Privacy

Architecture, not policy.

If I could read what you write, I'd be a liability the moment someone asked. So I made it impossible. The keys are on your device. The server holds locked boxes. I hold nothing I can read.

How it works

One trip. Only you can open it.

Picture writing a letter, putting it in a locked box, and being the only person with a key. Your phone does the locking before the box leaves. The server holds the box. Nobody can open it but you.

01
On device
You type.
The words exist in memory on your laptop or phone while you edit. They never leave in plaintext.
02
In transit
It is encrypted before it leaves.
A key that lives only in your browser scrambles the text before it goes anywhere. Only the scrambled version travels over the wire.
03
At rest
The server stores a blob.
No key, no words. Reading the file yields noise. Nobody can open it, because the server never had the key.

Four guarantees

Four guarantees. Verifiable, not promised.

The full technical version, for the people who want it.

If you're a security researcher, journalist, or engineer, this is the rest of the story. If not, the four cards above are the whole story.

Cipher

Journal entries and chat transcripts are encrypted with AES-256-GCM. Each payload has a unique 96-bit IV. GCM's authentication tag guards against tampering.

Key derivation

Your content is encrypted with a random 256-bit key generated in your browser, never derived from anything guessable. Your passphrase is run through PBKDF2 (310,000 iterations, SHA-256, 16-byte salt) to derive a separate key that wraps the content key. A second wrap comes from your 24-word recovery phrase, using an independent salt. Changing your passphrase re-wraps the content key without re-encrypting your data. The passphrase and recovery phrase never leave your device.

What the server can read

Vitne never sees your passphrase, your keys, or the words you write in the chat or the journal. Those are stored only as ciphertext with a per-item IV. Readable on our side: your email and the display name you enter (held by the login provider, Clerk), the settings you choose, timestamps, and how your sessions and entries are organised. What you write is not among them.

Reflection requests

Messages sent to the AI travel over TLS. To reply, the AI provider (Anthropic) has to read them in plaintext. Under Anthropic's commercial terms they do not train on API content, and they delete it under a standard retention window (up to 30 days) rather than keeping it indefinitely. Vitne does not have a zero-retention agreement in place today; if that changes, this line changes with it. The request is sent from Vitne's server, not your device, so your IP address, name, and email are never attached, and no stable per-user identifier is sent either.

Retention

Journal entries live, encrypted, until you delete them. Chat transcripts are stored encrypted too, so a past conversation is still there when you come back, not kept only on your device. Deleting your account removes your encrypted rows right away. Backups roll off on their own cycle.

Crypto package

The cryptographic primitives and the client-side encryption layer live in a separate @vitne/crypto package, kept narrow on purpose so it's small enough to reason about. The package isn't public yet; the full architecture is published at /privacy/deep-overview.

Threat model

The model assumes a compromised server, a subpoena, and a curious operator. It does not, and cannot, protect against a compromised client (keylogger, malicious extension) or a weak password. Pick a strong one.

Subpoena posture

If a government asks, the most I can hand over is what I can actually read: the ciphertext (useless without your keys), your email and display name, the settings you chose, timestamps, and the shape of your account. Not the words you wrote. A transparency report goes up the first time I receive a request.

The whole machine is written up at the deep overview: the key hierarchy, the threat model, the known limits, and how to check each claim yourself.

Architecture, not policy.

One trip. Only you can open it.

You type.

It is encrypted before it leaves.

The server stores a blob.

Four guarantees. Verifiable, not promised.

Architecture, not policy.

One trip. Only you can open it.

You type.

It is encrypted before it leaves.

The server stores a blob.

Four guarantees. Verifiable, not promised.

Your phone does the locking.

I never see your passphrase.

Your words are not training data.

No trackers where you write.

If you lose your passphrase, your data is gone.

The full technical version, for the people who want it.

That's the architecture. Want to try it?