<p>This cannot happen because of <a href="https://en.bitcoin.it/wiki/Transactions">the way each transaction is designed</a>. Every single transaction must reference an output of another transaction. Essentially you can only spend the money that you already have. You cannot create BTC out of thin-air.</p>

<p>The consensus algorithm is programmed in all nodes to only create coins out of thin-air based on the <a href="https://en.bitcoin.it/wiki/Coinbase">coinbase</a> transaction, and all the transaction fees available in that block.</p>

<p>You can't just transfer 100 BTC out of nowhere, because all the nodes in the network would invalidate your transaction and probably ban your IP if you try to do so.</p>

CC BY-SA 3.0
2014-01-31T12:03:26.010Z
what if the BadMiner was able to create two blocks very quickly.. one fake and a followup legal one.. and sent both of them to the network..
Smagula
CC BY-SA 3.0
2014-01-31T12:06:55.643Z
Even if badminer got two blocks in a row he wouldn't be able to create coins out of thin air, he would only be able to double-spend coins he already has: https://en.bitcoin.it/wiki/Weaknesses#Attacker_has_a_lot_of_computing_power
Luca Matteis
CC BY-SA 3.0
2014-01-31T12:16:53.450Z
not very clear sir.. what happens to the second legal block after the first fake block is rejected - suppose other miners start accepting the second block and grow the blockchain further..?
Smagula
CC BY-SA 3.0
2014-09-16T07:37:18.743Z
@Smagula it doesn't matter. You can write a cheque for $100000 to your bank account and you won't get the money for the same reason; throwing multiple bad cheques is going to 1) get you IDd as a fraud peddler, 2) writing on paper or in a block means nothing if the ledger doesn't back up the request.
Wizard Of Ozzie
CC BY-SA 3.0
2015-10-24T01:25:47.353Z
maybe a dumb question but as im learning bitcoin at this point... where does the initial input come from then?? (obviously, bitcoin is mined but how did it all start from 0)
dtc
CC BY-SA 3.0
2015-10-24T20:38:45.940Z
@dtc It is created in the mining process by consensus, much the same as gold is mined when on a gold standard. It started from 0 and the amount grows (for some time still) as more is mined.  The miners place it into circulation (or not) as they spend it or exchange it for fiat etc.
KalleMP
CC BY-SA 4.0
2021-05-04T20:24:59.110Z
Can you go into more detail on why you can't create 100 BTC out of nowhere? Is it enforced by using the UTXOs in the transaction's digital signature, or is it enforced by the Bitcoin nodes kicking you off the network?
tjr226
CC BY-SA 3.0
2014-01-31T11:54:52.077Z
2014-01-31T11:54:52.077Z
Luca Matteis
<p>You can create fake transactions and blocks including fake transactions all day long if you want. Your problem would be getting other people to accept those blocks and they won't because they can very easily see that it contains fake (better word: invalid) transaction(s) and simply disregard those blocks completely.</p>

<p>The first invalid block wil never be accepted by any non-accomplice so it doesn't matter how many blocks are put on top of that, they won't be accepted either. </p>

CC BY-SA 3.0
2014-01-31T12:32:27.440Z
got it.. since most of the network would have rejected the first block, the blockchain will not have the fake block.. other miners intending to add to the block chain will not see the fake block in majority of the cases... hence the honest block chain will grow faster and survive..
Smagula
CC BY-SA 3.0
2014-01-31T14:05:17.000Z
actually it's better to say that nodes won't relay the transactions, nor include them in their block in the first place.
Luca Matteis
CC BY-SA 3.0
2014-01-31T12:27:38.103Z
2014-01-31T12:27:38.103Z
Jannes
<p>AttackerAlice has a BTC Wallet with 0 BTC.
AccompliceBob has a BTC Wallet.</p>

<p>Is it possible to transfer 100 BTC from AttackerAlice to AccompliceBob? </p>

<p>Suppose a BadMiner accepted this as a valid transaction, and puts this fake transaction into a block, how will it be detected and rejected?</p>

CC BY-SA 3.0
2014-01-31T11:47:02.487Z
to add to the question... Also if the BadMiner is able to create an additional block, will https://en.bitcoin.it/wiki/Protocol_rules be enough to keep the offending blocks out of the blockchain?
Smagula
<security><fraud>
Creating a fake transaction
Smagula
# Creating a fake transaction

(Asked by: username_0 on 2014-01-31)

AttackerAlice has a BTC Wallet with 0 BTC.
AccompliceBob has a BTC Wallet.

Is it possible to transfer 100 BTC from AttackerAlice to AccompliceBob?

Suppose a BadMiner accepted this as a valid transaction, and puts this fake transaction into a block, how will it be detected and rejected?

**Tags:** security, fraud

> **Comments:**
> **username_0**: to add to the question... Also if the BadMiner is able to create an additional block, will https://en.bitcoin.it/wiki/Protocol_rules be enough to keep the offending blocks out of the blockchain?  

---

## 2 answers

### Answer by username_6 on 2014-01-31. Score: 12 | Accepted answer

You can create fake transactions and blocks including fake transactions all day long if you want. Your problem would be getting other people to accept those blocks and they won't because they can very easily see that it contains fake (better word: invalid) transaction(s) and simply disregard those blocks completely.

The first invalid block wil never be accepted by any non-accomplice so it doesn't matter how many blocks are put on top of that, they won't be accepted either.

> **Comments:**
> **username_0**: got it.. since most of the network would have rejected the first block, the blockchain will not have the fake block.. other miners intending to add to the block chain will not see the fake block in majority of the cases... hence the honest block chain will grow faster and survive..  
> **username_1**: actually it's better to say that nodes won't relay the transactions, nor include them in their block in the first place.  

---

### Answer by username_1 on 2014-01-31. Score: 5

This cannot happen because of [the way each transaction is designed](https://en.bitcoin.it/wiki/Transactions). Every single transaction must reference an output of another transaction. Essentially you can only spend the money that you already have. You cannot create BTC out of thin-air.

The consensus algorithm is programmed in all nodes to only create coins out of thin-air based on the [coinbase](https://en.bitcoin.it/wiki/Coinbase) transaction, and all the transaction fees available in that block.

You can't just transfer 100 BTC out of nowhere, because all the nodes in the network would invalidate your transaction and probably ban your IP if you try to do so.

> **Comments:**
> **username_0**: what if the BadMiner was able to create two blocks very quickly.. one fake and a followup legal one.. and sent both of them to the network..  
> **username_1**: Even if badminer got two blocks in a row he wouldn't be able to create coins out of thin air, he would only be able to double-spend coins he already has: https://en.bitcoin.it/wiki/Weaknesses#Attacker_has_a_lot_of_computing_power  
> **username_0**: not very clear sir.. what happens to the second legal block after the first fake block is rejected - suppose other miners start accepting the second block and grow the blockchain further..?  
> **username_2**: @username_0 it doesn't matter. You can write a cheque for $100000 to your bank account and you won't get the money for the same reason; throwing multiple bad cheques is going to 1) get you IDd as a fraud peddler, 2) writing on paper or in a block means nothing if the ledger doesn't back up the request.  
> **username_3**: maybe a dumb question but as im learning bitcoin at this point... where does the initial input come from then?? (obviously, bitcoin is mined but how did it all start from 0)  
> **username_4**: @username_3 It is created in the mining process by consensus, much the same as gold is mined when on a gold standard. It started from 0 and the amount grows (for some time still) as more is mined.  The miners place it into circulation (or not) as they spend it or exchange it for fiat etc.  
> **username_5**: Can you go into more detail on why you can't create 100 BTC out of nowhere? Is it enforced by using the UTXOs in the transaction's digital signature, or is it enforced by the Bitcoin nodes kicking you off the network?  

---

