<s>
PrivatOS	B-Application
was	O
an	O
operating	B-General_Concept
system	I-General_Concept
used	O
in	O
the	O
Blackphone	B-Application
from	O
June	O
1	O
,	O
2014	O
,	O
to	O
June	O
30	O
,	O
2016	O
.	O
</s>
<s>
PrivatOS	B-Application
was	O
a	O
modified	O
version	O
of	O
Android	B-Application
,	O
forked	B-Application
from	O
Android	B-Application
4.4.2	O
,	O
that	O
came	O
with	O
a	O
bundle	O
of	O
security-minded	O
tools	O
.	O
</s>
<s>
However	O
,	O
in	O
contrast	O
to	O
Android	B-Application
,	O
PrivatOS	B-Application
was	O
not	O
open	O
source	O
.	O
</s>
<s>
The	O
company	O
that	O
shipped	O
PrivatOS	B-Application
,	O
SGP	O
Technologies	O
is	O
a	O
joint	O
venture	O
between	O
the	O
makers	O
of	O
GeeksPhone	O
,	O
and	O
Silent	O
Circle	O
.	O
</s>
<s>
The	O
concept	O
of	O
an	O
encrypted	O
phone	O
had	O
long	O
been	O
an	O
interest	O
of	O
Silent	O
Circle	O
founder	O
and	O
PGP	B-Application
creator	O
,	O
Phil	O
Zimmerman	O
.	O
</s>
<s>
In	O
a	O
video	O
on	O
Blackphone	B-Application
's	O
website	O
,	O
Zimmerman	O
said	O
,	O
</s>
<s>
The	O
company	O
stated	O
its	O
operating	B-General_Concept
system	I-General_Concept
was	O
able	O
to	O
“	O
close	O
all	O
backdoors	O
”	O
which	O
were	O
usually	O
found	O
on	O
major	O
mobile	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Some	O
major	O
features	O
of	O
PrivatOS	B-Application
were	O
anonymous	O
search	O
,	O
privacy-enabled	O
bundled	O
apps	O
,	O
smart	O
disabling	O
of	O
Wi-Fi	O
except	O
trusted	O
hotspots	O
,	O
more	O
control	O
in	O
app	O
permissions	O
,	O
private	O
communication	O
(	O
calling	O
,	O
texting	O
,	O
video	O
chat	O
,	O
browsing	O
,	O
file	O
sharing	O
and	O
conference	O
calls	O
)	O
.	O
</s>
<s>
Geeksphone	O
also	O
claimed	O
the	O
phone	O
would	O
receive	O
frequent	O
secure	O
updates	O
from	O
Blackphone	B-Application
directly	O
.	O
</s>
<s>
Ars	O
Technica	O
praised	O
that	O
the	O
Blackphone	B-Application
's	O
Security	O
Center	O
in	O
PrivatOS	B-Application
gave	O
control	O
over	O
app	O
permissions	O
and	O
liked	O
that	O
PrivatOS	B-Application
came	O
bundled	O
with	O
the	O
Silent	O
Phone	O
,	O
Silent	O
Text	O
,	O
Disconnect	O
VPN	O
and	O
Disconnect	O
Search	O
services	O
.	O
</s>
<s>
Ars	O
did	O
not	O
like	O
that	O
the	O
phone	O
’s	O
performance	O
was	O
mediocre	O
,	O
using	O
a	O
custom	O
OS	O
meant	O
no	O
Google	B-Application
Play	I-Application
or	O
any	O
of	O
the	O
other	O
benefits	O
of	O
the	O
Google	O
ecosystem	O
,	O
spotty	O
support	O
for	O
sideloaded	O
apps	O
,	O
and	O
reliance	O
on	O
Amazon	O
or	O
other	O
third-party	O
app	O
stores	O
.	O
</s>
<s>
After	O
a	O
month	O
of	O
using	O
the	O
device	O
,	O
Joshua	O
Drake	O
from	O
Accuvant	O
concluded	O
that	O
Blackphone	B-Application
's	O
security	O
claims	O
were	O
overstated	O
,	O
criticizing	O
the	O
closed-source	B-Application
nature	O
of	O
the	O
OS	O
and	O
a	O
lack	O
of	O
OS	O
or	O
kernel	O
hardening	O
features	O
,	O
but	O
praising	O
its	O
fast	O
patching	O
and	O
added	O
features	O
.	O
</s>
