Courier · LockWhisper v9
Private messages.
A mailbox you choose.
Courier brings optional, one-to-one encrypted messaging to LockWhisper. Choose an independent server or run your own on a Mac with Courier Host.
Encrypted before it leaves your device.
- Your LockWhisperSign & encrypt
Text and attachments are protected together on your device.
- Recipient’s serverHold encrypted mail
The mailbox stores ciphertext until the recipient retrieves it.
- Their LockWhisperVerify & decrypt
The recipient checks the message and opens it locally.
Courier is designed for delayed delivery. The server does not need either person’s plaintext message to deliver it.
Inside LockWhisper
A private conversation, under your control.
Messages and attachments
Send signed, end-to-end encrypted text and files. LockWhisper v9 supports up to 8 MiB of attachments in total per message, with encrypted local history and saved drafts.
Tor delivery
Tor direct delivery sends to the recipient’s server without relaying through your home server. Tor-only accounts and onion recipients require Tor. A failed Tor connection never silently switches to a regular connection.
Verify who you’re talking to
Compare a contact’s fingerprint through a separate trusted channel, using a QR code or hexadecimal text. Courier remembers the identity and blocks a changed fingerprint until you explicitly resolve it.
Choose your mailbox
Register with a server you operate or an independent operator. Hosted and self-hosted servers speak the same Courier protocol. LockWhisper does not operate a Courier server for you.
Courier Host · macOS 14+
Your Mac.
Your personal server.
Courier Host is a separate Mac app for creating and managing personal Courier servers. It handles the server and Tor setup through a native interface.
Set up without Terminal
The installation flow uses a disk image: drag Courier Host to Applications, approve background items, and authorize setup. No Homebrew or separate Tor installation is required.
Unlock, run, then seal
Setup requires FileVault and a host-volume passphrase. In the default secure/manual mode, the encrypted host volume stays sealed after reboot until you choose Unlock & Start Host. Use Stop & Seal Host to close it again.
Manage access and health
Share the private onion server address by text or QR code, create expiring registration invitations, manage users, and check server and Tor reachability. You can operate multiple servers on the same Mac.
Back up and rehearse recovery
Create encrypted backups of Courier data and the onion identity, export them, and test a restore in an isolated rehearsal before restoring live service data.
Closing the Courier Host window leaves a running server active and its data unlocked. Choose Stop & Seal Host when you want the protected volume sealed.
Getting connected
From server to first conversation.
Choose a server
Use an independent Courier operator or set up Courier Host on a Mac. Obtain the server address and a registration invitation if the operator requires one.
Create your identity
Open Courier in LockWhisper, enter the server address, choose your connection policy, and register. The self-hosted setup includes connection checks.
Verify your contact
Exchange Courier addresses and compare fingerprints through another trusted channel before relying on the conversation.
A few things to know.
Does Courier change my offline vault?
Courier is optional and needs network access to exchange messages. It does not turn your LockWhisper vault into a hosted cloud database. Courier Host is separate from the app’s private vault stores.
What can a server operator see?
The server handles your address, public key, encrypted mailbox items, delivery metadata, and network abuse signals. Message text and attachments are end-to-end encrypted. Encryption and Tor do not remove every form of metadata or guarantee anonymity.
Is this a live chat service?
Courier v1 focuses on delayed, one-to-one messages. It does not include group chat, presence, typing indicators, read receipts, or push notifications. A server delivery response does not mean a person has read the message.
Can I block a contact or delete my account?
LockWhisper includes local contact blocking and a Delete Courier Account request to your selected operator. Server-side deletion follows that operator’s retention policy. Local message history is cleared separately.