Topic: Isn't bitcoin too SLOW to be called "instantaneous"? - page 3. (Read 3958 times)

Corrections, is 6x0.5Gb is 3GB an hour and that is 72GB a day, still BIG!

Theoretically, yes.

But this kind of attack would require an individual person to mine a specifically forged block (which takes extremely long, with today's difficulty), and then right at that moment, immediately double-spend the money at some retailer, before the rest of the network finds the next block. Seems like a *very* slim chance to me. Somebody would literally have to spend months outside a retail shop, trying to mine his specially prepared block, and then once he does, quickly go in and double spend some cash. Definitely not worth the trouble to buy some groceries or paying for a diner. As long as you require at least 1 confirmation for considerable amounts of money (e.g. buying houses or cars), I wouldn't consider this a real threat.

The transaction time is related to the processing fee you offer, but yeah I think Bitcoin is too slow for over the counter.

Litecoin is faster and more likely to be every day currency.

Gold has a slow transaction time too, Germany will have to wait 6 years to get that transaction done with the Fed.  

Ok, this is the kind of response I was looking for, reasoning about design and its consequences... And replying to the post before this. I would be stupid to start to code something or even to purpose a new design BEFORE arguing with others more experienced in Bitcoin its possible pitfalls.

For a computer system 10 minutes is an awful lot of time, even 2 seconds is an awful lot of time. Computers lives in milliseconds, nanoseconds...

If the problem of that "instant transactions block chain" is just that mining would not be worth it, then we could just remove mining prizes altogether on that block chain. The incentive on that chain will only be transaction fees, the prices of "instant security" and for mining you have the parent traditional block chain that will work just as it does now.

As for the last part "Unconfirmed transactions are nearly instant./to pull off a double-spend is nearly impossible" doesn't change the fact that the restaurant or any merchant or receiver will probably prefer to have confirmation before letting the costumer go. The system should aim to provide that confirmation.

Another question, what is wrong with ripple consensus? (for "instant" transactions)

And, have you considered the scalability problems on 10 minute block transactions if bitcoin ever reaches VISA traffic?
Sooner than later bitcoin-qt will be made obsolete, at least trying to keep the block chain locally on a PC.
TODAY is ALREADY not feasible to have it on your mobile phone, you need to trust someone else service.

2000tps*512bytes= 0.97 megabytes per second (from here https://en.bitcoin.it/wiki/Scalability)
In 10 minutes that means that the block will be 0.5GByte, in an hour that means 3.5GB (more or less)... if your wallet was of for 24h then it has to download 84GB for each day offline!
You need a new HD every week! (with todays technology)

These are real problems to take into account.
(They can probably be fixed more or less easily, but first we need to accept we have them.)

Well said, sir.

Same problem with personal checks (regarding confirmations), yet many stores still accept them. Not everyone needs to operate on zero-trust, and that includes commercial operations. Paypal/CCs are reversible, cash can be faked. Bitcoin won't create utopia, but nobody in business thinks everything will be ideal. Shit happens.

You'd be vulneralbe to a finney attack. https://en.bitcoin.it/wiki/Double-spending#Finney_attack

So first: get your blood pressure under control. I'm not really telling you how to live your life. What I am telling you is that your impatience today does little to change the way that a decentralized system in its infancy actually works. Getting impatient about it doesn't help matters at all--in fact, it doesn't bother me at all, since I'm not going to go pay 1 BTC for a loaf of bread any time soon (considering that today's prices would get me 100 loaves of bread).


So, first: you're taking what I said extremely out of the context it was offered. But let's look at the absurdity of what you're suggesting:

We can't scan bread in the middle of the store and take it home because there is no trust. Consumerism has caused the idea that such a resource is scarce, that it must be protected at all costs, and so people in Greece rioted when free bread was handed out. Is that the waste you're talking about?

Or how about the waste of spending 2 hours in a checkout line, when we should be able to shop all the way through and simply verify a purchase for the items... it would take almost the same amount of time (and could be streamlined over time, I'm sure), though the process would be a little more efficient and there would be less of a tendency for dishonesty in the supermarket. It takes only a change in the way we think about things to make anything work... so your little diatribe actually doesn't apply all that well.

When we build personal trust into a system, then stores can offer their own credit to customers who have built up a reputation--no need for credit checks, just look at habits, which we can easily look at within a given store. This allows for a social aspect of currency.

Patience is a virtue. It breeds trust. Trust, in turn, breeds speed.



Why would I say such a silly thing? I'm merely saying that being impatient about it doesn't help. If we had 3 billion people on this system, imagine how little time it would take to generate the confirmation. With more peers on the network, confirmation is a very simple matter, and will tend to take less time (not always, mind you, but in general).

10 minutes is an "average" under current conditions. In my own case, my first transaction took under 2 minutes. The bank transfer is still "pending" in my account, though the funds were already issued. How is that actually faster?


Speed reduces security. Security reduces speed. It's a computational rule.

Banks issue their money on my behalf because of trust. They know the money is there (they can see it). But they also want to give time for me to reverse the transaction. The banking system takes FAR longer than 10 minutes to actually transfer the funds (more like 2-4 business days); but because they are more established, they can issue funds based on the credited amount in my bank account.


BTC doesn't really have much in the way of intermediaries... EVERYONE is potentially an intermediary. The confirmations happen transparently, based on the block and share records stored at random in each client. Not a lot of room for lacking trust there, though I'm sure someone will figure out a way to (temporarily) break it sooner or later. Perhaps by "intermediary" you are referring to the exchanges?

But that's the beauty of open source software. Even if someone figures out how to break it, the community of programmers who maintain it will generally jump at the chance to fix the problems very quickly, and restore the system's trust



Bitcoin is not a company. That would imply a central authority who is "in charge" of the currency. It's the swarm that's "in charge" of it, not a queen bee.

Cryptocurrency systems are not overseen by ANY central authority. If anyone says "instant" then it's that organization or individual, not the whole world of Bitcoin. If you're dissatisfied with it, stop trying to use it to buy bread at the store.

Well, not really, I could have a forged client that right before it sends a transaction, it sends a duplicate transaction to another address (of myself) in the background. On-screen it only shows the 2nd transaction.

However, even for unconfirmed transactions, double spending is very easy to detect. You can see the unconfirmed transaction appear in the network right away, and likewise you can immediately see if there were any other (also unconfirmed) transactions being sent from the same address(es). If they exist, and they exceed the total balance prior to the transactions, you simply refuse it. Can be done fully automatically.

In other words, if I were a retailer, I'd simply demand that Bitcoin payments are made from addresses that do not have any pending outgoing unconfirmed transactions that exceed the remaining balance required for their payment to me.

Instant payment FTW.

The reason for the 10 minute time-frame is to decrease the possibility of miners solving the same block at the same time, potentially creating orphaned blocks. Currently, the average of the network is set to be 10min, however, you CAN get lucky, and solve the block in 1 minute. This IS happening. If the "time-frame" is too small, it means the window is too small, increasing the chances of orphaned blocks occurring.

Litecoin is 2.5min. This is a gamble, because miners who solve orphaned blocks don't get paid a fee. The risk of mining is thus greater. It's a trade-off.

Also. To add:

Unconfirmed transactions are nearly instant. If you are in a restaurant and you are paying someone (with say the wallet app), to pull off a double-spend is nearly impossible. This guy who is standing there is paying a small amount for meal. He then has to somehow have a mining pool at the ready (with enough hashing power) to quickly come in, and hopefully force a double-spend on a $20 meal. The incentive for the mining pool to do this is just so unfeasible, it's just extremely unlikely it will happen.

For low-value transactions, 0 or 1 confirmation is usually enough. In retail, a person is standing in front of you. For them to coordinate a double-spend is nigh impossible.

Sure WE can. When are you going to design, code and release it?

Please, reply to this:

Are you (all) saying that WE cannot have a decentralized system THAT confirms my transactions in 12-18 seconds instead of 1hour.
Interesting...
Why is that?
Why is 10 minutes such a magical timeframe?

Why 10, and not 5 or 20?

Like Litecoin? It was released well over a year ago, I think.

Right. for high value transactions, waiting an hour is no big deal. Everything else takes way longer than that. For low value transactions, you do not need 6 confirmation. Of course, faster wuld be better though.

Nobody is saying that Bitcoin isn't a VERY GOOD idea...

It really is!!

What I say is that it could be fixed to be an EVEN better idea without losing ANY of its current uses and properties.

What you have to understand is that for something to be "a good money" it needs to be able to be used ON ANY KIND of transactions, not just one or a few of them.

Instant transactions (meaning in seconds) are too important NOT to support!

Otherwise another currency that can do what BTC can and ALSO supports transacting in half a minute will replace bitcoin in many uses and will devaluate your BTCs.

It's just like food stamps, if they can ony buy food there are less liquid, less useful that those stinky dollars or euros that don't have that limitation.

I know many think of bitcoin just as a niche currency & payment system, but to succeed even in being that it has to be tackle the decentralised instant payment problem or at least be honest about it and concede defeat, saying it is not really that instantaneous, just faster than traditional fiat based payment payments.

Keep in mind you don't ALWAYS have to wait for 6 confirmations.

+1 ^^^^
It's simple observations like this that show you haw important Bitcoin will be

The transaction is instant. I see it in my client within seconds of it being sent.

Confirmation is a little slower. I don't mind waiting a few minutes. It's better than what we had before Bitcoin and whatever replaces it will most likely be quicker.

Or you could stick with Paypal and not have to worry about how slow and terrible Bitcoin is.

A unconfirmed transaction is (nearly) instant.

Still 10minutes is way too long for some transactions.