<s>
CopperheadOS	B-Application
is	O
a	O
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
for	O
smartphones	B-Application
,	O
based	O
on	O
the	O
Android	B-Application
mobile	I-Application
platform	O
.	O
</s>
<s>
It	O
adds	O
privacy	O
and	O
security	O
features	O
to	O
the	O
official	O
releases	O
of	O
the	O
Android	B-Application
Open	B-License
Source	I-License
Project	O
by	O
Google	B-Application
.	I-Application
</s>
<s>
CopperheadOS	B-Application
is	O
developed	O
by	O
Copperhead	O
,	O
a	O
Canadian	O
information	O
security	O
company	O
.	O
</s>
<s>
CopperheadOS	B-Application
supports	O
smartphones	B-Application
in	O
the	B-Application
Google	I-Application
Pixel	B-Device
product	O
line	O
;	O
other	O
devices	O
are	O
not	O
targeted	O
in	O
order	O
to	O
preserve	O
the	O
resources	O
of	O
the	O
development	O
team	O
.	O
</s>
<s>
It	O
has	O
several	O
security	O
features	O
not	O
found	O
in	O
stock	O
Android	B-Application
,	O
such	O
as	O
a	O
hardened	O
version	O
of	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
and	O
the	O
ability	O
to	O
use	O
separate	O
passwords	O
for	O
unlocking	O
the	O
device	O
and	O
for	O
encryption	O
.	O
</s>
<s>
Rather	O
than	O
use	O
the	B-Application
Google	I-Application
Play	O
Store	O
found	O
on	O
most	O
Android	B-Application
devices	O
,	O
CopperheadOS	B-Application
ships	O
with	O
the	O
F-Droid	B-Application
store	O
in	O
order	O
to	O
reduce	O
the	O
risk	O
of	O
users	O
installing	O
malicious	O
apps	O
.	O
</s>
<s>
Development	O
of	O
CopperheadOS	B-Application
began	O
in	O
2014	O
,	O
and	O
the	O
operating	O
system	O
had	O
an	O
initial	O
alpha	O
release	O
in	O
August	O
2015	O
.	O
</s>
<s>
This	O
was	O
followed	O
by	O
a	O
beta	O
release	O
in	O
February	O
2016	O
,	O
followed	O
by	O
several	O
other	O
releases	O
targeting	O
the	B-Application
Google	I-Application
Nexus	B-Device
and	O
Pixel	B-Device
phones	O
.	O
</s>
<s>
The	O
project	O
was	O
initially	O
released	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
with	O
the	O
project	O
's	O
source	O
code	O
publicly	O
available	O
on	O
GitHub	B-Application
.	O
</s>
<s>
The	O
CopperheadOS	B-Application
project	O
was	O
started	O
in	O
2014	O
by	O
Copperhead	O
,	O
an	O
information	O
security	O
company	O
based	O
in	O
Toronto	O
,	O
Canada	O
.	O
</s>
<s>
During	O
this	O
work	O
,	O
the	O
founders	O
noticed	O
an	O
absence	O
of	O
secure	O
,	O
open-source	B-License
operating	O
systems	O
for	O
mobile	O
devices	O
,	O
and	O
they	O
created	O
CopperheadOS	B-Application
under	O
an	O
open	B-License
source	I-License
license	O
to	O
try	O
to	O
address	O
this	O
need	O
.	O
</s>
<s>
Copperhead	O
announced	O
the	O
development	O
of	O
CopperheadOS	B-Application
in	O
April	O
2015	O
.	O
</s>
<s>
According	O
to	O
the	O
announcement	O
,	O
the	O
operating	O
system	O
was	O
designed	O
to	O
be	O
a	O
"	O
secure-by-default	O
version	O
of	O
Android	B-Application
"	O
aimed	O
at	O
privacy-conscious	O
users	O
.	O
</s>
<s>
At	O
first	O
,	O
CopperheadOS	B-Application
was	O
licensed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
and	O
the	O
project	O
's	O
code	O
was	O
located	O
on	O
GitHub	B-Application
.	O
</s>
<s>
Copperhead	O
contributed	O
several	O
of	O
their	O
bug	O
fixes	O
and	O
improvements	O
developed	O
for	O
CopperheadOS	B-Application
to	O
the	O
Android	B-Application
Open	B-License
Source	I-License
Project	O
,	O
the	O
main	O
project	O
for	O
Android	B-Application
development	O
by	O
Google	B-Application
.	I-Application
</s>
<s>
In	O
August	O
2015	O
,	O
Copperhead	O
released	O
the	O
first	O
alpha	O
version	O
of	O
CopperheadOS	B-Application
.	O
</s>
<s>
At	O
this	O
point	O
,	O
the	O
project	O
was	O
based	O
on	O
CyanogenMod	B-Application
,	O
and	O
included	O
support	O
for	O
the	B-Application
Google	I-Application
Nexus	B-Device
5	I-Device
and	O
Samsung	B-Application
Galaxy	I-Application
S4	I-Application
.	O
</s>
<s>
This	O
was	O
followed	O
by	O
a	O
beta	O
version	O
in	O
February	O
2016	O
,	O
with	O
support	O
for	O
the	O
Nexus	B-Device
5	I-Device
,	O
Nexus	B-Device
9	I-Device
and	O
Nexus	B-Device
5X	I-Device
.	O
</s>
<s>
The	O
beta	O
was	O
based	O
directly	O
on	O
the	O
Android	B-Application
Open	B-License
Source	I-License
Project	O
instead	O
of	O
using	O
CyanogenMod	B-Application
,	O
as	O
were	O
subsequent	O
releases	O
.	O
</s>
<s>
The	O
move	O
away	O
from	O
CyanogenMod	B-Application
and	O
the	O
lack	O
of	O
vendor	O
support	O
led	O
to	O
dropping	O
support	O
for	O
the	O
Samsung	B-Application
Galaxy	I-Application
S4	I-Application
.	O
</s>
<s>
In	O
May	O
2016	O
,	O
Copperhead	O
launched	O
an	O
online	O
store	O
where	O
the	O
Nexus	B-Device
5X	I-Device
could	O
be	O
purchased	O
directly	O
with	O
CopperheadOS	B-Application
pre-loaded	O
.	O
</s>
<s>
The	O
Nexus	B-Device
6P	I-Device
was	O
made	O
available	O
for	O
purchase	O
from	O
the	O
store	O
in	O
July	O
of	O
the	O
same	O
year	O
.	O
</s>
<s>
From	O
October	O
2016	O
,	O
for	O
versions	O
of	O
CopperheadOS	B-Application
based	O
on	O
Android	B-Application
7.0	O
Nougat	O
,	O
Copperhead	O
changed	O
the	O
CopperheadOS	B-Application
license	O
to	O
the	O
Creative	O
Commons	O
Attribution-NonCommercial-ShareAlike	O
(	O
BY-NC-SA	O
)	O
license	O
.	O
</s>
<s>
According	O
to	O
Donaldson	O
,	O
this	O
was	O
to	O
prevent	O
other	O
companies	O
from	O
using	O
the	O
CopperheadOS	B-Application
code	O
without	O
paying	O
Copperhead	O
for	O
licensing	O
,	O
in	O
order	O
to	O
keep	O
the	O
project	O
sustainable	O
.	O
</s>
<s>
Copperhead	O
began	O
selling	O
Google	B-Device
Pixel	I-Device
phones	O
pre-loaded	O
with	O
CopperheadOS	B-Application
in	O
March	O
2017	O
,	O
in	O
addition	O
to	O
their	O
lineup	O
of	O
Nexus	B-Device
phones	I-Device
.	O
</s>
<s>
For	O
Nexus	B-Device
devices	O
,	O
users	O
could	O
download	O
and	O
install	O
CopperheadOS	B-Application
for	O
free	O
;	O
however	O
,	O
this	O
option	O
was	O
not	O
made	O
available	O
for	O
Pixel	B-Device
phones	O
.	O
</s>
<s>
For	O
Pixel	B-Device
phones	O
,	O
users	O
could	O
either	O
buy	O
a	O
phone	O
from	O
the	O
Copperhead	O
store	O
with	O
CopperheadOS	B-Application
pre-loaded	O
,	O
or	O
send	O
their	O
own	O
phone	O
to	O
Copperhead	O
for	O
the	O
operating	O
system	O
to	O
be	O
installed	O
on	O
it	O
.	O
</s>
<s>
This	O
was	O
done	O
to	O
prevent	O
violations	O
of	O
CopperheadOS	B-Application
's	O
non-commercial	O
license	O
;	O
Copperhead	O
competitors	O
had	O
been	O
selling	O
Nexus	B-Device
phones	I-Device
with	O
CopperheadOS	B-Application
installed	O
without	O
obtaining	O
a	O
commercial	O
license	O
,	O
and	O
Copperhead	O
wanted	O
to	O
avoid	O
this	O
issue	O
with	O
the	O
Pixel	B-Device
.	O
</s>
<s>
The	O
issue	O
came	O
to	O
a	O
head	O
in	O
November	O
the	O
same	O
year	O
,	O
when	O
Copperhead	O
briefly	O
shut	O
down	O
the	O
update	O
server	O
for	O
Nexus	B-Device
devices	O
in	O
order	O
to	O
stop	O
the	O
continued	O
license	O
violations	O
.	O
</s>
<s>
Copperhead	O
released	O
an	O
alpha	O
version	O
of	O
CopperheadOS	B-Application
for	O
the	O
Pixel	B-Device
2	I-Device
and	O
Pixel	B-Device
2	I-Device
XL	I-Device
in	O
January	O
2018	O
.	O
</s>
<s>
Official	O
releases	O
for	O
the	O
Pixel	B-Device
2	I-Device
and	O
2	O
XL	O
were	O
marked	O
as	O
"	O
for	O
internal	O
use	O
"	O
,	O
and	O
could	O
not	O
be	O
downloaded	O
from	O
the	O
Copperhead	O
website	O
without	O
authentication	O
.	O
</s>
<s>
This	O
maintained	O
the	O
status	O
quo	O
of	O
only	O
Nexus	B-Device
releases	O
being	O
available	O
for	O
public	O
download	O
.	O
</s>
<s>
Micay	O
responded	O
by	O
posting	O
his	O
dismissal	O
notice	O
on	O
Reddit	B-Application
,	O
and	O
by	O
deleting	O
the	O
cryptographic	O
keys	O
necessary	O
to	O
release	O
updates	O
for	O
the	O
project	O
.	O
</s>
<s>
Copperhead	O
failed	O
to	O
provide	O
CopperheadOS	B-Application
updates	O
for	O
several	O
months	O
afterwards	O
.	O
</s>
<s>
Micay	O
continued	O
the	O
development	O
of	O
the	O
open	B-License
source	I-License
parts	O
of	O
CopperheadOS	B-Application
as	O
the	O
Android	B-Operating_System
Hardening	I-Operating_System
project	O
,	O
which	O
was	O
later	O
rebranded	O
as	O
GrapheneOS	B-Operating_System
.	O
</s>
<s>
The	O
next	O
release	O
of	O
CopperheadOS	B-Application
following	O
Micay	O
's	O
departure	O
was	O
in	O
March	O
2019	O
;	O
this	O
version	O
was	O
based	O
on	O
Android	B-Application
Pie	I-Application
(	O
9	O
)	O
,	O
and	O
had	O
support	O
for	O
the	O
Pixel	B-Device
,	O
Pixel	B-Device
XL	O
,	O
Pixel	B-Device
2	I-Device
and	O
Pixel	B-Device
2	I-Device
XL	I-Device
.	O
</s>
<s>
Pixel	B-Device
devices	O
pre-installed	O
with	O
CopperheadOS	B-Application
could	O
be	O
purchased	O
from	O
Copperhead	O
's	O
website	O
.	O
</s>
<s>
This	O
was	O
followed	O
in	O
February	O
2020	O
with	O
a	O
version	O
of	O
CopperheadOS	B-Application
based	O
on	O
Android	B-Application
10	O
,	O
available	O
for	O
the	O
Pixel	B-Device
2	I-Device
and	O
Pixel	B-Device
2	I-Device
XL	I-Device
.	O
</s>
<s>
As	O
of	O
June	O
2020	O
,	O
CopperheadOS	B-Application
sources	O
and	O
installation	O
files	O
were	O
no	O
longer	O
available	O
for	O
public	O
download	O
and	O
could	O
only	O
be	O
obtained	O
from	O
Copperhead	O
's	O
partner	O
network	O
.	O
</s>
<s>
Copperhead	O
released	O
a	O
version	O
of	O
CopperheadOS	B-Application
based	O
on	O
Android	B-Application
11	I-Application
in	O
November	O
2020	O
.	O
</s>
<s>
This	O
was	O
followed	O
with	O
a	O
version	O
based	O
on	O
Android	B-Application
12	I-Application
in	O
February	O
2022	O
.	O
</s>
<s>
This	O
version	O
added	O
support	O
for	O
the	O
Pixel	B-Device
4a	I-Device
,	O
the	O
Pixel	B-Device
4a	I-Device
5G	I-Device
,	O
the	O
Pixel	B-Device
5	I-Device
,	O
the	O
Pixel	B-Device
5a	I-Device
,	O
and	O
the	O
Pixel	B-Device
6	I-Device
.	O
</s>
<s>
In	O
February	O
2023	O
,	O
the	O
project	O
added	O
support	O
for	O
Pixel	B-Device
6a	I-Device
and	O
Pixel	B-Device
7	I-Device
with	O
the	O
Android	B-Application
13	I-Application
update	O
.	O
</s>
<s>
CopperheadOS	B-Application
is	O
focused	O
on	O
hardening	O
the	O
Android	B-Application
operating	I-Application
system	I-Application
to	O
make	O
it	O
more	O
difficult	O
for	O
attackers	O
to	O
exploit	O
any	O
potential	O
security	O
vulnerabilities	O
.	O
</s>
<s>
The	O
operating	O
system	O
features	O
several	O
security	O
improvements	O
over	O
stock	O
Android	B-Application
related	O
to	O
how	O
programs	O
interact	O
with	O
memory	B-General_Concept
.	O
</s>
<s>
It	O
implements	O
the	O
PaX	B-Device
security	O
patches	O
for	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
which	O
improves	O
resistance	O
against	O
executing	O
code	O
that	O
has	O
managed	O
to	O
find	O
its	O
way	O
into	O
writeable	O
memory	B-General_Concept
.	O
</s>
<s>
It	O
also	O
features	O
improved	O
address	O
space	O
layout	O
randomization	O
,	O
a	O
version	O
of	O
malloc	B-Language
with	O
better	O
memory	B-General_Concept
layout	O
randomization	O
,	O
and	O
more	O
secure	O
SELinux	B-Application
policies	O
.	O
</s>
<s>
CopperheadOS	B-Application
also	O
features	O
verified	O
boot	O
,	O
which	O
protects	O
against	O
malware	O
taking	O
over	O
the	O
boot	O
process	O
or	O
the	O
recovery	O
process	O
of	O
the	O
device	O
.	O
</s>
<s>
There	O
are	O
also	O
various	O
changes	O
from	O
stock	O
Android	B-Application
in	O
user-facing	O
features	O
.	O
</s>
<s>
CopperheadOS	B-Application
separates	O
the	O
password	O
used	O
to	O
unlock	O
the	O
device	O
from	O
the	O
device	O
's	O
encryption	O
password	O
;	O
users	O
can	O
use	O
a	O
relatively	O
simple	O
password	O
to	O
unlock	O
their	O
devices	O
,	O
but	O
if	O
the	O
wrong	O
password	O
is	O
entered	O
five	O
times	O
in	O
a	O
row	O
,	O
the	O
device	O
reboots	O
and	O
the	O
encryption	O
password	O
must	O
be	O
entered	O
,	O
which	O
would	O
be	O
presumably	O
more	O
difficult	O
for	O
an	O
attacker	O
to	O
guess	O
.	O
</s>
<s>
The	O
operating	O
system	O
ships	O
with	O
the	O
F-Droid	B-Application
store	O
,	O
from	O
which	O
users	O
can	O
install	O
open-source	B-License
applications	O
,	O
instead	O
of	O
the	B-Application
Google	I-Application
Play	O
Store	O
usually	O
found	O
on	O
Android	B-Application
phones	I-Application
.	O
</s>
<s>
The	O
project	O
supports	O
smartphones	B-Application
in	O
the	B-Application
Google	I-Application
Pixel	B-Device
product	O
line	O
.	O
</s>
<s>
This	O
is	O
done	O
to	O
preserve	O
Copperhead	O
's	O
development	O
resources	O
,	O
and	O
to	O
enable	O
quick	O
patching	O
when	O
Google	B-Application
releases	O
security	O
updates	O
.	O
</s>
<s>
,	O
the	O
supported	O
phones	O
are	O
the	O
Pixel	B-Device
3a	I-Device
,	O
the	O
Pixel	B-Device
3a	I-Device
XL	I-Device
,	O
the	O
Pixel	B-Device
4	I-Device
,	O
the	O
Pixel	B-Device
4	I-Device
XL	I-Device
,	O
the	O
Pixel	B-Device
4a	I-Device
,	O
the	O
Pixel	B-Device
4a	I-Device
5G	I-Device
,	O
the	O
Pixel	B-Device
5	I-Device
,	O
the	O
Pixel	B-Device
5a	I-Device
,	O
and	O
the	O
Pixel	B-Device
6	I-Device
.	O
</s>
<s>
In	O
January	O
2018	O
,	O
Tarus	O
Balog	O
of	O
opensource.com	O
was	O
favorably	O
impressed	O
by	O
features	O
in	O
CopperheadOS	B-Application
,	O
but	O
he	O
found	O
the	O
lack	O
of	O
Google	B-Application
applications	O
difficult	O
,	O
and	O
was	O
confused	O
by	O
licensing	O
terms	O
and	O
conditions	O
.	O
</s>
<s>
Balog	O
said	O
he	O
initially	O
used	O
a	O
Nexus	B-Device
6P	I-Device
because	O
available	O
Pixel	B-Device
and	O
Pixel	B-Device
XL	O
phones	O
from	O
Copperhead	O
were	O
too	O
expensive	O
.	O
</s>
<s>
In	O
2016	O
,	O
The	O
Tor	B-Application
Project	I-Application
released	O
a	O
prototype	O
smartphone	B-Application
based	O
on	O
CopperheadOS	B-Application
named	O
the	O
Tor	B-Application
Phone	I-Application
,	O
which	O
gave	O
users	O
the	O
ability	O
to	O
route	O
their	O
network	O
connections	O
through	O
Tor	B-Application
for	O
anonymity	O
.	O
</s>
<s>
CopperheadOS	B-Application
was	O
chosen	O
for	O
its	O
focus	O
on	O
security	O
,	O
in	O
particular	O
its	O
use	O
of	O
verified	O
boot	O
and	O
its	O
prevention	O
of	O
system	O
apps	O
being	O
overridden	O
by	O
apps	O
from	O
the	B-Application
Google	I-Application
Play	O
Store	O
.	O
</s>
<s>
The	O
prototype	O
only	O
worked	O
on	O
Google	B-Device
Nexus	I-Device
and	O
Pixel	B-Device
hardware	O
,	O
and	O
had	O
many	O
unfinished	O
pieces	O
.	O
</s>
