BATTERY POWERED AIR-GAPPED SIGNER
No cable in the signing path CordlessAirgappedStatelessVerifiable
The same SeedSigner Plus, off the leash. Three AAA batteries in the back, up to eight hours of signing, and nothing to plug in. Load a seed, sign through the camera and the screen, then pull the power and the seed is gone.
Includes a setup session with me.
I do not sell a signing device to someone I have not spoken to.
Plus the €150.00 setup session · what that is →
POWER, NOT A CABLE
Runs on three AAA batteries
Three AAA cells sit in a compartment in the back and give you up to eight hours on a fresh set. There is no charger to find, no power bank on the desk, and no USB cable running to the machine you are trying to stay away from.
EASY ACCESS
Swap the batteries in seconds
The rear hatch pops off by hand. Drop in three fresh cells and close it. Nothing is soldered shut, so the one part that wears out is the one part you can replace without tools.
STATELESS
Nothing left to steal
Your seed sits in memory only while the device has power. Take the batteries out and it is wiped. There is no key material stored on the device for anyone to find later.
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 and a spring loaded microSD slot. Everything that makes the Plus easy to use, with the cable removed.
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 to take on faith. You can flash and check the firmware yourself, and rebuild it if you want to.
“A vault that only exists while it is powered, and now nothing even tethers it to the wall.
SeedSigner Plus Battery Edition specifications
- Power
- 3x AAA batteries, up to 8 hours on a fresh set
- Core hardware
- Raspberry Pi Zero 1.3, 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
- Software
- SeedSigner, open source under MIT, stateless by design
- Works with
- Sparrow, Specter Desktop, Nunchuk, BlueWallet, Keeper
In the box
- SeedSigner Plus Battery Edition (assembled, or as a DIY kit)
- 8GB microSD card
- Batteries are not included
Questions
How long do the batteries last?
Up to eight hours of use on a fresh set of three AAA cells. Signing is quick, so in practice a set lasts a long time. When they run low you swap them through the hatch in the back, no tools needed.
Do I still need a cable for anything?
No. The batteries power it, the camera reads the unsigned transaction, and the screen shows the signed one back as a QR code. There is no data cable in the signing path at all.
What is the difference between the assembled and the DIY option?
The assembled one arrives built and tested, ready to power on. The DIY kit is every part in the box for you to put together yourself, fifteen euro cheaper, and you end up knowing exactly what is inside your signing device. Pick either one with the toggle above.
Is my seed stored on the device?
No. It is held in memory while the device is powered and wiped when you pull the batteries. If the device is lost or taken, there is nothing on it to extract.
Can I check the firmware myself?
Yes, and you should. Download the image from the SeedSigner project, then drop the file onto verify.bitsaga.be: it compares the SHA-256 against the hash the project published, in your browser. Nothing is uploaded and we host no firmware of our own.
Can I try it before I buy it?
Yes, and it costs nothing. The real firmware runs in a browser tab at bitsaga.be/seedsigner-simulator, so you can walk the menus, load a seed, export an xpub and sign a transaction first. Use a public test seed, never one of your own.
Sign it, wipe it, no strings attached
One device, any number of seeds, singlesig or multisig. Nothing stored, nothing plugged into your computer, and now not even a cable to the wall.