Shamir Backup

iOS Universel / Utilitaires

Shamir Backup splits your cryptocurrency seed phrase into multiple shares so that no single share reveals your secret. Only a minimum number of shares (threshold) is needed to recover the original phrase.

HOW IT WORKS

Shamir's Secret Sharing is a proven cryptographic scheme used by security professionals worldwide. You choose how many shares to create (e.g. 5) and how many are needed to recover (e.g. 3). Any combination of 3 shares will restore your seed phrase — but 2 or fewer reveal absolutely nothing.

SPLIT
• Enter your seed phrase
• Choose total shares (2–16) and recovery threshold
• Generate shares instantly
• Select, copy, or share individual shares via AirDrop, Messages, or any sharing method

RECOVER
• Paste the required number of shares
• Instantly reconstruct your original seed phrase
• Copy the recovered phrase with one tap

SECURITY FIRST
• 100% offline — no internet connection, no servers, no cloud
• No third-party libraries — cryptography implemented from scratch
• Sensitive data is automatically cleared when you leave the app
• Clipboard is cleared on app termination
• No analytics, no tracking, no data collection

PAID ONCE, YOURS FOREVER
• No subscriptions, no in-app purchases, no trial limits
• All features available immediately
• No ads, ever

WORKS EVERYWHERE
• iPhone, iPad, and Mac (Apple Silicon)
• Adaptive interface — tabs on iPhone, two-column layout on iPad and Mac
• Full Dark Mode support

BUILT ON PROVEN MATH
• Galois Field GF(256) arithmetic with AES polynomial
• Lagrange interpolation for share reconstruction
• Industry-standard scheme used by hardware wallets and exchanges

Perfect for cryptocurrency holders who want to distribute their seed phrase backup across multiple secure locations — a safe deposit box, a trusted family member, a fireproof safe — knowing that no single location compromises their funds.