Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-16 Thread Adam Back
On Wed, May 15, 2013 at 07:45:34PM -0700, Gregory Maxwell wrote: [committed coins] depending on how its done, at most conceals the transactions from people who aren't a party to them... though as time goes on eventually everyone becomes a party to a sufficiently old coin, and avoiding publication

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-16 Thread Adam Back
More somewhat improved crypto stuff... On Thu, May 16, 2013 at 01:32:22PM +0200, Adam Back wrote: I suggested fixed size committed coin spends [...] (blind-sender, auth-tag, encrypted-tx-commit) (pub key P = xG, G = base point) blind-sender = cP (public key EC multiplied by constant c)

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Peter Todd
On Wed, May 15, 2013 at 12:25:09PM +0200, Adam Back wrote: Protocols aren't set in stone - any attacker that controls enough hashing power to pose a 51% attack can simply demand that you use a Bitcoin client modified to provide the attack with the full transactions from the beginning. Any blocks

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Caleb James DeLisle
I can't see this working, if 51% of the mining power doesn't like your coins, when you create the commitment they will reject it. If the commitment is opaque at the time of inclusion in the block then I will create multiple commitments and then after revealing the commitment and spend to you I

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Adam Back
On Wed, May 15, 2013 at 08:40:59AM -0400, Caleb James DeLisle wrote: If the commitment is opaque at the time of inclusion in the block then I will create multiple commitments and then after revealing the commitment and spend to you I will reveal the earlier commitment which commits the coins to an

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Caleb James DeLisle
On 05/15/2013 12:21 PM, Adam Back wrote: On Wed, May 15, 2013 at 08:40:59AM -0400, Caleb James DeLisle wrote: If the commitment is opaque at the time of inclusion in the block then I will create multiple commitments and then after revealing the commitment and spend to you I will reveal the

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Adam Back
btw I posted some of this thread on the dev forum: https://bitcointalk.org/index.php?topic=206303.msg2157994#msg2157994 A related idea is occuring to me that maybe these committed transactions could actually as a side effect make bitcoin scale slightly better by reducing the p2p flood filled

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Gregory Maxwell
On Wed, May 15, 2013 at 6:24 PM, Gavin gavinandre...@gmail.com wrote: Busy with pre-conference stuff, not following details of this conversation... ... but it sounds a lot like the guy fawkes protocol Zooko was thinking about a year or so ago. Sort of, but in a guy fawkes signature you use

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Mike Hearn
Conceptually it sounds a lot like ZeroCoin (not in implementation)? I'm not really convinced miner cartels that try to exclude transactions are likely to be a big deal, but such schemes could I suppose be kept in a back pocket in case one day I'm proven wrong. On Wed, May 15, 2013 at 6:39 PM,

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Gregory Maxwell
On Wed, May 15, 2013 at 7:22 PM, Mike Hearn m...@plan99.net wrote: Conceptually it sounds a lot like ZeroCoin (not in implementation)? Zerocoin conceals the connection from everyone forever, assuming the underlying trapdoor problem is computational infeasible, but at great cost. Adamcoin,

Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint unilateral revocability)

2013-05-15 Thread Caleb James DeLisle
Not only does the size of the proof grow endlessly as the coin is passed around, the size of the UTXO set grows endlessly as more and more of the already spent coins cannot be proven to have been spent because the proofs are passed out-of-band. I never said the idea was good, just interesting :)