Bitcoin Seed Backup and Signing Devices
Tools for Bitcoin self-custody: sign transactions air-gapped and store your recovery phrase in steel, safe from fire and water.
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Two jobs: signing and backup
Self-custody means your private keys never sit with an exchange. That leaves two tasks: signing transactions without exposing the keys, and keeping a backup of the recovery phrase that survives fire and water.
Signing: SeedSigner
The SeedSigner is an open-source signing device without any network connection. Transactions go in and out as QR codes, the private keys stay offline. Hardware and software are open, so anyone can check what the device does.
Backup: Steel Seed Set
Paper burns and gets wet. With the Steel Seed Set you stamp your recovery phrase into 24 steel discs and keep them in an aluminium tube. The set comes in orange, forest green and black. It is our own product, sold under the Nerdminer Store name.
Good practice
- Write the recovery phrase down offline only, never as a photo or in a cloud note.
- Keep the steel backup in a different place from the signing device.
- Test the backup: restore a wallet from it before you move larger amounts.