Split and protect your secrets
Use the Shamir scheme to split any secret into independent parts. Only the required parts can reconstruct it.
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What is it
A cryptographic algorithm that splits a secret into multiple parts called shares. Only a minimum number of shares — the threshold — can reconstruct the original secret.
For example, split a secret into 5 shares with a 3-of-5 threshold. Any 3 shares recover the secret; fewer than 3 reveal nothing at all. This is called information-theoretic security.
Use Cases
Split your Bitcoin seed phrase into shares distributed among trusted people or locations. No single point of failure for your wallet recovery.
Secure multisig backup keys using Shamir splitting. Ideal for organizations managing Bitcoin multisig wallets with distributed key holders.
Split master passwords, API keys, or any sensitive text. Distribute shares to family members, colleagues, or secure locations.
How It Works
Type or paste any text — a seed phrase, password, private key, or any sensitive data you want to protect.
Choose how many total shares to create and the minimum threshold needed to reconstruct the secret.
Each share is a self-contained string. Distribute them to trusted people, devices, or secure locations.
Features
All cryptographic operations happen in your browser. Your secret never leaves your device — no servers, no uploads, no tracking.
Uses Galois Field arithmetic over GF(2^8), the same mathematics behind proven implementations of Shamir's Secret Sharing scheme.
Each share encodes its index, threshold, and data. Shares can be reconstructed using any compatible SSS implementation.
Install as a Progressive Web App and use it without internet. Perfect for air-gapped environments and secure setups.
Security
ShamirVault is designed with a zero-trust architecture. We can't see your data because it never reaches us.
FAQ
Shamir's Secret Sharing (SSS) is a cryptographic algorithm invented by Adi Shamir in 1979. It splits a secret into multiple parts called shares. Only a minimum number of shares (the threshold) can reconstruct the original secret. For example, you can split a secret into 5 shares where any 3 can recover it, but 2 or fewer reveal absolutely nothing.
Use ShamirVault to split your Bitcoin seed phrase into multiple shares using Shamir's Secret Sharing. Choose a threshold (e.g., 3-of-5) so that any 3 shares can recover your seed, but fewer cannot. Distribute shares to trusted locations or people. Unlike simply cutting a seed phrase in half, Shamir splitting provides information-theoretic security — fewer shares than the threshold reveal zero information about the original seed.
Yes. ShamirVault runs 100% in your browser. No data is ever sent to a server. The tool uses standard GF(256) Galois Field arithmetic for the Shamir scheme, which is mathematically proven secure. You can verify this by using the tool offline or in an air-gapped environment. There is no tracking, no analytics on your secrets, and no server-side processing.
Multisig (multi-signature) is a Bitcoin protocol feature that requires multiple keys to authorize a transaction. Shamir Secret Sharing splits a single secret (like a private key or seed phrase) into parts. They are complementary: you can use Shamir splitting to back up each key in a multisig setup, providing an extra layer of security for key recovery.
Yes. ShamirVault is a Progressive Web App (PWA) that can be installed on your device and used without an internet connection. This makes it ideal for air-gapped environments where maximum security is required for splitting sensitive secrets like Bitcoin seed phrases or private keys.