Topic: Alt chains and atomic transfers - page 2. (Read 27398 times)

Since broadcasting custom transactions is such a pain, maybe we can come up with a way to do all the custom transactions off-chain?
And then we broadcast the final standard transaction normally?

Here is working sketch of trade flow:
https://github.com/kactech/atomictc/blob/pub/src/test/java/com/kactech/atomictc/AtomicTests.java
ASCII armored messages from test run:
https://github.com/kactech/atomictc/wiki/Five-Steps-Trade-communication
To simplify things there are only 2 pubKeys(and related addresses) used, traders exchange only things needed to recreate transactions at their side(instead of sending full refund transactions they send bailInHash and amount), trade state is POJO saved to JSON.
It would be nice to hear your thoughts
Sorry for spelling
Cheers
###
TODOS:
* UTXOs locking
* spam prevention: if Bob doesn't know Alice(or chains have significantly different transaction costs) he can f.e. require her refund to be partitioned (refund amount split over more outputs) to make Alice's refund more expensive than his

The point I meant was that it you exchange BTC for coloured coins, then it is inherently atomic.

Handling more than 1 chain is more complex.

However, ignoring large scale chain reversals, the atomic transfer system in this thread would be atomic too.

I think you need to do a lot more work to prove this fully.  A lot of the publications surrounding this project have been flimsy as of late.

One of the big benefits of colored coins is that the transactions are atomic.

Socrates1024, I have never written any forth code, but I am pretty sure that how you are using "op_if" is incorrect.

What if Alice (because she likes to do arbitrage and is speculating on shifting values) reveals her x very late (after 23:59h and 59 seconds)? This would lead to the case that she doesn't get her altcoin but bob can still claim the Bitcoin, right?

This is an explanation of TierNolan's atomic cross transaction technique. It's similar to one by luxgladius, except this protocol avoids a race condition by using asymmetry - only Alice has a secret, and the timeout on one chain is much longer than the other. https://bitcointalksearch.org/topic/m.2224949

Alice has 1btc (Bitcoin) and Bob has 1atc (Altcoin). They would like to conduct an atomic exchange, so that after a finite time, either Alice has 1atc and Bob has 1btc, or the transaction was aborted and their positions are both unchanged. We assume that both the Bitcoin and Altcoin chains are loosely synchronized to eachother, such that neither chain gets more than 12 hours ahead of the other.

Phase 1: Alice bails in

Alice draws a random secret x. Alice constructs TX1 to bail in a bitcoin. TX1 has a single txout with 1 btc, containing the following scriptPubkey:

Alice signs TX1 but does not yet publish it. She creates TX2, her refund transaction, which has a locktime of +48 hours. It contains TX1[0] as a txin, and the txout is a standard spend to A. The scriptSig for this txin looks like
which proceeds through the main branch of the IF. Alice signs TX2, obtaining sigA2.

Alice transmits TX2 to Bob, and requests that Bob signs and returns it. Once Alice receives Bob’s signature sigB2, then Alice publishes TX1, knowing that she will be able to claim her refund after 48 hours, as long as she does not reveal x. Alice is now bailed in.


Phase 2: Bob bails in

Bob received TX2 in the first phase, and therefore knows H(x). Bob also signed Alice’s refund transaction, but that will not be active until after 48 hours. If Bob is honest, he’ll get what he wants within 24 hours in any case. Bob has also seen that TX1 has been published.

Bob creates TX3, which bails in an Altcoin. TX3 is symmetric with TX1, and has a single txout with 1atc, containing the following scriptPubkey:

Bob also creates TX4, which is his own Altcoin refund. TX4 is timelocked for only 24 hours, uses TX3[0] as a txin, and the scriptSig looks like
which proceeds through the main branch of the if. Bob signs TX4, obtaining sigB, and transmits TX4 to Alice, asking her to sign it. When Bob receives sigA4, he can safely publish TX3, knowing that he will be able to abort and reclaim his coin after 24 hours. Bob is now bailed in.


Phase 3: Alice reveals x and triggers both transactions.

Alice has 24 hours to claim the Altcoin, using the following scriptSig:
which triggers the ELSE branch of the conditional. However in doing so, she must necessarily reveal x. If Alice reveals x within 24 hours, then Bob can also claim his Bitcoin before 48 hours:
.


This is atomic because:
   a) each party *bails in* their coins only after receiving a *refund signature* from the other party.
   b) the refund delay is significantly larger on the Bitcoin chain than on the Altcoin chain, and Alice, who initially knows x, bails in her coin first.

Maybe do it on testnet

I was thinking of trying this out.

Does anyone know if there is a pool like Eligius for Litecoin that accepts non-standard transactions?