Quote from: andytoshi on September 02, 2018, 01:39:06 AM

Quote from: aliashraf on September 01, 2018, 07:13:59 PM

Quote

It is not possible to do a cross-chain atomic swap with only two transactions because you need at least one transaction on each chain, and the first transaction on each chain can be invalidated by publishing a conflicting transaction alongside it.

I doubt it. Using this proposal:

Alice issues tx1 on aliceChain sending m aliceCoins to Bob hash-locked with H(s1) after privately handing Bob (t, H(s1), H(s2))

Bob does the same by issuing tx2 on bobCahin hash-locked with H(s2), AFTER tx1 is confirmed on aliceChain.

Now Alice should wait for tx2 to get confirmed before spending its outpoint and Bob should wait for Alice spending tx2 (and revealing s2) to be able to calculate s1 = t-s2 and spend tx1's outpoint.

I count four transactions in what you described.

Actually, the spend transactions are not part of the protocol itself because both parties would be able to do it as regular transactions for other purposes but if you feel more comfortable counting this way, I've no objections.