Adding a XMPP proof

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Let's add a decentralized XMPP proof to your OpenPGP keys.

Add a message to your XMPP vCard

Using a XMPP client that supports editing the vCard (such as Dino and Gajim), append the following message to the About section (make sure to replace FINGERPRINT):

This is an OpenPGP proof that connects my OpenPGP key to this XMPP account. For details check out https://keyoxide.org/guides/openpgp-proofs

[Verifying my OpenPGP key: openpgp4fpr:FINGERPRINT]

Update the PGP key (basic edition)

First, edit the key (make sure to replace FINGERPRINT):

gpg --edit-key FINGERPRINT

Add a new notation:

notation

Enter the notation (make sure to replace XMPP-ID):

proof@metacode.biz=xmpp:XMPP-ID

The XMPP-ID looks something like an email address: user@domain.org.

Save the key:

save

Upload the key to WKD or use the following command to upload the key to keys.openpgp.org (make sure to replace FINGERPRINT):

gpg --keyserver hkps://keys.openpgp.org --send-keys FINGERPRINT

And you're done! Reload your profile page, it should now show a XMPP account.

Update the PGP key (OMEMO edition)

XMPP communication can be end-to-end encrypted with OMEMO. Verifying OMEMO fingerprints is essential to trust your communication and keep it safe from Man-in-the-Middle attacks.

Keyoxide makes the fingerprint verification process easy for all. Add a special identity proof that not only contains your XMPP-ID but also the fingerprints of all your OMEMO keys.

If your XMPP identity proof is verified, a QR code is shown. Anyone can scan this QR code using XMPP apps like Conversations (free on F-Droid) to not only add you as a contact, but also verify your OMEMO keys with the highest level of trust.

Making this identity proof yourself can be a tad difficult when using clients like Gajim, but luckily for us, Conversations can directly generate the proof by going to Account details > Share > Share as XMPP URI. The resulting URI should look something like:

xmpp:user@domain.org?omemo-sid-123456789=A1B2C3D4E5F6G7H8I9...

To take advantage of the easy and secure XMPP identity proof including OMEMO fingerprints, follow the basic edition guide above but replace XMPP-ID with the URI obtained through the Conversations app.