mailing list
>> Bitcoin-development@lists•sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>>
>
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
> from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>
>

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 permalink raw reply	[|nested]
2013-09-29  9:46     ` Melvin Carvalho

  
From: Mike Hearn @ 2013-09-29 11:33 UTC ( / )
  To: Melvin Carvalho;  Bitcoin Dev



This kind of thing is better discussed in the dev forum of bitcointalk.org


On Sun, Sep 29, 2013 at 11:46 AM, Melvin Carvalho
<melvincarvalho@gmail•com>wrote:

>
>
>
> On 29 September 2013 04:28, Neil Fincham <neil@asdf•co.nz> wrote:
>
>> I subscribe to this list so I can keep up-to date with bitcoin
>> development, can we keep philosophy and tax evasion out of it?
>>
>
> Hi Neil, perhaps I didnt present the use case clearly.  It was not about
> evasion, it was about voluntary donations going to the correct place, being
> verified by an oracle.  I dont wish to stray off topic, so I'll leave it at
> that.
>
>
>>
>> Neil
>>
>>
>> On 29 September 2013 09:15, <rob.golding@astutium•com> wrote:
>>
>>> > But the regulatory environment in many geographical regions in
>>> > uncertain.   Do we need to pay capital gains?   Do we need to pay a
>>> > sales taxs etc. etc.
>>>
>>> In most regions it's not only 'simple' but trivial - BTC is just
>>> 'another currency' and accounted for exactly the same way - it doens't
>>> matter if you sell your hose for GBP, USD, EUR, BTC or sacks of Pig
>>> Dung, you still have a GBP tax issue ...
>>>
>>> > So my idea is to voluntarily pre empt legislation by giving donations
>>> > to govt (aka taxation) for bitcoin service providers.
>>>
>>> You want to volunteer to pay tax ? I'd suggest stronger medication ...
>>>
>>> > However, there is something of a problem with voluntary donations.
>>> > Most people are not satisfied with the way they are spent.
>>>
>>> 80% of 'donations' end up spent on 'adminsitration' and not what they
>>> were donated for, this is a 'greed' issue not a 'currency' issue.
>>>
>>> > In the UK
>>> > a recent survey said that only 18% of people thought that tax money
>>> > was wisely spent.
>>>
>>> Tax isn't voluntary or a donation. The 18% who think UK tax is well
>>> spent are the 18% of the population who get the tax money, not the 82%
>>> that pay it ;)
>>>
>>> > Can we fix it?
>>>
>>> First we kill all the politicians ...
>>>
>>> > So let's say I run a business and I make 1 million euros.  I wish to
>>> > donate 10% of my profits to society.  But let's say I dont want that
>>> > money to go to wars of aggression, but rather, to the fire
>>> > de[department.
>>>
>>> So give it to the FD - what you do with your post-tax profits are up to
>>> you ;)
>>>
>>> > At this point everyone wins.  The business person is happy to make a
>>> > contribution.  The govt. is happy that it gets more revenue.  The
>>> > fire dept. is happy that it has revenue to do its work.  And
>>> > everything has gone to the right place in a kind of democratic way.
>>>
>>> Where does gov't come into this ? I think you're confusing 'tax' which
>>> you have zero control over and 'donations' which you already have 100%
>>> control over.
>>>
>>> Rob
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> October Webinars: Code for Performance
>>> Free Intel webinars can help you accelerate application performance.
>>> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
>>> from
>>> the latest Intel processors and coprocessors. See abstracts and register
>>> >
>>>
>>> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
>>> _______________________________________________
>>> Bitcoin-development mailing list
>>> Bitcoin-development@lists•sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>> October Webinars: Code for Performance
>> Free Intel webinars can help you accelerate application performance.
>> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
>> from
>> the latest Intel processors and coprocessors. See abstracts and register >
>>
>> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
>> _______________________________________________
>> Bitcoin-development mailing list
>> Bitcoin-development@lists•sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>>
>>
>
>
> ------------------------------------------------------------------------------
> October Webinars: Code for Performance
> Free Intel webinars can help you accelerate application performance.
> Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most
> from
> the latest Intel processors and coprocessors. See abstracts and register >
> http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>
>
2013-09-29  9:37       ` Adam Back

  2013-10-01 14:26           ` [Bitcoin-development] homomorphic coin value (validatable but encrypted) (Re: smart contracts -- possible use case? yes or no?) Adam Back
  
From: Mark Friedenbach @ 2013-09-29 17:49 UTC (permalink / raw)
  To: Adam Back, Bitcoin Dev

This kind of thing - providing external audits of customer accounts
without revealing private data - would be generally useful beyond
taxation. If you have any solutions, I'd be interested to hear them
(although bitcoin-dev is probably not the right place yet).

Mark

On 9/29/13 2:37 AM, Adam Back wrote:
> taxation in particular there are examples where even the political sphere
> accepts significantly anonymous taxation.  eg for europeans with certain
> types of investment in a swiss bank, the swiss bank sends however many
> million as a single payment across all users per european country to their
> passport home country (minus 25% cut for the swiss government).  Perhaps
> such things could be possible for bitcoin.  Again I think bitcoin talk would
> be a good place for such a discussion if that was the OP question
> indirectly.



 permalink raw reply	[|nested]
2013-09-29 17:49         ` Mark Friedenbach

  2013-10-01 19:11             ` Adam Back
  
From: Adam Back @ 2013-10-01 14:26 UTC (permalink / raw)
  To: Mark Friedenbach;  Bitcoin Dev

On Sun, Sep 29, 2013 at 10:49:00AM -0700, Mark Friedenbach wrote:
>This kind of thing - providing external audits of customer accounts
>without revealing private data - would be generally useful beyond
>taxation. If you have any solutions, I'd be interested to hear them
>(although bitcoin-dev is probably not the right place yet).

Thanks for providing the impetus to write down the current state, the
efficient version of which I only figured out a few days ago :)

I have been researching this for a few months on and off, because it seems
like an interesting construct in its own right, a different aspect of
payment privacy (eg for auditable but commercial sensistive information) but
also that other than its direct use it may enable some features that we have
not thought of yet.

I moved it to bitcointalk:

https://bitcointalk.org/index.php?topic=305791.new#new

Its efficient finally (after many dead ends): approximately 2x cost of
current in terms of coin size and coin verification cost, however it also
gives some perf advantages back in a different way - necessary changes to
schnorr (EC version of Schnorr based proofs) allow n of n multiparty sigs,
or k of n multiparty sigs for the verification cost and signature size of
one pair of ECS signatures, for n > 2 its a space and efficiency improvement
over current bitcoin.

Adam



 permalink raw reply	[|nested]
2013-10-01 14:26           ` [Bitcoin-development] homomorphic coin value (validatable but encrypted) (Re: smart contracts -- possible use case? yes or no?) Adam Back

  2013-10-07 19:01               ` Adam Back
  
From: Adam Back @ 2013-10-01 19:11 UTC (permalink / raw)
  To: Mark Friedenbach;  Bitcoin Dev

Err actually not (efficient) I made a mistake that came out when I started
writing it up about how the t parameter in the proof relates to bitcoin
precision and coin representation (I thought t=2, but t=51).  Damn!  Back to
the not so efficient version (which is more zerocoin-esque in size/cost), or
the more experimental Schoenmaker non-standard p, q non EC one, or other
creative ideas to change the coin representation to simplify the proof (of
which this was a failed attempt).  See the bitcointalk thread for details.

https://bitcointalk.org/index.php?topic=305791.new#new

Adam

On Tue, Oct 01, 2013 at 04:26:03PM +0200, Adam Back wrote:
>On Sun, Sep 29, 2013 at 10:49:00AM -0700, Mark Friedenbach wrote:
>>This kind of thing - providing external audits of customer accounts
>>without revealing private data - would be generally useful beyond
>>taxation. If you have any solutions, I'd be interested to hear them
>>(although bitcoin-dev is probably not the right place yet).
>
>Thanks for providing the impetus to write down the current state, the
>efficient version of which I only figured out a few days ago :)
>
>I have been researching this for a few months on and off, because it seems
>like an interesting construct in its own right, a different aspect of
>payment privacy (eg for auditable but commercial sensistive information) but
>also that other than its direct use it may enable some features that we have
>not thought of yet.
>
>I moved it to bitcointalk:
>
>https://bitcointalk.org/index.php?topic=305791.new#new
>
>Its efficient finally (after many dead ends): approximately 2x cost of
>current in terms of coin size and coin verification cost, however it also
>gives some perf advantages back in a different way - necessary changes to
>schnorr (EC version of Schnorr based proofs) allow n of n multiparty sigs,
>or k of n multiparty sigs for the verification cost and signature size of
>one pair of ECS signatures, for n > 2 its a space and efficiency improvement
>over current bitcoin.
>
>Adam



 permalink raw reply	[|nested]
2013-10-01 19:11             ` Adam Back

  
From: Adam Back @ 2013-10-07 19:01 UTC (permalink / raw)
  To: Mark Friedenbach;  Bitcoin Dev

An update on the homomorphic coins, some more math validation & a test
implementation needs to be done, but a surprisingly good outcome so far of
predicted 2.5kB homomorphic valued coin.  Only coin splitting has to incur
the 2.5kB range proof.  Coin adding, full spending and mining is "free",
because adding existing range proofed and validated coins cant overflow by
definition (21 mil coin cap).  You can also (obviously I guess) add a
homomorphicaly encrypted "0" value to a few other peoples coin balance to
get a kind of taint mitigation.

https://bitcointalk.org/index.php?topic=305791.msg3294618#msg3294618

Adam

On Tue, Oct 01, 2013 at 09:11:43PM +0200, Adam Back wrote:
>Err actually not (efficient) I made a mistake that came out when I started
>writing it up about how the t parameter in the proof relates to bitcoin
>precision and coin representation (I thought t=2, but t=51).  Damn!  Back to
>the not so efficient version (which is more zerocoin-esque in size/cost), or
>the more experimental Schoenmaker non-standard p, q non EC one, or other
>creative ideas to change the coin representation to simplify the proof (of
>which this was a failed attempt).  See the bitcointalk thread for details.
>
>https://bitcointalk.org/index.php?topic=305791.new#new
>
>Adam
>
>On Tue, Oct 01, 2013 at 04:26:03PM +0200, Adam Back wrote:
>>On Sun, Sep 29, 2013 at 10:49:00AM -0700, Mark Friedenbach wrote:
>>>This kind of thing - providing external audits of customer accounts
>>>without revealing private data - would be generally useful beyond
>>>taxation. If you have any solutions, I'd be interested to hear them
>>>(although bitcoin-dev is probably not the right place yet).
>>
>>Thanks for providing the impetus to write down the current state, the
>>efficient version of which I only figured out a few days ago :)
>>
>>I have been researching this for a few months on and off, because it seems
>>like an interesting construct in its own right, a different aspect of
>>payment privacy (eg for auditable but commercial sensistive information) but
>>also that other than its direct use it may enable some features that we have
>>not thought of yet.
>>
>>I moved it to bitcointalk:
>>
>>https://bitcointalk.org/index.php?topic=305791.new#new
>>
>>Its efficient finally (after many dead ends): approximately 2x cost of
>>current in terms of coin size and coin verification cost, however it also
>>gives some perf advantages back in a different way - necessary changes to
>>schnorr (EC version of Schnorr based proofs) allow n of n multiparty sigs,
>>or k of n multiparty sigs for the verification cost and signature size of
>>one pair of ECS signatures, for n > 2 its a space and efficiency improvement
>>over current bitcoin.
>>
>>Adam



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