Storage Crypto Wallet USB

[ABCbits]

Just for curiosity, i finally got an answer from the seller. Indeed, i sent him a message some days ago, and forgot about it since i though i won't get any answer. I was wrong. Although i gave up the idea of buying from him, i'm puzzled regarding his answer: "We actually install Coinomi wallet onto the device as a default but the the USB can certainly work with electrum as well!"

What makes you puzzled? I think they mean you can install Electrum and store Electrum's data on USB device they sell. Although Coinomi have mixed reputation since in past,
1. Switched from open source to closed source wallet.
2. There was time interval where they doesn't upgrade their software and active in social media.
3. They send generated seed phrase to google server.

On side note, i just noticed that ebay mentioned 11 sold of those USB have been sold.

[Forsyth Jones]

Just for curiosity, i finally got an answer from the seller. Indeed, i sent him a message some days ago, and forgot about it since i though i won't get any answer. I was wrong. Although i gave up the idea of buying from him, i'm puzzled regarding his answer: "We actually install Coinomi wallet onto the device as a default but the the USB can certainly work with electrum as well!"

Remember that you can use any USB flash drive as a cold storage method, as long as you correctly follow the recommended security steps, such as having a computer exclusively for this purpose (with TailsOS installed on the device or bootable on the USB), where device1will be offline (only to sign transactions) and device2 will be online and the master public key will be stored on it to monitor and assemble transactions (to transfer to the offline device).

1 - Device1 must have wallets such as Electrum, Sparrow, Bitcoin Core... installed and it must be permanently disconnected from the internet (you can consider removing the network card). Once the device is in air-gapped mode, you can create your wallet, write down the backup wallet, add an encryption passphrase to protect the keystore (Don't confuse this with BIP-39 passphrase or electrum seed extension, where you can optionally enable it as well.) and copy the extended public key to device2 online via QR-Code or USB drive.

2 - Device2 can be used normally and will have the aforementioned wallets installed and transactions will be created through it. You can copy the PSBT via QR-Code or USB Drive (the USB Drive will be for exclusive use for this purpose) to device1 to sign and then, with the transaction signed, return to device2 to transmit the transaction.

I recommend that you run a full node such as bitcoin core on the online device to transmit the transactions themselves.

[bestcoin_59]

Just for curiosity, i finally got an answer from the seller. Indeed, i sent him a message some days ago, and forgot about it since i though i won't get any answer. I was wrong. Although i gave up the idea of buying from him, i'm puzzled regarding his answer: "We actually install Coinomi wallet onto the device as a default but the the USB can certainly work with electrum as well!"

Remember that you can use any USB flash drive as a cold storage method, as long as you correctly follow the recommended security steps, such as having a computer exclusively for this purpose (with TailsOS installed on the device or bootable on the USB), where device1will be offline (only to sign transactions) and device2 will be online and the master public key will be stored on it to monitor and assemble transactions (to transfer to the offline device).

1 - Device1 must have wallets such as Electrum, Sparrow, Bitcoin Core... installed and it must be permanently disconnected from the internet (you can consider removing the network card). Once the device is in air-gapped mode, you can create your wallet, write down the backup wallet, add an encryption passphrase to protect the keystore (Don't confuse this with BIP-39 passphrase or electrum seed extension, where you can optionally enable it as well.) and copy the extended public key to device2 online via QR-Code or USB drive.

2 - Device2 can be used normally and will have the aforementioned wallets installed and transactions will be created through it. You can copy the PSBT via QR-Code or USB Drive (the USB Drive will be for exclusive use for this purpose) to device1 to sign and then, with the transaction signed, return to device2 to transmit the transaction.

Assuming Device=Computer, i think this is more or less what i was doing.

add an encryption passphrase to protect the keystore

I assume encryption passphrase = electrum password
So that the Electrum data files in the offline computer is encrypted

I recommend that you run a full node such as bitcoin core on the online device to transmit the transactions themselves.

Would be interested to learn how. I guess i would have to download the whole blockchain, would't i?

Just for curiosity, i finally got an answer from the seller. Indeed, i sent him a message some days ago, and forgot about it since i though i won't get any answer. I was wrong. Although i gave up the idea of buying from him, i'm puzzled regarding his answer: "We actually install Coinomi wallet onto the device as a default but the the USB can certainly work with electrum as well!"

What makes you puzzled? I think they mean you can install Electrum and store Electrum's data on USB device they sell. Although Coinomi have mixed reputation since in past,
1. Switched from open source to closed source wallet.
2. There was time interval where they doesn't upgrade their software and active in social media.
3. They send generated seed phrase to google server.

On side note, i just noticed that ebay mentioned 11 sold of those USB have been sold.

Do you mean that, according to the seller answer, the USB stick the seller sells *would work* as a ledger nano?
OR
The seller sells a live OS with Coinomi installed on a USB device
OR
The seller sells a USB device with a *portable* version of Coinomi on it?

3. They send generated seed phrase to google server.

Is it true? This red red flag and an absolute NO GO for me.

[takuma sato]

Learn how to use the 2 setup software:

1st device holds the private keys and never connects to the internet,
2nd device broadcasts the raw transaction created on the 1st device

This is the foundation of good security when dealing with Bitcoin. Also never use any device that has been created to be used with crypto, even if they are Bitcoin-only, because they make you stand out. You want a generic laptop, a generic USB, things that don't say you hold any coins. And stop dealing in altcoins, they are fundamentally not safe, stick to BTC and that's it.

[Forsyth Jones]

Assuming Device=Computer, i think this is more or less what i was doing.

I assume encryption passphrase = electrum password
So that the Electrum data files in the offline computer is encrypted

Would be interested to learn how. I guess i would have to download the whole blockchain, would't i?

You've reasoned well,

Just download Bitcoin Core and make sure you have an SSD (HDD will also work, but I recommend using SSD) with a capacity of at least 1TB or 2TB ~ currently the Bitcoin network weighs around 700GB (I haven't checked it for a while).

Optionally, you can enable pruning so you don't need to keep the entire blockchain stored and the node will only download and check the recent blocks and delete the old ones, you can set the size manually.

[ABCbits]

Just for curiosity, i finally got an answer from the seller. Indeed, i sent him a message some days ago, and forgot about it since i though i won't get any answer. I was wrong. Although i gave up the idea of buying from him, i'm puzzled regarding his answer: "We actually install Coinomi wallet onto the device as a default but the the USB can certainly work with electrum as well!"

What makes you puzzled? I think they mean you can install Electrum and store Electrum's data on USB device they sell. Although Coinomi have mixed reputation since in past,
1. Switched from open source to closed source wallet.
2. There was time interval where they doesn't upgrade their software and active in social media.
3. They send generated seed phrase to google server.

On side note, i just noticed that ebay mentioned 11 sold of those USB have been sold.

Do you mean that, according to the seller answer, the USB stick the seller sells *would work* as a ledger nano?
OR
The seller sells a live OS with Coinomi installed on a USB device
OR
The seller sells a USB device with a *portable* version of Coinomi on it?

It's probably 2nd or 3rd option.

3. They send generated seed phrase to google server.

Is it true? This red red flag and an absolute NO GO for me.

It's true. Here's link to their official statement, Official Statement on Spell Check findings. And here's link to the initial report, http://avoid-coinomi.com/.

P.S. Do your own research about this past controversy.

[bestcoin_59]

Learn how to use the 2 setup software:

1st device holds the private keys and never connects to the internet,
2nd device broadcasts the raw transaction created on the 1st device

That's the fundamental rule. I agree with this.

This is the foundation of good security when dealing with Bitcoin. Also never use any device that has been created to be used with crypto, even if they are Bitcoin-only, because they make you stand out. You want a generic laptop, a generic USB, things that don't say you hold any coins. And stop dealing in altcoins, they are fundamentally not safe, stick to BTC and that's it.

Can you please elaborate on your last sentence. What do you mean when you say: "And stop dealing in altcoins, they are fundamentally not safe"  

Regards

Just download Bitcoin Core and make sure you have an SSD (HDD will also work, but I recommend using SSD) with a capacity of at least 1TB or 2TB ~ currently the Bitcoin network weighs around 700GB (I haven't checked it for a while).

Optionally, you can enable pruning so you don't need to keep the entire blockchain stored and the node will only download and check the recent blocks and delete the old ones, you can set the size manually.

I tried to dig a little further. Here are some links related:
https://www.reddit.com/r/Bitcoin/comments/ywarm9/how_to_make_electrum_connect_to_my_node_and/?rdt=34579
https://github.com/chris-belcher/electrum-personal-server
From what i read:
Bitcoin Core = software programmed to decide which block chain contains valid transactions.
Bitcoin Node = Electrum Personal server which rely on Bitcoin Core

I still have one question though; When i use the Electrum wallet (client), i can see, at the beginning that
multiple nodes are "synchronized" (for redundancy and safety?). In case i run my own bitcoin node, i guess i will
ask Electrum to rely only on my node (for privacy).

So here is the question:
Should i understand that redundancy is mandatory for nodes ran by strangers, and that since i trust my own node, i don't
need redundancy? I'm apologize if i'm not clear...

Also correct me if i'm wrong, but there is no rewards in running a BTC node, although it is not the case for the Ethereum network.

Cheers
 

Do you mean that, according to the seller answer, the USB stick the seller sells *would work* as a ledger nano?
OR
The seller sells a live OS with Coinomi installed on a USB device
OR
The seller sells a USB device with a *portable* version of Coinomi on it?

It's probably 2nd or 3rd option.

In that case, for me, it is NOT a hardware wallet, it is a software wallet which, at best, brings the same
security level as TailOS.

[Forsyth Jones]

I tried to dig a little further. Here are some links related:
https://www.reddit.com/r/Bitcoin/comments/ywarm9/how_to_make_electrum_connect_to_my_node_and/?rdt=34579
https://github.com/chris-belcher/electrum-personal-server
From what i read:
Bitcoin Core = software programmed to decide which block chain contains valid transactions.
Bitcoin Node = Electrum Personal server which rely on Bitcoin Core

I still have one question though; When i use the Electrum wallet (client), i can see, at the beginning that
multiple nodes are "synchronized" (for redundancy and safety?). In case i run my own bitcoin node, i guess i will
ask Electrum to rely only on my node (for privacy).

So here is the question:
Should i understand that redundancy is mandatory for nodes ran by strangers, and that since i trust my own node, i don't
need redundancy? I'm apologize if i'm not clear...

Also correct me if i'm wrong, but there is no rewards in running a BTC node, although it is not the case for the Ethereum network.

Cheers

If you've an Electrum server (like Electrs), it would be best to use Electrum with your own Electrum server. The Raspibolt guide is the best I've found for setting up an Electrum server.

Ideally, you should configure Electrum to connect exclusively to your own Electrum server.

Examples:

Normal connection:
Electrum_location_on_PC --oneserver --server=ADDRESS:50002:s

Onion/Tor connection:
Electrum_location_on_PC --oneserver --server=TOR-ADDRESS.onion:50002:s --proxy socks5:127.0.0.1:9150 (or 9050).

The --oneserver parameter forces Electrum to connect to only one server, it can be yours or a server from the list of your choice.

If you don't run your own Electrum server, you can still have privacy on electrum by connecting to other nodes with tor enabled - https://electrum.readthedocs.io/en/latest/tor.html

Edit: But for you who are a beginner, perhaps it would be easier for you to simply run an Umbrel (on a Raspberry PI for example) which already comes with the bitcoin node, electrs server and + apps installed all in one. There are several guides that can be found both on YouTube and on various websites.

[ABCbits]

I tried to dig a little further. Here are some links related:
https://www.reddit.com/r/Bitcoin/comments/ywarm9/how_to_make_electrum_connect_to_my_node_and/?rdt=34579
https://github.com/chris-belcher/electrum-personal-server
From what i read:
Bitcoin Core = software programmed to decide which block chain contains valid transactions.
Bitcoin Node = Electrum Personal server which rely on Bitcoin Core

Bitcoin node and Electrum server are 2 different thing. Bitcoin node refer to a device that run full node software (such as Bitcoin Core) to store blockchain, relay data and perform verification. Meanwhile Electrum server connect to full node to get blockchain data and index it, so it can give data wanted by Electrum clients.

I still have one question though; When i use the Electrum wallet (client), i can see, at the beginning that
multiple nodes are "synchronized" (for redundancy and safety?). In case i run my own bitcoin node, i guess i will
ask Electrum to rely only on my node (for privacy).

So here is the question:
Should i understand that redundancy is mandatory for nodes ran by strangers, and that since i trust my own node, i don't
need redundancy? I'm apologize if i'm not clear...

Yes, you should configure Electrum client only connect to your Electrum server if you care about privacy. If you're interested with why exactly Electrum client connect to multiple server, read https://electrum.readthedocs.io/en/latest/faq.html#does-electrum-trust-servers.

Also correct me if i'm wrong, but there is no rewards in running a BTC node, although it is not the case for the Ethereum network.

Yeah, there's no financial reward a BTC node. Although on ETH network, IIRC you also need to be validator or sequencer to get financial reward.

[bestcoin_59]

Thanks a lot ABCbits and Forsyth Jones. The information provided is very useful.

I understand that the Electrum server is *between* the Electrum client (=Wallet) and Bitcoin node. In fact, the Electrum server, after asking Bitcoin Core, fulfill the Electrum client request. Due to the decentralized nature of the blockchain, a full node is like a local copy of the blockchain. Am i right?

Still, and although it might not be safe, would it possible to tell the Electrum server to rely on a Bitcoin node hosted remotely by somebody that i trust? I know it might not be very good for the safety of the blockchain (if everybody does that the system becomes centralized), In other words is it possible for several Electrum servers to use the same Bitcoin node?

Also, is the only benefit of running (hosting) a Bitcoin node and an Electrum server is to avoid public servers (therefore ran by strangers) to associate a wallet with an IP? Also since my IP has already been associated to the btc transactions already made, don't you think it is too late? Only future transactions, and if never rely on a public server again would be private.

Cheers 

[ABCbits]

I understand that the Electrum server is *between* the Electrum client (=Wallet) and Bitcoin node.

That's true.

In fact, the Electrum server, after asking Bitcoin Core, fulfill the Electrum client request.

That's generally true.

Due to the decentralized nature of the blockchain, a full node is like a local copy of the blockchain. Am i right?

Node also expected to verify and share blockchain with other connected nodes.

Still, and although it might not be safe, would it possible to tell the Electrum server to rely on a Bitcoin node hosted remotely by somebody that i trust?

It's impossible. Besides, how would you know whether Electrum server actually connect to specific Bitcoin node.

I know it might not be very good for the safety of the blockchain (if everybody does that the system becomes centralized), In other words is it possible for several Electrum servers to use the same Bitcoin node?

It's theoretically possible. But Electrum server connect to Bitcoin Core to using RPC-JSON protocol which require authentication (either username/password or cookie).

Also, is the only benefit of running (hosting) a Bitcoin node and an Electrum server is to avoid public servers (therefore ran by strangers) to associate a wallet with an IP?

Yeah, it's common reason why people run their own Electrum server. Although Electrum server may be used if you also run your own block explorer or developer who need to get list of transaction related with certain Bitcoin address.

Also since my IP has already been associated to the btc transactions already made, don't you think it is too late? Only future transactions, and if never rely on a public server again would be private.

It's "better late than never". And regarding this matter, some member may suggest you to move your Bitcoin to new wallet (which have different list of address). Although you need to be very careful since moving Bitcoin from multiple address may reduce your privacy further since it'll also leave trace on blockchain.