Quote from: Argwai96 on October 16, 2014, 11:15:15 PM

Quote from: Este Nuno on October 15, 2014, 07:41:11 AM

Quote from: OrientA on October 14, 2014, 08:42:28 AM

Quote from: Este Nuno on October 13, 2014, 11:16:31 AM

So I wonder why people haven't been asking the core team to change the confirm time on the next hard fork? This is a perfect time to do it considering we're very likely going to be doing a hard fork any way to increase the block size from 1 mb.

It takes about 1 hour to make sure the confirmation is solid due to orphan blocks or some kind of attacks. 6 confirmation of 10 minute block takes 1 hour. If you reduce the block time to 1 min, then it will take 60 confirmation to avoid double spend.

Right, so we might as well have shorter confirms since no one is going to be rewriting blocks on the Bitcoin chain for any transaction that's worth less than the cost to do so. And for the ones that are, we wait an hour. Sounds pretty good to me.

Quote from: FattyMcButterpants on October 15, 2014, 04:55:05 AM

Quote from: the joint on October 13, 2014, 08:54:34 AM

Quote from: Este Nuno on October 13, 2014, 08:41:31 AM

Quote from: mnmShadyBTC on October 13, 2014, 02:07:06 AM

Quote from: jonald_fyookball on October 12, 2014, 09:43:56 PM

Quote from: mnmShadyBTC on October 12, 2014, 09:41:37 PM

Quote from: leopard2 on October 12, 2014, 07:05:49 PM

Quote from: franky1 on October 11, 2014, 08:10:39 AM

Quote from: Bit_Happy on October 11, 2014, 05:10:53 AM

Over 30 minutes for a single confirmation does not (and will not ever) work in the real world.
(Almost) Every time I start to believe that BTC is "going mainstream", I have a delay waiting for a 30+ minute block.... Shocked

solution:
if your paying for a coffee or a mars bar, dont wait. if your buying a house wait 30 minutes

solution:
if your paying for a coffee or a mars bar, use LTC or DOGE. if your buying a house wait 30 minutes Wink

One confirmation with LTC or DOGE is much less secure then a 0/unconfirmed TX with bitcoin. Both of their network is not secure so it would be easy to attack the network and reverse your TX. Once a TX is propagated throughout the network, nodes will not accept TXs that use the same inputs so you will not be able to broadcast a TX that spends the same inputs, the only way to double spend is to confirm a block that uses at least one of the same inputs as what you just spent. As long as the value of your cup of coffee is less then what it costs to mine the next block then you are almost certainly safe to accept a 0/unconfirmed TX after the TX has been properly propigated

Not disagreeing with you , but isnt LTC fairly secure?

It is the most secure altcoin out there as of now but the short block time gives a misleading picture as to how secure it's network is. Even if it has the same difficulty as bitcoin it's 2.5 minute block time means that it takes 25% of the work to find one block and there will be at least 4x as many orphaned blocks.

If you want to do an apple to apples comparison of network security the LTC network has a difficulty of ~36.5 thousands now, compared to 35 million for bitcoin. Granted BTC and LTC miners are not interchangeable but I think this gives a pretty good comparison as to how easy it would be to attack either network.

The thing is that one confirmation is more secure than zero confirmations as it prevents a whole category of zero confirmation double spend attacks. So that confirmation comparison you're making is only accurate for a comparison of attacks where a rogue miner is actually publishing blocks. And the amount of time you need to wait for the same amount of security is the same so they're actually equivalent. Like I said up thread, the only disadvantage to shorter block times seems to be more orphans, but since it's something that benefits the end user I would think most people who aren't miners would actually be behind such a change. And the smart ones who are miners will see that despite the fact that they will be wasting some hash in some cases, the potential gains in demand and positive perception due to people not having to wait around 30 minutes for a confirmation often enough should make up for it in the long run. That's just conjecture of course, but considering the amount of complaints we hear about Bitcoin's slow block targets I wouldn't be surprised if that was the case.

It's not just more secure, it's infinitely more secure.

Fast-confirm coins absolutely have a niche, in my opinion.

Fast confirm coins are much less secure and having one confirmation on a fast confirm network is less secure then a 0/unconfirmed TX on a 10 minute network. The reason for this is that nodes will not accept a double spend transaction when there is a propagated TX that spends certain inputs. As long as nodes are sufficiently diverse and TXs are able to propagate quickly, then it will not be possible to double spend certain inputs you have spent on a 0/unconfirmed TX unless you find a block and include the double spend TX in that found block. At the very least you will need to wait for enough confirmations to equal one "10 minute" confirmations to get the same security of a 0/unconfirmed TX assuming the hashrate is the same.

The problem with this is that shorter confirmation blockchains also give miners more of an incentive to mine on shorter blockchains to prevent their chain from being orphaned. This will result in more orphaned chains and longer chains, ones that will potentially exceed the equivalent of a 10 minute confirmation

But it is possible to double spend unconfirmed transactions if you know how to do it correctly(not saying it's easy). Which is why the 1 confirmation is better, since that whole category of double spend attacks that are possible are protected against with one confirm.

I think at this point it's pretty clear that Bitcoin could upgrade to 2 minute blocks on the next hard fork and people would be happy with the change. One confirmation, even if it's 1/5th as secure as a one 10 minute confirm is still very secure on the Bitcoin network. I think it would beneficial for Bitcoin to make this change.

Here's Peter Todd's take on unconfirmed transactions: http://www.reddit.com/r/Bitcoin/comments/239bj1/doublespending_unconfirmed_transactions_is_a_lot/

Note: I'm not saying that unconfirmed transactions aren't fine for microtransactions and such.

Changing to 2 minute blocks would not be an upgrade. The only way to double spend an unconfirmed transaction if you do not control the miner that finds a block that confirms a double spend TX is to control a well connected node that miners connect to (you would probably actually need to control several well connected nodes)

How would it not be an upgrade to receive one confirmation that provides 1/5th of the security in 1/5th of the time? When 1/5th of the security is very significant and sufficient for all but the highest value transactions.

The cost benefit trade off seems pretty clear to me. A bit more wasted hashing shouldn't be a concern when considering increasing the usability of Bitcoin.