Author

Topic: Unconfirmed Transaction to Confirmation (Read 716 times)

legendary
Activity: 1792
Merit: 1111
December 29, 2013, 10:18:30 AM
#7
....... or the unconfrmed transactions will always be confirmed at some point of time ?

The answer is quite obvious: if this was true, no one would ever need to wait for confirmation
full member
Activity: 165
Merit: 102
December 29, 2013, 05:00:16 AM
#6
Lets assume the transaction amount for a single Tx will be very small, less that 1 BTC against which people will download some music or something. But how do I address the following problem with 0 confirmation ?

I guy come and pay 0.001 BTC with 0 Tx fee. Tx happens with 0 confirmation and he gets to download his music, but the music owner will never get that 0.001 BTC !!!

In the above scenario, problem remains same as of PayPal chargeback NOT supporting virtual things like music, pdf etc. And if I force the buyer to wait for confirmation even when he pays Tx fee, the overall process gets delayed, NOT instant, leading to a drawback against PayPal !!!
newbie
Activity: 44
Merit: 0
December 28, 2013, 05:42:49 PM
#5
So if I am running a POS system - the business advice is if the transaction is small, take the risk.... on the technical side, just to be sure.... must the double-spend first transaction appear on the block-chain to be identified with or without confirmations for the second spend to be id'd as such or ...... is the test for a potential double-spend done for transactions in the mempool as well?

Also, in one of the referenced links there is a suggestion that the best way for a person to 'get away' with it if they are determined is to have a 0 transaction fee in the first spend, and add a transaction fee in the second spend.... can anyone tell me why?  It appears to be related to the way the miners can configure their software.... but I am still unclear on this.

Any help appreciated.

bob
legendary
Activity: 4256
Merit: 1313
December 28, 2013, 04:10:54 PM
#4
If I accept a transaction with zero confirmation and allow people to get what they are purchasing, then can they revert or bypass that spent in a later stage or the unconfrmed transactions will always be confirmed at some point of time ?

You may want to read these discussions here, plus a ton more:

https://bitcointalksearch.org/topic/if-confirmation-takes-10-minutes-how-will-i-buy-coffee-at-starbucks-359934
https://bitcointalksearch.org/topic/is-a-0-confirmation-double-spend-for-retail-possible-159994
https://bitcointalksearch.org/topic/making-0-conf-txs-relatively-safe-again-208167


The summary is that zero confirm transactions are perfectly fine for small value items because the cost to do a double spend is not worth it as long as you verify that the transaction has appeared on the network and you've paid a fee.  The other relevant quotation is:  "If credit cards take 180 days to be confirmed how will you buy coffee at Starbucks?"

Don't believe the FUD about zero confirmation transactions for small value items, a double spend is less likely than someone just walking out on the bill for small items.  Just like credit cards, if someone were to successfully scam you - or dispute the transaction a month later - you'd be out the money and it is a cost of business.

For larger purchases, you want confirmations.  E.g. buying something for 5000 BTC, I'd want a lot of confirmations.
full member
Activity: 165
Merit: 102
December 28, 2013, 11:36:34 AM
#3
Indeed, you should not accept zero confirmation transactions

I know that, but calculating confirmation of a transaction through API is a difficult process. So I need to know this...
newbie
Activity: 5
Merit: 0
December 28, 2013, 05:32:02 AM
#2
Indeed, you should not accept zero confirmation transactions
full member
Activity: 165
Merit: 102
December 28, 2013, 04:30:43 AM
#1
If I accept a transaction with zero confirmation and allow people to get what they are purchasing, then can they revert or bypass that spent in a later stage or the unconfrmed transactions will always be confirmed at some point of time ?
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