Digital legacy

When someone dies, their bank accounts get sorted out. Their photos, their password manager and the deeds scanned on a hard drive usually do not. Leaving all of it written down in one envelope solves the problem by creating a worse one: anyone who finds the envelope has everything.

The idea: nobody holds the whole thing

ShamirVault splits a secret into parts and lets you decide how many are needed to rebuild it. Give one to each of your children and one to your lawyer, and say that any two of the three recover it. One part on its own reveals nothing at all — not half the password, not a clue. That is a mathematical property, not a promise.

Nobody has to trust anybody completely, which is exactly what makes it work between people who will have to agree at a bad moment.

What you can leave behind

Anything that fits in a text, and any file up to 25 MB:

• The master password of your password manager, which is usually the key to everything else.
• A document with instructions: where the accounts are, which insurer, who to call.
• Scanned deeds, wills, policies. Or a .zip with all of it together.
• Photos you would not want lost, and would not want public either.

With a file, ShamirVault encrypts it and splits only the key. The encrypted file can live anywhere — the cloud, a USB stick — because without the key it is noise. Both halves are needed, and the app says so plainly while you set it up.

Family on one side, lawyer on the other

You can also split into groups with different rules: the lawyer counts as a whole group on his own, the family needs two of three siblings, and any two groups recover the secret. That way the lawyer alone cannot, and the family alone cannot either — but the lawyer plus one sibling can.

It is the same structure a notary would draw on paper, done with arithmetic instead of trust.

Check it now, not when it is too late

The failure that hurts is not discovering it when you hand out the parts: it is discovering it years later, when someone needs to recover them and one part was copied wrong. So the app makes you check each part against the copy you actually stored, and tells you which one is wrong if any is.

Where to start

Open the app, write what you want to leave behind, choose how many parts and how many are needed, and check them. It runs on your device: nothing you type reaches us, and there is no account to create.