Silk

An intimate wellness tracker with a working calculator on the front. Tap the icon, get a calculator. Type the PIN, get the tracker. The App Store approval story is in Apple's Problem with Bodies.

Technical Implementation ¶

• AES-256 encryption for all stored data via CryptoKit
• Calculator disguise that works as a real calculator until you enter the PIN
• Core Data with encrypted SQLite
• Biometric unlock via LocalAuthentication
• No network calls. Completely offline.

Privacy Architecture ¶

• No analytics, no third-party SDKs
• No cloud sync by default (optional encrypted iCloud backup)
• All processing on-device
• Export uses encrypted containers

Related consulting: iOS security audit, App Store review strategy.