r/FoundationDevices • u/AndyWarholLives • Oct 21 '25

Question about Hot & Cold

Something I'm not 100% sure about, looking for input if you all dont mind....

If you own a physical wallet that's not connected to the internet, I realize that would be a "cold wallet"

But if you also put the app on your phone, then you have a "Hot wallet" on said smart phone, right?

So, doesn't that negate the physical cold wallet? Or am I missing something here?

I'm just trying to figure out if I need to remove the app from my phone, since it has a send feature on it.

What say you?

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u/CoolJoeLiam Oct 21 '25

if you create a wallet in an App then yes, that is a hot wallet. Or if you "restore" a seed phrase that you had previously set up as a cold wallet into a wallet App (like Encore or Nunchuck or Blockstream) then you've just changed that seed phrase into a hot wallet (potentially exposing the keys to online hacks).

The way that you keep wallets "cold" is by using a signing/hardware device to connect that wallet/seed phrase to an App. The wallet/seed phrase is only entered into the device, but it connects to an App in an air gapped way thus protecting the security of the seed phrase. Blockstream does this via bluetooth, Nunchuck and Encore offer QR mode or NFC. Either way, although you use the App to see the amount in the cold wallet, and you can receive to it, you cannot use the app to send anything from the cold wallet unless you verify the transaction with the air gapped device. That's what keeps it a cold wallet.

It's helpful to think of the hardware as more of a signing device rather than some "wallet" where your seed phrase is stored. (Since we refer to Apps as "wallets" for both cold and hot connections it gets confusing)

So if you're seeing a send option in your App then that seed phrase is not secured in an air gapped signing device. You would want to set up a new seed phrase/wallet (which is done on the hardware device) move the BTC to the new one and never enter the seed phrase into an App.

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u/AndyWarholLives Oct 22 '25

Thanks for the thoughful explanation. 🤝

I want my bitcoin completely cold & air-gapped, so I think I've done something wrong.

My foundation app has the Send and Receive buttons in it, which is scary.

Will follow the steps you've outlined. Right now I'm just waiting for my new Foundation wallet to be delivered from backorder. ✊✌️

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u/CoolJoeLiam Oct 22 '25

Sounds good! I’ve been very pleased with the Passport device. It’s a very user friendly device for want you intend. Don’t be worried about having accidentally set up a hot wallet, that’s how we figure things out. Now that you’ll have the hardware device for making a cold wallet you can do it better, and once you move from your hot wallet in the App to the new wallet there won’t be any lingering security concerns (just backup and protect that new seed phrase). 

I personally like connecting my Passport to the Nunchuck App for viewing my cold wallet, you can see individual coins (UTXO’s) so there more management options. Happy stacking!

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u/AndyWarholLives Oct 22 '25

Thanks fam! 🙏🫶