What is a Dead Man's Switch for Crypto?
How a cryptographic dead man's switch works, why it is the only reliable way to automate crypto inheritance, and what to look for in an implementation.
A dead man's switch is a mechanism that triggers automatically when a person stops confirming they are alive. Originally used in trains and industrial machinery, the concept translates directly to cryptocurrency inheritance.
How it works
- →You set a check-in interval — for example, 30 days.
- →You check in periodically (via app, email link, or API) to reset the timer.
- →If you miss your interval, the system sends warnings to you and your heir.
- →If you still don't check in, the system delivers your encrypted vault to your heir automatically.
What gets delivered
A well-designed system never delivers your plaintext seed phrase. It delivers an encrypted vault blob and the heir's shard of the decryption key. Your heir then reconstructs the decryption key and decrypts the vault locally in their browser — no server required.
Shamir's Secret Sharing
Shamir's Secret Sharing (SSS) is the mathematical technique used to split a secret into N shards where any M shards can reconstruct it. A 2-of-3 split means: you hold Shard 1, your heir holds Shard 2, and a neutral third node holds Shard 3. Any two shards reconstruct the key. Neither party alone can decrypt the vault.
What to look for
- →Client-side encryption only — the service should never see your plaintext.
- →Open-source decryption code — your heir must be able to decrypt without the company being online.
- →Configurable intervals — 30, 60, 90 days depending on your travel and health situation.
- →Grace period and warnings — a proper implementation warns you multiple times before triggering.
What to avoid
Avoid any service that stores your seed phrase server-side, even encrypted by them. Avoid services that require your heir to trust a live API to decrypt. Avoid services with no open-source recovery path — if they shut down, your heir is locked out.
Protect your crypto legacy
VaultPass is a zero-knowledge inheritance protocol. Your seed phrases are encrypted in your browser — we never see them.