May be also interesting for other people:

see white paper page 1:
..Users can also issue assets whose transfers are not published to
the database, and therefore not visible to third parties. Instead, the information about the
transfer is exchanged privately between users (…. and their paired devices), and only a hash of the transaction and a spend proof (to prevent double-spends) are published to the database…

To use any privacy feature in Byteball (i.e. the chat function or blackbyte transfer / blackbyte trading), you have to pair the involved devices.

You need also to pair your own devices if you like to build a multisig / multidevice wallet.
Such a wallet (i.e. 2 of 3) is in Byteball very easy to build.
And it’s very recommended to do this in relation of security / backup and redundancy.

•   Paired Devices -> Add new Device
•   Use QR Code and Cam or send pairing Code by mail
•   Make the devices known to each other (pairing):

Invite Device 1 -> Accept Device 2
Invite Device 1 -> Accept Device 3
Invite Device 2 -> Accept Device 1
Invite Device 2 -> Accept Device 3
Invite Device 3 -> Accept Device 1
Invite Device 3 -> Accept Device 2

Test: Chat between the devices (both directions) -> O.K.

•   use new wallet -> Multidevice wallet -> total number of co-signers: 3
•   Required number of signatures: 2
•   select your paired devices 1-3 as co-signers

Done - 10 minutes and  very secure in any case..