Banana Split

Banana Split uses Shamir's Secret Sharing to split secrets into QR-code shards. Any majority of shards can reconstruct the secret — fewer reveal nothing.

How it works

1. Enter your secret (e.g., a seed phrase, private key, password).
2. Choose how many shards to create and how many are required to reconstruct.
3. Use the auto-generated passphrase or enter your own.
4. Banana Split encrypts the secret with the passphrase, then splits the ciphertext into N QR codes using Shamir's scheme.
5. Print or save the QR codes. Write the passphrase by hand on every sheet.

To reconstruct: scan a majority of QR code shards, enter the passphrase, and your secret is restored.

Features

• Offline — all cryptography happens on-device, no server communication
• Save shards as PNGs or PDF with full Unicode font support
• Open saved shards in another app, save them to Downloads or any folder, or share them
• Camera and gallery QR scanning with multi-file import
• Custom or auto-generated passphrases
• User-selectable quorum (how many shards needed)
• 9 languages: English, Russian, Turkish, Belarusian, Georgian, Ukrainian, Polish, Spanish, Italian
• Cross-platform shard compatibility with the Banana Split web app

Security

Encryption: scrypt key derivation + NaCl secretbox (XSalsa20-Poly1305).
Splitting: Shamir's Secret Sharing over GF(256).
No data collection, no analytics, no trackers.

Web App

Also available as a web app — no installation needed: https://nfcarchiver.com/banana/
Shards created in the app and web version are fully compatible.

Open Source

This app is a fork of banana_split by Parity Technologies, licensed under GPLv3.
Source code: https://github.com/mezinster/banana_split