[guardian-dev] Multiple Signal identities

Matej Kovacic matej.kovacic at owca.info
Mon Dec 12 16:38:44 EST 2016


> You could use the multiple user support on Android. It allows for the
> same app, but with separate users and instances of the app user data. I
> often use this as a kind of incognito mode.

Well, I tried to add another user under Settings. Then I registered
Google Play and installed Signal. I can send messages between my main
user and this new user, but the other user is not getting notifications
until it is logged into his account.

Also I have noticed quite strange behavior of Signal. In second user
account I did not have Signal lock enabled, but on my main account I
have encrypted storage and lock, however password should be cached for
quite long time.

After I installed Signal on the other user account and swiched back to
my main identity, password was expired, and I need to enter it each time...

So, this is not good solution, because you cannot get notifications for
both accounts at the same time.

However, then I tried something else...

I tried to use Test DPC:

It is a testing device policy controller for Android for Work. It
creates a "work profile", but you can have work apps on your main screen
(the icons are the same, except they contain a small briefcase), GCM
works normally and notifications also work normally (i.e. you do not
need to be logged into another profile).

I installed it and under it's settings enabled Play Store (Enable System
apps - Google Play Store).

I registered new Google account and installed Signal.

In Signal I registered my other telephone number.

For that I needed to add 3 custom firewall rules to AFWall:

iptables -A afwall -m owner --uid-owner 1110079 -j ACCEPT
iptables -A afwall -m owner --uid-owner 1110014 -j ACCEPT
iptables -A afwall -m owner --uid-owner 1110013 -j ACCEPT

The first UID is Signal, the second Google Play and the third Google
account verification.

BTW: I reinstalled Test DPC, and after reinstall, the applications got
new UID's (1210079, 1210014, 1210013)... Weird.

BTW, you can remove Test DPC under Settings, Accounts and from Play
Store to remove it completely...

Then I tried to send a Signal message to my new Signal number, and it
actually works. Well, sort of...

I can get notification about new message, I can also see the
notification, but when I want to see the actual message inside Signal,
it just crash.

It also crash when I try to add a new number to start conversation
with... So it is not really working. It is also not working if I disable
firewall completely...

Also, Orbot can see only one instance of a Signal in that case...

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