one-show signatures (Re: The relationship between Proof-of-Publication and Anti-Replay Oracles)

one-show signatures (Re: The relationship between Proof-of-Publication and Anti-Replay Oracles)
2014-12-21 18:51 ` Peter Todd
  
From: Adam Back @ 2014-12-21 18:10 UTC (permalink / raw)
  To: Peter Todd;  Bitcoin Dev

Yes you could for example define a new rule that two signatures
(double-spend) authorises something - eg miners to take funds. (And
this would work with existing ECDSA addresses & unrestricted R-value
choices).

I wasnt really making a point other than an aside that it maybe is
sort-of possible to do with math what you said was not possible where
you said "This [preventing signing more than one message] is
impossible to implement with math alone".

Adam

On 21 December 2014 at 15:29, Peter Todd <pete@petertodd•org>
> There's no need to get into the specifics of crypto math so early; you
> can just as easily and only slightly less efficiently obtain the same
> result with a few extensions to the Bitcoin scripting system to verify
> ECDSA signatures directly.



 permalink raw reply	[|nested]
2014-12-21 18:10 [Bitcoin-development] one-show signatures (Re: The relationship between Proof-of-Publication and Anti-Replay Oracles) Adam Back

  2014-12-22  0:56   ` paul snow
  
From: Peter Todd @ 2014-12-21 18:51 UTC (permalink / raw)
  To: Adam Back;  Bitcoin Dev

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On Sun, Dec 21, 2014 at 06:10:47PM +0000, Adam Back wrote:
> Yes you could for example define a new rule that two signatures
> (double-spend) authorises something - eg miners to take funds. (And
> this would work with existing ECDSA addresses & unrestricted R-value
> choices).
> 
> I wasnt really making a point other than an aside that it maybe is
> sort-of possible to do with math what you said was not possible where
> you said "This [preventing signing more than one message] is
> impossible to implement with math alone".

Introducing a bunch of clever ECDSA math doesn't change the fact that
the clever math isn't what is preventing double-spending, clever
economics is. Just like Bitcoin itself.

No sense getting people potentially confused by a bunch of complex
equations that aren't relevant to the more fundemental and much more
important principle that math alone can't prevent double-spending.

-- 
'peter'[:-1]@petertodd.org
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 permalink raw reply	[|nested]
2014-12-21 18:51 ` Peter Todd

  
From: paul snow @ 2014-12-22  0:56 UTC ( / )
  To: Peter Todd;  Bitcoin Dev



On Sun, Dec 21, 2014 at 12:51 PM, Peter Todd <pete@petertodd•org> wrote:

> On Sun, Dec 21, 2014 at 06:10:47PM +0000, Adam Back wrote:
> > Yes you could for example define a new rule that two signatures
> > (double-spend) authorises something - eg miners to take funds. (And
> > this would work with existing ECDSA addresses & unrestricted R-value
> > choices).
> >
> > I wasnt really making a point other than an aside that it maybe is
> > sort-of possible to do with math what you said was not possible where
> > you said "This [preventing signing more than one message] is
> > impossible to implement with math alone".
>
> Introducing a bunch of clever ECDSA math doesn't change the fact that
> the clever math isn't what is preventing double-spending, clever
> economics is. Just like Bitcoin itself.
>
> No sense getting people potentially confused by a bunch of complex
> equations that aren't relevant to the more fundemental and much more
> important principle that math alone can't prevent double-spending.


Math alone describes all of Bitcoin's structure; as math is a way to model
reality, it has no limits. Saying Math can't prevent double-spending is
near equivalent to saying it cannot be done.