SeedVault — Threshold Backup for Seed Phrases

Splits a recovery phrase into shares so that a threshold of them restores the wallet and any smaller number reveals nothing, replacing one phrase in one place with a distributed backup.

The backup problem

A single written seed is one point of failure: a fire, a theft or the wrong person finding it ends the story. Making more copies does not fix it, because every copy is another complete key. SeedVault changes the shape of the problem instead of the number of copies.

Shamir secret sharing

The protocol uses Shamir's Secret Sharing, implemented to the SLIP-39 standard, to split the seed into shards with an M-of-N threshold you choose — three of five, for example. Any three reconstruct the seed; one or two reveal no information about it at all, which is a mathematical property of the scheme, not a policy.

What that buys you

Shares can be separated geographically or between people, so no single location, disaster or individual is enough to lose the wallet or to take it. It addresses losing the seed; it is not a defence against someone who already holds enough shares.

Availability

SeedVault is part of the Nyxor edition.