> Level 1 (red): The ID and public key have been obtained from the server because you received a message from this contact for the first time or added the ID manually. No matching contact was found in your address book (by phone number or email), and therefore you cannot be sure that the person is who they claim to be in their messages.
> Level 2 (orange): The ID has been matched with a contact in your address book (by phone number or email). Since the server verifies phone numbers and email addresses (via an SMS or email with the activation link), you can be reasonably sure that the person is who they claim to be.
> Level 3 (green): You have personally verified the ID and public key of the person by scanning their QR code. Assuming their device has not been hijacked, you can be very sure that messages from this contact were really written by the person that they indicate.
> Level 1 (red): The ID and public key have been obtained from the server because you received a message from this contact for the first time or added the ID manually. No matching contact was found in your address book (by phone number or email), and therefore you cannot be sure that the person is who they claim to be in their messages.
> Level 2 (orange): The ID has been matched with a contact in your address book (by phone number or email). Since the server verifies phone numbers and email addresses (via an SMS or email with the activation link), you can be reasonably sure that the person is who they claim to be.
> Level 3 (green): You have personally verified the ID and public key of the person by scanning their QR code. Assuming their device has not been hijacked, you can be very sure that messages from this contact were really written by the person that they indicate.