Is Monero in I2P secure now, and how do I do it?

Question

First I'd like to say I love this project and I wanna support it and use it as best I can, but I'm a little bad with computers, and with English, so please excuse me.

I am interested to set a Monero full node through the I2P network, like I saw some others to did (see "Hidden Nodes" section of moneroworld.com, though I'm not understanding why they don't want full blockchain sync, I thought a common use of I2P is for torrents of large files). So far I set I2P, it's running nice, but I have a couple questions before proceeding. Maybe very foolish or basic, again I apologize.

1. This question [After Kovri arrives will some full nodes need to remain on clearnet? ] deals with peer discovery through Kovri. How about peer discovery right now if I wanna run a full node in I2P? Will the current client know to connect to only I2P nodes?

2. If my client is gonna connect with clear net nodes also, does it know to send my transactions only to the known I2P nodes? Again I'm asking about functionality right now, not what is planned with Kovri. If not then is there any security and anonymity benefit to using I2P right now?

3. When I broadcast a transaction txid in I2P, the only info the I2P nodes know is, 'Somebody over I2P has broadcasted transaction txid'. True or false?

4. (*) If the answer to #3 is true, then is there any anonymity or security benefit to running a full I2P node VERSUS connecting to a remote I2P node over I2P? This is a big question so I'll tip some fraction of Monero or maybe whole Monero for the first expert who gives the comprehensive list of current attacks (including 'combined with other info' type stuff), and bonus for simple ways to avoid and eta of plug. I appreciate considering likely or known current conditions like, there probably aren't many I2P nodes, and probably even fewer bridge nodes. Even better if you also consider attacks to I2P itself ([https://geti2p.net/en/docs/how/threat-model] - note I understand almost none of this page, write out the details of the attack for others to see and argue, but please include a tldr...ty)

5. (*) How can I set a full Monero node in I2P? I already did the I2P part, and I know how to google standard stuff that a million other people ask. I can google and copy-paste, basically.

Thank you very much and I hope these answers will at least help and inform others.

Answer 1

This question [After Kovri arrives will some full nodes need to remain on clearnet? ] deals with peer discovery through Kovri. How about peer discovery right now if I wanna run a full node in I2P? Will the current client know to connect to only I2P nodes?

Kovri does not yet integrate with Monero. In the future when integrated, there will be three modes: IP only, bridged, and I2P-only. If you use the extreme I2P-only option, then it will only connect to other nodes that use I2P. These nodes can be ones run in either bridged mode (most likely) or also in I2P-only mode.

If my client is gonna connect with clear net nodes also, does it know to send my transactions only to the known I2P nodes? Again I'm asking about functionality right now, not what is planned with Kovri. If not then is there any security and anonymity benefit to using I2P right now?

If you are connected only with I2P, all your connections to other nodes will occur through I2P. These can be to nodes who are running only I2P connections or both I2P and clearnet connections.

When I broadcast a transaction txid in I2P, the only info the I2P nodes know is, 'Somebody over I2P has broadcasted transaction txid'. True or false?

Mostly true. There is some slight metadata leak such as time, but this is as little information leaked as reasonably possible. It's not 100% perfect, but it's the best tool available and would make attacks incredibly difficult.

(*) If the answer to #3 is true, then is there any anonymity or security benefit to running a full I2P node VERSUS connecting to a remote I2P node over I2P? This is a big question so I'll tip some fraction of Monero or maybe whole Monero for the first expert who gives the comprehensive list of current attacks (including 'combined with other info' type stuff), and bonus for simple ways to avoid and eta of plug. I appreciate considering likely or known current conditions like, there probably aren't many I2P nodes, and probably even fewer bridge nodes. Even better if you also consider attacks to I2P itself ([https://geti2p.net/en/docs/how/threat-model] - note I understand almost none of this page, write out the details of the attack for others to see and argue, but please include a tldr...ty)

Yes, there is a major security difference between using your own node compared to using someone else's node, including over I2P. This remote node will get certain metadata information: the time, what blocks you are requesting, etc. They will not get the most important leak which is your IP address, but the amount of metadata leaked is nontrivial. A local full node over I2P provides more privacy than a remote node, period.

(*) How can I set a full Monero node in I2P? I already did the I2P part, and I know how to google standard stuff that a million other people ask. I can google and copy-paste, basically.

Until Kovri supports Monero directly, it is unreasonable for most people to run full nodes exclusively through I2P, since it will be difficult or perhaps impossible for you to find other nodes to sync to. If you want better privacy than what is currently available, I suggest instead running a node through Tor, since Tor has significantly better connections to the clearnet than I2P.