<p>To add to Vojtěch's answer, take the point of view of nodes validating blocks on the network. How would they enforce that a transaction must have been propagated before it's included in a block?</p>
<p>Not only is this rule unenforceable on historical blocks, it also requires a synchronization mechanism across the network on what transactions are valid in the next block. But this synchronization mechanism <em>is</em> the block chain itself, you can see how it is circular.</p>
<p>No consensus rule can be based on the content of a node's mempool. Different nodes have different mempools (they usually only differ slightly). Maintaining a mempool has <a href="https://bitcoinops.org/en/blog/waiting-for-confirmation/" rel="nofollow noreferrer">plenty of advantages</a>, but it is not a requirement for using Bitcoin.</p>

CC BY-SA 4.0
2023-11-25T14:30:59.667Z
2023-11-25T14:30:59.667Z
Antoine Poinsot
<p>Yes, since miners (pools) construct the blocks they mine, they can insert any valid transactions they want, including transactions that were never broadcasted to the wider network. They don't even need 51% of the global hashrate, they just need to create blocks often enough that they don't have to wait too long for their transactions to confirm.</p>
<p>Some mining pools commonly do this. For example, <a href="https://mempool.space/tx/e1f3008c1b8db58917aef2a8b47077712ad332940471e0173fd82dfa4c2a8eb4" rel="nofollow noreferrer">here</a> is a transaction mined by F2Pool that most likely distributes mining rewards to the pool's miners. It pays no fee which means it was never broadcasted, since zero-fee transactions aren't propagated by nodes through the network.</p>

CC BY-SA 4.0
2023-11-23T22:28:48.410Z
2023-11-26T21:09:01.790Z
2023-11-26T21:09:01.790Z
Vojtěch Strnad
<p>Let's imagine that you have 51% of all mining power. Is it possible to put a single transaction in the next block without putting it into the mempool and/or propagating the tx to the other peers through the bitcoin network?</p>

<transactions><mining-pools><mining-theory><mempool>
If you have the required mining power, is it possible to mine your transaction in the next block without propagating it to the network?
Efe
# If you have the required mining power, is it possible to mine your transaction in the next block without propagating it to the network?

(Asked by: username_0 on 2023-11-23)

Let's imagine that you have 51% of all mining power. Is it possible to put a single transaction in the next block without putting it into the mempool and/or propagating the tx to the other peers through the bitcoin network?

**Tags:** transactions, mining-pools, mining-theory, mempool


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## 2 answers

### Answer by username_2 on 2023-11-23. Score: 8 | Accepted answer

Yes, since miners (pools) construct the blocks they mine, they can insert any valid transactions they want, including transactions that were never broadcasted to the wider network. They don't even need 51% of the global hashrate, they just need to create blocks often enough that they don't have to wait too long for their transactions to confirm.

Some mining pools commonly do this. For example, [here](https://mempool.space/tx/e1f3008c1b8db58917aef2a8b47077712ad332940471e0173fd82dfa4c2a8eb4) is a transaction mined by F2Pool that most likely distributes mining rewards to the pool's miners. It pays no fee which means it was never broadcasted, since zero-fee transactions aren't propagated by nodes through the network.


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### Answer by username_1 on 2023-11-25. Score: 2

To add to username_2's answer, take the point of view of nodes validating blocks on the network. How would they enforce that a transaction must have been propagated before it's included in a block?

Not only is this rule unenforceable on historical blocks, it also requires a synchronization mechanism across the network on what transactions are valid in the next block. But this synchronization mechanism *is* the block chain itself, you can see how it is circular.

No consensus rule can be based on the content of a node's mempool. Different nodes have different mempools (they usually only differ slightly). Maintaining a mempool has [plenty of advantages](https://bitcoinops.org/en/blog/waiting-for-confirmation/), but it is not a requirement for using Bitcoin.


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