<p>Because on the lowest level of bitcoin protocol there is no accounts. There are scripts inside transaction. The most common script says: show me public key, I will compute Hash160 of it, compare with given Hash160, and if they are equal, I will check signature.</p>

<p>Let imagine, transaction contains single output with 1 bitcoin. Script contains Hash160 (which we treat as account). There is no way to spent part of bitcoin. We have to spent entire output, which is equal to 1 BTC in our case.
Transactions, like blocks, form some kind of chain.</p>

CC BY-SA 3.0
2017-08-17T10:42:15.440Z
thanks for the answer! if you can share any documentation about this, that wud b very helpful
Lakshay Dulani
CC BY-SA 3.0
2017-08-17T11:29:18.247Z
You can use official wiki: https://en.bitcoin.it/wiki/Protocol_documentation#Transaction_Verification https://en.bitcoin.it/wiki/Script
Zergatul
CC BY-SA 3.0
2017-08-17T10:10:20.953Z
2017-08-17T10:10:20.953Z
Zergatul
<p>I guess this is called Circular spending.</p>

<p>Why is it required in the bitcoin protocol?</p>

<bitcoin-core>
Why is it so that if some bitcoin is spent by any user, the rest of his account's amount should also be spent and paid him back?
Lakshay Dulani
# Why is it so that if some bitcoin is spent by any user, the rest of his account's amount should also be spent and paid him back?

(Asked by: username_0 on 2017-08-17)

I guess this is called Circular spending.

Why is it required in the bitcoin protocol?

**Tags:** bitcoin-core


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## 1 answers

### Answer by username_1 on 2017-08-17. Score: 1

Because on the lowest level of bitcoin protocol there is no accounts. There are scripts inside transaction. The most common script says: show me public key, I will compute Hash160 of it, compare with given Hash160, and if they are equal, I will check signature.

Let imagine, transaction contains single output with 1 bitcoin. Script contains Hash160 (which we treat as account). There is no way to spent part of bitcoin. We have to spent entire output, which is equal to 1 BTC in our case.
Transactions, like blocks, form some kind of chain.

> **Comments:**
> **username_0**: thanks for the answer! if you can share any documentation about this, that wud b very helpful  
> **username_1**: You can use official wiki: https://en.bitcoin.it/wiki/Protocol_documentation#Transaction_Verification https://en.bitcoin.it/wiki/Script  

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