<p>You are not being hacked.  These are not two separate transactions; it is one transaction with two outputs.  The second output was automatically created by your wallet client and sends back to a new address which also belongs to you.  This is a normal and necessary feature of how Bitcoin works, called "change". See <a href="https://bitcoin.stackexchange.com/questions/736/how-does-change-work-in-a-bitcoin-transaction">How does change work in a bitcoin transaction?</a></p>

<p>If this transaction were malicious, it would mean that someone had access to your private key; if so, they would also have stolen your earlier transaction.  Moreover, they would  have stolen the coins as soon as they obtained the key; they wouldn't have waited for you to make your own transaction.</p>

CC BY-SA 3.0
2017-08-23T16:56:38.287Z
Thank You Nate Eldredge for your response, I had no idea about this feature, and because the change address is not written in the bitcoin client, that idea couldn't of crossed my mind.
After googling I found that when using bitcoin-qt it is possible to enter the command "listaddressgroupings" in the debug console, to see all addresses including change addresses.
https://bitcoin.stackexchange.com/questions/9077/how-to-get-all-addresses-including-the-change-addresses-from-bitcoind.
Adam Shem-Tov
CC BY-SA 3.0
2017-08-23T17:00:24.817Z
@AdamShem-Tov: Yeah, I think the Bitcoin Core developers took the view that this is a technical detail that end users don't need to be bothered with.  But of course when you look "under the hood" with a block explorer like blockchain.info, you see the details, and they can be confusing when they don't appear to match the high-level view presented by the client.
Nate Eldredge
CC BY-SA 3.0
2017-08-23T13:55:49.917Z
2017-08-26T21:20:57.093Z
2017-08-26T21:20:57.093Z
Nate Eldredge
<p>I have just sent bitcoins from one account of mine to another, and after I sent it I checked on blockchain.info to get updated about confirmation.
There, I noticed something peculiar, it said that I made two transactions at the same time, when I made only one. The first transaction was to the correct address and the correct amount.
But the second transaction was not one that I made. The second thing I noticed is the SUM of both transactions, together they form the exact amount I last received to this account a few days ago.
This looks to me like a hack. At this moment these transactions have net yet been confirmed, can I do anything about it?
Can a transaction be created fraudulently and accepted by the miners?
How can a hack like this be accomplished (if it is a hack).</p>

CC BY-SA 3.0
2017-08-23T11:11:11.127Z
Did you create the transaction yourself or did simply send bitcoin wuth the help of a wallet?
Ivano Donadi
CC BY-SA 3.0
2017-08-23T16:46:22.567Z
I am running a full node, so I guess I created it myself
Adam Shem-Tov
<hacking>
Am I being hacked, can I prevent it?
Adam Shem-Tov
# Am I being hacked, can I prevent it?

(Asked by: username_0 on 2017-08-23)

I have just sent bitcoins from one account of mine to another, and after I sent it I checked on blockchain.info to get updated about confirmation.
There, I noticed something peculiar, it said that I made two transactions at the same time, when I made only one. The first transaction was to the correct address and the correct amount.
But the second transaction was not one that I made. The second thing I noticed is the SUM of both transactions, together they form the exact amount I last received to this account a few days ago.
This looks to me like a hack. At this moment these transactions have net yet been confirmed, can I do anything about it?
Can a transaction be created fraudulently and accepted by the miners?
How can a hack like this be accomplished (if it is a hack).

**Tags:** hacking

> **Comments:**
> **username_1**: Did you create the transaction yourself or did simply send bitcoin wuth the help of a wallet?  
> **username_0**: I am running a full node, so I guess I created it myself  

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## 1 answers

### Answer by username_2 on 2017-08-23. Score: 4

You are not being hacked. These are not two separate transactions; it is one transaction with two outputs. The second output was automatically created by your wallet client and sends back to a new address which also belongs to you. This is a normal and necessary feature of how Bitcoin works, called "change". See [How does change work in a bitcoin transaction?](https://bitcoin.stackexchange.com/questions/736/how-does-change-work-in-a-bitcoin-transaction)

If this transaction were malicious, it would mean that someone had access to your private key; if so, they would also have stolen your earlier transaction. Moreover, they would have stolen the coins as soon as they obtained the key; they wouldn't have waited for you to make your own transaction.

> **Comments:**
> **username_0**: Thank You username_2 username_2 for your response, I had no idea about this feature, and because the change address is not written in the bitcoin client, that idea couldn't of crossed my mind. After googling I found that when using bitcoin-qt it is possible to enter the command "listaddressgroupings" in the debug console, to see all addresses including change addresses. https://bitcoin.stackexchange.com/questions/9077/how-to-get-all-addresses-including-the-change-addresses-from-bitcoind.  
> **username_2**: @username_0: Yeah, I think the Bitcoin Core developers took the view that this is a technical detail that end users don't need to be bothered with.  But of course when you look "under the hood" with a block explorer like blockchain.info, you see the details, and they can be confusing when they don't appear to match the high-level view presented by the client.  

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