Your pattern unlocks the vault.
A second factor confirms it is you.

Your pattern produces the encryption key. Two-factor authentication adds a second check after that. Even if someone learns your pattern, they must pass Face ID, enter the PIN, or use your hardware key. The vault opens only after both checks pass.

Face ID or Touch ID

The fastest second factor. Your face or fingerprint unlocks the vault in under a second. Biometric data never leaves your device's Secure Enclave.

Fastest

6-digit PIN

A separate six-digit code, independent of your iPhone passcode. A code you know, no biometric hardware required, works in any conditions.

Simplest

YubiKey over NFC

A physical hardware key you tap against your phone. Even if your phone is stolen or infected with malware, the key itself is separate. The only factor that is not on the phone at all. Read more about YubiKey.

Most isolated
Step by step

What happens after you draw the pattern.

Two-factor authentication in ArkWarden is not a sign-in screen with a code from your email. It is a second check that runs after your pattern has already produced the encryption key. The order matters.

1

The pattern produces the key

You draw your pattern. ArkWarden runs the key derivation, the candidate key tries to unwrap the master key, and either the unwrap succeeds or it does not. If it fails, you never see the second factor screen, because there is no master key to protect at that point. This is how the cryptography decides that the pattern was correct.

2

The second factor decides whether the vault opens

If you have a second factor enabled, ArkWarden does not show you the vault yet. It hands control to the second factor flow:

  • Face ID or Touch ID prompts you through Apple's biometric system.
  • A PIN screen asks for your six digits.
  • A YubiKey prompt asks you to hold your hardware key against the back of your phone.

The vault stays locked until the second factor returns a clear success. Cancel, fail it, or close the app and you go back to the lock screen.

3

The vault opens

The second factor passes, the vault appears, and the master key stays in memory until you lock the app or close it. The next time you return, the full sequence runs again from the beginning. Pattern first, second factor second, every time.

ArkWarden does not implement its own biometric matching, comparison logic, or FIDO stack. Each method goes through Apple's frameworks or Yubico's SDK. We use the standards as designed, with no shortcuts.

The difference

Why a second factor is worth the extra second.

A single factor is a single point of failure. Two factors split the failure modes. Someone who observes your pattern still cannot get in. A lost phone still cannot get in. Both factors have to be yours.

Pattern only Pattern + Face ID Pattern + PIN Pattern + YubiKey
What you need to unlock The pattern Pattern and your face Pattern and six digits Pattern and the physical key
Resists shoulder surfing the pattern No Yes Yes Yes
Works in low light or with a mask Yes Sometimes not Yes Yes
Factor remains separate from a cloned device Depends on method Yes. Biometrics bound to Secure Enclave. Yes. PIN does not migrate to other devices. Yes. Hardware key is separate equipment.
Factor is not on the phone at all No No No Yes
Convenience Highest Highest High Slightly slower (NFC tap)

The pattern controls decryption. The second factor controls access.

Your pattern decides whether the encryption opens. Your second factor decides whether the vault is shown after the pattern succeeds. Splitting these two responsibilities is what makes the combination stronger than either control alone.

Choose the second factor that fits your situation.

Pick Face ID if your main concern is casual access, a lost phone, or someone who knows your pattern from watching you draw it. Pick a PIN for a code you know with no biometric dependency. Pick a YubiKey for a factor that is not on the phone at all. ArkWarden supports all three, and you can change your choice later.

Two-factor authentication is optional.

Some people want maximum convenience. Some people want maximum protection. ArkWarden lets you choose. You can use the pattern alone, which is already a serious cryptographic system. You can add a second factor at any time from Settings. You are not pushed into either choice during onboarding. If you use a YubiKey and lose it, your recovery phrase lets you bypass 2FA and regain access.

For the curious

What each second factor actually is.

ArkWarden supports three methods. Pick the one that fits how you actually use your phone.

Face ID and Touch ID

ArkWarden uses Apple's LocalAuthentication framework for biometric verification. The actual matching happens inside the Secure Enclave, a dedicated security chip on your iPhone. The Face ID or Touch ID data never enters the regular iOS file system, never touches ArkWarden's process memory, and never leaves the device.

What ArkWarden gets back is a binary result: success or failure. We do not see the biometric template, we do not see partial scores, and we do not see what the camera saw. The full biometric path runs inside Apple's security boundary.

The 6-digit PIN

The PIN is a six-digit secret you choose during setup. It is stored on your device, with the iOS accessibility class that requires the device to be unlocked and prevents migration to a different device. There is no cloud copy and no sync.

The PIN is independent of your iPhone's own passcode. Setting a PIN inside ArkWarden does not change anything about your iPhone's lock screen, and changing your iPhone's passcode does not change anything inside ArkWarden. We recommend picking a different value for each so the two systems remain fully independent.

YubiKey over NFC

A YubiKey is a small physical security key made by Yubico. ArkWarden talks to it using FIDO2 / WebAuthn, the same standard used by Google, Microsoft, and financial institutions worldwide for their highest-value accounts.

When you register a YubiKey, the key generates a public and private key pair internally and gives ArkWarden the public key. The private key never leaves the YubiKey. At unlock time, ArkWarden sends the YubiKey a random challenge, the YubiKey signs it using the internal private key, and ArkWarden verifies the signature. This means:

  • An attacker who clones your phone does not get a YubiKey. They have to also possess the physical hardware.
  • An attacker who steals the YubiKey alone cannot read your vault. They still need the pattern.
  • The same YubiKey can be used for unrelated services without giving those services any access to your ArkWarden vault.

You can register up to two YubiKeys per vault. The second key is a backup. If you misplace one, the other still works. For the full setup flow, screenshots, and recovery details, see the YubiKey page.

The verification chain, end to end

Part What it does Where the secret is stored
Pattern Produces the encryption key through key derivation In your head and your muscle memory
Master key unwrap Authenticated decryption that opens only for the right derived key Wrapped master key in the iOS Keychain, encrypted at rest by the Secure Enclave
Face ID or Touch ID Verifies the face or fingerprint Biometric template inside the Secure Enclave, never seen by ArkWarden
PIN Matches the six digits you set Stored in the iOS Keychain, encrypted at rest by the Secure Enclave, device-locked
YubiKey Signs a fresh random challenge with FIDO2 / WebAuthn The signing key is stored on the YubiKey itself, not on the phone

What changes when you change your second factor

You can switch methods at any time from Settings. Switching does not re-encrypt your files, because the encryption is tied to your pattern, not your second factor. The second factor is a verification check before the unlocked vault is shown. Changing it changes the check, not the encryption.

Common questions

What people usually ask next.

Is two-factor authentication required?
No. ArkWarden works with the pattern alone, and the pattern alone is already a real cryptographic system that produces the encryption key for your vault. The second factor is an optional check you add when you want extra protection against the case where your pattern itself is compromised.
Does ArkWarden ever see my face or my fingerprint?
No. Face ID and Touch ID are handled entirely inside the Secure Enclave on your iPhone. ArkWarden gets back a binary success or failure. The biometric template stays inside the dedicated security chip, never touches ArkWarden's process, and never leaves the device.
Is the PIN the same as my iPhone passcode?
No. The PIN you set in ArkWarden is independent of your iPhone's passcode. Changing your iPhone passcode does not change your ArkWarden PIN, and your ArkWarden PIN does not change anything about how you unlock the phone itself. We recommend picking a different value for each so the two remain fully independent.
Can I use a YubiKey on iPhone?
Yes, over NFC. You tap the YubiKey against the back of your iPhone the same way you would tap a contactless card or transit pass. ArkWarden uses FIDO2 / WebAuthn, the modern standard for hardware-backed authentication. See the YubiKey setup guide for the full flow.
How do I set up a YubiKey with ArkWarden?
Open two-factor authentication in Settings and choose YubiKey, draw your pattern to confirm it is you, then hold the key to the top of your iPhone to register it over NFC. You can register up to two keys as backups. The YubiKey page walks through every screen step by step, how to add a second key, how to rename your keys, and what to do if one is lost.
Does the YubiKey work with USB-C on iPhone?
Not yet. ArkWarden currently supports YubiKey over NFC only. USB-C wired authentication for third-party apps is not supported by Apple's current frameworks. NFC works on every iPhone that supports NFC, regardless of charging port. We are watching the space and will add USB-C support when Apple makes it possible.
Can I register more than one YubiKey?
Yes. You can register up to two YubiKeys per vault. The second one acts as a backup. If you lose one, you still have the other, and you can unregister the lost key from Settings using the remaining one. The YubiKey page covers registering a backup key in detail.
What happens if I lose my YubiKey and have no backup?
You use your BIP-39 recovery phrase to bypass two-factor authentication and regain access to your vault. On the lock screen, choose the recovery phrase option, enter your words, and once inside you can disable YubiKey or register a new one. The recovery phrase is always the final recovery method, regardless of which second factor you have set. Learn more about the recovery phrase.
What if I lose access to my second factor entirely, Face ID, PIN, or YubiKey?
Your BIP-39 recovery phrase bypasses the second factor entirely. Enter your recovery phrase on the lock screen to access your vault, then go to Settings to reconfigure or remove the second factor. This is by design. The recovery phrase is a second way to access your vault that bypasses all other checks.
Is the PIN stored anywhere outside my phone?
No. The PIN is stored on the device only, with the iOS accessibility class that prevents access while the device is locked and prevents migration to a different device. There is no cloud copy. If you erase the app or the vault, the PIN goes with it.
Does ArkWarden work without internet for second factor verification?
Yes. All three methods work fully offline. Face ID happens on the device. The PIN is verified on the device. The YubiKey communicates directly with the iPhone over NFC. None of the second factors require a network connection.
Can I change my second factor later?
Yes. Settings has a 2FA section where you can switch between Face ID, PIN, YubiKey, or none at any time. Switching does not re-encrypt your files because the encryption is tied to your pattern, not your second factor. Only the verification check changes.
What if I am compelled to unlock my vault?
ArkWarden has a feature called Wing, a second vault opened by a different pattern. Drawing the Wing pattern opens a separate vault with its own files and appearance. Your real vault, and its second factor, stay untouched. The person asking you to unlock sees a fully functional vault. They do not see your real one.
See it in practice

Situations where a second factor matters.

ArkWarden

One pattern is good.
Two factors are better.

Your pattern is the encryption key. Your second factor is an additional check before the vault opens. Choose the method that works for you. ArkWarden supports all three, and you can change it at any time.

Scan to download ArkWarden
Install on iPhone. No account, no email.
Point your camera at the code.
Download on the App Store
Read about pattern unlock
Face ID and Touch ID through Apple's Secure Enclave 6-digit PIN stored only on your device YubiKey over NFC with FIDO2 / WebAuthn