<s>
Covid	B-Application
Watch	I-Application
was	O
an	O
open	B-License
source	I-License
nonprofit	O
founded	O
in	O
February	O
2020	O
with	O
the	O
mission	O
of	O
building	O
mobile	O
technology	O
to	O
fight	O
the	O
COVID-19	O
pandemic	O
while	O
defending	O
digital	O
privacy	O
.	O
</s>
<s>
The	O
Covid	B-Application
Watch	I-Application
founders	O
became	O
concerned	O
about	O
emerging	O
,	O
mass	O
surveillance-enabling	O
digital	B-Protocol
contact	I-Protocol
tracing	I-Protocol
technology	O
and	O
started	O
the	O
project	O
to	O
help	O
preserve	O
civil	O
liberties	O
during	O
the	O
pandemic	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
began	O
as	O
an	O
independent	O
research	O
collaboration	O
between	O
students	O
at	O
Stanford	O
University	O
,	O
United	O
States	O
and	O
the	O
University	O
of	O
Waterloo	O
,	O
Canada	O
and	O
it	O
was	O
the	O
first	O
team	O
in	O
the	O
world	O
to	O
publish	O
a	O
white	O
paper	O
,	O
develop	O
,	O
and	O
open	B-License
source	I-License
a	O
fully	O
anonymous	O
Bluetooth	O
exposure	B-Application
alert	I-Application
protocol	O
-	O
the	O
CEN	B-Protocol
Protocol	I-Protocol
,	O
later	O
renamed	O
the	O
TCN	B-Protocol
Protocol	I-Protocol
-	O
in	O
collaboration	O
with	O
CoEpi	O
in	O
early	O
March	O
2020	O
.	O
</s>
<s>
This	O
was	O
followed	O
by	O
the	O
rapid	O
development	O
of	O
very	O
similar	O
decentralized	O
protocols	O
in	O
early	O
April	O
2020	O
like	O
DP-3T	B-Protocol
,	O
PACT	O
,	O
and	O
Google/Apple	O
Exposure	B-Application
Notification	I-Application
.	O
</s>
<s>
The	O
Covid	B-Application
Watch	I-Application
team	O
had	O
over	O
200	O
active	O
volunteers	O
from	O
around	O
the	O
world	O
including	O
advisers	O
in	O
public	O
health	O
,	O
epidemiology	O
,	O
privacy	O
,	O
policy	O
,	O
and	O
law	O
from	O
universities	O
like	O
Stanford	O
,	O
Waterloo	O
,	O
UW	O
,	O
UCSF	O
,	O
and	O
Berkeley	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
also	O
built	O
a	O
fully	O
open	B-License
source	I-License
mobile	O
app	O
for	O
sending	O
anonymous	O
exposure	B-Application
alerts	I-Application
first	O
using	O
their	O
own	O
TCN	B-Protocol
Protocol	I-Protocol
in	O
April	O
2020	O
and	O
later	O
using	O
the	O
nearly	O
identical	O
protocol	O
within	O
the	O
Google/Apple	O
exposure	B-Application
notification	I-Application
(	O
GAEN	B-Application
)	O
framework	O
when	O
the	O
GAEN	B-Application
APIs	O
were	O
released	O
in	O
May	O
2020	O
.	O
</s>
<s>
Also	O
in	O
May	O
2020	O
,	O
Covid	B-Application
Watch	I-Application
launched	O
the	O
first	O
calibration	O
and	O
beta	O
testing	O
pilot	O
of	O
the	O
GAEN	B-Application
APIs	O
in	O
the	O
United	O
States	O
at	O
the	O
University	O
of	O
Arizona	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
volunteers	O
and	O
staff	O
also	O
collaborated	O
with	O
the	O
University	O
of	O
Arizona	O
on	O
research	O
to	O
improve	O
the	O
estimation	O
of	O
infection	O
risk	O
from	O
anonymous	O
Bluetooth	O
data	O
to	O
better	O
inform	O
private	O
quarantine	O
recommendations	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
2020	O
,	O
the	O
Covid	B-Application
Watch	I-Application
nonprofit	O
closed	O
,	O
but	O
the	O
Covid	B-Application
Watch	I-Application
app	O
and	O
related	O
open	B-License
source	I-License
technologies	I-License
continue	O
to	O
be	O
implemented	O
for	O
public	O
health	O
departments	O
by	O
the	O
WeHealth	O
organization	O
.	O
</s>
<s>
The	O
two	O
researchers	O
began	O
the	O
research	O
collaboration	O
between	O
Stanford	O
and	O
Waterloo	O
,	O
which	O
formed	O
into	O
the	O
nonprofit	O
Covid	B-Application
Watch	I-Application
.	O
</s>
<s>
Anonymous	O
,	O
decentralized	O
Bluetooth	O
exposure	B-Application
alerts	I-Application
first	O
publicly	O
appeared	O
on	O
March	O
2	O
,	O
2020	O
,	O
when	O
CW	O
's	O
James	O
Petrie	O
posted	O
a	O
PDF	O
describing	O
the	O
privacy	O
model	O
in	O
CW	O
public	O
slack	O
channels	O
,	O
shared	O
with	O
researchers	O
and	O
collaborators	O
worldwide	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
's	O
description	O
of	O
the	O
technology	O
and	O
procedure	O
for	O
anonymous	O
exposure	B-Application
alerts	I-Application
was	O
shared	O
widely	O
on	O
social	O
media	O
and	O
on	O
the	O
original	O
Covid	B-Application
Watch	I-Application
blog	O
written	O
by	O
Rhys	O
Fenwick	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
developer	O
Zsombor	O
Szabo	O
built	O
the	O
first	O
open	B-License
source	I-License
,	O
decentralized	O
,	O
anonymous	O
exposure	B-Application
alert	I-Application
protocol	O
called	O
the	O
CEN	B-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
Finally	O
,	O
on	O
March	O
20	O
,	O
2020	O
,	O
the	O
CW	O
team	O
published	O
a	O
White	O
Paper	O
describing	O
the	O
CEN	O
/	O
TCN	B-Protocol
protocol	I-Protocol
.	O
</s>
<s>
After	O
that	O
,	O
Covid	B-Application
Watch	I-Application
began	O
receiving	O
significant	O
news	O
coverage	O
.	O
</s>
<s>
Covid	B-Application
Watch	I-Application
then	O
helped	O
other	O
groups	O
like	O
the	O
TCN	O
Coalition	O
and	O
MIT	O
SafePaths	O
implement	O
the	O
TCN	B-Protocol
Protocol	I-Protocol
within	O
their	O
open	B-License
source	I-License
projects	O
to	O
further	O
the	O
development	O
of	O
decentralized	O
technology	O
and	O
foster	O
global	O
interoperability	O
of	O
contact	O
tracing	O
and	O
exposure	O
alerting	O
apps	O
,	O
a	O
key	O
aspect	O
of	O
achieving	O
widespread	O
adoption	O
.	O
</s>
<s>
Finally	O
,	O
after	O
CW	O
and	O
CoEpi	O
published	O
their	O
reference	O
implementation	O
CEN	O
(	O
TCN	O
)	O
protocol	O
and	O
along	O
with	O
several	O
other	O
teams	O
communicated	O
to	O
Apple	O
the	O
issues	O
they	O
faced	O
regarding	O
a	O
successful	O
exposure	B-Application
notification	I-Application
app	O
,	O
Apple	O
and	O
Google	O
announced	O
their	O
contact	O
tracing	O
API	O
on	O
April	O
10	O
,	O
2020	O
.	O
</s>
<s>
On	O
April	O
28	O
,	O
2020	O
,	O
CW	O
implemented	O
the	O
TCN	B-Protocol
protocol	I-Protocol
in	O
a	O
fully	O
functional	O
anonymous	O
exposure	B-Application
alert	I-Application
app	O
with	O
Android	O
bridging	O
,	O
first	O
available	O
in	O
Apple	O
TestFlight	O
via	O
the	O
Stanford	O
App	O
Store	O
.	O
</s>
<s>
In	O
May	O
2020	O
,	O
Covid	B-Application
Watch	I-Application
launched	O
the	O
first	O
calibration	O
and	O
beta	O
testing	O
pilot	O
of	O
the	O
GAEN	B-Application
protocol	O
in	O
the	O
United	O
States	O
at	O
the	O
University	O
of	O
Arizona	O
.	O
</s>
