Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-31 Thread James MacWhyte via bitcoin-dev
On Tue, Jan 29, 2019 at 6:46 PM wrote: > > If the sender refuses to sign the final transaction, the receiver just > propagates the template transaction which pays the receiver! So it's a > pretty weak attack. > > The only real attack is that the sender could double-spend the >

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-30 Thread ZmnSCPxj via bitcoin-dev
Good morning Adam, > And I'm reminded that a related point is made by belcher in the gist > comment thread iirc (after we discussed it on IRC): over time a > "PayJoin-only" merchant doing the simplest thing - using a single utxo > over and over again, will concentrate more and more funds into it,

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-30 Thread Ryan Havar via bitcoin-dev
On Tuesday, January 29, 2019 6:06 PM, James MacWhyte wrote: > I'm not convinced this is a valid concern, at least not valid enough to add > extra complications to the process. Signing a transaction is something a wallet needs to be able to do anyway AND at the final-step. And actually a

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-30 Thread James MacWhyte via bitcoin-dev
James On Sun, Jan 27, 2019 at 2:11 PM wrote: > > It isn't passed "back and forth so many times". > You are right, I got the wrong impression the first time I read it. > This is an important anti-DoS/anti-spy tactic, as it proves the sender > actually owns those inputs and if the protocol is

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-29 Thread Adam Gibson via bitcoin-dev
ZmnSCPxj, thanks, responses inline. On 28. 01. 19 5:14, ZmnSCPxj wrote: > Good morning Ryan and Adam, > >> [UIH2 snipped] > > Perhaps I am being naive, but I seem, the B2EP and similar do not need to > worry about UIH2. > > From the github discussion: > >> "UIH2": one input is larger than

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread ZmnSCPxj via bitcoin-dev
Good morning Ryan and Adam, > [UIH2 snipped] Perhaps I am being naive, but I seem, the B2EP and similar do not need to worry about UIH2. >From the github discussion: > "UIH2": one input is larger than any output. . I.e. there exists an input, for all outputs, input > output To avoid this, we

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread Ryan Havar via bitcoin-dev
> Why does the template transaction need to be signed in step one and passed > back and forth so many times? What is wrong with: It isn't passed "back and forth so many times". It works exactly as you proposed, with the only difference is in "Step 1" the sender uses a *signed* transaction

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread James MacWhyte via bitcoin-dev
Why does the template transaction need to be signed in step one and passed back and forth so many times? What is wrong with: 1. Sender creates unsigned tx with their relevant inputs and outputs. This tx is passed to receiver. 2. Receiver adds their relevant inputs and outputs and signs their

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread Ryan Havar via bitcoin-dev
> Is there a missing word. "by giving a person.."? Not actually sure what > you're getting at here but I suspect it's again tangential to this BIP > discussion. Correct on both points. I meant to say "giving a (txid:vout:privkey)" to a person as means of payment. > So I think the limiting

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread Adam Gibson via bitcoin-dev
On 27. 01. 19 8:36, rha...@protonmail.com wrote: > Thanks Adam, > > I have fixed the mistakes you have pointed out: > https://github.com/bitcoin/bips/pull/754 > > Thanks for the detailed look! > >> but its virtue of steganographic hiding means only minimal uptake >> is still enormously

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-27 Thread Ryan Havar via bitcoin-dev
Thanks Adam, I have fixed the mistakes you have pointed out: https://github.com/bitcoin/bips/pull/754 Thanks for the detailed look! > but its virtue of steganographic hiding means only minimal uptake > is still enormously interesting and worth pursuing; that's my current feeling. I very much

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2019-01-26 Thread Adam Gibson via bitcoin-dev
Ryan and list, I want to add some commentary to this (BIP79) to see if we can get further in standardizing this idea. When I first mulled it over I thought it too impractical, but its virtue of steganographic hiding means only minimal uptake is still enormously interesting and worth pursuing;

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2018-09-10 Thread Ryan Havar via bitcoin-dev
Thanks Sjors, It's nice to get hear feedback like that, it'll help make me clear some stuff up. Right now I've been working on getting a reference client for both sending and receiving, while juggling some stuff in real life. But here is the evolving document:

Re: [bitcoin-dev] bustapay BIP :: a practical sender/receiver coinjoin protocol

2018-09-10 Thread Sjors Provoost via bitcoin-dev
> Op 30 aug. 2018, om 22:24 heeft Ryan Havar via bitcoin-dev > het volgende geschreven: > > ==Motivation== > > One of the most powerful heuristic's employed by those whose goal is to > undermine > bitcoin's fungiblity has been to assume all inputs of a transaction are > signed by > a single