Double slending?

[Robertt]

Let's say you have 0.025 BTC.
You give it to someone, and they send you 0.026 BTC.
They double spend it, and you have around 0.5 left in your wallet.
If you send the 0.5 while the other transaction is unconfirmed, what happens to the 0.5?
Just something I've always wondered about

[shorena]

Let's say you have 0.025 BTC.
You give it to someone, and they send you 0.026 BTC.
They double spend it, and you have around 0.5 left in your wallet.
If you send the 0.5 while the other transaction is unconfirmed, what happens to the 0.5?
Just something I've always wondered about

I doubt the 0.5 would even be a valid transaction, because it requires conflicting inputs. In any way, as soon as once of the competing TX confirms the 0.5 TX is invalid because one of its inputs became invalid.

[Robertt]

Let's say you have 0.025 BTC.
You give it to someone, and they send you 0.026 BTC.
They double spend it, and you have around 0.5 left in your wallet.
If you send the 0.5 while the other transaction is unconfirmed, what happens to the 0.5?
Just something I've always wondered about

I doubt the 0.5 would even be a valid transaction, because it requires conflicting inputs. In any way, as soon as once of the competing TX confirms the 0.5 TX is invalid because one of its inputs became invalid.

So would you eventually get the 0.5 BTC back and lose the 0.026?
Or would you end up with nothing left in your wallet.
Thanks.

[shorena]

Let's say you have 0.025 BTC.
You give it to someone, and they send you 0.026 BTC.
They double spend it, and you have around 0.5 left in your wallet.
If you send the 0.5 while the other transaction is unconfirmed, what happens to the 0.5?
Just something I've always wondered about

I doubt the 0.5 would even be a valid transaction, because it requires conflicting inputs. In any way, as soon as once of the competing TX confirms the 0.5 TX is invalid because one of its inputs became invalid.

So would you eventually get the 0.5 BTC back and lose the 0.026?
Or would you end up with nothing left in your wallet.
Thanks.

I probably misunderstood where the 0.5 btc came from on my first answer, let me try again.

It depends. Lets say you have a single input of 0.75 BTC and alice has a single input of 0.26

Code:

you	alice
0.75	0.26

You send 0.25 to alice (the (u) marks unconfirmed coins)

Code:

you	alice
0.5(u)	0.26
	0.25(u)

Alice now sends you 0.26.

Code:

you	alice
0.26(u) 0.25(u)
0.5(u)	

and the same input to bob (the (c) marks conflicting transactions)

Code:

you		alice		bob
0.26(u,c) 	0.25(u)		0.26(u,c)
0.5(u)

Now, if the first TX confirms, we have this.

Code:

you		alice		bob
0.26(u,c) 	0.25		0.26(u,c)
0.5

If the double spend to bob confirms, your 0.26 from alice are invalid and will disappear (or still show as conflicted/pending depending on your wallet).

Code:

you		alice		bob
0.5 		0.25		0.26

If the TX from alice to you confirms, bobs 0.26 from alice are invalid and will disappear.

Code:

you		alice		bob
0.26	 	0.25		-
0.5

So the 0.5 change is unaffected by alice's double spend. This is also true if the 0.5 was a different input and not created by the TX sending 0.25 to alice.

[Robertt]

Let's say you have 0.025 BTC.
You give it to someone, and they send you 0.026 BTC.
They double spend it, and you have around 0.5 left in your wallet.
If you send the 0.5 while the other transaction is unconfirmed, what happens to the 0.5?
Just something I've always wondered about

I doubt the 0.5 would even be a valid transaction, because it requires conflicting inputs. In any way, as soon as once of the competing TX confirms the 0.5 TX is invalid because one of its inputs became invalid.

So would you eventually get the 0.5 BTC back and lose the 0.026?
Or would you end up with nothing left in your wallet.
Thanks.

I probably misunderstood where the 0.5 btc came from on my first answer, let me try again.

It depends. Lets say you have a single input of 0.75 BTC and alice has a single input of 0.26

Code:

you	alice
0.75	0.26

You send 0.25 to alice (the (u) marks unconfirmed coins)

Code:

you	alice
0.5(u)	0.26
	0.25(u)

Alice now sends you 0.26.

Code:

you	alice
0.26(u) 0.25(u)
0.5(u)	

and the same input to bob (the (c) marks conflicting transactions)

Code:

you		alice		bob
0.26(u,c) 	0.25(u)		0.26(u,c)
0.5(u)

Now, if the first TX confirms, we have this.

Code:

you		alice		bob
0.26(u,c) 	0.25		0.26(u,c)
0.5

If the double spend to bob confirms, your 0.26 from alice are invalid and will disappear (or still show as conflicted/pending depending on your wallet).

Code:

you		alice		bob
0.5 		0.25		0.26

If the TX from alice to you confirms, bobs 0.26 from alice are invalid and will disappear.

Code:

you		alice		bob
0.26	 	0.25		-
0.5

Wait.. Sorry I'm not exactly the best with this lol but thanks for trying to explain it
Maybe I could ask the question in another way

Let's say I have 1 Bitcoin.
I then send 0.1 Bitcoin to 1swag
1swag returns 0.2 Bitcoin to me and then does something (double spends?) that doesn't allow it to confirm
I send the 1.1 BTC I have to 1Lol
The 1Lol and the transaction I received are both unconfirmed, but the one I sent confirmed.
What happens to the unconfirmed BTC?

[Alaki]

 

Let's say I have 1 Bitcoin.
I then send 0.1 Bitcoin to 1swag
1swag returns 0.2 Bitcoin to me and then does something (double spends?) that doesn't allow it to confirm
I send the 1.1 BTC I have to 1Lol
The 1Lol and the transaction I received are both unconfirmed, but the one I sent confirmed.
What happens to the unconfirmed BTC?

Care to temme(us) about the(your) wallet name? AFAIK, blockchain(I'd guess, you're using blockchain wallet) won't(doesn't) allow you to spend 0.2BTC(u), unless & until they're confirmed.
Let's say 1Swag sends 0.2BTC(u) to you(someone), Therefore, 1.1(t)-0.2(u)= 0.9BTC-fee(spendable)
(u)-> unconfirmed.
(t)-> total.
P.S.-> Other wallets-> https://bitcointalk.org/index.php?topic=1356144.msg13803990#msg13803990

[shorena]

-snip-
Wait.. Sorry I'm not exactly the best with this lol but thanks for trying to explain it
Maybe I could ask the question in another way

Let's say I have 1 Bitcoin.
I then send 0.1 Bitcoin to 1swag
1swag returns 0.2 Bitcoin to me and then does something (double spends?) that doesn't allow it to confirm
I send the 1.1 BTC I have to 1Lol
The 1Lol and the transaction I received are both unconfirmed, but the one I sent confirmed.
What happens to the unconfirmed BTC?

Code:

you		swag		else
1		0.1		0
--- you send .1 to swag (tx1)
0.9(u)		0.1		0
		0.1(u)
--- swag send 0.2 to you (tx2)
0.9(u)		0		0
0.2(u)		
--- you send 1.1 to someone else (tx3)
0		0		1.1(u)
0		
--- swag also sends 0.2 to alice (tx4)
you		swag		else		alice
0		0		1.1(u,c)	0.2(u,c)

tx2 can only confirm if tx1 is confirmed and tx3 can only confirm if tx1 and tx2 are confirmed.

tx4 can only confirm if tx1 is confirmed.

If tx4 confirms, tx2 and tx3 are invalid, they never happened (you still have 0.9 btc).

If tx3 confirms, tx4 is invalid.