Bitcoin Forum

Hi i just found some posted here in other thread and section about double spend but honestly i do not know what it is.
But i have idea that double spend means that you double your send bitcoin but i do not understand someone that why they need to wait for confirmation before accepting and the other said that they want to wait because of double spending..
So if the receiver receive double spending i think it is lucky that he receive double? am i right?

Sorry for noob question.. even i am sr.member i never experience double spending in my life..

https://en.bitcoin.it/wiki/Double-spending
read with carefully, And typewrite some word in the search toolbar for accessing a lot of previous thread was discussing double spend.

double spend means you spend again not doubling anything!

sending bitcoin means spending the transactions that you have received and not yet spent aka UTXO.
you can send them to many different destinations and only one can be confirmed and this is what they call double spending, spending the same UTXO in more than one transaction.

No, the term double spend is used in a rather confusing way. A true double spend where coins are used twice is not possible in bitcoin. At least not after one transaction has a confirmation. While two transactions can spend the same bitcoin, only one of them can be confirmed. Whichever is confirmed first is the "correct" one, the other is invalid. Now double spend is commonly used to refer to a second transaction that is in conflict (neither is confirmed) of another one.

So it means the double spend if you send mistaken and double the send  the only first send will confirm and the 2nd one will not confirm and it can be also possible to confirm?
Sorry i'm confuse i am always reading for some comments there but different answer that is why i didn't search it in our forum..
I heard that there is someone can scam for double spending?

I guess the scam approach is the simplest to understand. Lets say you are selling coffee and you accept bitcoin as payment without confirmation. Its coffee after all who has time to wait 10 minutes to get one. I am a scammer and order a coffee at your place. You show me the QR code with your address and the amount and I send with my phone as requested. The fee I pay you will be a little low, but your wallet will see the transaction, I take my coffee and go. In secret I have prepared another transaction that uses the same bitcoin, sends them to myself and pays a large fee. I send it into the network from my server that has plenty of connections into the network. Now its very likely that my 2nd transaction, the bad one, will reach most parts of the network before the 1st one. Whenever one of the transaction reaches a node the other will be rejected when it arrives. Its like a race through a maze. Each transaction blocks the other. My hope - as the scammer - is that the 2nd transaction will win this race and I get coffee for free. Even though I have only used the bitcoin once, this is called a double spend attack.

If you wait for a confirmation you wait for the race to be over. You would know for sure which transaction won. In order to replace a confirmed transaction I would have to replace an entire block and thats very expensive. This attack is commonly called 51% or >50% attack, because it requires (in its simplest form) that the attacker has the majority of hash power.

Double spending is similar to a bank overdraft. Spending something twice with funds that you don't really have.

That is why some scammer out there are doing it.. i just heard it in other forum.now i understand why we have double spend.. honesty when i was newbie last year never heard about double spending
This year starting on january i heard about double spending but i do not understand what it is actually..
Now i am confused because someone are not the same answer or different anser about double spending..  and main topic from other forum..

Now i asking that if i am receive the double spending which means the 2nd transaction win and i receive it but not deducted from sender?
If the 1st transaction is failed and the 2 transaction is win it will still be deducted in their bitcoin balance or there is no effect?

Hmm, there is no balance in bitcoin. Only inputs. Lets say your address is 1Abcdef... and someone sends you 0.1 BTC. You now have 1 input worth 0.1 btc. Lets say 9 more people send you 0.1 each. You have now 10 inputs worth 0.1 btc each. If you have another address 1Bcefg... and you received 1 BTC on that address with a single address you have 1 input worth 1 btc. Your total balance as your wallet would show you is 2 BTC, but when you create a transaction for a double spend its important to use the same inputs, because only then its the same coins. Thats why only one of the transactions can be valid. Balance is only shown to you so its easier to handle. Thats why we have wallets.

You can find a pretty detailed explanation here - https://en.bitcoin.it/wiki/Double-spending

Technically a Double spend is Counterfeiting .

The coins you receive are not Valid , and you are unable to redeem them.

Double Spend will destroy any trust in a Crypto almost overnight.


 8)

Technically, there is no "counterfeiting" in the Bitcoin definition of the term.
Before Bitcoin and thus the blockchain was created, that was a problem with online currencies.
Counterfeiting implies that a doubling already took place, when in reality only when you receive a
confirmation do you control the coin. So counterfeiting is the old definition of doublespending.

Before Bitcoin = Double spending: double coins, counterfeiting
After Bitcoin = Double spending: two or more unconfirmed transactions that share the same input.

It may not be included but counterfeiting is exactly what a doublespend is.
And easiest correlation to fiat for a someone to understand.

3 confirmations are the recommend number to wait to avoid a double spend.

But to be honest since the Chinese mining pools have over 51%, they could double spend anytime within the last 10 hours or so.
Since technically they can overwrite the blockchain, it would take them ~ 1 day and everyone would know it, but technically they could do it.

Which Means
BTC=  Better Trust China

 8)

Then they would have purposefully destroyed their golden goose.
It is not profitable to do that in any way, accept to kill Bitcoin for the Chinese government.

What your arguing is like saying they have nuclear warheads and they can use it.
So what? If they use it the whole world would be destroyed, so let them double spend then.
Let them watch their investments go up in flames.

LOL,

If BTC became the world's currency , then China Controls it.
Meaning they don't have to destroy it, but can use the threat to get their way in matters more important to them.
Because they can destroy it for everyone else but keep it working for China only.

Since you mentioned Nuclear

Modified for China & BTC
China could Destroy all foreign use of BTC through the promise of blocked transactions using 51% attack,
therefore no other country may argue with any of their Political Stances for fear of this retaliation.
Diabolical aren't they.   ;)

Bitcoin can never be the "world's currency" if it is controlled by a Communistic Dictatorship.
Either it doesn't become the "world's currency" or Communist China collapses.
Each choice is very unlikely right now.
If China likes the concepts behind Bitcoin so much, they will use their own version, before Bitcoin.



Mutually Assured Destruction assumes both sides has about equal destructive ability.
As for hashing power, it is clearly in the favor of China.
If China destroyed all foreign use of BTC though power plays or etc, they would be
making BTC as worthless even to themselves.

If this was their plan, it would have been smarter to wait till it became the
"world's currency" before playing power games. "It's the slow knife...".

LOL,
They devalue the Yuan all of the time, their people still use it.
BTC would be no different.

They had to tip their hand to keep their 51% control, allowing the updates would have removed their dominance.

 8)

FYI:
You freely admit they control BTC and have the power to pull off a 51% attack.
But you want to pretend that they will never use it. With 51% China has absolute power over BTC transactions.

FYI2:
What they could do is make BTC directly trade-able for gold in China only and it would stabilize it there, while they destroyed it in foreign countries.  ;)
http://www.bloomberg.com/news/articles/2015-04-20/mystery-of-china-s-gold-stash-may-soon-be-solved-as-imf-beckons
(Don't think they have not thought this thru.)
All of the rest of you are playing catch up on a Plan that was designed years in advance.

We are way offtopic so I'm not going to continue from here,
but your opinion is incorrect. Their people are forced to use it like all national currencies.
BTC is a threat to the Chinese Communist System. If you think they will use BTC as their
main currency you obviously don't know the Chinese government.



China controls more hash from LTC than they do with BTC, why are you supporting that coin more?



Your crazy, the Chinese financial systems and government love gold more than anything.
They will never allow Gold/BTC exchanges. If they do, they aren't the masters, but the pawns.

Actually , I know them quite well.  :)
Personally Love the Chinese People, it is their rulers, I have a problem with.
https://en.wikipedia.org/wiki/When_China_Rules_the_World





I support ZEIT, but I will recommend LTC or Doge over BTC,
Both are Chinese Controlled, and LTC is faster and cheaper to send , with 0 transaction problems.
You think I would recommend the more inferior coin, I recommend the best for the situation.
The questions you should ask yourself , is why are you afraid of LTC, when it will save you time and money over the inferior BTC.
False Belief of BTC superiority, is my best guess.  :)




Hmm, so you believe people would rather carry a pound of gold instead a few ounces of paper or a Cellphone Wallet,  that can represent that Gold Value.

You should study history, People have been carrying lighter items instead of heavier items as money for Centuries.
If Barter was that wonderful , Banks would have never launched Paper Fiat.
Or let me phrase it this way, if you have $100 on you , is it four $20 bills or $100 worth of pennies already rolled up.
What that you say, it is the lighter and easier to carry paper bills instead of the rolled up pennies. (There is your answer.)  ;)

 8)

Almost every one of your answers to my statements are either out of context or total spin.
Either you are intentionally misconstruing the conversation or your are defective in some way.
I don't need a lesson in the history of gold and currency. Maybe you need a lesson in reading
and comprehension. I stated I would not continue posting in this thread due to being offtopic,
but these responses deserved a response: You don't discuss ideas, you preach your opinions.

My reading comprehension is fine,
example you stated you were done in the earlier post and you posted again a few below it, just for the record that is technically a lie or falsehood.  ;)

The fact people prefer lighter methods of carrying money is a Historic Fact, not opinion.

It is funny, how you want to call what I say an opinion , but claim your False Religion of BTC as factual evidence of reality.  :D

If you not happy , that the truth shows your idea/opinions are wrong quit stating false information based on your false belief that BTC is perfect, it is not.

The current transactions queue drama shows how broken BTC really is , and how flaccid the devs are at fixing it.
https://bitcointalk.org/index.php?topic=1689151.0

Update over 57525 Unconfirmed Transactions at the time of this post, spin that in your false religion.  ;)

 8)

Lol. You basically just proved you're mentally defective.

1. It doesn't matter if coming back is a lie or a falsehood, that is irrelevant.
You see the world and discussions as a child would. How old are you, 15? 17?
2. No one disputes that at one time fiat was backed by gold. You're talking to yourself.
I never disputed that. I disputed that the Chinese Gov would allow physical gold conversion into bitcoins.
3. I never stated or claimed any religious fanaticism to Bitcoin. You're straying again.
4. I'm very happy about my opinion because its founded on facts, unlike you.
If we had an actual conversation where you didn't roam from topic to topic never
directly addressing the prior points, then you would be aware of that, but you don't
since you are not interested in anything other than pushing your agenda, likely altcoin pumping.
5. The current mempool size is not proof of anything. You're straying again.
You fling arguments like a monkey throwing turds.
There were times where the mempool had over 120,000 txs. Call me when that happens.
Otherwise you are an alarmist who also doesn't understand how to send a tx.

Congratulations on living in your bubble of delusion.

 8)

FYI:
http://www.theblaze.com/stories/2013/06/22/592k-to-study-why-chimps-throw-poop-the-irs-isnt-the-only-one-wasting-your-money/
The Government wastes Money Like AgentofCoin wastes time.  :D

For the sake of completeness, can you directly quote the part when I said or implied that "the
Chinese populace would carry gold instead of Fiat or use a Crypto."? Thanks.