Double spent

[CIYAM]

Speed up which process? You can send a transaction with a higher fee to get a faster confirmation.

No you can't (maybe some certain nodes running non-standard software might do this but just try it yourself using say blockchain.info to see that you can't do what you suggest).

(note that we are talking about using the "same UTXOs as part of a different tx" not just creating a completely different tx using different UTXOs)

All nodes running the standard Satoshi software will simply reject any attempt to "double spend" so any "replacement tx" would have to wait until the first tx has been dropped from the memory pool of each node.

[LOBSTER]

Speed up which process? You can send a transaction with a higher fee to get a faster confirmation.

No you can't (maybe some certain nodes running non-standard software might do this but just try it yourself using say blockchain.info to see that you can't do what you suggest).

Example: if I send a transaction with zero fees to another address and I get no confirmation, I can repeat the transaction by sending it's again with a fee. This is what I meant   Am I right? 

[redsn0w]

....
No you are quite right. If you have 1BTC in your wallet and you send it ~2 times (2x1BTC), only one transaction gets confirmed.

....
Yes - you are not wrong - this is why it is really more correctly described as a "double spend attempt" as blockchains do not allow "double spends" (if they did then they would be absolutely useless in performing the very job they were created for).
...

Ok ,  I understand. Maybe they "should" change the page name  in "double spend attempt"  as you told in your post.

[CIYAM]

Example: if I send a transaction with zero fees to another address and I get no confirmation, I can repeat the transaction by sending it's again with a fee. This is what I meant   Am I right? 

Okay - it depends upon the actual tx. If you have insufficient fees for the tx to be "valid" then sure you can repeat with a "valid tx". But if your tx is "valid" (but just has no or a very low fee) then it will be propagated but may not get included in a block before it is removed from each node's memory pool.

[sgk]

This was a known case of a successful double-spend:
https://bitcointalk.org/index.php?topic=152348.0

The event took place during a planned hard fork of the protocol.  If we feel it necessary to fork the code again (and we likely will), I think it would be wise for exchanges to require a full day of confirmations for large deposits.  Once it is clear that the fork was handled properly, services can reduce the confirmation requirements back to normal.

[CIYAM]

This was a known case of a successful double-spend:
https://bitcointalk.org/index.php?topic=152348.0

Again - the word "double-spend" is not technically correct as far as the blockchain goes.

There has never been (and never will be) an actual "double spend" in any blockchain worth using.

If an exchange decides to give you say USD after X commits then they are taking the risk that X commits is "safe enough" but in reality Bitcoin can actually re-org all the way back to the last checkpoint (which could be hundreds or even thousands of blocks).

If I was selling a house for BTC I certainly would not be using 6 confirmations (more likely I would require hundreds if not thousands).

[LOBSTER]

This was a known case of a successful double-spend:
https://bitcointalk.org/index.php?topic=152348.0

Again - the word "double-spend" is not technically correct as far as the blockchain goes.

There has never been (and never will be) an actual "double spend" in any blockchain worth using.

If an exchange decides to give you say USD after X commits then they are taking the risk that X commits is "safe enough" but in reality Bitcoin can actually re-org all the way back to the last checkpoint (which could be hundreds or even thousands of blocks).

If I was selling a house for BTC I certainly would not be using 6 confirmations (more likely I would require hundreds if not thousands).

https://blockchain.info/de/double-spends

[CIYAM]

https://blockchain.info/de/double-spends

I don't grok German - and again - just because bitcoin.info insists upon using the incorrect term "double spend" doesn't somehow make it correct.

Unfortunately Ben (the guy who *is* blockchain.info) doesn't listen to other people and therefore doesn't fix up fundamental things like that (and even worse doesn't get proper reviewing done of the wallet code which led to people nearly losing around 1000 BTC recently).

[LOBSTER]

https://blockchain.info/de/double-spends

I don't grok German - and again - just because bitcoin.info insists upon using the incorrect term "double spend" doesn't somehow make it correct.

Unfortunately Ben (the guy who *is* blockchain.info) doesn't listen to other people and therefore doesn't fix up fundamental mistakes like that (and even worse mistakes that led to people losing a lot of BTC with their wallet implementation).

Then here: https://blockchain.info/en/double-spends

[CIYAM]

Then here: https://blockchain.info/en/double-spends

So he adds a "disclaimer" but sticks to the "alarmist double-spend" term. Unfortunately most users are going to be alarmed rather than click further to be informed.

[LOBSTER]

Then here: https://blockchain.info/en/double-spends

So he adds a "disclaimer" but sticks to the "alarmist double-spend" term. Unfortunately most users are going to be alarmed rather than click further to be informed.

Double spends on this page may be unintentional. In the event that a double spend is maliciously crafted being listed on this page is no indication that it was successful or any merchant or user lost money as a result.

(Quote from Blockchain)

[CIYAM]

Double spends on this page may be unintentional. In the event that a double spend is maliciously crafted being listed on this page is no indication that it was successful or any merchant or user lost money as a result.

Yes - I read that - did you read my reply?

So he adds a "disclaimer" but sticks to the "alarmist double-spend" term. Unfortunately most users are going to be alarmed rather than click further to be informed.

I am not sure whether there is a "perfect term" but "double-spend attempt" would at least be far more technically accurate.

When it comes down to it explaining the details is something that most people unfortunately are going to pay about as much attention to as they do all the fine print in their credit card contract or the like.

So if they use the term "double spend" then that will sink in just like the term "charge back" does.

[twister]

This was a known case of a successful double-spend:
https://bitcointalk.org/index.php?topic=152348.0

The event took place during a planned hard fork of the protocol.  If we feel it necessary to fork the code again (and we likely will), I think it would be wise for exchanges to require a full day of confirmations for large deposits.  Once it is clear that the fork was handled properly, services can reduce the confirmation requirements back to normal.

Again, I don't think this was a double spend, someone got scammed maybe because they didn't wait for confirmations on a Tx and the sender made another Tx with the same unspent output as Danny already explained before. I think this is what happened here.

[CIYAM]

Again, I don't think this was a double spend

You can be a *lot more confident* than that.

There *was no double spend* as *you simply cannot double spend* because otherwise Bitcoin would have *no point to exist*.

[Somekindabitcoin]

Basically, it's a major flaw when it comes to 0 confirm systems.

[lolx]

there`s no way to double spend btc

[Ingatqhvq]

i want to know that double spent is actually is ?

 

It means you can spent your money twice.

[Buziss]

This was a known case of a successful double-spend:
https://bitcointalk.org/index.php?topic=152348.0

The event took place during a planned hard fork of the protocol.  If we feel it necessary to fork the code again (and we likely will), I think it would be wise for exchanges to require a full day of confirmations for large deposits.  Once it is clear that the fork was handled properly, services can reduce the confirmation requirements back to normal.

Again, I don't think this was a double spend, someone got scammed maybe because they didn't wait for confirmations on a Tx and the sender made another Tx with the same unspent output as Danny already explained before. I think this is what happened here.

CMIIW, that incident has nothing to do with 0-confirmation transaction but caused by the hard fork. It happened because the merchant was on the "wrong" fork, and the transaction was confirmed only on the "wrong" fork.

[lolx]

i want to know that double spent is actually is ?

 

It means you can spent your money twice.

ahan !! tell me how i can spent my money twice tell me getting naughty ?