<p>This is the scriptSig of a coinbase transaction (the first transaction in every block is special; it doesn't actually spend anything but brings new coins into existence).</p>
<p>Coinbase transactions have a number of special rules that apply to them:</p>
<ul>
<li>They must be the first transaction in a block, and cannot occur anywhere else.</li>
<li>They must have exactly one input, for which:
<ul>
<li>The prevout must have hash <em>0000...0000</em> and vout index <em>0xFFFFFFFF</em>.</li>
<li>The scriptSig must be between 2 and 100 bytes long, but otherwise has no meaning. Miners typically use this space to store what is called an extranonce, to be able to grind through more hashes per second then the block header nonce space allows for.</li>
<li>Since the activation of BIP34 in 2012 (which your block predates), the coinbase scriptSig must start with a push of the block height.</li>
</ul>
</li>
<li>They can claim the block's subsidy and all fees paid in the block (implicitly).</li>
<li>They must have 1 or more outputs like every other transaction, determining where the mining rewards get paid to.</li>
</ul>
<p>So in short, this script has no actual meaning, except for being space miners can fill in as they wish.</p>

CC BY-SA 4.0
2023-10-21T21:10:06.510Z
2023-10-21T21:10:06.510Z
Pieter Wuille
<p>I'm parsing the <code>block</code> response of my bitcoin node and everything is going ok.  The only thing I don't understand is how to parse the input transaction of the block reward.</p>
<p>This is the array that I see as the <code>signature_script</code>  of the 4th block of the Bitcoin blockchain, which has only one transaction and is the <code>signature_script</code> which each byte is in it's decimal form: <code>&lt;&lt;4,255,255,0,29,1,3&gt;&gt;</code>.</p>
<p>What does this mean?  I could not found information about it in the documentation.</p>

CC BY-SA 4.0
2023-10-22T09:59:57.047Z
Related: https://bitcoin.stackexchange.com/q/114846/13866
RedGrittyBrick
CC BY-SA 4.0
2023-10-22T12:41:32.710Z
Possible duplicate of https://bitcoin.stackexchange.com/q/20721/5406
Murch
<raw-transaction><coinbase-transaction><input-script>
Processing bitcoin reward block's input transaction
Monte Conte
# Processing bitcoin reward block's input transaction

(Asked by: username_0 on 2023-10-21)

I'm parsing the `block` response of my bitcoin node and everything is going ok. The only thing I don't understand is how to parse the input transaction of the block reward.

This is the array that I see as the `signature_script` of the 4th block of the Bitcoin blockchain, which has only one transaction and is the `signature_script` which each byte is in it's decimal form: `<<4,255,255,0,29,1,3>>`.

What does this mean? I could not found information about it in the documentation.

**Tags:** raw-transaction, coinbase-transaction, input-script

> **Comments:**
> **username_1**: Related: https://bitcoin.stackexchange.com/q/114846/13866  
> **username_2**: Possible duplicate of https://bitcoin.stackexchange.com/q/20721/5406  

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## 1 answers

### Answer by username_3 on 2023-10-21. Score: 4 | Accepted answer

This is the scriptSig of a coinbase transaction (the first transaction in every block is special; it doesn't actually spend anything but brings new coins into existence).

Coinbase transactions have a number of special rules that apply to them:

* They must be the first transaction in a block, and cannot occur anywhere else.
* They must have exactly one input, for which:
  + The prevout must have hash *0000...0000* and vout index *0xFFFFFFFF*.
  + The scriptSig must be between 2 and 100 bytes long, but otherwise has no meaning. Miners typically use this space to store what is called an extranonce, to be able to grind through more hashes per second then the block header nonce space allows for.
  + Since the activation of BIP34 in 2012 (which your block predates), the coinbase scriptSig must start with a push of the block height.
* They can claim the block's subsidy and all fees paid in the block (implicitly).
* They must have 1 or more outputs like every other transaction, determining where the mining rewards get paid to.

So in short, this script has no actual meaning, except for being space miners can fill in as they wish.


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