AIR-GAPPED BITCOIN SIGNING DEVICE
Nothing to steal off this device AirgappedStatelessOpenVerifiable
Fully assembled and ready to use. Load a seed, sign a transaction through the camera and the screen, then pull the power and the seed is gone.
STATELESS
Nothing left to steal
Your seed sits in memory only while the device has power. Remove the power and it is wiped. There is no key material stored on the device for anyone to find later.
AIR-GAPPED
Separated by nothing but air
No WiFi. No Bluetooth. The unsigned transaction goes in through the camera. The signed one comes back out as a QR code on the screen. Your keys never touch a networked machine.
BUILT FOR HANDS
Bigger screen, real buttons
A 2.8 inch IPS display at 240x320, so addresses and seed words are readable without squinting. DPAD style controls. A spring-loaded microSD slot. Outgoing QR data moves faster than on the original hardware.
POWER ONLY
A port that carries no data
The USB-C port takes power and nothing else. There is no cable path in or out for your keys, by design. The camera and the screen are the only two doors.
OPEN SOURCE
Do not trust, verify
SeedSigner is MIT licensed, built by volunteers, with reproducible builds and commodity parts. No sealed black box, no company claims to take on faith. Ten dollars from every assembled unit goes to the project maintainer.
“A vault that only exists while it is powered, and holds nothing at all once it is not.
SeedSigner Plus specifications
- Core hardware
- Raspberry Pi Zero v1.3, no WiFi, no Bluetooth
- Display
- 2.8 inch IPS, 240x320
- Camera
- Zero Cam, used for QR scanning and photo entropy
- Controls
- DPAD style buttons
- Storage
- Spring-loaded microSD slot
- Power
- USB-C, power only
- Software
- SeedSigner, open source under MIT, stateless by design
- Works with
- Sparrow, Specter Desktop, Nunchuk, BlueWallet, Keeper
In the box
- SeedSigner Plus, fully assembled and ready to use
- MicroSD card
- USB-C power cable
- 25x25 SeedQR code cards
Questions
Is my seed stored on the device?
No. It is held in memory while the device is powered and wiped when power is removed. If the device is lost or taken, there is nothing on it to extract.
Which wallet software does it work with?
Any coordinator that speaks QR. Sparrow, Specter Desktop, Nunchuk, BlueWallet and Keeper are the common ones. You keep watching your balance there, and only the signing happens here.
Can I use it for multisig?
Yes. Load your seeds one at a time, export the xpubs to your coordinator, and sign each key on the same device. It is the cheapest honest way to try multisig.
Do I have to build it myself?
No. It arrives assembled with a microSD card, ready to power on. The hardware and the software are public, so you can still verify or rebuild it yourself later.
Images: hero.jpg · in-hand.jpg · controls.jpg · camera-back.jpg · usb-c-port.jpg · device-cutout.png
Sign it, then wipe it
One device, any number of seeds, singlesig or multisig. Nothing stored, nothing plugged into your computer, nothing you have to take on trust.