<s>
Sicher	B-Protocol
(	O
German	O
language	O
word	O
meaning	O
"	O
safe	O
"	O
,	O
"	O
secure	O
"	O
or	O
"	O
certain	O
"	O
)	O
is	O
a	O
freeware	B-License
instant	B-Application
messaging	I-Application
application	O
for	O
iOS	B-Application
,	O
Android	B-Application
,	O
and	O
Windows	B-Protocol
Phone	I-Protocol
.	O
</s>
<s>
Sicher	B-Protocol
allows	O
users	O
to	O
exchange	O
end-to-end	O
encrypted	O
text	O
messages	O
,	O
media	O
files	O
and	O
documents	O
in	O
both	O
private	O
and	O
group	O
chats	O
.	O
</s>
<s>
Sicher	B-Protocol
uses	O
phone	O
number	O
for	O
user	O
authentication	O
due	O
to	O
phone	O
number	O
being	O
a	O
unique	O
identifier	O
that	O
can	O
be	O
easily	O
confirmed	O
and	O
an	O
efficient	O
anti-spam	O
measure	O
.	O
</s>
<s>
User	O
's	O
address	B-Operating_System
book	I-Operating_System
is	O
used	O
for	O
discovery	O
of	O
Sicher	B-Protocol
contacts	O
,	O
however	O
address	B-Operating_System
book	I-Operating_System
data	O
is	O
not	O
stored	O
on	O
Sicher	B-Protocol
servers	O
.	O
</s>
<s>
Because	O
Sicher	B-Protocol
is	O
a	O
closed	O
source	O
proprietary	O
application	O
,	O
it	O
is	O
not	O
possible	O
to	O
verify	O
whether	O
the	O
claimed	O
encryption	O
standards	O
are	O
properly	O
used	O
and	O
well	O
implemented	O
.	O
</s>
