A dead man’s switch is a mechanism that acts when it stops hearing from you. Scrinium’s version watches for inactivity and, after a threshold and a grace period you choose, releases your notes to a trustee you nominate — without the server ever being able to read them.
The concept comes from safety engineering: a switch that stays closed only while a person keeps pressing it. Applied to a notebook, it answers a question encryption usually makes unanswerable — if something happens to me, how does anyone else get in? A service that cannot read your notes cannot hand them over either, so the naive version of this feature is impossible.
Copying your password into an email to a solicitor, or storing it in a shared vault, both solve the problem by giving up the property that made the notes worth protecting. That trade is usually made silently, years before it matters.
Scrinium splits a Legacy Key into two shares using Shamir’s Secret Sharing with a threshold of two. Mathematically, one share reveals nothing about the secret — the information simply is not there. Two shares reconstruct it exactly.
After the inactivity threshold passes, the switch enters a grace period rather than acting immediately. Signing in cancels it. If the grace period expires, your trustee is emailed a link to a recovery page, which releases the server’s share and the encrypted bundle. The trustee enters the share they were given, the browser reconstructs the Legacy Key, unwraps the vault key, and their notes appear — decrypted locally, in their browser, by the same code path that decrypts them in yours.
At no point does anyone receive your password, and at no point does the server hold a key it can use alone.
Source material, notes, and drafts that someone else may need to reach if you cannot reach them.
A one-person business is one point of failure. The operational notes, account inventory, and handover instructions live somewhere only you can currently open.
Where things are, who to tell, what to do first. The note is useless if it is locked behind the password of the person who is unavailable.
Not a substitute for a will or a lawyer — a supplement, for the digital half of your life that a will has no vocabulary for.
A dead man’s switch is about access, not distribution. Legal instructions, probate, and who is entitled to what are a different conversation with a different professional.
You are given the recovery share once, when you set the switch up. If it is never handed over, or it is lost, the released data stays unreadable — the correct failure mode, but it needs to be said out loud.
The clock resets every time you sign in. If you keep using Scrinium, the switch never fires, no matter how the timer is configured.
The released material reconstructs the vault key, so whoever holds the trustee share can read your notes. If that is more than you intend to share, keep the sensitive material in a separate vault — or leave it out.
The Dead Man’s Switch is part of Scrinium Pro ($5/mo), alongside burner notes, encrypted attachments, version history, graph view, and templates.
A mechanism that waits for a signal which stops arriving — in practice, your logins — and then releases something to a person you nominated. In Scrinium, if you do not sign in for the inactivity period you chose, and you do not return during the grace period after that, your trustee is emailed a link that lets them recover your notes.
By splitting the key. Scrinium uses Shamir’s Secret Sharing with a threshold of two: one share is stored on the server and the other is given to your trustee. Neither share reveals anything on its own, and the server can only ever release its own half.
Mathematics. One share of a 2-of-2 split carries no information about the secret, so the server cannot reconstruct the key at any point — not on the timer, not under subpoena, not if the database is stolen. The release email tells the trustee that their half can now be combined with the server’s, and the combining happens in the trustee’s browser.
Yes. Signing in resets the inactivity clock, and the switch can be disabled from settings at any time, which deletes the server’s share and the stored bundle.
No. Your password is never involved. The trustee never receives your credentials, and you never hand over anything that would let them log in as you — they recover a separate copy of the vault using the share you gave them.
The Dead Man’s Switch is part of Pro. Free accounts keep unlimited notes and sync.