<s>
Corona-Warn-App	B-Application
is	O
the	O
official	O
and	O
open-source	B-License
COVID-19	B-Application
contact	I-Application
tracing	I-Application
app	I-Application
used	O
for	O
digital	B-Protocol
contact	I-Protocol
tracing	I-Protocol
in	O
Germany	O
made	O
by	O
SAP	B-Application
and	O
Deutsche	O
Telekom	O
subsidiary	O
T-Systems	O
.	O
</s>
<s>
The	O
app	O
works	O
with	O
the	O
Exposure	B-Application
Notification	I-Application
Framework	O
(	O
what	O
is	O
implemented	O
in	O
Google	O
Play	O
Services	O
for	O
Android	B-Application
and	O
in	O
iOS	B-Application
)	O
by	O
using	O
Bluetooth	B-Protocol
to	O
exchange	O
codes	O
with	O
app	O
users	O
that	O
are	O
within	O
1.5	O
meters	O
of	O
each	O
other	O
for	O
a	O
period	O
of	O
at	O
least	O
10	O
minutes	O
.	O
</s>
<s>
Based	O
on	O
the	O
Client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
model	I-Operating_System
five	O
servers	O
are	O
operated	O
within	O
the	O
app	O
backend	O
:	O
</s>
<s>
the	O
Corona-Warn-App	B-Application
server	O
.	O
</s>
<s>
It	O
connects	O
to	O
the	O
national	O
Corona-Warn-App	B-Application
servers	O
of	O
participating	O
EU	O
countries	O
to	O
enable	O
transnational	O
key	O
exchange	O
.	O
</s>
<s>
The	O
app	O
provides	O
a	O
function	O
to	O
warn	O
other	O
app	O
users	O
by	O
uploading	O
their	O
positive	O
test	O
result	O
on	O
a	O
voluntarily	O
and	O
anonymous	O
basis	O
to	O
the	O
Corona-Warn-App	B-Application
server	O
.	O
</s>
<s>
In	O
both	O
cases	O
,	O
the	O
user	O
can	O
upload	O
their	O
diagnosis	O
keys	O
of	O
the	O
last	O
14	O
days	O
to	O
the	O
Corona-Warn-App	B-Application
server	O
in	O
case	O
their	O
consent	O
to	O
share	O
the	O
information	O
is	O
given	O
.	O
</s>
<s>
The	O
Corona-Warn-App	B-Application
server	O
then	O
verifies	O
the	O
uploaded	O
keys	O
by	O
asking	O
the	O
Verification	O
server	O
if	O
the	O
keys	O
are	O
valid	O
and	O
if	O
they	O
are	O
,	O
the	O
Corona-Warn-App	B-Application
server	O
stores	O
them	O
in	O
its	O
database	O
.	O
</s>
<s>
The	O
app	O
implements	O
decentralized	B-Application
data	I-Application
storage	I-Application
to	O
ensure	O
data	O
privacy	O
.	O
</s>
<s>
Employers	O
can	O
require	O
that	O
Corona-Warn	B-Application
be	O
installed	O
on	O
company	O
phones	O
,	O
but	O
can	O
not	O
compel	O
its	O
use	O
on	O
private	O
phones	O
.	O
</s>
<s>
The	O
open	B-License
source	I-License
app	O
,	O
which	O
costs	O
€20	O
million	O
to	O
develop	O
is	O
intended	O
to	O
supplement	O
human	O
contact	O
tracing	O
efforts	O
,	O
which	O
Germany	O
put	O
in	O
place	O
during	O
the	O
early	O
stages	O
of	O
the	O
COVID-19	O
pandemic	O
in	O
Germany	O
.	O
</s>
<s>
With	O
the	O
update	O
published	O
on	O
19	O
October	O
2020	O
the	O
app	O
supports	O
key-exchanges	O
with	O
the	O
EU	O
Interoperability	O
Gateway	O
and	O
is	O
therefore	O
able	O
to	O
communicate	O
with	O
contact	B-Application
tracing	I-Application
apps	I-Application
from	O
Ireland	O
and	O
Italy	O
.	O
</s>
<s>
Austria	O
,	O
Belgium	O
,	O
Czech	O
Republic	O
,	O
Croatia	O
,	O
Cyprus	O
,	O
Denmark	O
,	O
Finland	O
,	O
Ireland	O
,	O
Italy	O
,	O
Latvia	O
,	O
Malta	O
,	O
Netherlands	O
,	O
Norway	O
,	O
Poland	O
,	O
Slovenia	O
,	O
Spain	O
and	O
Switzerland	B-Protocol
had	O
joined	O
the	O
gateway	O
as	O
well	O
and	O
are	O
also	O
able	O
to	O
exchange	O
keys	O
with	O
Corona-Warn-App	B-Application
.	O
</s>
<s>
An	O
unofficial	O
Corona-Warn-App	B-Application
has	O
been	O
released	O
on	O
F-Droid	B-Application
,	O
making	O
the	O
app	O
available	O
without	O
proprietary	O
components	O
on	O
Android	B-Application
phones	I-Application
.	O
</s>
<s>
Thomas	O
Köllmann	O
:	O
Die	O
Corona-Warn-App	B-Application
–	O
Schnittstelle	O
zwischen	O
Datenschutz	O
-	O
und	O
Arbeitsrecht	O
.	O
</s>
