Topic: 1 Confirmation versus 6 (Read 4902 times)

There were 2 significant events that caused large forks.

Other than those, I have seen a 2-block orphan happen 8 times since 2012. I have seen a 3-block orphan only 2 times. No 4 or 5-block orphans, but we did have a 6-block orphan happen once.

I tried to deposit from poloniex to coins.ph a site that convert bitcoin to cash, I noticed that unlike other exchanges, coins.ph allow the coin sent from poloniex to be spendable after one confirmation.  That was my first time experience to have bitcoin spendable with just  1 confirmation.   In a standard basis it needs  3 confirmation for the transaction to make your bitcoin spendable in that site.

In my opinion 0 confirmations would be enough in most cases, if your software / wallet is advanced enough and checks how many nodes received your transaction and if no competing transactions are broadcasted to the network.

If you are a webshop accepting payments a 0-confirmation bitcoin payment is far more secure than any creditcard transaction.

Today pump and btc newtork slow. 

I think some are waiting for 3-4 confirmations because the fact that it cannot be undo anymore so the transaction is safe. Other than 1 confirmation only then you can cancel it and they will got nothing.

New to Bitcoin, and apologies if this question has been answered before in another way.

I have a very basic idea on what confirmations are (the depth of the transaction, how many blocks have been completed since etc).

What I do not get is why some places would need 6 or more confirmations while others are pretty happy with 1 or 2. Isn't the blockchain and mining invented in such a way that once a block has been completed that it's 100% secure and perfectly confirmed?  In other words that x confirmation(s) should in theory always be as good as y confirmation(s), provided neither x or y = 0?  What makes something like 1 or 2 confirmations so much "less secure" than 6 or more? Can something go wrong after 3 or 4 that 6 is really needed?
Has anyone ever lost coins because they didn't wait for enough confirmations?
Thank you.

If you're requiring more than 0 confirmations, it's nice if you show the current balance (0 confirmations) and the available balance (1 or more confirmations), so they can immediately see that their payment is acknowledged.  Not all sites need to wait for confirmations, so the dual current & available should be optional.  Most sites selling digital goods are fine to accept 0 confirmations.

That means a lot coming from you

wait, I know BitPay, it's most secure and many famous companies worked with them. Also once I had experience to integrate their API on one company's website as payment system but I remember that there wasn't any similar things, transactions with zero confirmation. Can you link me the information about that on their website? I can't find it.

So what's about this thread, of course 6 confirmations wins here Many websites usually need 5-6 confirmation to make transaction, not more than 6. Also you are more secured with 6 transaction than 1 but it depends on how is payment options because some websites give you permission to use bitcoin deposited money once it is registered but you can't withdraw it if's not confirmed because we can remove transactions that has no more than 1-2 confirmation

BitPay uses zero confirmation. They have their own algo to determine if a transaction looks unlikely to be double spent. I'm not sure but I think it looks like this:

1. Wait for transaction; see it. (they ask you to pay a particular address, so that's all they have to watch.)
2. Look at transaction; see if it has at least a minimum tx fee and inputs are already confirmed.
3. Wait for a few seconds; see if there are any other transactions using the same inputs (double spend)
4. If the above looks good, accept the transaction and credit the user or payer; give them their receipt or whatever.

According to transaction propagation statistics, on average, 5 seconds later your tx has been seen by 50% to 90% of nodes on the network. 10 seconds later 99% of nodes have seen your tx. Blocks take maybe a minute or two to be seen by 90% of nodes.

Even if there are 2 or 3 block orphans, that does not mean your particular transaction is being double-spent or an attempt on it. The only one who can do that is the one who has control of the private keys of the inputs in question. Your transaction or the transaction you are watching will likely be included in the any or all forks or orphans, or will be included in the next block.

I just stick to 1 confirmation. To me, that means a miner included it in that block, and other miners will probably include that particular one I am interested in in the next block if an orphan happens.

I recently constructed a rather large transaction with several inputs worth 50 BTC. Since I was the one doing it, I did not even bother to wait for a confirmation when I was combining all the inputs, I just did it one after the other. (No one is going to double spend my stuff, except me, right?) Turns out the whole thing (4 transactions all together) confirmed in about 20 minutes since I broadcast them.

...some places would need 6 or more confirmations ...
... than 6 or more...