6 confirmations is not enough

[odolvlobo]

A rational miner is going to attempt to sabotage the system for possible short term gain? If he succeeds, the coins are soon going to be worthless. Now the "rational" miner's hardware is also worthless.

While I agree with your first statement that no "rational" miner will sabotage Bitcoin for a short term gain, I don't agree that such an event will necessarily sabotage Bitcoin. After all, only the victim loses. Nobody else is materially affected, and most people won't even notice.

Anyway, back to the original thesis:

Yes, 6 confirmations is not necessarily enough. The number of confirmations depends on the amount of the transaction (or the amount of the fee in your specific attack). 6 confirmations has always been just a rule of thumb.

[Come-from-Beyond]

This will not happen. People think that it is easy to trick the network, well it is not.
You're making inexperienced people fear Bitcoin for no valid reason..

Explain why this won't work when cloud mining dominates?

[MrTeal]

This will not happen. People think that it is easy to trick the network, well it is not.
You're making inexperienced people fear Bitcoin for no valid reason..

Explain why this won't work when cloud mining dominates?

Because no current cloud mining allows you to choose what transactions get included in blocks. You just buy a certain percentage of their hashrate. Some allow you to choose a pool and so you could create your own malicious pool, but those are nowhere near the 50% you'd want.

Keep in mind there's not any alt's out there (even all combined) where you can buy up 1000BTC in one shot without destroying the market and way overpaying. You'll never be able to get 1000BTC worth of alt's and withdraw them. The other large technical hurdle would be that you need to have 50% of the hashing power lined up ahead of time for your attack. As soon as it hits 6 confirmations the majority would have to start reorging the blockchain. If you hadn't notified them ahead of time, or they had rules in place to examine potentially lucrative double spends, it might be several times longer than 6 blocks by the time the majority of miners even noticed the possibility of the double spend was there.

[Come-from-Beyond]

So Bitcoin is protected as long as the mentioned upthread assumptions regarding cloud mining are actual. Got it.

[MrTeal]

So Bitcoin is protected as long as the mentioned upthread assumptions regarding cloud mining are actual. Got it.

This isn't an attack on Bitcoin, it's an attack on whatever exchange you're trying to defraud.

[Come-from-Beyond]

So Bitcoin is protected as long as the mentioned upthread assumptions regarding cloud mining are actual. Got it.

This isn't an attack on Bitcoin, it's an attack on whatever exchange you're trying to defraud.

I stand corrected.

[MrTeal]

So Bitcoin is protected as long as the mentioned upthread assumptions regarding cloud mining are actual. Got it.

This isn't an attack on Bitcoin, it's an attack on whatever exchange you're trying to defraud.

I stand corrected.

And you are correct in that for certain transactions, more than 6 transactions might be prudent. I might accept a $1M payment in BTC from a known entity that I have had business dealing with before and have a legal means of pursuing if something goes wrong. If it was an anonymous entity over the internet, waiting more than an hour might be wise.

[funtotry]

Interesting theory, time will tell if anyone tries anything like this. Exchanges watch out!!! lol

[BADecker]

I think a negative 6 confirmations would be better.   

[steven.G999]

I've seen my friend has 92 confirmed, still - red

[R2D221]

Why 6? I think more than 2 is overkill, even for large value transactions. How probable is that 2 or more blocks get orphaned? Or has it happened before?

[Come-from-Beyond]

Why 6? I think more than 2 is overkill, even for large value transactions. How probable is that 2 or more blocks get orphaned? Or has it happened before?

6 for a round number (1 hour).

[colinistheman]

This will not happen. People think that it is easy to trick the network, well it is not.
You're making inexperienced people fear Bitcoin for no valid reason..

^ Yes, I agree.

While Come-from-Beyond's OP may be a valid question, it also seems to be an effort try to pick apart and undermine Bitcoin. I believe this is because of vested interests in NXT.

Here's why:

I remember over a year ago when I was talking in the NXT thread and Come-from-Beyond posted replies to all questions and was basically acting in charge. This was very early on, when there was only one NXT exchange (dgex.com) (and it didn't look like it does now-- it was a very new and rough design). He may be one of the Devs for NXT. And I feel fairly certain he is an early bag holder for NXT. So whatever his position, rest assured he very much wants NXT to succeed.

So based on his OP attempting to pick apart bitcoin, that leads me to believe Come-from-Beyond has a desire to see bitcoin fail for the reason of his own potential future economic gain in NXT if bitcoin were to be crippled or fail.

Two questions for Come-from-Beyond:

1.) Are you a developer for NXT, or have you ever been?
2.) Are you in possession of NXT?

[Come-from-Beyond]

Two questions for Come-from-Beyond:

1.) Are you a developer for NXT, or have you ever been?
2.) Are you in possession of NXT?

1) No, yes.
2) Yes.

Now my turn.
I suspect that you possess a substantial amount of bitcoins and are trying to hide facts that show that Bitcoin is flawed.

Two questions for colinistheman:

1.) Are you a developer for BTC, or have you ever been?
2.) Are you in possession of BTC?

[Klestin]

Look at the following scenario:

I send 1'000 BTC to an exchange. After 6 confirmations my account is credited and I buy 1'000 BTC worth of altcoins and withdraw them. Then I create a double-spending transaction that sends 50% of those bitcoins to another my address and 50% as the transaction fee.

What will rational miners do? Depends on the amount of the fee and number of confirmations I think. It would be interesting to see the formula that tells what values are enough to convince 51% of the miners to re-mine the last blocks...

There is no "6 confirmations" rule. It does not exist in the system. It is a suggested general convention that absolutely nobody is forced to use.

Why not just rob a bank/steal a car/extort rich person/etc? Much more straightforward, and in either case, the counterparty will come after you.

[colinistheman]

Two questions for Come-from-Beyond:

1.) Are you a developer for NXT, or have you ever been?
2.) Are you in possession of NXT?

1) No, yes.
2) Yes.

Now my turn.
I suspect that you possess a substantial amount of bitcoins and are trying to hide facts that show that Bitcoin is flawed.

Two questions for colinistheman:

1.) Are you a developer for BTC, or have you ever been?
2.) Are you in possession of BTC?

Sure

1.) I'm not a developer for BTC, nor have I ever been.
2.) And yes I possess BTC.
As a bonus answer, I also possess NXT.

You also earlier claimed to own 0 btc in this thread. Just another interesting fact:

I haven't even tried. With my current balance of 0 BTC it's quite hard.

The difference between us is I'm not trying to pick apart NXT or BTC. But you are.

You just confirmed that you have been a NXT developer in the past and you posses NXT (my pure guess would be a very large amount, based on how early you were involved in NXT and the fact that you were a dev).

So my claims have been even more substantiated by your confirmations.

So please stop trying to spread FUD.



TL/DR:  Come-from-Beyond states he was a NXT dev and currently holds NXT. He currently holds no BTC and is trying to pick apart bitcoin. The motives seem pretty clear-cut to me.

[SirChiko]

This will not happen. People think that it is easy to trick the network, well it is not.
You're making inexperienced people fear Bitcoin for no valid reason..

Explain why this won't work when cloud mining dominates?

Cloud mining will never dominate, experienced users don't use cloud mining as they know it's useless and unprofitable.

[LiQio]

Cloud mining will never dominate, experienced users don't use cloud mining as they know it's useless and unprofitable.

Care to share some current numbers/quotas?
(Because my gut tells me otherwise)

[Come-from-Beyond]

TL/DR:  Come-from-Beyond states he was a NXT dev and currently holds NXT. He currently holds no BTC and is trying to pick apart bitcoin. The motives seem pretty clear-cut to me.

It's a wrong TL;DR. You assume that only a holder of bitcoins is eligible to question Bitcoin internals which is obviously a fallacy.

PS: I wouldn't trust to reasonings of colinistheman because he is biased:

2.) And yes I possess BTC.

[User705]

This will not happen. People think that it is easy to trick the network, well it is not.
You're making inexperienced people fear Bitcoin for no valid reason..

Explain why this won't work when cloud mining dominates?

Why will cloud mining dominate?

Regardless, let's assume it does.

Someone owns the hardware. Will the providers continue to sell hashrate to someone who's actions will render the hardware (and therefore their entire business model) worthless? Maybe, if they are extremely stupid.

What happens when the hardware is already worthless (doesn't mine enough to cover electricity costs)?