Bitcoin Forum

Bitcoin => Bitcoin Technical Support => Topic started by: codehtcmail on May 08, 2016, 11:23:37 AM



Title: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: codehtcmail on May 08, 2016, 11:23:37 AM
Hello,
I have been trading bitcoin for a while, and until now I never had any problem when receiving a transaction.
Everytime someone sends me an amount of BTC, I send the goods to him once I see the transaction in Blockchain, even without a confirmation yet, this is for speed of service and because I believe there is no easy way for him to double spend and get my transaction rejected. If I have to wait for a confirmation it may take up to 10 minutes even with a high enough fee, so I usually don't wait for one. I have been doing this for 3 years at least without issues, am I wrong in doing it ? should I start waiting for confirmations before sending the goods to the buyer ?


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: shorena on May 08, 2016, 11:57:48 AM
Hello,
I have been trading bitcoin for a while, and until now I never had any problem when receiving a transaction.
Everytime someone sends me an amount of BTC, I send the goods to him once I see the transaction in Blockchain, even without a confirmation yet, this is for speed of service and because I believe there is no easy way for him to double spend and get my transaction rejected.

Its probably better to make decision based on knowledge dont you think?

If I have to wait for a confirmation it may take up to 10 minutes even with a high enough fee, so I usually don't wait for one. I have been doing this for 3 years at least without issues, am I wrong in doing it ? should I start waiting for confirmations before sending the goods to the buyer ?

I wont comment on how you do business since this was moved in the tech support section. Its easy to double spend an unconfirmed transaction. Its easy to delay a confirmation (e.g. by low or no fee) long enough to give plenty of time for a double spend. Its also easy to chain unconfirmed transactions so that the person you are trading with can reasonably blame someone else for a TX that suddenly disappears from your wallet.


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: codehtcmail on May 08, 2016, 12:13:30 PM
So, if I wait for a confirmation, am I lees exposed to double spending and being scammed ?


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: altcoinhosting on May 08, 2016, 12:20:10 PM
So, if I wait for a confirmation, am I lees exposed to double spending and being scammed ?

Yes... Once you have 1 confirmation, you're pretty safe (not 100%, you can still be included in an orphaned block, but chances of experiencing this combined with a double spend are low)

If the block that included your tx is orphaned, chances are really high you were also included in the other block, or you'll probably be included pretty soon, unless you're a victim of a double spend


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: codehtcmail on May 08, 2016, 12:26:53 PM
Thank you all
Then when I feel the buyer is kind of shady, I will tell him to add a high enough transaction fee, I read somewhere about 40 satoshi/byte is more than enough, and wait for a first confirmation before sending.


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: cr1776 on May 08, 2016, 02:39:47 PM
Thank you all
Then when I feel the buyer is kind of shady, I will tell him to add a high enough transaction fee, I read somewhere about 40 satoshi/byte is more than enough, and wait for a first confirmation before sending.

And if it is a physical good, you can easily wait more than one confirmation. 


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: achow101 on May 08, 2016, 02:58:04 PM
Thank you all
Then when I feel the buyer is kind of shady, I will tell him to add a high enough transaction fee, I read somewhere about 40 satoshi/byte is more than enough, and wait for a first confirmation before sending.
For the fees, you can check https://bitcoinfees.21.co/ for the current fee state of the network and choose what is best for you. IMO you should always wait for one confirmation before sending because sometimes users will pay a low fee accidentally and the transaction will disappear from the network so you won't get your money.


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: Bitcoinbee on May 12, 2016, 07:21:41 AM
So, if I wait for a confirmation, am I lees exposed to double spending and being scammed ?

Yes... Once you have 1 confirmation, you're pretty safe (not 100%, you can still be included in an orphaned block, but chances of experiencing this combined with a double spend are low)

If the block that included your tx is orphaned, chances are really high you were also included in the other block, or you'll probably be included pretty soon, unless you're a victim of a double spend

always be careful and be vigilant when trading.
sometimes everything's going smooth and sometime's it takes long to complete a transaction.  :)


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: Cyaren on May 12, 2016, 07:24:01 AM
It is extremely difficult to double spend either way, but with 1 confirmation it's way harder than 0 confs.

If you're dealing with extremely large amounts of BTC, and with a stranger, don't send the BTC without a confirmation. If you're dealing with a trusted person with a small amount, it's probably safe to say that you won't get scammed.


Title: Re: Am I wrong to send after only seeing the transaction or 1 confirmation ?
Post by: altcoinhosting on May 12, 2016, 05:52:46 PM
It is extremely difficult to double spend either way, but with 1 confirmation it's way harder than 0 confs.

If you're dealing with extremely large amounts of BTC, and with a stranger, don't send the BTC without a confirmation. If you're dealing with a trusted person with a small amount, it's probably safe to say that you won't get scammed.

It's not that hard to do actually.. I've created a couple double spends when my transactions got stuck when I added a to low fee.
I'm pretty sure that I can create a double spend in a matter of minutes when I have had time to prepare beforehand.