Is it possible to fake the BTC blockchain? - page 3.

NeuroticFish

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Quote from: johnwhitestar on November 08, 2019, 02:59:48 AM

Is this situation technically possible?

The buyer has to check the transaction. It depends a lot on how he does that. I would check a reputable blockchain explorer.

Let's say that the buyer checks in his own wallet.
If he has a full wallet, it may work, but that would mean the buyer comes with his laptop (why would he do that if all he needs for checking is a browser which he already have on the smartphone?)
If he has a SPV (Electrum, Mycelium), I think that there's a possibility he can have a corresponding (fake) server in his own network. But he will have to know what wallet to expect (to prepare the corresponding server), he will have to have his own custom DNS...

Overall I think that, although possible, it's not viable.
The seller has to know too much info about the buyer to have everything right. And quite some skills to get the buyer into that certain situation. And nowadays people just use the mobile data, there are far too many warnings to avoid using 3rd party WiFi.

mk4

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Quote from: johnwhitestar on November 08, 2019, 03:33:55 AM

So, the receiver's bitcoin-qt wallet syncing the 'forked blockchain' through the sender's wifi? I'm really not sure, ~~but I don't think that's really possible~~ (apparently, it is). But if it is indeed possible, I assume that it would be very difficult to pull off, and the sender probably needs to do some stuff to the receiver's wallet for this to work. But again, I'm not sure.

Very interesting question nonetheless. Let's wait for other replies.

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Quote from: mk4 on November 08, 2019, 03:24:33 AM

As far as I know, the receiver cant get tricked assuming:

The receiver has had his bitcoin address ready(probably pre-copied address to his notes app, or a screenshotted QR code)
The receiver is viewing his bitcoin address through a reputable and untampered app(Mycelium, Electrum, etc)

Not sure how a 'fake blockchain' can affect the receiver's mobile app, unless the sender asks the receiver to download a wallet of this 'fake blockchain'. And take note that the receiver can verify through block explorers if he actually received the funds in the first place.

In the top of my head, the only way the sender could tricked the receiver is probably through a double spend, or through a phishing site redirection through the wifi's DNS settings if the receiver is going to use a web wallet through a browser(and not a wallet app).

Correct me if I'm wrong of course.

I was thinking about the receiver that is using bitcoin-qt wallet.
So if he connects to the forked BTC blockchain he'll download wrong blocks then the sender will send him BTC, a valid transaction on the forked blockchain, and then the receiver will go home, connect to the right blockchain and see the transaction has never occurred.
This is of course not possible with Electrum, but is it possible with bitcoin-qt wallet, assuming the receiver doesn't check on any other source his transaction when he is still at his host's home?

mk4

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As far as I know, the receiver cant get tricked assuming:

The receiver has had his bitcoin address ready(probably pre-copied address to his notes app, or a screenshotted QR code)
The receiver is viewing his bitcoin address through a reputable and untampered app(Mycelium, Electrum, etc)

Not sure how a 'fake blockchain' can affect the receiver's mobile app, unless the sender asks the receiver to download a wallet of this 'fake blockchain'. And take note that the receiver can verify through block explorers if he actually received the funds in the first place.

In the top of my head, the only way the sender could tricked the receiver is probably through a double spend, or through a phishing site redirection through the wifi's DNS settings if the receiver is going to use a web wallet through a browser(and not a wallet app).

Correct me if I'm wrong of course.

johnwhitestar

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It's a bit of time I'm asking myself this question.
Let's imagine the following situation:
A guy visits another guy to receive a payment in BTC.
He doesn't have mobile internet connection, so he asks his host to connect to his host's wi-fi.
His host, that we assume for the sake of our inquiry wants to scam his guest, connects him to a fake internet in which the real BTC blockchain was forked in order to fake a transaction that in really will never happen.
So once the first guy will go back home he'll see that his payment has disappeared.
Is this situation technically possible?

Topic: Is it possible to fake the BTC blockchain? - page 3. (Read 528 times)