<s>
Skype	B-Application
(	O
)	O
is	O
a	O
proprietary	B-Application
telecommunications	O
application	O
operated	O
by	O
Skype	B-Application
Technologies	O
,	O
a	O
division	O
of	O
Microsoft	O
,	O
best	O
known	O
for	O
VoIP-based	O
videotelephony	B-Application
,	O
videoconferencing	B-Application
and	O
voice	O
calls	O
.	O
</s>
<s>
It	O
also	O
has	O
instant	B-Application
messaging	I-Application
,	O
file	O
transfer	O
,	O
debit-based	O
calls	O
to	O
landline	B-Application
and	O
mobile	O
telephones	O
(	O
over	O
traditional	O
telephone	O
networks	O
)	O
,	O
and	O
other	O
features	O
.	O
</s>
<s>
Skype	B-Application
is	O
available	O
on	O
various	O
desktop	O
,	O
mobile	O
,	O
and	O
video	O
game	O
console	O
platforms	O
.	O
</s>
<s>
Skype	B-Application
was	O
created	O
by	O
Niklas	O
Zennström	O
,	O
Janus	O
Friis	O
,	O
and	O
four	O
Estonian	O
developers	O
and	O
first	O
released	O
in	O
August	O
2003	O
.	O
</s>
<s>
In	O
September	O
2005	O
,	O
eBay	B-Application
acquired	O
Skype	B-Application
for	O
$2.6	O
billion	O
.	O
</s>
<s>
In	O
September	O
2009	O
,	O
Silver	O
Lake	O
,	O
Andreessen	O
Horowitz	O
,	O
and	O
the	O
Canada	O
Pension	O
Plan	O
Investment	O
Board	O
bought	O
65%	O
of	O
Skype	B-Application
for	O
$1.9	O
billion	O
from	O
eBay	B-Application
,	O
valuing	O
the	O
business	O
at	O
$2.92	O
billion	O
.	O
</s>
<s>
In	O
May	O
2011	O
,	O
Microsoft	O
bought	O
Skype	B-Application
for	O
$8.5	O
billion	O
and	O
used	O
it	O
to	O
replace	O
their	O
Windows	B-Protocol
Live	I-Protocol
Messenger	I-Protocol
.	O
</s>
<s>
Skype	B-Application
originally	O
featured	O
a	O
hybrid	O
peer-to-peer	O
and	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
system	O
.	O
</s>
<s>
It	O
became	O
entirely	O
powered	O
by	O
Microsoft-operated	O
supernodes	B-Protocol
in	O
May	O
2012	O
;	O
in	O
2017	O
,	O
it	O
changed	O
from	O
a	O
peer-to-peer	O
service	O
to	O
a	O
centralized	O
Azure-based	O
service	O
.	O
</s>
<s>
As	O
of	O
March	O
2020	O
,	O
Skype	B-Application
was	O
used	O
by	O
100	O
million	O
people	O
at	O
least	O
once	O
a	O
month	O
and	O
by	O
40	O
million	O
people	O
each	O
day	O
.	O
</s>
<s>
During	O
the	O
COVID-19	O
pandemic	O
,	O
Skype	B-Application
lost	O
a	O
large	O
part	O
of	O
its	O
market	O
share	O
to	O
Zoom	B-Application
.	O
</s>
<s>
Dropping	O
the	O
final	O
"	O
r	O
"	O
left	O
the	O
current	O
title	O
"	O
Skype	B-Application
"	O
,	O
for	O
which	O
domain	O
names	O
were	O
available	O
.	O
</s>
<s>
Skype	B-Application
was	O
founded	O
in	O
2003	O
by	O
Niklas	O
Zennström	O
,	O
from	O
Sweden	O
,	O
and	O
Janus	O
Friis	O
,	O
from	O
Denmark	O
.	O
</s>
<s>
The	O
Skype	B-Application
software	O
was	O
created	O
by	O
Estonians	O
Ahti	O
Heinla	O
,	O
Priit	O
Kasesalu	O
,	O
Jaan	O
Tallinn	O
,	O
and	O
Toivo	O
Annus	O
.	O
</s>
<s>
Friis	O
and	O
Annus	O
are	O
credited	O
with	O
the	O
idea	O
of	O
reducing	O
the	O
cost	O
of	O
voice	O
calls	O
by	O
using	O
a	O
P2P	O
protocol	O
like	O
that	O
of	O
Kazaa	B-Protocol
.	O
</s>
<s>
In	O
June	O
2005	O
,	O
Skype	B-Application
entered	O
an	O
agreement	O
with	O
the	O
Polish	O
web	O
portal	O
Onet.pl	O
for	O
an	O
integrated	O
offering	O
on	O
the	O
Polish	O
market	O
.	O
</s>
<s>
On	O
12	O
September	O
2005	O
,	O
eBay	B-Application
Inc	I-Application
.	I-Application
agreed	O
to	O
acquire	O
Luxembourg-based	O
Skype	B-Application
Technologies	O
SA	O
for	O
approximately	O
US	O
$2.5	O
billion	O
in	O
up-front	O
cash	O
and	O
eBay	B-Application
stock	O
,	O
plus	O
potential	O
performance-based	O
consideration	O
.	O
</s>
<s>
On	O
1	O
September	O
2009	O
,	O
eBay	B-Application
announced	O
it	O
was	O
selling	O
65%	O
of	O
Skype	B-Application
to	O
Silver	O
Lake	O
,	O
Andreessen	O
Horowitz	O
,	O
and	O
the	O
Canada	O
Pension	O
Plan	O
Investment	O
Board	O
for	O
US	O
$1.9	O
billion	O
,	O
valuing	O
Skype	B-Application
at	O
US	O
$2.75	O
billion	O
.	O
</s>
<s>
On	O
14	O
July	O
2011	O
,	O
Skype	B-Application
partnered	O
with	O
Comcast	O
to	O
bring	O
its	O
video	B-Application
chat	I-Application
service	O
to	O
Comcast	O
subscribers	O
via	O
HDTV	O
sets	O
.	O
</s>
<s>
On	O
17	O
June	O
2013	O
,	O
Skype	B-Application
released	O
a	O
free	B-Application
video	O
messaging	B-Protocol
service	O
,	O
which	O
can	O
be	O
operated	O
on	O
Windows	O
,	O
Mac	B-Application
OS	I-Application
,	O
iOS	B-Application
,	O
iPadOS	B-Operating_System
,	O
Android	B-Application
,	O
and	O
BlackBerry	B-Operating_System
.	O
</s>
<s>
Between	O
2017	O
and	O
2020	O
,	O
Skype	B-Application
collaborated	O
with	O
PayPal	O
to	O
provide	O
a	O
money-send	O
feature	O
.	O
</s>
<s>
It	O
allowed	O
users	O
to	O
transfer	O
funds	O
via	O
the	O
Skype	B-Application
mobile	B-Application
app	I-Application
in	O
the	O
middle	O
of	O
a	O
conversation	O
.	O
</s>
<s>
In	O
2019	O
,	O
Skype	B-Application
was	O
announced	O
to	O
be	O
the	O
sixth	O
most	O
downloaded	O
mobile	B-Application
app	I-Application
of	O
the	O
decade	O
,	O
from	O
2010	O
to	O
2019	O
.	O
</s>
<s>
On	O
10	O
May	O
2011	O
,	O
Microsoft	O
Corporation	O
acquired	O
Skype	B-Application
Communications	O
,	O
S.à	O
r.l	O
for	O
US	O
$8.5	O
billion	O
.	O
</s>
<s>
Shortly	O
after	O
the	O
acquisition	O
,	O
Microsoft	O
began	O
integrating	O
the	O
Skype	B-Application
service	O
with	O
its	O
own	O
products	O
.	O
</s>
<s>
Along	O
with	O
taking	O
over	O
the	O
development	O
of	O
existing	O
Skype	B-Application
desktop	O
and	O
mobile	B-Application
apps	I-Application
,	O
the	O
company	O
developed	O
a	O
dedicated	O
client	O
app	O
for	O
its	O
then-newly	O
released	O
,	O
touch-focused	O
Windows	B-Application
8	I-Application
and	O
Windows	B-Operating_System
RT	I-Operating_System
operating	O
systems	O
.	O
</s>
<s>
They	O
were	O
made	O
available	O
from	O
Windows	B-Application
Store	I-Application
when	O
the	O
then-new	O
OS	O
launched	O
on	O
26	O
October	O
2012	O
.	O
</s>
<s>
The	O
following	O
year	O
,	O
it	O
became	O
the	O
default	O
messaging	B-Application
app	I-Application
for	O
Windows	B-Device
8.1	I-Device
,	O
replacing	O
the	O
Windows	B-Application
8	I-Application
Messaging	B-Application
app	I-Application
at	O
the	O
time	O
,	O
and	O
became	O
pre-installed	O
software	O
on	O
every	O
device	O
that	O
came	O
with	O
or	O
upgraded	O
to	O
8.1	B-Device
.	O
</s>
<s>
In	O
a	O
month-long	O
transition	O
from	O
8	O
to	O
30	O
April	O
2013	O
,	O
Microsoft	O
discontinued	O
two	O
of	O
its	O
own	O
products	O
in	O
favor	O
of	O
Skype	B-Application
,	O
including	O
its	O
Windows	B-Protocol
Live	I-Protocol
Messenger	I-Protocol
instant	B-Application
messaging	I-Application
service	O
,	O
although	O
Messenger	O
continued	O
to	O
be	O
available	O
in	O
mainland	O
China	O
until	O
October	O
2014	O
.	O
</s>
<s>
On	O
11	O
November	O
2014	O
,	O
Microsoft	O
announced	O
that	O
in	O
2015	O
,	O
its	O
Lync	O
product	O
would	O
be	O
replaced	O
by	O
Skype	B-Protocol
for	I-Protocol
Business	I-Protocol
.	O
</s>
<s>
This	O
combined	O
features	O
of	O
Lync	O
and	O
the	O
consumer	O
Skype	B-Application
software	O
.	O
</s>
<s>
There	O
are	O
two	O
user	O
interfaces	O
,	O
organizations	O
could	O
switch	O
their	O
users	O
between	O
the	O
default	O
Skype	B-Protocol
for	I-Protocol
Business	I-Protocol
interface	O
to	O
the	O
Lync	O
interface	O
.	O
</s>
<s>
On	O
12	O
August	O
2013	O
,	O
Skype	B-Application
released	O
the	O
4.10	O
update	O
to	O
the	O
app	O
for	O
Apple	O
iPhone	O
and	O
iPad	B-Device
that	O
allows	O
HD	O
quality	O
video	O
for	O
iPhone	O
5	O
and	O
fourth-generation	O
iPads	B-Device
.	O
</s>
<s>
On	O
20	O
November	O
2014	O
,	O
Microsoft	O
Office	O
's	O
team	O
announced	O
that	O
a	O
new	O
chat	O
powered	O
by	O
Skype	B-Application
would	O
be	O
implemented	O
in	O
their	O
software	O
,	O
giving	O
tools	O
to	O
be	O
able	O
to	O
chat	O
with	O
co-workers	O
in	O
the	O
same	O
document	O
.	O
</s>
<s>
On	O
15	O
September	O
2015	O
,	O
Skype	B-Application
announced	O
the	O
release	O
of	O
Mojis	O
,	O
"	O
a	O
brand	O
new	O
way	O
to	O
express	O
yourself	O
on	O
Skype	B-Application
"	O
.	O
</s>
<s>
Mojis	O
are	O
short	O
clips/gifs	O
featuring	O
characters	O
from	O
films	O
and	O
TV	O
shows	O
to	O
be	O
entered	O
into	O
conversations	O
with	O
the	O
same	O
ease	O
as	O
emoticons	B-Protocol
.	O
</s>
<s>
They	O
worked	O
with	O
Universal	B-Application
Studios	I-Application
,	O
Disney	O
Muppets	O
,	O
BBC	O
and	O
other	O
studios	O
to	O
add	O
to	O
the	O
available	O
collection	O
of	O
Mojis	O
.	O
</s>
<s>
Later	O
that	O
year	O
,	O
Gurdeep	O
Singh	O
Pall	O
,	O
Corporate	O
Vice	O
President	O
of	O
Skype	B-Application
,	O
announced	O
that	O
Microsoft	O
had	O
acquired	O
the	O
technology	O
from	O
Talko	O
.	O
</s>
<s>
In	O
July	O
2016	O
,	O
Skype	B-Application
introduced	O
an	O
early	O
Alpha	O
version	O
of	O
a	O
new	O
Skype	B-Application
for	O
Linux	B-Application
client	O
,	O
built	O
with	O
WebRTC	B-Protocol
technology	O
,	O
after	O
several	O
petitions	O
had	O
asked	O
Microsoft	O
to	O
continue	O
development	O
for	O
Linux	B-Application
.	O
</s>
<s>
In	O
September	O
of	O
that	O
year	O
,	O
Skype	B-Application
updated	O
their	O
iOS	B-Application
app	O
with	O
new	O
features	O
,	O
including	O
an	O
option	O
to	O
call	O
contacts	O
on	O
Skype	B-Application
through	O
Siri	O
voice	O
commands	O
.	O
</s>
<s>
In	O
October	O
of	O
that	O
year	O
,	O
Microsoft	O
launched	O
Skype	B-Protocol
for	I-Protocol
Business	I-Protocol
for	O
Mac	O
.	O
</s>
<s>
In	O
February	O
2017	O
,	O
Microsoft	O
announced	O
plans	O
to	O
discontinue	O
its	O
Skype	B-Application
Wi-Fi	O
service	O
globally	O
.	O
</s>
<s>
On	O
5	O
June	O
2017	O
,	O
Microsoft	O
announced	O
its	O
plans	O
to	O
revamp	O
Skype	B-Application
with	O
similar	O
features	O
to	O
Snapchat	B-Application
,	O
allowing	O
users	O
to	O
share	O
temporary	O
copies	O
of	O
their	O
photos	O
and	O
video	O
files	O
.	O
</s>
<s>
In	O
late	O
June	O
2017	O
,	O
Microsoft	O
rolled	O
out	O
their	O
latest	O
update	O
for	O
iOS	B-Application
,	O
incorporating	O
a	O
revamped	O
design	O
and	O
new	O
third-party	O
integrations	O
,	O
with	O
platforms	O
including	O
Gfycat	O
,	O
YouTube	B-General_Concept
,	O
and	O
UpWorthy	O
.	O
</s>
<s>
Skype	B-Application
later	O
removed	O
this	O
"	O
makeover	O
"	O
.	O
</s>
<s>
In	O
December	O
2017	O
,	O
Microsoft	O
added	O
"	O
Skype	B-Application
Interviews	O
"	O
,	O
a	O
shared	O
code	O
editing	O
system	O
for	O
those	O
wishing	O
to	O
hold	O
job	O
interviews	O
for	O
programming	O
roles	O
.	O
</s>
<s>
Microsoft	O
eventually	O
moved	O
the	O
service	O
from	O
a	O
peer-to-peer	O
to	O
a	O
central	O
server	O
based	O
system	O
,	O
and	O
with	O
it	O
adjusted	O
the	O
user	O
interfaces	O
of	O
apps	O
to	O
make	O
text-based	O
messaging	B-Protocol
more	O
prominent	O
than	O
voice	O
calling	O
.	O
</s>
<s>
Skype	B-Application
for	O
Windows	O
,	O
iOS	B-Application
,	O
Android	B-Application
,	O
Mac	O
and	O
Linux	B-Application
all	O
received	O
significant	O
visual	O
overhauls	O
at	O
this	O
time	O
.	O
</s>
<s>
Registered	O
users	O
of	O
Skype	B-Application
are	O
identified	O
by	O
a	O
unique	O
Skype	B-Application
ID	O
and	O
may	O
be	O
listed	O
in	O
the	O
Skype	B-Application
directory	O
under	O
a	O
Skype	B-Application
username	O
.	O
</s>
<s>
Skype	B-Application
allows	O
these	O
registered	O
users	O
to	O
communicate	O
through	O
both	O
instant	B-Application
messaging	I-Application
and	O
voice	O
chat	O
.	O
</s>
<s>
Voice	O
chat	O
allows	O
telephone	O
calls	O
between	O
pairs	O
of	O
users	O
and	O
conference	O
calling	O
and	O
uses	O
proprietary	B-Application
audio	O
codec	B-General_Concept
.	O
</s>
<s>
Skype	B-Application
's	O
text	O
chat	O
client	O
allows	O
group	O
chats	O
,	O
emoticons	B-Protocol
,	O
storing	O
chat	O
history	O
,	O
and	O
editing	O
of	O
previous	O
messages	O
.	O
</s>
<s>
The	O
usual	O
features	O
familiar	O
to	O
instant	B-Application
messaging	I-Application
users	O
—	O
user	O
profiles	O
,	O
online	O
status	O
indicators	O
,	O
and	O
so	O
on	O
—	O
are	O
also	O
included	O
.	O
</s>
<s>
SkypeIn	O
,	O
service	O
allows	O
Skype	B-Application
users	O
to	O
receive	O
calls	O
on	O
their	O
computers	O
dialed	O
by	O
conventional	O
phone	O
subscribers	O
to	O
a	O
local	O
Skype	B-Application
phone	O
number	O
;	O
local	O
numbers	O
are	O
available	O
for	O
Australia	O
,	O
Belgium	O
,	O
Brazil	O
,	O
Chile	O
,	O
Colombia	O
,	O
Denmark	O
,	O
the	O
Dominican	O
Republic	O
,	O
Estonia	O
,	O
Finland	O
,	O
France	O
,	O
Germany	O
,	O
Hong	O
Kong	O
,	O
Hungary	O
,	O
India	O
,	O
Ireland	O
,	O
Japan	O
,	O
Mexico	O
,	O
Nepal	O
,	O
New	O
Zealand	O
,	O
Poland	O
,	O
Romania	O
,	O
South	O
Africa	O
,	O
South	O
Korea	O
,	O
Sweden	O
,	O
Switzerland	O
,	O
Turkey	O
,	O
the	O
Netherlands	O
,	O
the	O
United	O
Kingdom	O
,	O
and	O
the	O
United	O
States	O
.	O
</s>
<s>
A	O
Skype	B-Application
user	O
can	O
have	O
local	O
numbers	O
in	O
any	O
of	O
these	O
countries	O
,	O
with	O
calls	O
to	O
the	O
number	O
charged	O
at	O
the	O
same	O
rate	O
as	O
calls	O
to	O
fixed	B-Application
lines	I-Application
in	O
the	O
country	O
.	O
</s>
<s>
Skype	B-Application
supports	O
conference	O
calls	O
,	O
video	B-Application
chats	I-Application
,	O
and	O
screen	O
sharing	O
between	O
25	O
people	O
at	O
a	O
time	O
for	O
free	B-Application
,	O
which	O
then	O
increased	O
to	O
50	O
on	O
5	O
April	O
2019	O
.	O
</s>
<s>
Skype	B-Application
does	O
not	O
provide	O
the	O
ability	O
to	O
call	O
emergency	O
numbers	O
,	O
such	O
as	O
112	O
in	O
Europe	O
,	O
911	O
in	O
North	O
America	O
,	O
999	O
in	O
the	O
UK	O
or	O
100	O
in	O
India	O
and	O
Nepal	O
.	O
</s>
<s>
The	O
U.S.	O
Federal	O
Communications	O
Commission	O
(	O
FCC	O
)	O
has	O
ruled	O
that	O
,	O
for	O
the	O
purposes	O
of	O
section	O
255	O
of	O
the	O
Telecommunications	O
Act	O
,	O
Skype	B-Application
is	O
not	O
an	O
"	O
interconnected	O
VoIP	B-Application
provider	O
"	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
the	O
U.S.	O
National	O
Emergency	O
Number	O
Association	O
recommends	O
that	O
all	O
VoIP	B-Application
users	O
have	O
an	O
analog	O
line	O
available	O
as	O
a	O
backup	O
.	O
</s>
<s>
In	O
2019	O
,	O
Skype	B-Application
added	O
an	O
option	O
to	O
blur	O
the	O
background	O
in	O
a	O
video	B-Application
chat	I-Application
interface	O
using	O
AI	O
algorithms	O
purely	O
done	O
using	O
software	O
,	O
despite	O
a	O
depth-sensing	O
camera	O
not	O
being	O
present	O
in	O
most	O
webcams	O
.	O
</s>
<s>
In	O
2023	O
,	O
Skype	B-Application
added	O
the	O
Bing	O
AI	O
chatbot	O
to	O
the	O
platform	O
for	O
users	O
who	O
had	O
access	O
to	O
the	O
chatbot	O
.	O
</s>
<s>
Usage	O
and	O
traffic	O
Date	O
Total	O
user	O
accounts(millions )	O
Active	O
users	O
,	O
daily	O
use(millions )	O
Skype	B-Application
to	O
Skype	B-Application
minutes(billions )	O
SkypeOut	O
minutes(billions )	O
Revenue	O
USD(millions )	O
Q4	O
2005	O
74.7	O
10.8	O
Q1	O
2006	O
94.6	O
15.2	O
6.9	O
0.7	O
35	O
Q2	O
2006	O
113.1	O
16.6	O
7.1	O
0.8	O
44	O
Q3	O
2006	O
135.9	O
18.7	O
6.6	O
1.1	O
50	O
Q4	O
2006	O
171.2	O
21.2	O
7.6	O
1.5	O
66	O
Q1	O
2007	O
195.5	O
23.2	O
7.7	O
1.3	O
79	O
Q2	O
2007	O
219.6	O
23.9	O
7.1	O
1.3	O
90	O
Q3	O
2007	O
245.7	O
24.2	O
6.1	B-Device
1.4	O
98	O
Q4	O
2007	O
276.3	O
27.0	O
11.9	O
1.6	O
115	O
Q1	O
2008	O
309.3	O
31.3	O
14.2	O
1.7	O
126	O
Q2	O
2008	O
338.2	O
32.0	O
14.8	O
1.9	O
136	O
Q3	O
2008	O
370	O
33.7	O
16.0	O
2.2	O
143	O
Q4	O
2008	O
405	O
36.5	O
20.5	O
2.6	O
145	O
Q1	O
2009	O
443	O
42.2	O
23.6	O
2.9	O
153	O
Q2	O
2009	O
483	O
25.5	O
3.0	O
170	O
Q3	O
2009	O
521	O
27.7	O
3.1	O
185	O
Q4	O
2009	O
560	O
36.1	O
Q1	O
2010	O
190	O
12.8	O
860	O
Q2	O
2010	O
Q3	O
2010	O
Q4	O
2010	O
Q1	O
2011	O
Q2	O
2011	O
Q3	O
2011	O
663	O
Q4	O
2011	O
Q1	O
2012	O
Q2	O
2012	O
Users	O
may	O
have	O
more	O
than	O
one	O
account	O
;	O
it	O
is	O
not	O
possible	O
to	O
count	O
users	O
,	O
only	O
accounts	O
.	O
</s>
<s>
The	O
volume	O
of	O
international	O
traffic	O
routed	O
via	O
Skype	B-Application
is	O
significant	O
.	O
</s>
<s>
At	O
one	O
point	O
in	O
February	O
2012	O
,	O
there	O
were	O
34	O
million	O
users	O
concurrently	O
online	O
on	O
Skype	B-Application
.	O
</s>
<s>
In	O
January	O
2011	O
,	O
after	O
the	O
release	O
of	O
video	B-Application
calling	I-Application
on	O
the	O
Skype	B-Application
client	O
for	O
iPhone	O
,	O
Skype	B-Application
reached	O
a	O
record	O
27	O
million	O
simultaneous	O
online	O
users	O
.	O
</s>
<s>
On	O
25	O
February	O
2012	O
,	O
Skype	B-Application
announced	O
that	O
it	O
has	O
over	O
32	O
million	O
users	O
for	O
the	O
first	O
time	O
ever	O
.	O
</s>
<s>
By	O
5	O
March	O
2012	O
,	O
it	O
had	O
36	O
million	O
simultaneous	O
online	O
users	O
,	O
and	O
less	O
than	O
a	O
year	O
later	O
,	O
on	O
21	O
January	O
2013	O
,	O
Skype	B-Application
had	O
more	O
than	O
50	O
million	O
concurrent	B-License
users	I-License
online	O
.	O
</s>
<s>
In	O
June	O
2012	O
,	O
Skype	B-Application
had	O
surpassed	O
70	O
million	O
downloads	O
on	O
Android	B-Application
.	O
</s>
<s>
On	O
19	O
July	O
2012	O
,	O
Microsoft	O
announced	O
that	O
Skype	B-Application
users	O
had	O
logged	O
115	O
billion	O
minutes	O
of	O
calls	O
in	O
the	O
quarter	O
,	O
up	O
to	O
50%	O
since	O
the	O
last	O
quarter	O
.	O
</s>
<s>
On	O
15	O
January	O
2014	O
,	O
TeleGeography	O
estimated	O
that	O
Skype-to-Skype	O
international	O
traffic	O
has	O
gone	O
up	O
to	O
36%	O
in	O
2013	O
to	O
214	O
billion	O
minutes	O
.	O
</s>
<s>
Multiple	O
different	O
versions	O
of	O
Skype	B-Application
have	O
been	O
released	O
for	O
Windows	O
since	O
its	O
conception	O
.	O
</s>
<s>
The	O
original	O
line	O
of	O
Skype	B-Application
applications	O
continued	O
from	O
versions	O
1.0	O
through	O
4.0	O
.	O
</s>
<s>
Later	O
,	O
a	O
mobile	O
version	O
was	O
created	O
for	O
Windows	B-Protocol
Phones	I-Protocol
.	O
</s>
<s>
In	O
2012	O
,	O
Skype	B-Application
introduced	O
a	O
new	O
version	O
for	O
Windows	B-Application
8	I-Application
similar	O
to	O
the	O
Windows	B-Protocol
Phone	I-Protocol
version	O
.	O
</s>
<s>
On	O
7	O
July	O
2015	O
Skype	B-Application
modified	O
the	O
application	O
to	O
direct	O
Windows	O
users	O
to	O
download	O
the	O
desktop	O
version	O
,	O
but	O
it	O
was	O
set	O
to	O
continue	O
working	O
on	O
Windows	B-Operating_System
RT	I-Operating_System
until	O
October	O
2016	O
.	O
</s>
<s>
In	O
November	O
2015	O
,	O
Skype	B-Application
introduced	O
three	O
new	O
applications	O
,	O
called	O
Messaging	B-Protocol
,	O
Skype	B-Application
Video	I-Application
,	O
and	O
Phone	O
,	O
intended	O
to	O
provide	O
an	O
integrated	O
Skype	B-Application
experience	O
on	O
Windows	O
10	O
.	O
</s>
<s>
On	O
24	O
March	O
2016	O
,	O
Skype	B-Application
announced	O
the	O
integrated	O
applications	O
did	O
not	O
satisfy	O
most	O
users	O
 '	O
needs	O
and	O
announced	O
that	O
they	O
and	O
the	O
desktop	O
client	O
would	O
eventually	O
be	O
replaced	O
with	O
a	O
new	O
UWP	O
application	O
,	O
which	O
was	O
released	O
as	O
a	O
preview	O
version	O
for	O
the	O
Windows	O
10	O
Anniversary	O
Update	O
and	O
dubbed	O
as	O
the	O
stable	O
version	O
with	O
the	O
release	O
of	O
the	O
Windows	O
10	O
Creators	O
Update	O
.	O
</s>
<s>
The	O
latest	O
version	O
of	O
Skype	B-Application
for	O
Windows	O
is	O
Skype	B-Application
11	O
,	O
which	O
is	O
based	O
on	O
the	O
Universal	O
Windows	O
Platform	O
and	O
runs	O
on	O
various	O
Windows	O
10-related	O
systems	O
,	O
including	O
Xbox	B-Device
One	I-Device
,	O
Xbox	B-Device
Series	I-Device
X/S	I-Device
,	O
Windows	B-Protocol
phones	I-Protocol
,	O
and	O
Microsoft	B-General_Concept
Hololens	I-General_Concept
.	O
</s>
<s>
Microsoft	O
still	O
offers	O
the	O
older	O
Skype	B-Application
8	O
,	O
which	O
is	O
Win32-based	O
and	O
runs	O
on	O
all	O
systems	O
from	O
Windows	B-Application
XP	I-Application
(	O
which	O
is	O
otherwise	O
unsupported	O
by	O
Microsoft	O
)	O
to	O
the	O
most	O
recent	O
release	O
of	O
Windows	O
10	O
.	O
</s>
<s>
In	O
late	O
2017	O
,	O
this	O
version	O
was	O
upgraded	O
to	O
Skype	B-Application
12.9	O
in	O
which	O
several	O
features	O
were	O
both	O
removed	O
and	O
added	O
.	O
</s>
<s>
Linux	B-Application
(	O
Debian	O
,	O
Debian-based	O
(	O
Ubuntu	B-Operating_System
,	O
etc	O
.	O
</s>
<s>
Skype	B-Application
was	O
previously	O
available	O
on	O
Nokia	B-Application
X	I-Application
,	O
Symbian	B-Operating_System
,	O
BlackBerry	B-Application
OS	I-Application
and	O
BlackBerry	B-Application
10	I-Application
devices	O
.	O
</s>
<s>
In	O
May	O
2009	O
a	O
Version	O
3.0	O
was	O
available	O
on	O
Windows	O
Mobile	O
5	O
to	O
6.1	B-Device
,	O
and	O
in	O
September	O
2015	O
a	O
Version	O
2.29	O
was	O
available	O
on	O
Windows	B-Protocol
Phone	I-Protocol
8.1	I-Protocol
;	O
in	O
2016	O
Microsoft	O
announced	O
that	O
this	O
would	O
stop	O
working	O
in	O
early	O
2017	O
once	O
Skype	B-Application
's	O
transition	O
from	O
peer-to-peer	O
to	O
client-server	B-Operating_System
was	O
complete	O
.	O
</s>
<s>
The	O
Nokia	B-Operating_System
N9	I-Operating_System
,	O
which	O
runs	O
MeeGo	B-Operating_System
,	O
comes	O
with	O
Skype	B-Application
voice	O
calling	O
and	O
text	O
messaging	B-Protocol
integrated	O
;	O
however	O
,	O
it	O
lacks	O
video-calling	O
.	O
</s>
<s>
The	O
PlayStation	B-Operating_System
Portable	I-Operating_System
Slim	O
and	O
Lite	O
series	O
,	O
though	O
the	O
user	O
needs	O
to	O
purchase	O
a	O
specially	O
designed	O
microphone	O
peripheral	O
.	O
</s>
<s>
The	O
PSP-3000	O
has	O
a	O
built-in	O
microphone	O
,	O
which	O
allows	O
communication	O
without	O
the	O
Skype	B-Application
peripheral	O
.	O
</s>
<s>
The	O
PSP	B-Operating_System
Go	O
has	O
the	O
ability	O
to	O
use	O
Bluetooth	B-Protocol
connections	O
with	O
the	O
Skype	B-Application
application	O
,	O
in	O
addition	O
to	O
its	O
built-in	O
microphone	O
.	O
</s>
<s>
Skype	B-Application
for	O
PlayStation	B-Device
Vita	I-Device
may	O
be	O
downloaded	O
via	O
the	O
PlayStation	O
Network	O
in	O
the	O
U.S.	O
</s>
<s>
The	O
Samsung	O
Smart	O
TV	O
had	O
a	O
Skype	B-Application
app	O
,	O
which	O
could	O
be	O
downloaded	O
for	O
free	B-Application
.	O
</s>
<s>
Alternatively	O
,	O
a	O
separate	O
mountable	O
Skype	B-Application
camera	O
with	O
built-in	O
speakers	O
and	O
microphones	O
is	O
available	O
to	O
purchase	O
for	O
older	O
models	O
.	O
</s>
<s>
This	O
functionality	O
has	O
now	O
been	O
disabled	O
along	O
with	O
any	O
other	O
"	O
TV	O
Based	O
"	O
Skype	B-Application
clients	O
.	O
</s>
<s>
Some	O
devices	O
were	O
made	O
to	O
work	O
with	O
Skype	B-Application
by	O
talking	O
to	O
a	O
desktop	O
Skype	B-Application
client	O
or	O
by	O
embedding	O
Skype	B-Application
software	O
into	O
the	O
device	O
.	O
</s>
<s>
These	O
were	O
usually	O
either	O
tethered	O
to	O
a	O
PC	O
or	O
have	O
a	O
built-in	O
Wi-Fi	O
client	O
to	O
allow	O
calling	O
from	O
Wi-Fi	O
hotspots	O
,	O
like	O
the	O
Netgear	O
SPH101	O
Skype	B-Application
Wi-Fi	O
Phone	O
,	O
the	O
SMC	O
WSKP100	O
Skype	B-Application
Wi-Fi	O
Phone	O
,	O
the	O
Belkin	O
F1PP000GN-SK	O
Wi-Fi	O
Skype	B-Application
Phone	O
,	O
the	O
Panasonic	O
KX-WP1050	O
Wi-Fi	O
Phone	O
for	O
Skype	B-Application
Executive	O
Travel	O
Set	O
,	O
the	O
IPEVO	O
So-20	O
Wi-Fi	O
Phone	O
for	O
Skype	B-Application
and	O
the	O
Linksys	O
CIT200	O
Wi-Fi	O
Phone	O
.	O
</s>
<s>
Third-party	O
developers	O
,	O
such	O
as	O
Truphone	B-Language
,	O
Nimbuzz	B-Protocol
,	O
and	O
Fring	O
,	O
previously	O
allowed	O
Skype	B-Application
to	O
run	O
in	O
parallel	O
with	O
several	O
other	O
competing	O
VoIP/IM	O
networks	O
(	O
Truphone	B-Language
and	O
Nimbuzz	B-Protocol
provide	O
TruphoneOut	O
and	O
NimbuzzOut	O
as	O
a	O
competing	O
paid	O
service	O
)	O
in	O
any	O
Symbian	B-Operating_System
or	O
Java	O
environment	O
.	O
</s>
<s>
Nimbuzz	B-Protocol
made	O
Skype	B-Application
available	O
to	O
BlackBerry	B-Operating_System
users	O
and	O
Fring	O
provided	O
mobile	O
video	B-Application
calling	I-Application
over	O
Skype	B-Application
as	O
well	O
as	O
support	O
for	O
the	O
Android	B-Application
platform	I-Application
.	O
</s>
<s>
Skype	B-Application
disabled	O
access	O
to	O
Skype	B-Application
by	O
Fring	O
users	O
in	O
July	O
2010	O
.	O
</s>
<s>
Nimbuzz	B-Protocol
discontinued	O
support	O
of	O
Skype	B-Application
on	O
request	O
in	O
October	O
2010	O
.	O
</s>
<s>
Before	O
and	O
during	O
the	O
Microsoft	O
acquisition	O
,	O
Skype	B-Application
withdrew	O
licensing	O
from	O
several	O
third	O
parties	O
producing	O
software	O
and	O
hardware	O
compatible	O
with	O
Skype	B-Application
.	O
</s>
<s>
The	O
Skype	B-Application
for	O
Asterisk	B-Language
product	O
from	O
Digium	B-Protocol
was	O
withdrawn	O
as	O
"	O
no	O
longer	O
available	O
for	O
sale	O
"	O
.	O
</s>
<s>
The	O
Senao	O
SN358+	O
long-range	O
(	O
10	O
–	O
15km	O
)	O
cordless	O
phone	O
was	O
discontinued	O
due	O
to	O
loss	O
of	O
licenses	O
to	O
participate	O
in	O
the	O
Skype	B-Application
network	O
as	O
peers	O
.	O
</s>
<s>
Skype	B-Application
uses	O
a	O
proprietary	B-Application
Internet	B-Application
telephony	I-Application
(	O
VoIP	B-Application
)	O
network	O
called	O
the	O
Skype	B-Protocol
protocol	I-Protocol
.	O
</s>
<s>
The	O
protocol	O
has	O
not	O
been	O
made	O
publicly	O
available	O
by	O
Skype	B-Application
,	O
and	O
official	O
applications	O
using	O
the	O
protocol	O
are	O
also	O
proprietary	B-Application
.	O
</s>
<s>
Part	O
of	O
the	O
Skype	B-Application
technology	O
relies	O
on	O
the	O
Global	O
Index	O
P2P	O
protocol	O
belonging	O
to	O
the	O
Joltid	O
Ltd	O
.	O
corporation	O
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
Skype	B-Application
and	O
standard	O
VoIP	B-Application
clients	O
is	O
that	O
Skype	B-Application
operates	O
on	O
a	O
peer-to-peer	O
model	O
(	O
originally	O
based	O
on	O
the	O
Kazaa	B-Protocol
software	O
)	O
,	O
rather	O
than	O
the	O
more	O
usual	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
model	I-Operating_System
(	O
note	O
that	O
the	O
very	O
popular	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	O
)	O
model	O
of	O
VoIP	B-Application
is	O
also	O
peer-to-peer	O
,	O
but	O
implementation	O
generally	O
requires	O
registration	O
with	O
a	O
server	O
,	O
as	O
does	O
Skype	B-Application
)	O
.	O
</s>
<s>
On	O
20	O
June	O
2014	O
,	O
Microsoft	O
announced	O
the	O
deprecation	O
of	O
the	O
old	O
Skype	B-Protocol
protocol	I-Protocol
.	O
</s>
<s>
Within	O
several	O
months	O
from	O
this	O
date	O
,	O
in	O
order	O
to	O
continue	O
using	O
Skype	B-Application
services	O
,	O
Skype	B-Application
users	O
will	O
have	O
to	O
update	O
to	O
Skype	B-Application
applications	O
released	O
in	O
2014	O
.	O
</s>
<s>
The	O
new	O
Skype	B-Protocol
protocol	I-Protocol
,	O
Microsoft	O
Notification	O
Protocol	O
24	O
,	O
was	O
released	O
.	O
</s>
<s>
As	O
far	O
as	O
networking	O
stack	O
support	O
is	O
concerned	O
,	O
Skype	B-Application
only	O
supports	O
the	O
IPv4	B-Protocol
protocol	O
.	O
</s>
<s>
It	O
lacks	O
support	O
for	O
the	O
next-generation	O
Internet	O
protocol	O
,	O
IPv6	B-Protocol
.	O
</s>
<s>
Skype	B-Protocol
for	I-Protocol
Business	I-Protocol
,	O
however	O
,	O
includes	O
support	O
for	O
IPv6	B-Protocol
addresses	O
,	O
along	O
with	O
continued	O
support	O
of	O
IPv4	B-Protocol
.	O
</s>
<s>
Many	O
networking	O
and	O
security	O
companies	O
have	O
claimed	O
to	O
detect	O
and	O
control	O
Skype	B-Application
's	O
protocol	O
for	O
enterprise	O
and	O
carrier	O
applications	O
.	O
</s>
<s>
While	O
the	O
specific	O
detection	O
methods	O
used	O
by	O
these	O
companies	O
are	O
often	O
private	O
,	O
Pearson	B-General_Concept
's	I-General_Concept
chi-squared	I-General_Concept
test	I-General_Concept
and	O
naive	B-General_Concept
Bayes	I-General_Concept
classification	I-General_Concept
are	O
two	O
approaches	O
that	O
were	O
published	O
in	O
2008	O
.	O
</s>
<s>
Combining	O
statistical	O
measurements	O
of	O
payload	O
properties	O
(	O
such	O
as	O
byte	O
frequencies	O
and	O
initial	O
byte	O
sequences	O
)	O
as	O
well	O
as	O
flow	O
properties	O
(	O
like	O
packet	O
sizes	O
and	O
packet	O
directions	O
)	O
has	O
also	O
shown	O
to	O
be	O
an	O
effective	O
method	O
for	O
identifying	O
Skype	B-Application
's	O
TCP	O
-	O
and	O
UDP-based	O
protocols	O
.	O
</s>
<s>
Skype	B-Application
2.x	O
used	O
G.729	B-Algorithm
,	O
Skype	B-Application
3.2	O
introduced	O
SVOPC	B-Protocol
,	O
and	O
Skype	B-Application
4.0	O
added	O
a	O
Skype-created	O
codec	B-General_Concept
called	O
:SILK	O
,	O
intended	O
to	O
be	O
"	O
lightweight	O
and	O
embeddable	O
"	O
.	O
</s>
<s>
Additionally	O
,	O
Skype	B-Application
has	O
released	O
Opus	B-Algorithm
as	O
a	O
free	B-Application
codec	B-General_Concept
,	O
which	O
integrates	O
the	O
SILK	O
codec	B-General_Concept
principles	O
for	O
voice	O
transmission	O
with	O
the	O
CELT	B-Algorithm
codec	B-General_Concept
principles	O
for	O
higher-quality	O
audio	O
transmissions	O
,	O
such	O
as	O
live	O
music	O
performances	O
.	O
</s>
<s>
Opus	B-Algorithm
was	O
submitted	O
to	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
(	O
IETF	O
)	O
in	O
September	O
2010	O
.	O
</s>
<s>
Since	O
then	O
,	O
it	O
has	O
been	O
standardized	O
as	O
RFC	B-Algorithm
6716	I-Algorithm
.	O
</s>
<s>
VP7	O
is	O
used	O
for	O
versions	O
prior	O
to	O
Skype	B-Application
5.5	O
.	O
</s>
<s>
As	O
of	O
version	O
7.0	O
,	O
H.264	B-Application
is	O
used	O
for	O
both	O
group	O
and	O
one-on-one	O
video	B-Application
chat	I-Application
,	O
at	O
standard	B-Device
definition	I-Device
,	O
720p	O
and	O
1080p	O
high-definition	O
.	O
</s>
<s>
Skype	B-Application
acquired	O
the	O
video	O
service	O
Qik	B-Protocol
in	O
2011	O
.	O
</s>
<s>
After	O
shutting	O
down	O
Qik	B-Protocol
in	O
April	O
2014	O
,	O
Skype	B-Application
relaunched	O
the	O
service	O
as	O
Skype	B-Protocol
Qik	I-Protocol
on	O
14	O
October	O
2014	O
.	O
</s>
<s>
Although	O
Qik	B-Protocol
offered	O
video	B-Application
conferencing	I-Application
and	O
Internet	O
streaming	O
,	O
the	O
new	O
service	O
focuses	O
on	O
mobile	O
video	O
messaging	B-Protocol
between	O
individuals	O
and	O
groups	O
.	O
</s>
<s>
Skype	B-Application
uses	O
URIs	B-Protocol
as	O
skype:USER	O
?	O
call	O
for	O
a	O
call	O
.	O
</s>
<s>
Skype	B-Application
was	O
claimed	O
initially	O
to	O
be	O
a	O
secure	O
communication	O
,	O
with	O
one	O
of	O
its	O
early	O
web	O
pages	O
stating	O
"	O
highly	O
secure	O
with	O
end-to-end	O
encryption	O
"	O
.	O
</s>
<s>
Skype	B-Application
claims	O
to	O
use	O
publicly	O
documented	O
,	O
widely	O
trusted	O
encryption	O
techniques	O
for	O
Skype-to-Skype	O
communication	O
:	O
RSA	B-Architecture
for	O
key	O
negotiation	O
and	O
the	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
to	O
encrypt	O
conversations	O
.	O
</s>
<s>
Skype	B-Application
provides	O
an	O
uncontrolled	O
registration	O
system	O
for	O
users	O
with	O
no	O
proof	O
of	O
identity	O
.	O
</s>
<s>
A	O
third-party	O
paper	O
analyzing	O
the	O
security	O
and	O
methodology	O
of	O
Skype	B-Application
was	O
presented	O
at	O
Black	O
Hat	O
Europe	O
2006	O
.	O
</s>
<s>
It	O
analyzed	O
Skype	B-Application
and	O
found	O
a	O
number	O
of	O
security	O
issues	O
with	O
the	O
then-current	O
security	O
model	O
.	O
</s>
<s>
Skype	B-Application
incorporates	O
some	O
features	O
that	O
tend	O
to	O
hide	O
its	O
traffic	O
,	O
but	O
it	O
is	O
not	O
specifically	O
designed	O
to	O
thwart	O
traffic	O
analysis	O
and	O
therefore	O
does	O
not	O
provide	O
anonymous	O
communication	O
.	O
</s>
<s>
Some	O
researchers	O
have	O
been	O
able	O
to	O
watermark	O
the	O
traffic	O
so	O
that	O
it	O
is	O
identifiable	O
even	O
after	O
passing	O
through	O
an	O
anonymizing	B-Application
network	I-Application
.	O
</s>
<s>
In	O
an	O
interview	O
,	O
Kurt	O
Sauer	O
,	O
the	O
Chief	O
Security	O
Officer	O
of	O
Skype	B-Application
,	O
said	O
,	O
"	O
We	O
provide	O
a	O
safe	O
communication	O
option	O
.	O
</s>
<s>
This	O
does	O
not	O
deny	O
the	O
fact	O
that	O
the	O
U.S.	O
National	O
Security	O
Agency	O
(	O
NSA	O
)	O
monitors	O
Skype	B-Application
conversations	O
.	O
</s>
<s>
Skype	B-Application
's	O
client	O
uses	O
an	O
undocumented	O
and	O
proprietary	B-Application
protocol	O
.	O
</s>
<s>
The	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
(	O
FSF	O
)	O
is	O
concerned	O
about	O
user	O
privacy	O
issues	O
arising	O
from	O
using	O
proprietary	B-Application
software	I-Application
and	O
protocols	O
and	O
has	O
made	O
a	O
replacement	O
for	O
Skype	B-Application
one	O
of	O
their	O
high-priority	O
projects	O
.	O
</s>
<s>
Security	O
researchers	O
Biondi	O
and	O
Desclaux	O
have	O
speculated	O
that	O
Skype	B-Application
may	O
have	O
a	O
back	O
door	O
,	O
since	O
Skype	B-Application
sends	O
traffic	O
even	O
when	O
it	O
is	O
turned	O
off	O
and	O
because	O
Skype	B-Application
has	O
taken	O
extreme	O
measures	O
to	O
obfuscate	O
the	O
program	O
's	O
traffic	O
and	O
functioning	O
.	O
</s>
<s>
Several	O
media	O
sources	O
reported	O
that	O
at	O
a	O
meeting	O
about	O
the	O
"	O
Lawful	O
interception	O
of	O
IP	O
based	O
services	O
"	O
held	O
on	O
25	O
June	O
2008	O
,	O
high-ranking	O
unnamed	O
officials	O
at	O
the	O
Austrian	O
interior	O
ministry	O
said	O
that	O
they	O
could	O
listen	O
in	O
on	O
Skype	B-Application
conversations	O
without	O
problems	O
.	O
</s>
<s>
Austrian	O
public	O
broadcasting	O
service	O
ORF	O
,	O
citing	O
minutes	O
from	O
the	O
meeting	O
,	O
reported	O
that	O
"	O
the	O
Austrian	O
police	O
are	O
able	O
to	O
listen	O
in	O
on	O
Skype	B-Application
connections	O
"	O
.	O
</s>
<s>
Skype	B-Application
declined	O
to	O
comment	O
on	O
the	O
reports	O
.	O
</s>
<s>
One	O
easily	O
demonstrated	O
method	O
of	O
monitoring	O
is	O
to	O
set	O
up	O
two	O
computers	O
with	O
the	O
same	O
Skype	B-Application
user	O
ID	O
and	O
password	O
.	O
</s>
<s>
The	O
United	O
States	O
Federal	O
Communications	O
Commission	O
(	O
FCC	O
)	O
has	O
interpreted	O
the	O
Communications	O
Assistance	O
for	O
Law	O
Enforcement	O
Act	O
(	O
CALEA	O
)	O
as	O
requiring	O
digital	B-Application
phone	I-Application
networks	O
to	O
allow	O
wiretapping	O
if	O
authorized	O
by	O
an	O
FBI	O
warrant	O
,	O
in	O
the	O
same	O
way	O
as	O
other	O
phone	O
services	O
.	O
</s>
<s>
In	O
February	O
2009	O
,	O
Skype	B-Application
said	O
that	O
,	O
not	O
being	O
a	O
telephone	O
company	O
owning	O
phone	O
lines	O
,	O
it	O
is	O
exempt	O
from	O
CALEA	O
and	O
similar	O
laws	O
,	O
which	O
regulate	O
US	O
phone	O
companies	O
,	O
and	O
it	O
is	O
not	O
clear	O
whether	O
Skype	B-Application
could	O
support	O
wiretapping	O
even	O
if	O
it	O
wanted	O
to	O
.	O
</s>
<s>
It	O
has	O
been	O
suggested	O
that	O
Microsoft	O
made	O
changes	O
to	O
Skype	B-Application
's	O
infrastructure	O
to	O
ease	O
various	O
wiretapping	O
requirements	O
;	O
however	O
,	O
Skype	B-Application
denies	O
the	O
claims	O
.	O
</s>
<s>
Sometime	O
before	O
Skype	B-Application
was	O
sold	O
in	O
2009	O
,	O
the	O
company	O
had	O
started	O
Project	O
Chess	O
,	O
a	O
program	O
to	O
explore	O
legal	O
and	O
technical	O
ways	O
to	O
easily	O
share	O
calls	O
with	O
intelligence	O
agencies	O
and	O
law	O
enforcement	O
.	O
</s>
<s>
On	O
20	O
February	O
2009	O
,	O
the	O
European	O
Union	O
's	O
Eurojust	O
agency	O
announced	O
that	O
the	O
Italian	O
Desk	O
at	O
Eurojust	O
would	O
"	O
play	O
a	O
key	O
role	O
in	O
the	O
coordination	O
and	O
cooperation	O
of	O
the	O
investigations	O
on	O
the	O
use	O
of	O
internet	B-Application
telephony	I-Application
systems	O
(	O
VoIP	B-Application
)	O
,	O
such	O
as	O
'	O
Skype	B-Application
 '	O
.	O
</s>
<s>
 [ ... ] 	O
The	O
purpose	O
of	O
Eurojust	O
's	O
coordination	O
role	O
is	O
to	O
overcome	O
the	O
technical	O
and	O
judicial	O
obstacles	O
to	O
the	O
interception	O
of	O
internet	B-Application
telephony	I-Application
systems	O
,	O
taking	O
into	O
account	O
the	O
various	O
data	O
protection	O
rules	O
and	O
civil	O
rights.	O
"	O
</s>
<s>
In	O
November	O
2010	O
,	O
a	O
flaw	O
was	O
disclosed	O
to	O
Skype	B-Application
that	O
showed	O
how	O
computer	O
crackers	O
could	O
secretly	O
track	O
any	O
user	O
's	O
IP	B-Protocol
address	I-Protocol
.	O
</s>
<s>
Due	O
to	O
Skype	B-Application
's	O
peer-to-peer	O
nature	O
,	O
this	O
was	O
a	O
difficult	O
issue	O
to	O
address	O
,	O
but	O
this	O
bug	O
was	O
eventually	O
remedied	O
in	O
a	O
2016	O
update	O
.	O
</s>
<s>
In	O
2012	O
,	O
Skype	B-Application
introduced	O
automatic	O
updates	O
to	O
better	O
protect	O
users	O
from	O
security	O
risks	O
but	O
received	O
some	O
challenge	O
from	O
users	O
of	O
the	O
Mac	O
product	O
,	O
as	O
the	O
updates	O
cannot	O
be	O
disabled	O
from	O
version	O
5.6	O
on	O
,	O
both	O
on	O
Mac	B-Application
OS	I-Application
and	O
Windows	O
versions	O
,	O
although	O
in	O
the	O
latter	O
,	O
and	O
only	O
from	O
version	O
5.9	O
on	O
,	O
automatic	O
updating	O
can	O
be	O
turned	O
off	O
in	O
certain	O
cases	O
.	O
</s>
<s>
According	O
to	O
a	O
2012	O
Washington	O
Post	O
article	O
,	O
Skype	B-Application
"	O
has	O
expanded	O
its	O
cooperation	O
with	O
law	O
enforcement	O
authorities	O
to	O
make	O
online	O
chats	O
and	O
other	O
user	O
information	O
available	O
to	O
police	O
"	O
;	O
the	O
article	O
additionally	O
mentions	O
Skype	B-Application
made	O
changes	O
to	O
allow	O
authorities	O
access	O
to	O
addresses	O
and	O
credit	O
card	O
numbers	O
.	O
</s>
<s>
In	O
November	O
2012	O
,	O
Skype	B-Application
was	O
reported	O
to	O
have	O
handed	O
over	O
user	O
data	O
of	O
a	O
pro-WikiLeaks	O
activist	O
to	O
Dallas	O
,	O
Texas-based	O
private	O
security	O
company	O
iSIGHT	O
Partners	O
without	O
a	O
warrant	O
or	O
court	O
order	O
.	O
</s>
<s>
The	O
alleged	O
handover	O
would	O
be	O
a	O
breach	O
of	O
Skype	B-Application
's	O
privacy	O
policy	O
.	O
</s>
<s>
Skype	B-Application
responded	O
with	O
a	O
statement	O
that	O
it	O
launched	O
an	O
internal	O
investigation	O
to	O
probe	O
the	O
breach	O
of	O
user	O
data	O
privacy	O
.	O
</s>
<s>
On	O
13	O
November	O
2012	O
,	O
a	O
Russian	O
user	O
published	O
a	O
flaw	O
in	O
Skype	B-Application
's	O
security	O
,	O
which	O
allowed	O
any	O
person	O
to	O
take	O
over	O
a	O
Skype	B-Application
account	O
knowing	O
only	O
the	O
victim	O
's	O
email	O
by	O
following	O
seven	O
steps	O
.	O
</s>
<s>
On	O
14	O
May	O
2013	O
,	O
it	O
was	O
documented	O
that	O
a	O
URL	O
sent	O
via	O
a	O
Skype	B-Application
instant	B-Application
messaging	I-Application
session	O
was	O
usurped	O
by	O
the	O
Skype	B-Application
service	O
and	O
subsequently	O
used	O
in	O
a	O
HTTP	O
HEAD	O
query	O
originating	O
from	O
an	O
IP	B-Protocol
address	I-Protocol
registered	O
to	O
Microsoft	O
in	O
Redmond	O
(	O
the	O
IP	B-Protocol
address	I-Protocol
used	O
was	O
65.52.100.214	O
)	O
.	O
</s>
<s>
The	O
2013	O
mass	O
surveillance	O
disclosures	O
revealed	O
that	O
agencies	O
such	O
as	O
the	O
NSA	O
and	O
the	O
FBI	O
have	O
the	O
ability	O
to	O
eavesdrop	O
on	O
Skype	B-Application
,	O
including	O
the	O
monitoring	O
and	O
storage	O
of	O
text	O
and	O
video	B-Application
calls	I-Application
and	O
file	O
transfers	O
.	O
</s>
<s>
The	O
PRISM	O
surveillance	O
program	O
,	O
which	O
requires	O
FISA	O
court	O
authorization	O
,	O
reportedly	O
has	O
allowed	O
the	O
NSA	O
unfettered	O
access	O
to	O
its	O
data	O
center	O
supernodes	B-Protocol
.	O
</s>
<s>
On	O
10	O
November	O
2014	O
,	O
Skype	B-Application
scored	O
1	O
out	O
of	O
7	O
points	O
on	O
the	O
Electronic	O
Frontier	O
Foundation	O
's	O
secure	O
messaging	B-Protocol
scorecard	O
.	O
</s>
<s>
Skype	B-Application
received	O
a	O
point	O
for	O
encryption	O
during	O
transit	O
but	O
lost	O
points	O
because	O
communications	O
are	O
not	O
encrypted	O
with	O
a	O
key	O
the	O
provider	O
does	O
not	O
have	O
access	O
to	O
(	O
i.e.	O
</s>
<s>
not	O
available	O
to	O
merely	O
view	O
,	O
nor	O
under	O
a	O
free-software	B-License
license	I-License
)	O
,	O
the	O
security	O
design	O
is	O
not	O
properly	O
documented	O
,	O
and	O
there	O
has	O
not	O
been	O
a	O
recent	O
independent	O
security	O
audit	O
.	O
</s>
<s>
AIM	B-Protocol
,	O
BlackBerry	B-Application
Messenger	I-Application
,	O
Ebuddy	B-Application
XMS	I-Application
,	O
Hushmail	B-Application
,	O
Kik	B-Protocol
Messenger	I-Protocol
,	O
Viber	B-Application
and	O
Yahoo	B-Application
Messenger	I-Application
also	O
scored	O
1	O
out	O
of	O
7	O
points	O
.	O
</s>
<s>
As	O
of	O
August	O
2018	O
,	O
Skype	B-Application
now	O
supports	O
end-to-end	O
encryption	O
across	O
all	O
platforms	O
.	O
</s>
<s>
Cybersex	O
trafficking	O
has	O
occurred	O
on	O
Skype	B-Application
and	O
other	O
videoconferencing	B-Application
applications	O
.	O
</s>
<s>
Since	O
September	O
2007	O
,	O
users	O
in	O
China	O
trying	O
to	O
download	O
the	O
Skype	B-Application
software	O
client	O
have	O
been	O
redirected	O
to	O
the	O
site	O
of	O
TOM	O
Online	O
,	O
a	O
joint	O
venture	O
between	O
a	O
Chinese	O
wireless	O
operator	O
and	O
Skype	B-Application
,	O
from	O
which	O
a	O
modified	O
Chinese	O
version	O
can	O
be	O
downloaded	O
.	O
</s>
<s>
The	O
TOM	O
client	O
participates	O
in	O
China	O
's	O
system	O
of	O
Internet	O
censorship	O
,	O
monitoring	O
text	O
messages	O
between	O
Skype	B-Application
users	O
in	O
China	O
as	O
well	O
as	O
messages	O
exchanged	O
with	O
users	O
outside	O
the	O
country	O
.	O
</s>
<s>
Niklas	O
Zennström	O
,	O
then	O
chief	O
executive	O
of	O
Skype	B-Application
,	O
told	O
reporters	O
that	O
TOM	O
"	O
had	O
implemented	O
a	O
text	O
filter	O
,	O
which	O
is	O
what	O
everyone	O
else	O
in	O
that	O
market	O
is	O
doing	O
.	O
</s>
<s>
In	O
October	O
2008	O
,	O
it	O
was	O
reported	O
that	O
TOM	O
had	O
been	O
saving	O
the	O
full	O
message	O
contents	O
of	O
some	O
Skype	B-Application
text	O
conversations	O
on	O
its	O
servers	O
,	O
apparently	O
focusing	O
on	O
conversations	O
containing	O
political	O
issues	O
such	O
as	O
Tibet	O
,	O
Falun	O
Gong	O
,	O
Taiwan	O
independence	O
,	O
and	O
the	O
Chinese	O
Communist	O
Party	O
.	O
</s>
<s>
The	O
saved	O
messages	O
contain	O
personally	O
identifiable	O
information	O
about	O
the	O
message	O
senders	O
and	O
recipients	O
,	O
including	O
IP	B-Protocol
addresses	I-Protocol
,	O
usernames	O
,	O
landline	B-Application
phone	I-Application
numbers	O
,	O
and	O
the	O
entire	O
content	O
of	O
the	O
text	O
messages	O
,	O
including	O
the	O
time	O
and	O
date	O
of	O
each	O
message	O
.	O
</s>
<s>
Information	O
about	O
Skype	B-Application
users	O
outside	O
China	O
who	O
were	O
communicating	O
with	O
a	O
TOM-Skype	O
user	O
was	O
also	O
saved	O
.	O
</s>
<s>
Research	O
on	O
the	O
TOM-Skype	O
venture	O
has	O
revealed	O
information	O
about	O
blacklisted	O
keyword	O
checks	O
,	O
allowing	O
censorship	O
and	O
surveillance	O
of	O
its	O
users	O
.	O
</s>
<s>
All	O
attempts	O
to	O
visit	O
the	O
official	O
Skype	B-Application
web	O
page	O
from	O
mainland	O
China	O
redirects	O
the	O
user	O
to	O
skype.gmw.cn	O
.	O
</s>
<s>
The	O
Linux	B-Application
version	O
of	O
Skype	B-Application
is	O
unavailable	O
.	O
</s>
<s>
Skype	B-Application
comes	O
bundled	O
with	O
the	O
following	O
locales	O
and	O
languages	O
:	O
Arabic	O
,	O
Bulgarian	O
,	O
Catalan	O
,	O
Chinese	O
(	O
Traditional	O
and	O
Simplified	O
)	O
,	O
Croatian	O
,	O
Czech	O
,	O
Danish	O
,	O
Dutch	O
,	O
English	O
,	O
Estonian	O
,	O
Finnish	O
,	O
French	O
,	O
German	O
,	O
Greek	O
,	O
Hebrew	O
,	O
Hungarian	O
,	O
Indonesian	O
,	O
Italian	O
,	O
Japanese	O
,	O
Korean	O
,	O
Latvian	O
,	O
Lithuanian	O
,	O
Nepali	O
,	O
Norwegian	O
,	O
Polish	O
,	O
Portuguese	O
(	O
Brazilian	O
and	O
European	O
)	O
,	O
Romanian	O
,	O
Russian	O
,	O
Serbian	O
,	O
Slovak	O
,	O
Slovenian	O
,	O
Spanish	O
,	O
Swedish	O
,	O
Thai	O
,	O
Turkish	O
,	O
Ukrainian	O
,	O
and	O
Vietnamese	O
.	O
</s>
<s>
In	O
January	O
2010	O
,	O
Skype	B-Application
rescinded	O
its	O
policy	O
of	O
seizing	O
funds	O
in	O
Skype	B-Application
accounts	O
that	O
have	O
been	O
inactive	O
(	O
no	O
paid	O
call	O
)	O
for	O
180	O
days	O
.	O
</s>
<s>
Skype	B-Application
also	O
paid	O
up	O
to	O
US$4	O
to	O
persons	O
who	O
opted	O
into	O
the	O
action	O
.	O
</s>
<s>
As	O
of	O
February	O
2012	O
,	O
Skype	B-Application
provides	O
support	O
through	O
their	O
web	O
support	O
portal	O
,	O
support	O
community	O
,	O
@skypesupport	O
on	O
Twitter	O
,	O
and	O
Skype	B-Application
Facebook	B-Application
page	O
.	O
</s>
<s>
Chat	O
Support	O
is	O
a	O
premium	O
feature	O
available	O
to	O
Skype	B-Application
Premium	O
and	O
some	O
other	O
paid	O
users	O
.	O
</s>
<s>
Skype	B-Application
's	O
refund	O
policy	O
states	O
that	O
they	O
will	O
provide	O
refunds	O
in	O
full	O
if	O
customers	O
have	O
used	O
less	O
than	O
1	O
euro	O
of	O
their	O
Skype	B-Application
Credit	O
.	O
</s>
<s>
"	O
Upon	O
a	O
duly	O
submitted	O
request	O
,	O
Skype	B-Application
will	O
refund	O
you	O
on	O
a	O
pro-rata	O
basis	O
for	O
the	O
unused	O
period	O
of	O
a	O
Product	O
"	O
.	O
</s>
<s>
Skype	B-Application
has	O
come	O
under	O
some	O
criticism	O
from	O
users	O
for	O
the	O
inability	O
to	O
completely	O
close	O
accounts	O
.	O
</s>
<s>
Users	O
not	O
wanting	O
to	O
continue	O
using	O
Skype	B-Application
can	O
make	O
their	O
account	O
inactive	O
by	O
deleting	O
all	O
personal	O
information	O
,	O
except	O
for	O
the	O
username	O
.	O
</s>
<s>
Due	O
to	O
an	O
outage	O
on	O
21	O
September	O
2015	O
that	O
affected	O
several	O
users	O
in	O
New	O
Zealand	O
,	O
Australia	O
,	O
and	O
other	O
countries	O
,	O
Skype	B-Application
decided	O
to	O
compensate	O
their	O
customers	O
with	O
20	O
minutes	O
of	O
free	B-Application
calls	O
to	O
over	O
60	O
landline	B-Application
and	O
8	O
mobile	O
phone	O
destinations	O
.	O
</s>
<s>
Although	O
Skype	B-Application
is	O
a	O
commercial	O
product	O
,	O
its	O
non-paid	O
version	O
is	O
used	O
with	O
increasing	O
frequency	O
among	O
teachers	O
,	O
schools	O
,	O
and	O
charities	O
interested	O
in	O
global	O
education	O
projects	O
.	O
</s>
<s>
The	O
video	B-Application
conferencing	I-Application
aspect	O
of	O
the	O
software	O
has	O
been	O
praised	O
for	O
its	O
ability	O
to	O
connect	O
students	O
who	O
speak	O
different	O
languages	O
,	O
facilitate	O
virtual	O
field	O
trips	O
,	O
and	O
engage	O
directly	O
with	O
experts	O
.	O
</s>
<s>
Skype	B-Application
in	O
the	O
classroom	O
is	O
another	O
free-of-charge	O
tool	O
that	O
Skype	B-Application
has	O
set	O
up	O
on	O
its	O
website	O
,	O
designed	O
to	O
encourage	O
teachers	O
to	O
make	O
their	O
classrooms	O
more	O
interactive	O
,	O
and	O
collaborate	O
with	O
other	O
teachers	O
around	O
the	O
world	O
.	O
</s>
<s>
There	O
are	O
various	O
Skype	B-Application
lessons	O
in	O
which	O
students	O
can	O
participate	O
.	O
</s>
<s>
The	O
educational	O
program	O
Skype	B-Application
a	O
Scientist	O
,	O
set	O
up	O
by	O
biologist	O
Sarah	O
McAnulty	O
in	O
2017	O
,	O
had	O
in	O
two	O
years	O
connected	O
14,312	O
classrooms	O
with	O
over	O
7000	O
volunteer	O
scientists	O
.	O
</s>
<s>
However	O
,	O
Skype	B-Application
is	O
not	O
adopted	O
universally	O
,	O
with	O
many	O
educational	O
institutions	O
in	O
the	O
United	O
States	O
and	O
Europe	O
blocking	O
the	O
application	O
from	O
their	O
networks	O
.	O
</s>
