Keys are born in your browser
You generate the OpenPGP key pair on your own device. The server never receives your private key in plain form.
OpenPGP · Curve25519
Security
Privacy by design, not by policy.
This is how encryption works in mbox: concrete, with algorithm names and an honest list of trade-offs. No “military-grade”, no magic.
- EU servers (Hetzner, Falkenstein)
- No ads
- No data sold
- No AI training on your mail
Architecture
Six layers, one rule: the server should know as little as possible.
From key generation to transport. You can verify every step, because the encryption happens in your browser.
Your browserYou generate keys
The OpenPGP pair is created locally.
Your browserYou encrypt the private key
With your passphrase, before upload.
mbox servers · EUWe store ciphertext
The public key and the encrypted private key.
Private key encrypted with your passphrase
So you can sign in on another device, we store your private key, but only after it's encrypted with a passphrase only you know. Without it, it's random bytes.
passphrase → encrypted private key
End-to-end between users
The content is encrypted in the browser to the recipients' public keys and yours, so the message stays readable in Sent. Nobody along the way can read it, including us.
client-side encryption
Password emails to anyone
A recipient without mbox gets a link. A key is derived from the password and decrypts the message in their browser. We never send the password to the server.
AES-256-GCM · PBKDF2-SHA256 · 310,000 iterations
Zero-access for incoming mail
Turn the mode on and every new email is encrypted to your public key as soon as it arrives. Only ciphertext stays on disk, and only you can read it.
encrypted on arrival · only ciphertext at rest
Transport and sender identity
TLS everywhere. Outgoing mail is DKIM-signed and incoming mail is checked for SPF, DKIM and DMARC. A phishing shield sits on top.
TLS · DKIM · SPF · DMARC
Four modes, one decision that's yours
You choose the level of protection. More protection means the server, and so the AI, sees less.
| Mode | Who can read the content | AI and content search | When |
|---|---|---|---|
| Standard (TLS) | You; the server processes mail to deliver it | Work | Everyday email |
| End-to-end (OpenPGP) | Only sender and recipient | No, the server can't see content | Sensitive conversations |
| Password-protected | A recipient who knows the password | No, the server can't see content | Messages to people without keys |
| Zero-access | Only you | No, content is encrypted | A mailbox needing maximum confidentiality |
Trade-offs
An honest look at what privacy costs.
Encryption has a price, and we'd rather you know it before you choose, not after.
- 1
AI can't read zero-access mail
If the server can't see the content, neither can a model. You choose this per mailbox.
- 2
A lost passphrase means lost messages
Your private key is encrypted with your passphrase. We don't have it and can't recreate it, so we can't recover encrypted emails.
- 3
Metadata doesn't disappear
Sender, recipient and time are needed to deliver mail and aren't covered by content encryption.
- 4
You can only encrypt where there's a key
Outside mbox users we need the recipient's public key or a password. Otherwise the message goes out as standard mail, protected by TLS.
The rest of the safeguards
2FA and recovery codes
TOTP two-factor authentication and one-time recovery codes. Passwords need at least 10 characters.
Session control
A list of active sessions with device and IP, each one revocable with a click.
Phishing shield
Every incoming email gets a risk score and a list of reasons, and suspicious links are flagged.
SPF, DKIM, DMARC
You see on each message whether the sender passed verification. Our outgoing mail is DKIM-signed.
EU hosting
Hetzner servers in Falkenstein, Germany. Your mail itself doesn't leave Europe.
No ads, no data trade
We don't profile you, sell your data or use your mail to train models.
Found a vulnerability? Write to kontakt@mbox.ulewicz.space. We reply like humans and thank you like humans.
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