Topic: Electrum 4.3.4 Android, privacy of wallets (Read 149 times)

To extend this, using Tor to view your wallet gives a false sense of privacy (even if you change circuit for each address), because what matters the most (IMO) is for the third party to map your addresses, not your IP address specifically (that isn't always desired, but linking your outputs does say a lot).

I'm definitely in favor of running your own node, but I don't find that necessarily bad. You do take advantage of Internet reputation some times. You do trust complete stranger for mixing your coins, regardless of whether it's a centralized mixer or a decentralized. I wouldn't mind much if a trusted mixer provided me an Electrum server URI to connect in case of an emergency.

This is a reasonable mitigation. Even better if you can use a new Tor circuit for each connection rather than a new VPN server.

I agree with DaveF above - searching for a "pro-privacy" Electrum server is the wrong path to go down. I am a very hardcore privacy advocate as many users will tell you, and I run an Electrum server that you could use. However, you are then simply trusting me completely to continue to be honest, as well as trusting my competence in that my set up will not accidentally leak your information, as well as trusting my security that no one is able to hack in to my server and monitor your usage, as well as being dependent on me not shutting down my server for any reason. It's a very precarious situation to be in, based entirely on trust of a completely unknown individual with nothing you can independently verify. You would be far better served setting up your own node and server.

Right. But note that the addresses have been already sent to the server when you created the wallet unless you generated that wallet offline.

If you want to protect your privacy, you should run your own server.
You can also use TOR connection to be completely anonymous.

1) Just because they are pro-privacy today does not mean they will be pro-privacy tomorrow. Once you broadcast out there it's out there. Look into using TOR this way even if they can link addresses to wallets it can never come back to your IP.

2) In addition to nodes on RPi there are a few pre packed ones that run done as a VM. Don't know your computer knowledge so can't say if that would be easier or more difficult for for in terms of setup& running one.

Also, when you shut down your node and electrum server it's not just the node that resysncs it's the electrum sever that has to also fill in it's database after your node finishes syncing. As others have said, it's more PC speed (and RAM) dependent then download speed.

-Dave

AES with your master public key's various hashes: github.com/spesmilo/electrum...plugins/labels/labels.py#L32-L48 & /labels.py#L188-L192
The "data" by the way is just your labels, not a security issue but privacy rather.

Quantum... Aren't those just supercomputers emulating quantum computing?
(I don't know much about those, don't answer, it's off-topic)

Right, so if I don't 'open' the other wallet, it's addresses don't get sent to the server?
And if so, then for better privacy I should separate my sessions (time-wise),
connect to different servers when opening different wallets and perhaps change VPN server/country I guess.



Yeah, this is what I'm trying to verify. The dormant wallet does nothing, doesn't dial anywhere if not opened.

Right, that's how little I know. Will look into it.

Yeah, good point, things do get cranky, been there.
Thanks, very helpful insights to get me started.

Right. The master public key isn't sent to the server. But it's not that only used addresses are sent to the server, since without getting response from the server, it's not possible to know an address has been used or not.
All the addresses that are within the gap limit are sent to the server. By default, the gap limit is 20. This means that electrum sends the addresses to the server until there are 20 consecutive unused addresses.

I admit not to know in detail how the Electrum protocol actually works. From past reading I remember that Extended Public Keys are not sent for inquiries to an Electrum server. An Electrum Wallat has a finite set of so far used addresses and to check their balances those are submitted to the Electrum server.
The Electrum server gets to know only your set of addresses that are currently in use by your Electrum wallet.


Only addresses in use by the current and open Electrum wallet are broadcast to an Electrum server (to my limited knowledge).


It doesn't matter if Standard wallet or not: any different seed produces via standardized derivation unique and different Private Keys --> Public Keys --> Public Addresses.


While your ISP link speed is not unimportant, you can't assume to saturate your link speed with your Bitcoin node's peers. My ISP link speed is about double of yours and I never observed that my link speed was in any way an important factor for blockchain syncing.
The last time my RaspiBlitz node had a hickup, it needed to resync 190 blocks to get back to the blockchain tip (from blockheight 773416 to 773606), both for Bitcoin Core and my Fulcrum Electrum server (of course both run in parallel). This took ~118 minutes to complete (Bitcoin Core also had to rebuild the Coinstats index and I don't know how much influence this had to the download requests and speed for yet unknown blocks from my node's peers).
In a day you have roughly 144 new blocks to the blockchain, expect about 60-90 minutes for a resync with a Raspi based node. This is just a guess based on past numbers from my personal Raspi node.


A Raspi 4B with 8GB RAM costs around 100€ in Europe, but you need to be patient to fetch one. (I would never pay the scalper prices on Amazon or ebay or whereever the scalper scumbags do their dirty business.) A 1TB Sandisk Plus SSD is recommended (low peak power consumption as a Raspi has a total 1.2A limit for all USB ports combined!) and should be somewhere between 65-70€, some heatsink, a USB3-SATA case and a microSD card is all you need. Likely approx. 200€ hardware cost, depending on where you live, of course.
RaspiBlitz and especially Umbrel is pretty easy to get running. It's easy until something goes wrong for whatever reason. Then men separate from todlers... 

Once you open your wallet, all the generated addresses are sent to the server, so electrum can show your balance. The master public key (xpub or zpub) isn't sent to the server.
Addresses generated on the other wallet are also sent to the server when you open that wallet.

Correct.

Apologies, I meant my public keys, xPub? The ones where you derive the addresses from.
So the server can see my addresses derived from a given XPub key whenever I use the wallet and thus can link those addresses.
But does my wallet broadcast xPub keys from both of the wallets within Electrum?
Standard wallets with different seeds produce different public keys, correct?


Indeed my mac is offline most of the day. How long would it take to sync at 50Mpbs?
Are there any known pro-privacy advocates who run Electrum Servers that I could connect to?

For a node for dummies, how much would the set-up cost be and are they really easy to run?


Agree with you on that. I am using cold storage.
But as for hot wallets on mobile with the way LN and other developments are advancing, it's becoming neat to have some sats ready to go.

I'm probably about 90% open source on my Graphene and I try to restrict my phone activities as much as I can.
I'm considering device isolation as well.


Right, btw what is the encryption and would you worry about it?
Quantum squad?

Does your Mac run 24/7? Technically an Electrum server doesn't need to run 24/7, but if not you'll always need to wait for it to be fully synchronized again. As MacOS is some kind of unixoid OS, I see no reason why it can't run an Electrum server. Though, I have no links or resources for you as I don't use Apple devices.

While not easy to source these days, I'd stick to a Raspberry Pi 4B with 8GB RAM for a personal Bitcoin Node and Electrum server. I run RaspiBlitz as my main node. I run also an Umbrel node, but only to look at the progress of this project (I don't like certain aspects of their security modell). A Raspi node hardly consumes 6W and thus doesn't hurt much to run 24/7.



I haven't tried it myself, but Orbot on Android might be a solution to route through Tor on your Android device.



Personally I don't think a smartphone is a suitable platform for cryptocurrency wallets, maybe except if you use them together with a hardware wallet that secures the private keys. With all the daily "shit" we do on our mobiles, I'd only put no more money in my Android wallet than I usually put in my fiat wallet (normally two-digit Euro/US-$ amounts, rarely more).

Additionally, with trampoline nodes enabled, you're limited to the hard-coded trampoline nodes so by opening a channel with them, it's already a given that you're using Electrum.

For recoverable channels, you're also correct.
There's an additional data in the form of OP_RETURN which usual open channel transactions doesn't have.

If you decided to follow the "restore seed phrase" route to circumvent that limitation,
you can enable "Label Sync" plugin in the settings so that when you restore the wallet from seed, it'll restore the labels as well.
The downside is your data will be stored (encrypted) to a central server.

Your private keys are never broadcasted to the server. You sign your transactions locally in your own device.


You can't change the name of existing wallets, but you can create a new wallet with importing your seed phrase and use any name you want.
Just note that your the labels you may have used for your transactions aren't backed up by your seed phrase.


No. That doesn't have anything to do with your security,

Hello all, average person here.

Some privacy questions regarding Electrum Android 4.3.4:

In the app I have two different standard wallets with different seeds, A and B.

1.
When I choose to use wallet A, does Electrum broadcast the private key to the server also from wallet B if I don't 'activate' it?
If not and used in this way can they be linked in any meaningful way? (without access to the wallet)

What if I do activate the other wallet mid-session, what sensitive information am I possibly compromising to the server?

Since these two wallets are for different purposes, I want to be absolutely certain that they can't be linked together by an adversary logging the server.
Until I'm sure, I am contemplating whether it would be safer to use completely different wallet-apps to ensure privacy.
Feel free to share other tips to ensure bulletproof separation of wallets or accounts. I will want to get to running my own node, but right at this moment not able to yet.

2.
Can wallet names be changed once they've been created? (I can't find a way on the Android app)

3.
I did these privacy tweaks to ensure better privacy on the LN side. Please comment if you find me totally lost here:

- Turned off trampoline nodes, going with gossip. Saw a few lectures and I understand that there are not enough trampoline nodes yet to increase anonymity set?
- create recoverable channels: no. - If it's on 'Analysis' will be able to identify my wallet as Electrum. Is that correct? - Downside is if I delete the wallet my LN channels are unrecoverable?

3.5
Btw does it matter where Electrum sources it's blockchain/price info? (As in Coingecko or what have you) Can that be a security vulnerability?

4.
Can macs run Electrum Personal Servers? Are they easy to set up and run?
If so, appreciate and links to easy tutorials or resources.

5.
This Electrum wallet does not run Tor, correct?


I'm really liking this wallet and the old-school feel and design, and would love to use it as my lightning wallet if I can let it trust me.

Thanks,