n of m

for iOS

Shamir's Secret Sharing with native camera performance

$2.99 -- full functionality, no in-app purchases.

A free version (2-of-3 only) is coming soon. Price will increase to $9.99-$19.99.

Why a native app?

Laptop webcams were not designed for QR code scanning.

Laptop / Desktop Camera
  • × Fixed focus -- struggles with close-range QR codes
  • × Low resolution sensors (720p typical)
  • × Poor low-light performance
  • × No optical image stabilization
  • × Wide-angle distortion at scanning distance
iPhone Camera
  • Autofocus with phase detection
  • 12-48MP sensors with computational photography
  • Night mode and adaptive exposure
  • Optical image stabilization
  • Near-instant QR detection via AVFoundation

Features

Everything the web app does, plus native iOS capabilities.

Native Camera Scanning

AVFoundation-powered QR detection. Point and scan -- no fumbling with webcam positioning or browser permissions.

FaceID / TouchID

Lock your vault with biometric authentication. iOS Keychain encryption keeps secrets safe even if the device is compromised.

Generate or Import

Create new BIP39 seed phrases (12 or 24 words) with cryptographic entropy, or import existing mnemonics from any wallet.

Shamir Splitting

Split into up to 10 shares with configurable thresholds. GF(2^8) finite field arithmetic -- information-theoretic security.

Print Share Cards

Export as full-page PDF cards with QR codes, metadata labels, instructions, and a notes section. Print and distribute.

Encrypted Vault

Store recovered secrets in an on-device encrypted vault. AES-256-GCM encryption with optional PIN protection.

HD Wallet Derivation

Derive addresses using MetaMask, Ledger Live, or custom BIP32/BIP44 paths. Verify your seed maps to the right addresses.

Fully Offline

Zero network calls. No telemetry, no analytics, no servers. Every operation runs entirely on your device.

How it works

Four steps from seed phrase to distributed cold storage.

1

Generate or Import

Create a new BIP39 seed phrase with device entropy (accelerometer + system CSPRNG), or import an existing 12/24-word mnemonic. Optionally derive HD wallet addresses to verify correctness.

2

Split into Shares

Choose your threshold (N) and total shares (M). The app constructs random polynomials over GF(2^8) and evaluates them to produce M share points. Each share is encoded as a QR code on a printable card.

3

Print and Distribute

Export share cards as PDF. Each card includes the QR-encoded share, share index, threshold requirement, and a notes section. Print on standard paper and store each card in a separate secure location.

4

Scan to Recover

When you need your seed phrase, scan any N share cards with the iPhone camera. The app performs Lagrange interpolation over GF(2^8) to reconstruct the original secret. Store the result in the encrypted vault.

Security Model

Defense in depth at every layer.

On-Device Only

All cryptographic operations execute locally. No server communication, no cloud sync, no third-party dependencies at runtime.

Information-Theoretic Security

Shamir's scheme guarantees that fewer than N shares reveal zero bits of information about the secret. This holds against unlimited computing power.

iOS Keychain

Vault data is encrypted via the iOS Keychain -- hardware-backed encryption tied to the device's Secure Enclave.

Biometric Gate

Vault access requires FaceID or TouchID. Failed biometric attempts fall back to device passcode, never to a weaker mechanism.

Open Source

The full source code is publicly auditable. No obfuscation, no binary blobs, no hidden network calls. Verify the implementation yourself.

Memory Safety

Sensitive data (seed phrases, shares, private keys) is cleared from memory after use. The app never writes plaintext secrets to disk.

Frequently Asked Questions

Requirements

Platform iOS 16.0 or later
Devices iPhone, iPad
Size < 15 MB
Price $2.99 (introductory)
In-App Purchases None -- full functionality included
Network Required No
Camera Required For QR scanning (generation works without)
License Open Source (MIT)

Get Started

Split your first seed phrase in under a minute.