idea: handheld password manager

I had this idea for a small pocket sized device with a tiny screen and a few buttons where you can securely store and look up passwords. Completely offline. No wifi, no bluetooth, no connection to your pc. Just a secure vault you carry with you.

I recently found my nano ledger s and thought how cool this little device is. You can do everything with just 2 buttons. I really like different devices for different stuff. I dont know why but I hate that everything is on your phone or a website.

So for the password manager I thought it should probably also be pin protected like the nano ledger s. Even if you lose it no one can access your passwords. You could store entries with website, username or email and password. Then simply search and read them on the screen and type them in manually when needed.

How would it work? The device has a small battery that you can charge via usb c. Only electricity. No data connection. Then you enter your pin and get access. If you put in the wrong pin you get locked out for a certain time just like the iphone lock screen. Maybe later a recovery phrase would be interesting but for a prototype I would just focus on the basics like an mvp.

After access you can create entries with domain, username and password. If you create a new account the device could generate a secure password for you so you dont have to think of one yourself.

When you log in somewhere you just open the device, enter your pin, look up the password and manually type it in. I like the idea because right now I either write down my passwords in a notebook or have them in plain text on my laptop which is really bad. My notebook is also not the most secure option. I have it since I was 12 and keep it in a safe place but if my house burns down all passwords are gone. The password manager device would just always be with me on my keychain or next to my phone. No one without the pin could view it.

I also had the idea to have a little notification after 30 days or something which is just a reminder to change your password to stay safe, you could just regenerate a new one on the device for the entry and then you would obviously have to manually change the password on the website and just enter the new password from your device.

Not sure how, but a backup system would be kinda smart, in case the device gets lost or something but then you would have to store it somewhere on your pc or something which I dont like.

Why this device and not just use existing products? I dont want my passwords in the cloud or on my pc where malware could grab them. I want a dedicated offline tool that is safe, simple and always with me. A gadget that only needs power to work, keeps everything encrypted and has no distractions.

I know there are password managers like 1password and they work fine but I have a weird feeling about storing all my passwords with a third party even if they are encrypted. There are also offline password managers like Mooltipass or USB devices like OnlyKey but they try to be everything at once with bluetooth, usb data, auto typing, 2FA and extra features I dont need. I just want a small gadget that is always offline, pin protected and only shows me the password so I can type it in myself.

Obviously this small password manager would not be the most secure thing in the world. If someone gets it they could probably hardware hack it. But there are ways to make it more secure on a hardware level. It also would not protect you from bad user behaviour or social engineering but that is always an issue.

Right now it is just an idea but I think it could be a nice mix of security and minimalism. Like a ledger wallet but for everyday passwords.

For a first prototype I put together a very rough parts list. This is just a starting point and will probably change a lot once I actually start building it:

- Raspberry Pi Pico
- LiPo battery 3.7V 100mAh
- Adafruit Micro Lipo charger
- 0.91" OLED display (128x32)
- 1 Slide switch to turn the power on and off
- 2-3 Tactile push button to navigate

If you have ideas for better parts or things I forgot let me know.