Face ID for Your Prayer Journal

Biometric unlock just shipped in Praying: open the app, glance at your phone (or touch the sensor), and your encrypted journal unlocks. No password typing.

Whenever a privacy-focused app adds a convenience feature, you should ask what it costs. So here's the honest, no-hand-waving explanation of what Face ID does in Praying — and, just as importantly, what it doesn't.

First, a quick recap of how your journal is locked

Everything you write in Praying is encrypted with AES-256-GCM before it leaves your device. The key that unlocks it is derived from your account password (PBKDF2, 600,000 iterations) — on your device, never on our servers. We store only ciphertext and wrapped keys. That's the zero-knowledge design, and nothing about it changed this week.

The practical consequence: your device needs your key in hand to decrypt your journal. Before biometric unlock, that meant typing your password whenever the app needed to re-establish it. Secure, but enough friction that some people were tempted toward shorter passwords — which is the one thing you should never weaken, because your password is your encryption.

What Face ID actually does

When you enable biometric unlock, your device caches your already-derived key in the operating system's keychain — the hardware-backed secure storage built into iOS and Android — and marks it as retrievable only after a successful biometric check.

Notice what's not in that list: your face. Face ID and fingerprint data never leave your device and are never available to apps — that's an operating-system guarantee, enforced in hardware. Praying never sees your biometrics; it only learns "the OS says this is the owner" and receives the key it cached earlier.

Your password is still the master key

This is the part to hold onto: biometrics gate the cached key; they don't replace the password. Your password remains the root of your encryption. If Face ID fails — you're wearing a mask, the sensor misreads, or the OS decides to be cautious after a restart — you fall back to typing your password, and everything works exactly as before. Disable biometrics anytime in Settings and the cached key is discarded; you're back to password-only.

It also means biometric unlock changes nothing about account recovery. Lose your device and your data is still recoverable with your password (or your one-time recovery code) on a new device — and still unreadable to anyone who has the old one.

Why this beats an app-level PIN

Plenty of journaling apps offer a 4-digit PIN screen. It feels similar. It isn't:

The point of all this

Security that's annoying gets turned off. The goal of biometric unlock is to make the private thing also the easy thing — so the journal you trust with your most honest prayers is one glance away, every morning, without a single compromise to the encryption underneath.

Convenience features should never quietly weaken the lock. This one doesn't — and now you know exactly why.