Is the 'industry standard' moving to three confirmations?

[Imahara]

I see several exchanges accepting bitcoin transfers after three confirmations (btc.sx for example). With a larger network it is becoming increasingly difficult to double spend given a fixed number of conformations, correct?

So where could this go, will a single or two confirmations ever be enough? Does it depend on the transaction size?

[kwest]

Yeah I just noticed this on Bitstamp as well. As long as it's secure I'm all for it, makes my transactions snappier and me happier.

[XBBlade]

It would make the Bitcoin economy even faster. I don't exactly know why they ask for 6 confirmations nowadays, can someone explain?

[Kazimir]

Common misconception, but Bitcoin transactions are instant.

It's only the confirmations that take some time. Confirmations is what makes a transaction 100% irreversible. But nowadays, for regular payments of 'normal' amounts (up to a few thousand $) it's completely safe to accept a payment as soon as it appears in the network (and has enough tx fee).

With todays network strength it's pretty much impossible (not to mention way, WAY too expensive) to successfully forge a valid looking transaction (thus it gets propagated through the network) that doesn't get confirmed. Only in order to accept or trust payments for BIG amounts, e.g. when literally sending tons of money around, you better await a few confirmations.

So, in most situations it's perfectly valid to say that Bitcoin payments are already instant. NOT 10-60 minutes!

[Kazimir]

Oh, one more thing. As for the so called 'faster processing' of altcoins with shorter block times: this is a delusion.

In the end, the certainty of a transaction is related to the amount of processing power that would be required to successfully forge it. You may think that for example Litecoin is 'faster' because it finds blocks 4 times as fast, but it would also require 4 times as much blocks to get the same amount of certainty - that is, if the total network power were equal. And the latter is not the case by far, the Bitcoin network harnesses much, MUCH more hashing power than all other altcoins combined.

So, when comparing the speed of processing transactions, not in terms of 'number of confirmations' but in terms of actual certainty and trustworthiness, Bitcoin is a few miles ahead.

[zimmah]

Common misconception, but Bitcoin transactions are instant.

It's only the confirmations that take some time. Confirmations is what makes a transaction 100% irreversible. But nowadays, for regular payments of 'normal' amounts (up to a few thousand $) it's completely safe to accept a payment as soon as it appears in the network (and has enough tx fee).

With todays network strength it's pretty much impossible (not to mention way, WAY too expensive) to successfully forge a valid looking transaction (thus it gets propagated through the network) that doesn't get confirmed. Only in order to accept or trust payments for BIG amounts, e.g. when literally sending tons of money around, you better await a few confirmations.

So, in most situations it's perfectly valid to say that Bitcoin payments are already instant. NOT 10-60 minutes!

Agreed, for the price it would cost to do a successful 51% attack you could buy an army big enough to invade countries like Qatar.

[Imahara]

Thanks! Great to know that. I didn't realize that faster block time doesn't mean that much.

In practice, when I move money between exchanges the confirmation time is making it slow, so I hope 3 or less confirmations is getting standard.

I guess the cost makes it unlikely for small amounts there would be a double spend. But someone could of course create lots of small double spends at once, that could still mean a big heist on the network..