AIR-GAPPED SIGNING · SMARTCARD
Your seed arrives by card, not by camera AirgappedStatelessProtectedDaily
The SeedSigner+ with a smartcard hat, paired with a Satochip SeedKeeper card. Your keys load into the device from the card, behind a PIN, without ever being exposed to your surroundings.
SMARTCARD
Keys that load without being shown
This build combines SeedSigner's stateless signing with a Satochip SeedKeeper card. The card holds your secret and the device reads it directly, so your keys go from card to memory without ever being exposed to your surroundings.
PIN PROTECTED
A PIN in front of your secrets
What is on the card is protected by a PIN code, and loading it into the device is fast and simple. The same card can also store a multisig descriptor or other passwords, so what you carry is one card rather than a folder of codes.
FIRMWARE
ShieldSigner, the Satochip fork
This model runs ShieldSigner, the Satochip fork, where the rest of the family runs stock SeedSigner. The firmware adds a suite of built-in tools for interacting with your smartcards and their features. Both are covered by verify.bitsaga.be, and both run in our browser simulator, where the smartcard build is the one that loads by default with three simulated cards whose PINs stick.
DAILY DRIVER
No SeedQR to handle every time
SeedQR still works, and the device can still create one. You simply no longer have to produce it in front of a camera where others might capture it. Your backup stays stored and encrypted instead of being retrieved for every transaction, which is what makes this the one to reach for daily.
BUILT FOR HANDS
A 2.8 inch screen and a proper pad
A 2.8 inch IPS display at 240x320, so addresses and seed words are readable without squinting, with DPAD style controls for precise menu navigation. The USB-C port carries power only.
“A backup you never have to take out of hiding is a backup you never expose.
Seedsigner+ Smartcard specifications
- Display
- 2.8 inch IPS, 240x320
- Controls
- DPAD style buttons
- Power
- USB-C, power only
- Smartcard
- Satochip SeedKeeper, protected by a PIN
- Enclosure
- 3D printed, black or orange
- Firmware
- ShieldSigner, the Satochip fork
- Storage
- 8 GB microSD card included
- Chosen at checkout
- Colour, and one to five SeedKeeper cards
- Works with
- Sparrow, Specter Desktop, Nunchuk, BlueWallet, Keeper
In the box
- Assembled SeedSigner+ with smartcard hat
- Satochip SeedKeeper card
- USB-C cable
- 8 GB microSD card
- Further SeedKeeper cards, up to five in total, if you add them at checkout
Questions
What does the smartcard actually change?
Where your seed comes from, not where it lives. The device is still stateless: the key sits in temporary memory while it has power and is gone when you unplug it. The card is what it loads from, behind a PIN, instead of a QR code you have to produce and hold up every time.
How many cards should I order?
One is enough to start, and it is included. People take more when they hold several seeds, keep a multisig descriptor on a card, or want a spare somewhere else. The colour is free and each extra SeedKeeper card adds 35 euro. The picker shows the total before anything reaches your cart.
Which enclosure do I get?
3D printed, black or orange. The aluminium version of the smartcard build is not available yet.
Can I still use a SeedQR?
Yes. The capability is still there, you are simply not obliged to use it for every signature.
Can I try it before buying?
Yes, and it costs nothing. The browser simulator at bitsaga.be/seedsigner-simulator loads this firmware by default, with three simulated smartcards whose PINs persist, so you can walk the card flows first. Use a public test seed, never one of your own. A browser tab has no secure element and no air gap.
Images: SeedsignerwithSmartcard-scaled.png · 4A89ACC4-2420-43F1-B38D-78BA818B378A-scaled.jpg · 9EDE381A-0F78-4E7E-A490-40DCA76DB56C-scaled.jpg · 83CECAC8-C5D8-4F46-91F3-BA4B30357C0C-scaled.jpg · 470879D7-30A3-49BD-B600-E5F65325A614-scaled.jpg
The one you will actually use every week
Stateless signing, with your seed behind a PIN on a card instead of on a piece of paper you keep fetching. Pick your colour and how many cards you want.