Zero-Access Architecture

Your data is encrypted on your device before it ever reaches our servers. We couldn't read your habit data even if we wanted to.

AES-256-CTR

We use the Advanced Encryption Standard with a 256-bit key in Counter Mode.

  • Unique 128-bit random IV per write
  • No block padding attacks

PBKDF2 Key Derivation

Your password never leaves your device. Instead, your device derives a cryptographic key from it using PBKDF2 with 200,000 rounds of SHA-256 hashing.

  • Unique 128-bit salt per user
  • Resistant to rainbow table attacks

How it works

1

Local Encryption

When you track a habit, your phone generates a unique Initialization Vector (IV) and encrypts the data locally using your derived key.

2

Integrity Signing

Your phone signs the encrypted blob with HMAC-SHA256 and appends the signature. Nobody, not even a server administrator, can tamper with your data without breaking it.

3

Secure Sync

Only the encrypted blob is sent to our servers. We store it, but we can never read it.

Because we use End-to-End Encryption, there is no "Forgot Password" feature. If you lose your password, your data is gone forever. That is the trade-off, and we are not going to pretend otherwise.

Get in touch →

The beta is at capacity right now.