SeedHammer

• Name: SeedHammer
• URL: https://seedhammer.com/
• Category: bitcoin recovery-backup hardware / descriptor-aware metal-engraving tool
• Tags: bitcoin-ecosystem
• Summary: SeedHammer is a small metal-backup engraver. Keep the note for one reason: it tries to put enough seed, share, and descriptor material on steel plates that multisig recovery does not depend on a separate backup-file mess.
• What it does:
  • Engraves seed phrases and related recovery data onto steel plates
  • Supports both single-sig and multisig backup workflows
  • Uses a descriptor-partitioning scheme so a multisig quorum can recover with the plates alone instead of hunting for separate descriptor files
  • Runs through an air-gapped Raspberry Pi Zero-based controller and publishes open-source firmware and hardware files
• Key claims:
  • This is backup gear, not an important wallet or custody control plane
  • The descriptor-partitioning scheme is the only reason to spend graph oxygen on it
  • The useful question is whether self-contained multisig backup packaging actually reduces operational fragility without creating a sloppier physical-secret footprint
• 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 signer and recovery-discipline reads: coinkite and seedsigner.
• Link this note only when physical backup discipline or self-contained multisig recovery packaging is actually the point.

Control surface

• The only real leverage is in the descriptor-partitioning scheme, how much recovery material gets engraved onto each plate, and the tradeoff between operational simplicity and physical disclosure risk.

• Open hardware is fine, but it is not the reason the note survives. The note survives because SeedHammer makes one narrow backup-design choice unusually explicit.

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

• Last reviewed: 2026-06-13 UTC