The Decoy Vault: Your Last
Line of Defence Under Pressure

Encryption protects your files from someone who steals your phone. But what about someone who's standing in front of you, demanding you unlock it?

Technical security can't solve a social problem. If someone with authority over you — a controlling partner, an overzealous border agent, a coercive family member — demands to see your phone, a locked vault just escalates the situation.

That's exactly the problem a decoy vault is designed to solve.

What Is a Decoy Vault?

A decoy vault is a second, completely separate PIN that opens a fake version of your vault — one that appears completely empty (or contains harmless files you placed there deliberately).

Here's how it works in practice:

• Your real PIN (e.g., 1234) opens your actual private vault
• Your decoy PIN (e.g., 5678) opens a different vault — empty, or containing benign content

If someone forces you to unlock the app, you enter the decoy PIN. They see an empty or innocent vault. Your real vault — and everything in it — remains completely hidden.

From a technical standpoint, both vaults exist independently. The app has no way to "prove" which one is the real vault, because there is no metadata or indicator that distinguishes them.

Who Needs This Feature?

The use cases for a decoy vault are more common than you might expect:

• Domestic situations — a partner who checks your phone regularly and has a history of controlling behaviour
• International travel — some border agencies can legally demand device access; a decoy vault gives you plausible compliance
• Nosy family members — parents, siblings, or flatmates who feel entitled to see your phone
• High-risk professions — journalists, activists, lawyers with sensitive source information
• General peace of mind — you don't need a dramatic reason to want a backup option

How to Set Up the Decoy Vault in Calculator Vault

1. Unlock your vault with your real PIN
2. Tap Settings (bottom right)
3. Go to Security → Decoy Vault
4. Tap "Enable Decoy Vault"
5. Set a 4-digit decoy PIN — make it different from your real PIN
6. Optionally add some decoy content (a few harmless photos, a shopping note)

From that point on, entering the decoy PIN opens the decoy vault. No prompts, no indicators — it looks identical to your real vault, just with different (or no) content.

Tips for Using the Decoy Vault Effectively

Add Some Content to the Decoy

An completely empty vault might look suspicious. Add a few harmless photos — screenshots, memes, or photos you'd be happy showing anyone. This makes the decoy look natural and lived-in.

Use a Plausible PIN

If you use 0000 as your decoy PIN, that itself looks suspicious. Use a normal-looking 4-digit number you can remember easily under stress.

Keep the PINs Mentally Separate

Under pressure, it's easy to accidentally enter the wrong PIN. Practice the distinction between your two PINs until it's automatic. Your real PIN should be as automatic as typing your lock screen password.

Pair With a Disguise Icon

The decoy vault is most effective when combined with an innocent app icon. If the app looks like "Notes" on your home screen, and the decoy vault looks like an empty notes folder, the entire story is coherent.

The Emergency PIN: An Extra Layer

Calculator Vault also includes an Emergency PIN — a third code for extreme situations. When entered, it triggers automatic data protection: the vault content is wiped immediately, leaving nothing behind.

Think of the three PINs as layers:

• Real PIN — your private vault, for everyday use
• Decoy PIN — shows nothing, used under social pressure
• Emergency PIN — wipes everything, used in extreme situations