Show HN: Shardium – open-source "Dead Man's Switch" for crypto inheritance
shardium.xyz
Hi HN, I'm Max.
I built this because I was terrified that if I die tomorrow, my family gets nothing. The existing solutions were either trusting a centralized custodian or complex hardware setups.
Shardium is a client-side tool that splits your seed phrase into 3 shards using Shamir's Secret Sharing.
Shard A: You keep.
Shard B: You give to a beneficiary (PDF).
Shard C: We hold (or you self-host).
It works as a dead man's switch: If you are inactive for 90 days (email ping), Shard C is released to your beneficiary. They combine B + C to recover the funds.
The Stack:
secrets.js-grempe for the math.
FastAPI + PostgreSQL backend.
Client-side encryption (seed never hits the network).
It is 100% Open Source and MIT Licensed. You can self-host it for free ($0), or use the managed version.
I'd love your feedback on the security model. Roast my code here: https://github.com/pyoneerC/shardium