Dead Man's Switch: How to Automate Crypto Inheritance

TL;DR: A dead man's switch is a mechanism that triggers automatically when you stop responding. Combined with Shamir's Secret Sharing, it enables trustless crypto inheritance without giving anyone premature access.

What Is a Dead Man's Switch?

The term comes from trains. Early locomotives had a pedal the driver had to keep pressed. If the driver had a heart attack, the pedal would release and automatically stop the train.

In the digital world, a dead man's switch is any system that requires periodic confirmation you're alive. If you stop confirming, it assumes something happened and takes action.

Why Crypto Needs This

The challenge with crypto inheritance is timing: - Too early: Someone could steal your funds while you're alive - Too late: Your heirs can't find the keys - Just right: Access transfers exactly when needed

A dead man's switch solves the timing problem automatically.

How Shardium's Switch Works

The Timeline

Day	What Happens
0	You create a vault and activate the switch
1-29	Nothing (you're presumably alive)
30	We send you an email: "Are you still there?"
30-59	If you click the link, timer resets to Day 0
60	Final warning email
90	If no response, Shard C is sent to your beneficiary

Why 90 Days?

We chose 90 days as the default because: - Long enough to handle vacations, hospital stays, or forgetting - Short enough that heirs don't wait forever - Multiple reminders prevent accidental triggers

Some users want shorter windows (30 days) or longer (180 days). We're working on customizable timers for pro users.

The Trust Model

Here's what makes this trustless:

What Shardium Has

Your email address
Your beneficiary's email
Shard C (encrypted, useless alone)

What Shardium Doesn't Have

Your seed phrase
Shard A (you keep it)
Shard B (beneficiary keeps it)
Any ability to access your funds

Even if we wanted to steal your crypto (we don't), we mathematically can't. Shard C alone reveals nothing.

Security Considerations

What if someone hacks Shardium?

They get a database of encrypted Shard C values. Without the corresponding Shard A or B, these are worthless. It's like having one piece of a two-piece puzzle—no picture emerges.

What if the heartbeat email goes to spam?

We send from a verified domain with proper SPF/DKIM. We also send multiple reminders over 60 days. But we recommend: 1. Adding our email to your contacts 2. Checking your spam folder occasionally 3. Setting a calendar reminder to check in

What if someone intercepts my heartbeat link?

The link contains a secure, random token. Even if intercepted, clicking it only resets YOUR timer. It doesn't give access to anything.

What if I die and someone else clicks the link?

This is a risk. If a family member has access to your email and keeps clicking, the switch won't trigger. Solutions: 1. Don't share your email password, or... 2. Create a dedicated email just for Shardium 3. Inform your beneficiary about the 90-day window

Alternative Approaches

Google Inactive Account Manager

Google offers a similar feature for your Google account. After N months of inactivity, it can share your data with designated contacts. But it only works for Google services.

Lawyers and Wills

Traditional estate planning can include crypto instructions. But lawyers can be expensive, slow, and don't understand crypto well.

Metal Plates in a Safe

Some people stamp their seed phrase on metal and put it in a safe deposit box with instructions. Works, but requires your heirs to find and access the box.

Multisig with Time Locks

Advanced users can set up Bitcoin transactions with time locks that activate after a certain block height. Very technical and error-prone.

The Shardium Advantage

We combine the best of all approaches:

✅ Automated: No manual action needed when you die ✅ Trustless: We can't access your funds ✅ Simple: No technical knowledge required ✅ Secure: Shamir's math protects against theft ✅ Reversible: You can recover with A+B anytime

Real-World Scenarios

Scenario 1: You Die

Day 0-30: Your family is grieving
Day 30: Email sent (ignored)
Day 60: Final warning (ignored)
Day 90: Shard C sent to beneficiary
Day 91: Beneficiary combines B+C, recovers seed, accesses funds

Scenario 2: You're Hospitalized

Day 30: Email sent to your hospital bed
Day 45: You recover, click the link
Timer resets, no drama

Scenario 3: You Forget

Day 30: Email sent (in spam)
Day 60: Final warning (you notice!)
Day 61: You click the link
Timer resets, crisis averted

Getting Started

Setting up your dead man's switch takes 5 minutes:

Go to shardium.maxcomperatore.com/app
Enter your seed phrase (client-side only)
Download/print Shard A and B
Enter your email and beneficiary's email
Activate the switch

That's it. You'll get reminders every 30 days. Your beneficiary gets access if you stop responding for 90 days.

Questions? Check our FAQ or contact us.