Metal Seed Backup

A metal seed backup is a recovery phrase recorded on steel or another durable metal — stamped, punched, or assembled from letter tiles — instead of on paper. The reasoning is that the threats to a written backup are mostly environmental rather than adversarial: fire, flood, damp, fading ink and ordinary decay destroy paper long before anyone finds it, and a phrase that cannot be read is the same loss as a phrase that was never written. Metal removes that failure mode and nothing else. It encrypts nothing, so a plate found in a drawer is exactly as spendable as a card would be, which is why location, concealment and, where used, a separate passphrase still carry the security. Two practical points: record enough to reconstruct the wallet, including which standard and derivation path the phrase belongs to, and read the finished plate back before the original is destroyed.