Air-gap your old smartphones (Hardware wallet alternative)

With what's been happening lately sa mga hardware wallet (Ledger drains, ColdCard hacks, etc.), it is better na may naka-setup ka na alternative cold storage wallet that's paired with a watch-only wallet. That's what this tutorial will be about.

May dalawang options ka (marami pang iba but for the sake of this tutorial, ito 'lang muna i-mention ko):

1. Use Airgap Vault (cold storage app) + Airgap Wallet (watch-only app)
[ Announcement thread ] [ Website ] [ Github ]

2. Use Cupcake (cold storage app) + Cake Wallet (watch-only app)
[ Discussion thread ] [ Website ] [ Github ]

Both of these apps run on any smartphone ('wag lang yung masyadong luma or Nokia 3310 Cheesy

), and both of them are open-source too.

✅Requirements:
One old (but functional) smartphone (Android or iOS), and your daily-driver smartphone (ito yung araw-araw mo ginagamit, your current smartphone).
Internet
Pen and paper

Steps:
1. ⚙️ Clean your old smartphone. Make sure to run a factory reset para mawala lahat ng mga user-installed apps when it was previously used.

2. ⬇️ Download and install your chosen watch-only app (pili ka sa taas: Airgap Wallet ba or Cake Wallet) on your current smartphone (ito yung smartphone na ginagamit mo araw-araw)
- Make sure to download only from legitimate sources: Google Play Store or Apple App Store or through their website

3. ⬇️ Download and install your chosen cold storage app (pili ka ulit sa taas: Airgap Vault ba or Cupcake) on your old smartphone
- Make sure to download only from legitimate sources: Google Play Store or Apple App Store or through their website

4. ‼️IMPORTANT: Once the cold storage app is installed sa iyong old smartphone. Turn off wifi, data, bluetooth, NFC, remove simcards, and any other connections; then turn ON Airplane mode.
This will cut off any connections on this smartphone and isolate it para hindi maabot ng hackers and potential exploits.

5. ⚙️ Set up your Cold storage app on your old smartphone.
- Go through the usual setup. Follow the instructions within the app itself.
- You will be asked to set a strong PIN or password para sa app. Make sure to remember it or write it down on a piece of paper and secure it. 📝
- Bibigyan ka rin ng set of seed phrases during the setup process. Again, write it down on a piece of paper and secure it.

6. Open your watch-only app from your current smartphone and set up your account (mostly, you also need to set a PIN for it).

7. ⚙️🔄️ Restore or sync your wallet/account on the watch-only app on your current smartphone.
- On Cupcake app: Open the app (from your old smartphone) and click the = button, then click Link to Cake Wallet; it will give you a QR code to scan
- Open your Cake wallet app (on your current smartphone) and choose Restore Wallet -> then choose QR Code. Once scanned, click Restore and that's it.
- On Airgap Vault app: Open the app (from your old smartphone) and click the 3 dots in the top right corner, then choose Sync All Accounts with Airgap Wallet. It will then give you a QR code to scan.
- Open your Airgap wallet app (on your current smartphone) and choose Scan QR. Once scanned, lalabas na lahat ng accounts mo on that app.

That's it, you have successfully made an air-gapped cold storage smartphone and a watch-only wallet. 🎉🎉

📩How to send transactions.
1. Open your Watch-only app (Airgap Wallet or Cake Wallet), make your transaction (send crypto to someone or any wallet address), and choose Create Transaction, magbibigay yan ng QR Code
2. Open your Cold-storage app (Airgap Vault or CupCake) and choose QR Code scanner. Scan the QR code and choose Sign transaction; magbibigay ulit yan ng panibagong QR code
3. Go back to your Watch-only app (Airgap Wallet or Cake Wallet), choose the QR Code scanner. Scan the QR code and choose Broadcast transaction.
4. Done. Your transaction is now broadcasted sa blockchain (antayin mo na lang ma-confirm). Grin

Additional Notes
* As of this writing (and AFAIK) ang CupCake app only supports BTC, LTC, and XMR, while Airgap Vault supports BTC, ETH, and lots of other altcoins and stablecoins.
* Hindi mo puwedeng paghaluin ang dalawang apps na ’yan (i.e., Airgap Vault + Cake Wallet). It has to be from the same company/devs.
* This method can also be done with Electrum Mobile; the difference 'lang is on Electrum, iisang app 'lang gagamitin mo, no need to download two apps (vault+watch-only app).
Install one Electrum app sa old smartphone, set it up, go to your current smartphone, install another Electrum mobile app, and restore your account. Also, make sure to download only from legitimate sources. Wink

* Smartphones don't have a secure element chip to them unlike most hardware wallets. So this is only for additional backup or something na temporarily magagamit mo especially now that lots of hardware wallets are being attacked. There are still good hardware wallets out there and if you can get your hands on those, better to use them primarily instead of this setup.

❓FAQs
1. Paano kapag nasira ang old smartphone?
- You can still restore your account/wallet sa ibang smartphone using your seed phrase. Just do the same setup, but this time, instead of creating a new set of seed phrases, choose Restore Wallet.
2. Puwede ba ang ganitong setup sa laptop at PC?
- Yes, given na totally offline ang isa sa device na gagamitin mo as cold storage (i.e laptop as cold storage, PC as watch only/transaction builder)
3. Gaano ka-secure ang ganitong setup?
- Kahit mawala o manakaw ang current smartphone mo, hindi ma-access at ma-move ang crypto mo without the old smartphone.
4. Ano-ano ang risks sa ganitong setup?
- Maaaring ma-access ang crypto mo sa old smartphone if the attacker knows your PIN/Password at pati na rin ang seed phrase mo (so make sure they are always secure).
- Kapag nawala ang old smartphone mo pati ang copy mo ng iyong seed phrase, hindi mo na ma-rerecover at magagamit ang cryptocurrencies mo (so again, secure them).
5. Anong additional steps ang dapat ko pang gawin to secure my crypto?
- Set up a strong PIN and password sa old smartphone (enable lock screen) and keep it safe.
- Gumawa ng copy ng seed phrase, PINs, at password used during the entire setup at ilagay ito sa ibang safe na lugar (ibang bahay nyo or bank personal vaults).
- Never plug your airgapped smartphone to any computer via USB. Dapat through QR codes 'lang ang tanging communication for it.
6. May video tutorials ba about this?
- Yes, hindi ko lang binigay agad ang link sa taas to force you to read the entire thread. Cheesy

For Airgap Vault: https://www.youtube.com/watch?v=M9ICKaLxuwQ
For CupCake: https://www.youtube.com/watch?v=JYqKGbH5b-o

If may ibang questions pa kayo or anything that I missed in this tutorial, feel free to comment below.