Bitcoin Forum

Mathematically - yes. Real World, nowhere near.
..

A lot of comments keep coming up where a user says - Bitcoin is SLOWW! You need to wait an hour (6 confirmations) before your txn is confirmed!

This is simply not backed up by the data.

When you look at the orphan block rate, Bitcoin has, on average, about 2-3 orphans a day. A DAY.. out of 144 blocks.

https://blockchain.info/charts/n-orphaned-blocks (https://blockchain.info/charts/n-orphaned-blocks)

AND - these are not consecutive blocks. So every few hours, 1 block gets orphaned. That means that there has been a mini-fork, but that it only lasts 1 block.

I would love to see a graph that showed the longest orphan chain per day, if someone knows where to get this ?

What this all boils down to, is that anyone who is waiting longer than 2 confirmations (just to be ULTRA sure) for a btc txn, is wasting their time. Since the BTC chain has consistently shown that after 2 confirmations your txn is going to be accepted 4 more blocks down the line..

And quite frankly, 1 confirmation is fine. (3/144 = 2% chance of being in an orphan block = 98% safe)

( And lets not even get started on how long it takes to send money across the world using conventional methods. That's a blood bath.. )

Enjoy!

0 confs are fine too if you just buy a cup of coffee or something like that.

Even exchanges go with 1 or 2 Confirmations now-a-days....
you're talking old school :D

I think it's only a "security" manner to manage each deposit for an exchange, normally a lot of sites accept one confirmation

even most of exchanges go with 2 confirmation, there's does exist some exchanger that require 6 confirmation and i've seen few debit card provider need 6 confirmation too

3 would be the safest bet, but that's for online deposits kind of transaction. For those simple on-purchases 3 would already be too long to wait.

LOL, am I so old already.. (strokes his grey-ish beard..)


ADDENDUM :

And even if your txn is in an orphan block, it can still, and almost certainly WILL, be added to the new chain. Your counterpart would actively need to be trying to cheat you.. for this not to be the case.

the orphan issue is near to be fixed anyway with sub chain, so if that is the problem for not wanting low number of confirmation, it will not be a problem anymore

but there are other attacks that can be done at 3-4-5 confirmations, merchants want to avoid those more than anything else

I think BTC-e have 3 confirmations, and they are safest btc exchange so far.
I'm satisfied how it works but the "graphic" is ridiculous and pointless..

Most people that are complaining about stuff like this go out and have no problem paying with credit cards with have 180 days of confirmation, bunch of idiots complaining as always.
Lightning Network will will allow for VISA level of volume transactions with several order of magnitude safer. Bitcoin with LN will kill every single competitor.

I think it boils down to transactions sizes... If you shift say $ 1 000 000 .... it would be better to wait for at least 6 to 7 confirmations as a merchant. The risk

is just that much lower, if you wait it out. It would be ridiculous to wait 6 to 7 confirmations for say $1 purchase. If you compare this with other payment

methods out there, 10 minutes will not be an issue for bigger amounts. If you want zero confirmations, use off-chain payment services.  ;)

I've made a transaction today and got 3 confirmations in a few minutes..that's not bad at all!

6 confirmations are mostly accepted by xapo, coinbase while other websites are OK with 2-3 confirmations which take about 10 mins minimum. I don't think anyone accepts 0 confirmations as the transaction can be dropped as well.

generally.. if the goods have to be delivered by post (taking days obviously) you can accept 0 confirms. because you can say payment received. and treat it as items ordered' and within the hour you can receive X amount to the actually dispatch the goods.

as for instant offering.. EG facebook credits. where its easy for facebook to rewind any credits if a orphan happens, that too could work with 0 confirmations.

but when the swap is instant and irreversible. then confirms need to be thought about.

many people say if the value is small.. you could accept the risk of 1 confirm. and add more confirms the higher the value is.
EG a sandwich 1 confirm max..
afterall for a 2% risk you dont want to piss off 100% of customers making them wait more then 10 minutes

a second hand car 3 confirms,
after all it takes over 30 minutes to do the 'pink slip' registration paperwork'

a new car 4 confirms.
after all it takes over 30 minutes to do the 'pink slip' registration paperwork'

and a house 6 confirms
after all it takes over an hour to do the property deed and land registration paperwork

Agreed with this. Like anything it is a trade-off between convenience and risk.

Buying a coffee or some low amount for $20-30, 0 confirmations would be fine as the risk is small and the inconvenience the make the customer wait around 10 minutes is great.

Medium transactions of $100+ you might want 1-3 transactions, but by then it is pretty safe, and asking someone to wait for 1 transaction in not unreasonable. Think maybe a shoe store, you buy $200 shoes and they ask you to wait for 1-2 confirmation, probably not a big deal.

Large transactions, maybe $10,000+ you would wait for 6 or more confirmations to be sure. Say you buying that Tesla for $100,000 using bitcoin, It would probably take longer to fill out all the paperwork than the time it would take the 6 confirmations to go through.

This is no different than a bank holding large check deposits before you can withdrawal against them. I can deposit a $100 check my grandma gave me for my birthday and spend it the same day. I deposit a $10,000 check and they might let me spend $100-$200 of the funds right away, but they will hold the rest of the balance until the check clear sin 2-3 days, which is a lot longer than waiting around for 6 bitcoin confirmations.

Update: franky1's comment was not there at the time I wrote this post. Seems in a matter of 3 minutes we had the same thoughts. :)

I see that direct dice actually roll the dice only with one confirmation!
Just to avoid some trick with low fees /etc etc / send other inputs and so on...

we no longer need 6 confirmations either, it is too useless, and furthermore, one confirmation is as slow as an hour sometimes.
for 6 confirmations, it could be at least 2 hours.

Yes, Xapo takes six confirmations and that gets ridiculous sometimes, but the trade off is that they pay all the transaction fees going out which are always high priority.  So, it takes awhile to receive my coin but it doesn't take long to spend it.  I use my Xapo as an intermediary between my Core and my daily activity so it's not too bad...load it once a day and I'm good to go.

i wanted to use xapo too but i don't exactly like the idea of not having access to my private keys and letting a third party control all my coin.


what attacks are you talking about can you explain?

attack that have to do with a great % of the network, you don't need 51% to do an attack even with 40% you can attack the network for 5 conf

"With less than 50%, the same kind of attacks are possible, but with less than 100% rate of success. For example, someone with only 40% of the network computing power can overcome a 6-deep confirmed transaction with a 50% success rate."

search for weakness of bitcoin

I just use my Xapo wallet for my daily spending so controlling a private key is no big deal.  I complete my big transactions with my Core wallet and keep my savings safe offline most of the time.  That's why I use Xapo...to isolate my savings from my spending.  It works out great.

I completely agree.  When I'm receiving bitcoin, I count it as "mine" as soon as I see that first confirmation.  The probability of it not really being "mine" at that point is very slim.  This is one of the features that I love most about bitcoin.

I'm really not as vigilant as I should be with confirmations. I'm usually ok with 0 or 1. I only do max $10-$30 transactions though.

I don't really understand all the technical jargon behind it so I just hope the person sending me BTC also doesn't want to go through the effort of learning how to double spend then implementing a double spend on a $20 transaction.

If I really didn't trust someone I would wait for at least 3 confirmations to feel safe.

...

I have done a variety of transactions with BTC, small and "large" (large for me).  Even with the large ones, one confirmation has been fine, even mixing coins with bitmixer.io (one is OK with them).

*   *   *

I have noticed though that blockchain.info's SharedCoin service sometimes needs multiple blocks to go by before the transaction is confirmed, they do mention that it can take up to six blocks before confirmation.  I do not know why (maybe so many transactions and//or large amounts of BTC on occasion).





EDIT: I see at bitmixer's website that one confirmation is OK with amounts of under 25 BTC, I have never mixed that much.  They require more confirmations for larger amounts.

https://bitmixer.io/faqs.html

You are right but often I have seen sites and people ( say exchangers, etc ) need just one confirmation, those sites which want to hold your coins for long ask such things like 6 confirmations. Like some betting sites, because they want you to gamble more and more and loose till the time comes to cashout.

I personally accept 1 confirmation. However, sites like Coinbase requires at least 3-6 confirmation before releasing the coins for you next transaction. As most of my hot-wallet transactions are done using Coinbase, I am still stuck with unconfirmed coins!

I think the sites those who ask for 6 confirmations is useless thing, because almost all sites accept only one confirmation, so one confirmation should be enough and if so why need 6 ?

I think sites like cryptsy need 6 confirmations, now days sites like bitcasino.io needs 6 confirms , I too feel pretty useles because 6 confirmation takes around 1 hour at the minimum.

Very clever idea because its safe and easy. I use Blockchain wallet always since its easy to use and I feel safe too, moreover often need to spend my bitcoins on various activities.

My wallet requires 4 confirmations and the last transaction I made took so frustratingly long. Maybe I need to find a new, faster Bitcoin wallet. Do you have any suggestion guys? Something with 2 confirmations max?

I can't think of any realistic scenario where you would be in danger with even 1 single confirmation... if it's confirmed once I think it's enough and more than that would be worth the wait if you are dealing with a lot of money and so you are more reasonably paranoid about it being as secured as possible.

Some service are fine with 1 confirmation like Prime Dice. Other services wait for more confirmations.

All of the exchanges have this common standard that 6 confirmations need to pass before it accepts your Bitcoins. I'd assume that if someone is trying to double spend, one confirmation would be enough, and if someone is trying to get 51% of the market, the number of confirmations don't matter.

Attacks that work after confirmations risk losing the block rewards on mined blocks and thus are only likely to be tried with worthless altcoins.

Yep , 1 confirm is enough, singe double spend is unlikely, and the funds are small, nobody would risk doing it for small money.

Ok if you send millions of $$, then wait for 10-20 confirm, but if you send satoshis, or up to say 0.5 BTC, I think 1 confirm is enough.