What is this type of transaction called?

ralle14

legendary

Activity: 3374

Merit: 1922

Shuffle.com

With most sites needing a confirmation for deposits to get credited, the other one is usually ignored even if it's still on the transaction logs of their website.

It looks like blockchain.com keeps these invalid transactions for months here's one example that's a few months older.

Quote from: mocacinno on February 12, 2020, 02:50:40 AM

I remember a long time ago where they would just print a big banned on top of their explorer telling people it's a transaction using double spend unspent outputs as input.

Those times were crazy some sites don't require confirmations and because of it deposits were sometimes getting credited twice.

mocacinno

legendary

Activity: 3584

Merit: 5243

https://merel.mobi => buy facemasks with BTC/LTC

Quote from: rsarkar on February 12, 2020, 02:46:03 AM

--snip--
I hit a roadblock on this id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c
"no transaction found with the hash"

Blockchain.com usually keeps those invalid transactions in their database for a longer time (not forever tough, so if you re-check this link in a couple of hours, the data might be deleted)
https://www.blockchain.com/btc/tx/81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c

To bad they don't analyse these invalid transactions in-depth anymore. I remember a long time ago where they would just print a big banned on top of their explorer telling people it's a transaction using double spend unspent outputs as input.

rsarkar

jr. member

Activity: 102

Merit: 5

Quote from: mocacinno on February 12, 2020, 02:32:34 AM

Quote from: rsarkar on February 12, 2020, 02:26:51 AM

Yet website like Localbitcoins.com shows this as an incoming transaction that is ready to be credited.

The transaction is real and was broadcasted, probably before the first transaction in the chain (the one doublespending the unspent output) was confirmed. At that point, it was reasonable of localbitcoins to conclude that, in normal circumstances, the transaction could have been confirmed in ~30 minutes.
However, given the fact that the first transaction in the chain of unconfirmed transactions uses an unspent output that's been double spent (and the double spending transaction was confirmed afterwards), this transaction became invalid and the funds should have been removed from your acocunt overview.

It's probably a bug in localbitcoin's accounting system, they should probably remove these funds cause they should not confirm.

Disclaimer: it's early in my country, i hope i didn't mess up when i was following the chain of transactions... I think i followed it correctly, but i have a habit of messing up when i'm tired... If you want to be 100% sure, you should follow the chain of transactions i posted in my previous post by yourself and see if everything adds up.

I hit a roadblock on this id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c
"no transaction found with the hash"

mocacinno

legendary

Activity: 3584

Merit: 5243

https://merel.mobi => buy facemasks with BTC/LTC

Quote from: rsarkar on February 12, 2020, 02:26:51 AM

Yet website like Localbitcoins.com shows this as an incoming transaction that is ready to be credited.

The transaction is real and was broadcasted, probably before the first transaction in the chain (the one doublespending the unspent output) was confirmed. At that point, it was reasonable of localbitcoins to conclude that, in normal circumstances, the transaction could have been confirmed in ~30 minutes.
However, given the fact that the first transaction in the chain of unconfirmed transactions uses an unspent output that's been double spent (and the double spending transaction was confirmed afterwards), this transaction became invalid and the funds should have been removed from your acocunt overview.

It's probably a bug in localbitcoin's accounting system, they should probably remove these funds cause they should not confirm.

Disclaimer: it's early in my country, i hope i didn't mess up when i was following the chain of transactions... I think i followed it correctly, but i have a habit of messing up when i'm tired... If you want to be 100% sure, you should follow the chain of transactions i posted in my previous post by yourself and see if everything adds up.

rsarkar

jr. member

Activity: 102

Merit: 5

Quote from: mocacinno on February 12, 2020, 02:18:24 AM

Quote from: TheNewAnon135246 on February 12, 2020, 02:07:03 AM

It hasn't been succesfully been transaction, the transaction is invalid.

"Transaction invalid: some outputs that it attempts to spend have been already spent or are no longer valid."

Correct... In more technical terms:
The transaction with id 7ae6a11ada3be68256bae7fb789a464f2451c0557bd56ecd07c03613cfdc3eb3 uses 1 unspent output as input:

the unspent output created by transaction with id 41a69f578bfa9bfd1064c32fe0d1450d2778aa27711bcbbd15dc8af65c30e36f

The transaction with id 41a69f578bfa9bfd1064c32fe0d1450d2778aa27711bcbbd15dc8af65c30e36f uses 1 unspent output as input:

the unspent output created by transaction with id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c

The transaction with id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c uses 2 unspent outputs as input:

the unspent output created by transaction with id c46d3a082977ba08e309ff7564adeb13775b3b619d05e4876d59f9ec3bde59d1
the unspent output created by transaction with id d159e103b5d5eb069e14a5a5c9a125942e8b3a6ed75d489096b93727c9688649

However, the first unspent output (created by c46d3a082977ba08e309ff7564adeb13775b3b619d05e4876d59f9ec3bde59d1) WAS already spent in the confirmed transaction with id 4e47b2f204e96562eb144b679b0a1554885fcf5b062ef5a73422bff2a7020e51

Since transaction with id 4e47b2f204e96562eb144b679b0a1554885fcf5b062ef5a73422bff2a7020e51 was confirmed, none of the other listed transaction can ever be considered to be valid, since they're using an unspent output that is no longer available for them to use

Yet website like Localbitcoins.com shows this as an incoming transaction that is ready to be credited.

mocacinno

legendary

Activity: 3584

Merit: 5243

https://merel.mobi => buy facemasks with BTC/LTC

Quote from: TheNewAnon135246 on February 12, 2020, 02:07:03 AM

It hasn't been succesfully been transaction, the transaction is invalid.

"Transaction invalid: some outputs that it attempts to spend have been already spent or are no longer valid."

Correct... In more technical terms:
The transaction with id 7ae6a11ada3be68256bae7fb789a464f2451c0557bd56ecd07c03613cfdc3eb3 uses 1 unspent output as input:

the unspent output created by transaction with id 41a69f578bfa9bfd1064c32fe0d1450d2778aa27711bcbbd15dc8af65c30e36f

The transaction with id 41a69f578bfa9bfd1064c32fe0d1450d2778aa27711bcbbd15dc8af65c30e36f uses 1 unspent output as input:

the unspent output created by transaction with id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c

The transaction with id 81c1fd6b34101ebf443d7d6f0c04080530fb2b819288107540b0f49c8238fa9c uses 2 unspent outputs as input:

the unspent output created by transaction with id c46d3a082977ba08e309ff7564adeb13775b3b619d05e4876d59f9ec3bde59d1
the unspent output created by transaction with id d159e103b5d5eb069e14a5a5c9a125942e8b3a6ed75d489096b93727c9688649

However, the first unspent output (created by c46d3a082977ba08e309ff7564adeb13775b3b619d05e4876d59f9ec3bde59d1) WAS already spent in the confirmed transaction with id 4e47b2f204e96562eb144b679b0a1554885fcf5b062ef5a73422bff2a7020e51

Since transaction with id 4e47b2f204e96562eb144b679b0a1554885fcf5b062ef5a73422bff2a7020e51 was confirmed, none of the other listed transaction can ever be considered to be valid, since they're using an unspent output that is no longer available for them to use

TheNewAnon135246

legendary

Activity: 2198

Merit: 1989

฿uy ฿itcoin

It hasn't been succesfully been transaction, the transaction is invalid.

"Transaction invalid: some outputs that it attempts to spend have been already spent or are no longer valid."

rsarkar

jr. member

Activity: 102

Merit: 5

The status of this transaction has been like this for 12 hrs now and some explorer doesn't recognise it at all.

https://live.blockcypher.com/btc/tx/7ae6a11ada3be68256bae7fb789a464f2451c0557bd56ecd07c03613cfdc3eb3

https://blockchair.com/search?q=7ae6a11ada3be68256bae7fb789a464f2451c0557bd56ecd07c03613cfdc3eb3

How can this be successfully transacted?

Topic: What is this type of transaction called? (Read 204 times)