<p>This secure, private, untraceable C++ implementation of the I2P anonymous network being developed for Monero could eventually be of use for Bitcoin too. It will address the IP address issue you are asking about.</p>

<p>Metadata related privacy issues continue to be researched both by those who want to perform blockchain analysis and those who want to protect the privacy of users</p>

<p><a href="https://github.com/monero-project/kovri" rel="nofollow">https://github.com/monero-project/kovri</a></p>

<p>Why I2P over Tor?
<a href="https://www.reddit.com/r/Monero/comments/2ti53m/why_is_monero_aiming_to_integrate_i2p/" rel="nofollow">https://www.reddit.com/r/Monero/comments/2ti53m/why_is_monero_aiming_to_integrate_i2p/</a></p>

CC BY-SA 3.0
2016-05-22T00:11:39.970Z
Thank you for your contribution, but this doesn't appear to answer the question that was asked.  The question was "Has anyone built such a service?"  It wasn't "Is there some other protocol that doesn't have this problem?".  Please reserve the answer box for material that answers the question that was asked.  We are a question-and-answer site, not a discussion forum, so we expect answers to answer the question, not to be merely discussion of related topics.  Thank you!
D.W.
CC BY-SA 3.0
2016-05-21T13:27:58.597Z
2016-05-21T13:27:58.597Z
John Adamson
<p>So a node that creates a transaction needs to propagate it. It will connect to other nodes. Usually to some reasonable number like 8 nodes (please see <code>getpeerinfo</code> on your client).</p>

<p>As a mental exercise: If the 8 nodes (that I randomly selected from the network) belong to the same person, that person will have the possibility to capture 100% of my traffic. My IP address will be known, but also there could be a selective attack that prevents my transaction from being broadcasted (i.e. he/she decides to drop it based on my sending bitcoin address). </p>

<p>The more nodes the attacker has, the more chances to have all outgoing connections from the victims plus the possibility to do data analysis. Also more chances of dropping (selected or random) transactions.</p>

<p>I don't know the economics behind an attack of this nature. Buying 5000 VMs to run nodes could cost a lot. </p>

<p>Examples are out there that they ask for bitcoin to set up full nodes, like <a href="https://classic-cloud.net/" rel="nofollow noreferrer">https://classic-cloud.net/</a> [1]. as 2016-04-01 they have 810 nodes running. So you can imagine that they could be able to track some transactions to IPaddress. </p>

<p>Edit: [1] as of 2019-05-17 this is not longer a page that has stats about nodes, but rather a blog.</p>

CC BY-SA 4.0
2016-04-02T03:15:23.507Z
2019-06-17T17:46:49.567Z
2019-06-17T17:46:49.567Z
nicocesar
<p>Dan Kaminsky has pointed out that it would be possible to build a service that tries to infer the source IP address of each Bitcoin transaction.  His idea, which he calls <a href="https://bitcoin.stackexchange.com/q/771/14915">Blitcoin</a>, works by maintaining connections to all nodes in the peer-to-peer network and noting the IP address of the first node to report the transaction.  This <a href="https://bitcoin.stackexchange.com/q/1514/14915">won't always</a> be the IP address of the source of the transaction (for instance, there are a number of ways to hide one's IP address), but sometimes it might be.</p>

<p>Has anyone built such a service?  How often does it work, in practice?  Are there any commercially available services that have maintained past archives of this information?</p>

<security><privacy><transaction-propagation>
Capturing IP address of transactions submitted to Bitcoin
D.W.
# Capturing IP address of transactions submitted to Bitcoin

(Asked by: username_0 on 2016-04-02)

Dan Kaminsky has pointed out that it would be possible to build a service that tries to infer the source IP address of each Bitcoin transaction. His idea, which he calls [Blitcoin](https://bitcoin.stackexchange.com/q/771/14915), works by maintaining connections to all nodes in the peer-to-peer network and noting the IP address of the first node to report the transaction. This [won't always](https://bitcoin.stackexchange.com/q/1514/14915) be the IP address of the source of the transaction (for instance, there are a number of ways to hide one's IP address), but sometimes it might be.

Has anyone built such a service? How often does it work, in practice? Are there any commercially available services that have maintained past archives of this information?

**Tags:** security, privacy, transaction-propagation


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## 2 answers

### Answer by username_1 on 2016-05-21. Score: 1

This secure, private, untraceable C++ implementation of the I2P anonymous network being developed for Monero could eventually be of use for Bitcoin too. It will address the IP address issue you are asking about.

Metadata related privacy issues continue to be researched both by those who want to perform blockchain analysis and those who want to protect the privacy of users

<https://github.com/monero-project/kovri>

Why I2P over Tor?
<https://www.reddit.com/r/Monero/comments/2ti53m/why_is_monero_aiming_to_integrate_i2p/>

> **Comments:**
> **username_0**: Thank you for your contribution, but this doesn't appear to answer the question that was asked.  The question was "Has anyone built such a service?"  It wasn't "Is there some other protocol that doesn't have this problem?".  Please reserve the answer box for material that answers the question that was asked.  We are a question-and-answer site, not a discussion forum, so we expect answers to answer the question, not to be merely discussion of related topics.  Thank you!  

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### Answer by username_2 on 2016-04-02. Score: 1

So a node that creates a transaction needs to propagate it. It will connect to other nodes. Usually to some reasonable number like 8 nodes (please see `getpeerinfo` on your client).

As a mental exercise: If the 8 nodes (that I randomly selected from the network) belong to the same person, that person will have the possibility to capture 100% of my traffic. My IP address will be known, but also there could be a selective attack that prevents my transaction from being broadcasted (i.e. he/she decides to drop it based on my sending bitcoin address).

The more nodes the attacker has, the more chances to have all outgoing connections from the victims plus the possibility to do data analysis. Also more chances of dropping (selected or random) transactions.

I don't know the economics behind an attack of this nature. Buying 5000 VMs to run nodes could cost a lot.

Examples are out there that they ask for bitcoin to set up full nodes, like <https://classic-cloud.net/> [1]. as 2016-04-01 they have 810 nodes running. So you can imagine that they could be able to track some transactions to IPaddress.

Edit: [1] as of 2019-05-17 this is not longer a page that has stats about nodes, but rather a blog.


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