<p>This is indeed a problem. While node-B and C cannot be sure that node-A is the originator, if they both belong to the same spy they can be increasingly confident if they have many other connections and both receive the transaction from node-A first.</p>
<p>This kind of attack has long been recognized and it is certainly being actively exploited by many blockchain analysis companies. There is research (see <a href="https://arxiv.org/abs/1701.04439" rel="nofollow noreferrer">Dandelion</a> and further developments of this idea) on how to make this attack harder, but it has some other tradeoffs and hasn't been included in bitcoin-core yet AFAIK.</p>

CC BY-SA 4.0
2022-10-17T18:34:53.827Z
Indeed, the Dandelion proposal is no longer pursued to be added to Bitcoin Core due to DOS attack concerns: https://bitcoin.stackexchange.com/q/81503/5406
Murch
CC BY-SA 4.0
2022-10-10T07:11:35.497Z
2022-10-10T07:11:35.497Z
stefanwouldgo
<p>Let's say <code>node-A</code> is propagating a transaction to it's peers on the network: <code>node-B</code>, <code>node-C</code>, etc. Is there any way for the other nodes to know that <code>node-A</code> is the <em>originator</em> of that transaction, as opposed to simply being a <em>source of gossip</em> about the transaction (&quot;gossip&quot; e.g. <code>node-B</code> sharing the transaction with <code>node-C</code>)?</p>
<p>It seems like it would be very important privacy-wise for the originator of the transaction to be obfuscated by appearing on-network in exactly the same way as nodes who gossip about the transaction. But I am not sure how things stand in the bitcoin protocol. Are all relayings of transactions created equal, or are some recognizable as the original source of transmission to the network?</p>

CC BY-SA 4.0
2022-10-09T07:49:18.833Z
Does this answer your question? [Are there any services that can reasonably guess what IP address a transaction originated from?](https://bitcoin.stackexchange.com/questions/75596/are-there-any-services-that-can-reasonably-guess-what-ip-address-a-transaction-o)
RedGrittyBrick
<transactions><privacy>
Is it possible to determine what node a transaction originated from?
ABTC
# Is it possible to determine what node a transaction originated from?

(Asked by: username_0 on 2022-10-09)

Let's say `node-A` is propagating a transaction to it's peers on the network: `node-B`, `node-C`, etc. Is there any way for the other nodes to know that `node-A` is the *originator* of that transaction, as opposed to simply being a *source of gossip* about the transaction ("gossip" e.g. `node-B` sharing the transaction with `node-C`)?

It seems like it would be very important privacy-wise for the originator of the transaction to be obfuscated by appearing on-network in exactly the same way as nodes who gossip about the transaction. But I am not sure how things stand in the bitcoin protocol. Are all relayings of transactions created equal, or are some recognizable as the original source of transmission to the network?

**Tags:** transactions, privacy

> **Comments:**
> **username_1**: Does this answer your question? [Are there any services that can reasonably guess what IP address a transaction originated from?](https://bitcoin.stackexchange.com/questions/75596/are-there-any-services-that-can-reasonably-guess-what-ip-address-a-transaction-o)  

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## 1 answers

### Answer by username_2 on 2022-10-10. Score: 1

This is indeed a problem. While node-B and C cannot be sure that node-A is the originator, if they both belong to the same spy they can be increasingly confident if they have many other connections and both receive the transaction from node-A first.

This kind of attack has long been recognized and it is certainly being actively exploited by many blockchain analysis companies. There is research (see [Dandelion](https://arxiv.org/abs/1701.04439) and further developments of this idea) on how to make this attack harder, but it has some other tradeoffs and hasn't been included in bitcoin-core yet AFAIK.

> **Comments:**
> **username_3**: Indeed, the Dandelion proposal is no longer pursued to be added to Bitcoin Core due to DOS attack concerns: https://bitcoin.stackexchange.com/q/81503/5406  

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