SeedHammer

• Name: SeedHammer
• URL: https://seedhammer.com/
• Category: bitcoin seed-backup hardware / multisig recovery-packaging tool
• Tags: bitcoin-ecosystem
• Summary: SeedHammer is mostly a small metal-backup engraver for Bitcoin seed phrases. The only reason to keep the note is the recovery packaging: it tries to put enough descriptor and share material onto the plates that multisig recovery does not depend on a separate pile of backup files.
• What it does:
  • Engraves seed phrases and related recovery data onto steel plates
  • Supports single-sig and multisig backup workflows
  • For multisig, packages enough recovery data onto the plates that the minimum quorum can recover without separately stored descriptor files
  • Uses an air-gapped Raspberry Pi Zero-based controller and publishes open-source firmware and hardware files
• Why it matters:
  • Mostly it does not. This is backup hardware, not an important protocol or control surface.
  • The only reason to keep a note is that the self-contained multisig backup design is a mildly interesting implementation detail.
• Whitepaper: none; use ../whitepapers/seedhammer-primary-sources-2026-05-01.md for the primary-source dump.
• Sources:
  • https://seedhammer.com/
  • https://seedhammer.com/faq
  • https://seedhammer.com/article/the-seedhammer-controller
  • https://seedhammer.com/article/the-seedhammer-descriptor-partitioning-scheme
  • https://seedhammer.com/article/attack-vectors
  • https://github.com/seedhammer/seedhammer
  • https://raw.githubusercontent.com/seedhammer/seedhammer/main/README.md
  • https://github.com/seedhammer/hardware
  • https://raw.githubusercontent.com/seedhammer/hardware/main/README.md

Internal linkages

• Upward recovery and signer references: coinkite and seedsigner
• Link this note only where physical seed-backup logistics or self-contained multisig recovery are specifically the point.

Control surface

• The only real control surface here is how recovery data gets packaged onto durable metal media and whether that packaging reduces reliance on separate descriptor backups.

• Treat it as backup gear with one interesting multisig-recovery wrinkle, not as a wallet or custody anchor.

• Last reviewed: 2026-06-02 UTC