Back up your wallet seed phrase across places no single fire, flood, or theft can reach. Any threshold restores it. We never see the words.
A handwritten phrase folded into a book, taped behind a frame, hidden under a floorboard. Single location, single fate. House sells, drawer empties, dies with the moving truck.
Steel survives fire. Steel does not survive being the only one. Forgotten combinations, lost keys, drilled-open safes, household disagreements about who can open it. One plate is one fate.
Two halves of the phrase in two locations. Either half compromised, the whole is closer to gone. This is not a threshold scheme. It is two single points of failure, stacked.
Your seed phrase is encrypted with AES-256-GCM on your device. The ciphertext is meaningless without the key.
The encryption key divides into 3 shares using Shamir's Secret Sharing. Threshold 2 of 3. Any single share alone is noise.
Home safe. Trusted person. Bank deposit box. Any two caches reconstruct the key. Any one loss is survivable.
One drawer is one fate. Three caches, with a threshold, is a backup.
Authenticated symmetric encryption. GCM mode detects tampering on recovery. The ciphertext alone is meaningless and indistinguishable from random noise without the encryption key.
Each share is a point on a polynomial over GF(256). K points reconstruct it, fewer than K reveal zero information about the key. Provable, not promised. 51 verified test vectors published.
Never transmitted. Encrypted on your device. We receive no data that could reconstruct it.
Generated locally. Split locally. Never crosses the wire. Not stored, not seen, not held.
Produced in your browser. Rendered to your shard cards. None reach our servers in any form.
A typical 2-of-3 for a self-custody wallet. Survives any single fire, flood, theft, or disagreement, without ever trusting one location alone.
Try the real cryptography on a throwaway phrase. No signup. When you are ready, the plans are one step away.