Instant Messaging

Normal encrypted text is a big block that starts with -----BEGIN PGP MESSAGE-----. It is obvious at a glance, it is long, and chat apps often break it by adding line breaks or turning parts of it into links.

Instant messaging solves that. It turns your encrypted message into a single short line of letters and numbers that pastes cleanly into any chat app, and that does not reveal what it is.

New in v2.2.2

Instant messaging was added in GpgFrontend v2.2.2.

Send a Message

1. Type your message in the Text Editor.

2. Tick the person you are writing to in the Key Toolbox.

3. Choose Operations, then IM Encrypt. The shortcut is Ctrl+M.

Your text is replaced by one long line. Copy it and paste it into your chat app.

If you also want the other person to know the message really came from you, use IM Encrypt & Sign instead. The shortcut is Ctrl+Shift+M.

Put the buttons on the toolbar

Open Settings, go to Appearance, and tick IM Encrypt or IM Encrypt Sign under Actions. The buttons then sit in the Operations Bar with the others.

Read a Message

Paste the line into the Text Editor and press Decrypt, exactly as you would for any other message. GpgFrontend works out on its own that it is an instant message.

There is no separate button for reading one. If the sender signed it, use Decrypt & Verify to check the signature too.

Share a Secret Phrase

Out of the box, your messages do not stand out to most people. But anyone who knows GpgFrontend can recognise them for what they are.

To stop that, you and the person you write to can share a secret phrase. Once you both have the same one, your messages look like plain random text to everyone else.

1. Open Settings and go to Instant Messaging.

2. Click Generate. A long phrase appears.

3. Click Copy and send the phrase to your friend privately. Not over the chat app you are trying to protect.

4. Your friend opens the same page and clicks Paste.

5. You both look at the Book Fingerprint, a short code such as 3F9A-1C4E. Read it out to each other. If the two codes match, you are set.

The fingerprint is safe to say out loud or send anywhere. The phrase is not.

You must both use exactly the same phrase

If the phrases do not match, your friend cannot read your messages at all. The fingerprint check exists so you catch this straight away.

What Happens Without a Phrase

Nothing breaks. Your message is still properly encrypted, and only the person you sent it to can read it.

The only thing you lose is the disguise. Without a shared phrase, GpgFrontend falls back to a built-in one that every copy of the program has, so anyone who knows the program can tell your message is an encrypted GpgFrontend message.

The first time you use IM Encrypt without a phrase, the program says so and offers to take you to the settings page.

If the Message Is Too Long

Instant messages are meant for short notes. If yours is too long, GpgFrontend tells you and leaves your text unchanged.

Either shorten the text, or send it the normal way with Encrypt. There is no length limit on a normal encrypted message.

Good to Know

• The shared phrase hides what kind of message you are sending. It is not what keeps the message secret. Your OpenPGP keys do that, with or without a phrase.
• The phrase is stored in GpgFrontend’s own protected storage, not in a plain settings file.
• GpgFrontend keeps one phrase at a time, and it is used for everyone you write to. If you want a different phrase for each person, you have to change the phrase in settings when you switch conversations.