Confidesk
Your passphrase
Exists in your head and, briefly, in your device's memory while you type it. It is never transmitted to us and never stored — anywhere, in any form. Everything else in the design follows from this one rule.
The Confidesk model
Most providers ask you to believe a policy: we won't look. Confidesk is built so belief isn't required. This page opens up the whole machine — where your key actually lives, what happens at every step, and the safeguards built into each layer. It's slightly technical, on purpose: this is the part you shouldn't have to take on faith.
1 Three things, three places
The design comes down to what lives where. Three things matter, and only one of them ever exists on our servers in a form anyone could use.
Exists in your head and, briefly, in your device's memory while you type it. It is never transmitted to us and never stored — anywhere, in any form. Everything else in the design follows from this one rule.
Generated in your browser, then encrypted with your passphrase before it's uploaded. We store the locked box so you can sign in from any device — but the thing that opens it never reaches us. It's only ever unlocked in your browser's memory.
Encrypted in your browser to your public key before they're sent. What sits in our database is scrambled data that only your unlocked private key can open — and that unlock only ever happens on your device.
2 Step by step
Each step below is marked with where it happens: on your device or on our servers. Watch what never crosses from one side to the other.
When you register, your browser — not our server — generates a modern OpenPGP keypair: an ed25519 signing key with a cv25519 encryption subkey (Curve25519 elliptic-curve cryptography, with AES-256 and SHA-256). Legacy algorithms are disabled outright, not just avoided.
Your browser then encrypts the private key with your passphrase and uploads only that locked copy, together with your public key. The plain private key and the passphrase never leave your device.
✓ Keys generated & locked on your deviceYou enter your username, and a one-time code goes to your external email address (or your authenticator app, if you've set one up). That code proves identity — by itself it unlocks nothing.
Your browser then downloads your locked key and asks for your passphrase. The unlock happens in browser memory only: nothing is written to disk, and when you sign out or close the browser, the unlocked key is gone. That's also why a page reload asks for your passphrase again — the memory it lived in was thrown away. It's the security working, not a bug.
✓ Key unlocked in memory, on your device onlyWhen you write to another Confidesk user, your browser encrypts the message to their public key before sending. Our server receives ciphertext, stores ciphertext, and delivers ciphertext — there is no step where it could read the message, because it never had a readable copy.
✓ Encrypted on your deviceHere's an honest limit no provider can escape: ordinary email from the outside world arrives unencrypted — that's how email between providers works. What we control is what happens next. The moment a message reaches us, it's encrypted to your public key and stored; the readable copy is not kept. From that point on, it's data only you can open.
Encrypted immediately on arrival — readable copy not keptEverything else in your account — file storage, notes, the password vault — is encrypted in your browser with the same keypair before upload, and decrypted only on your device when you open it. One key, one rule, no exceptions.
✓ Encrypted & decrypted on your device3 Built-in safeguards
Curve25519 keys, AES-256, SHA-256 or stronger — everywhere, with legacy options disabled. Even a key you bring yourself must be a modern Curve25519 keypair; older key types are rejected at the door.
There is no mechanism — for you, for support, for anyone — that opens an account without its passphrase. The proof is that we can't recover your data if you lose it. A back door for "just in case" would be a back door, full stop.
Your unlocked key exists only in browser memory, only while you're signed in. Sign out, close the tab, or reload, and it's erased. On your own machines you can mark a browser trusted, which keeps the key stored encrypted locally for about a month.
Messages open as plain text and remote content stays blocked, so tracking pixels never load. No read receipts, no silent "opened" signal, no hidden code running when you view a message.
Server-side search, auto-forwarding, and inbox filters all require a machine of ours to read your messages — so they don't exist here. It's the same rule that keeps us out, applied consistently, even when it costs convenience.
Your keys and data use the standard OpenPGP format. Export them any time and decrypt your mail and files with ordinary GPG tools, on any machine, with no Confidesk software involved. Your way out is always open — that keeps us honest.
4 Full disclosure
Encryption protects content. To run a mail service at all, some operational data has to be visible to us — no provider can honestly claim otherwise. Here is the exact split.
This is also why Confidesk is private but not anonymous: what you write is protected absolutely, but your account is tied to a real external address and a one-time payment. We'd rather tell you that plainly than let you assume otherwise.
Everything above is testable: try to reset a password, watch what a reload asks for, export your key and open your own mail with standard GPG tools. The design holds either way.