<s>
A	O
file-hosting	B-Application
service	I-Application
,	O
also	O
known	O
as	O
cloud-storage	O
service	O
,	O
online	O
file-storage	O
provider	O
,	O
or	O
cyberlocker	B-Application
is	O
an	O
internet	O
hosting	O
service	O
specifically	O
designed	O
to	O
host	O
user	O
files	O
.	O
</s>
<s>
These	O
services	O
allows	O
users	O
to	O
upload	B-Application
files	I-Application
that	O
can	O
be	O
accessed	O
over	O
the	O
internet	O
after	O
providing	O
a	O
username	O
and	O
password	O
or	O
other	O
authentication	O
.	O
</s>
<s>
Typically	O
,	O
file	B-Application
hosting	I-Application
services	I-Application
allow	O
HTTP	O
access	O
,	O
and	O
in	O
some	O
cases	O
,	O
FTP	O
access	O
.	O
</s>
<s>
video	O
and	O
image	B-Algorithm
)	O
,	O
virtual	O
storage	O
,	O
and	O
remote	O
backup	B-Protocol
solutions	O
.	O
</s>
<s>
Users	O
can	O
upload	B-Application
their	O
files	O
and	O
share	O
them	O
publicly	O
or	O
keep	O
them	O
password-protected	O
.	O
</s>
<s>
These	O
services	O
originally	O
targeted	O
files	O
such	O
as	O
PDFs	B-Application
,	O
word	O
processor	O
documents	O
,	O
and	O
spreadsheets	O
.	O
</s>
<s>
File	B-Application
syncing	I-Application
and	O
sharing	O
services	O
allow	O
users	O
to	O
create	O
special	O
folders	O
on	O
each	O
of	O
their	O
computers	O
or	O
mobile	O
devices	O
,	O
which	O
are	O
then	O
synchronized	O
across	O
all	O
devices	O
.	O
</s>
<s>
Consumer	O
products	O
such	O
as	O
OneDrive	B-Application
and	O
Google	B-Application
Drive	I-Application
have	O
made	O
file	B-Application
hosting	I-Application
and	O
sharing	O
more	O
accessible	O
and	O
popular	O
for	O
personal	O
and	O
business	O
use	O
.	O
</s>
<s>
Many	O
businesses	O
use	O
file	B-Application
hosting	I-Application
services	I-Application
as	O
part	O
of	O
their	O
backup	B-Protocol
and	O
disaster	O
recovery	O
strategies	O
.	O
</s>
<s>
By	O
storing	O
copies	O
of	O
important	O
files	O
offsite	O
in	O
a	O
secure	O
data	O
center	O
,	O
they	O
can	O
quickly	O
recover	O
from	O
data	B-General_Concept
loss	I-General_Concept
due	O
to	O
hardware	O
failure	O
,	O
natural	O
disasters	O
,	O
or	O
other	O
unexpected	O
events	O
.	O
</s>
<s>
Some	O
online	B-Application
file	I-Application
storage	I-Application
services	O
offer	O
space	O
on	O
a	O
per-gigabyte	O
basis	O
,	O
and	O
sometimes	O
include	O
a	O
bandwidth	O
cost	O
component	O
as	O
well	O
.	O
</s>
<s>
Some	O
services	O
require	O
a	O
software	O
download	B-Application
which	O
makes	O
files	O
only	O
available	O
on	O
computers	O
which	O
have	O
that	O
software	O
installed	O
,	O
others	O
allow	O
users	O
to	O
retrieve	O
files	O
through	O
any	O
web	O
browser	O
.	O
</s>
<s>
With	O
the	O
increased	O
inbox	O
space	O
offered	O
by	O
webmail	B-Protocol
services	O
,	O
many	O
users	O
have	O
started	O
using	O
their	O
webmail	B-Protocol
service	O
as	O
an	O
online	O
drive	O
.	O
</s>
<s>
One-click	O
hosting	O
,	O
sometimes	O
referred	O
to	O
as	O
cyberlocker	B-Application
,	O
generally	O
describes	O
web	O
services	O
that	O
allow	O
internet	O
users	O
to	O
easily	O
upload	B-Application
one	O
or	O
more	O
files	O
from	O
their	O
hard	B-Device
drives	I-Device
(	O
or	O
from	O
a	O
remote	O
location	O
)	O
onto	O
the	O
one-click	O
host	O
's	O
server	B-Application
free	O
of	O
charge	O
.	O
</s>
<s>
The	O
sites	O
make	O
money	O
through	O
advertising	O
or	O
charging	O
for	O
premium	O
services	O
such	O
as	O
increased	O
downloading	B-Application
capacity	O
,	O
removing	O
any	O
wait	O
restrictions	O
the	O
site	O
may	O
have	O
or	O
prolonging	O
how	O
long	O
uploaded	B-Application
files	O
remain	O
on	O
the	O
site	O
.	O
</s>
<s>
Premium	O
services	O
include	O
facilities	O
like	O
unlimited	O
downloading	B-Application
,	O
no	O
waiting	O
,	O
maximum	O
download	B-Application
speed	O
etc	O
.	O
</s>
<s>
Many	O
such	O
sites	O
implement	O
a	O
CAPTCHA	O
to	O
prevent	O
automated	O
downloading	B-Application
.	O
</s>
<s>
Several	O
programs	O
aid	O
in	O
downloading	B-Application
files	O
from	O
these	O
one-click	O
hosts	O
;	O
examples	O
are	O
JDownloader	B-Application
,	O
FreeRapid	O
,	O
Mipony	O
,	O
Tucan	O
Manager	O
and	O
CryptLoad	B-Application
.	O
</s>
<s>
File	B-Application
hosting	I-Application
services	I-Application
may	O
be	O
used	O
as	O
a	O
means	O
to	O
distribute	O
or	O
share	O
files	O
without	O
consent	O
of	O
the	O
copyright	O
owner	O
.	O
</s>
<s>
In	O
such	O
cases	O
one	O
individual	O
uploads	B-Application
a	O
file	O
to	O
a	O
file	B-Application
hosting	I-Application
service	I-Application
,	O
which	O
others	O
can	O
then	O
download	B-Application
.	O
</s>
<s>
For	O
example	O
,	O
in	O
the	O
case	O
of	O
SwissGerman	O
file	B-Application
hosting	I-Application
service	I-Application
RapidShare	O
,	O
in	O
2010	O
the	O
US	O
government	O
's	O
congressional	O
international	O
anti-piracy	O
caucus	O
declared	O
the	O
site	O
a	O
"	O
notorious	O
illegal	O
site	O
"	O
,	O
claiming	O
that	O
the	O
site	O
was	O
"	O
overwhelmingly	O
used	O
for	O
the	O
global	O
exchange	O
of	O
illegal	O
movies	O
,	O
music	O
and	O
other	O
copyrighted	O
works	O
"	O
.	O
</s>
<s>
By	O
contrast	O
in	O
January	O
2012	O
the	O
United	O
States	O
Department	O
of	O
Justice	O
seized	O
and	O
shut	O
down	O
the	O
file	B-Application
hosting	I-Application
site	O
Megaupload.com	B-Application
and	O
commenced	O
criminal	O
cases	O
against	O
its	O
owners	O
and	O
others	O
.	O
</s>
<s>
Their	O
indictment	O
concluded	O
that	O
Megaupload	B-Application
differed	O
from	O
other	O
online	B-Application
file	I-Application
storage	I-Application
businesses	O
,	O
suggesting	O
a	O
number	O
of	O
design	O
features	O
of	O
its	O
operating	O
model	O
as	O
being	O
evidence	O
showing	O
a	O
criminal	O
intent	O
and	O
venture	O
.	O
</s>
<s>
Examples	O
cited	O
included	O
reliance	O
upon	O
advertising	O
revenue	O
and	O
other	O
activities	O
showing	O
the	O
business	O
was	O
funded	O
by	O
(	O
and	O
heavily	O
promoted	O
)	O
downloads	B-Application
and	O
not	O
storage	O
,	O
defendants	O
 '	O
communications	O
helping	O
users	O
who	O
sought	O
infringing	O
material	O
,	O
and	O
defendants	O
 '	O
communications	O
discussing	O
their	O
own	O
evasion	O
and	O
infringement	O
issues	O
.	O
</s>
<s>
A	O
year	O
later	O
,	O
Megaupload.com	B-Application
relaunched	O
as	O
Mega	O
.	O
</s>
<s>
In	O
2016	O
the	O
file	B-Application
hosting	I-Application
site	O
Putlocker	O
has	O
been	O
noted	O
by	O
the	O
Motion	O
Picture	O
Association	O
of	O
America	O
for	O
being	O
a	O
major	O
piracy	O
threat	O
,	O
and	O
in	O
2012	O
Alfred	O
Perry	O
of	O
Paramount	O
Pictures	O
listed	O
Putlocker	O
as	O
one	O
of	O
the	O
"	O
top	O
5	O
rogue	O
cyberlocker	B-Application
services	O
"	O
,	O
alongside	O
Wupload	O
,	O
FileServe	O
,	O
Depositfiles	B-Application
,	O
and	O
MediaFire	O
.	O
</s>
<s>
The	O
emergence	O
of	O
cloud	B-Application
storage	I-Application
services	I-Application
has	O
prompted	O
much	O
discussion	O
on	O
security	O
.	O
</s>
<s>
Many	O
cloud	B-Application
storage	I-Application
services	I-Application
state	O
that	O
they	O
either	O
encrypt	O
data	O
before	O
it	O
is	O
uploaded	B-Application
or	O
while	O
it	O
is	O
stored	O
.	O
</s>
<s>
Consumer-grade	O
,	O
public	O
file	B-Application
hosting	I-Application
and	O
synchronization	O
services	O
are	O
popular	O
,	O
but	O
for	O
business	O
use	O
,	O
they	O
create	O
the	O
concern	O
that	O
corporate	O
information	O
is	O
exported	O
to	O
devices	O
and	O
cloud	O
services	O
that	O
are	O
not	O
controlled	O
by	O
the	O
organization	O
.	O
</s>
<s>
Append-only	O
support	O
is	O
especially	O
important	O
to	O
mitigate	O
the	O
risk	O
of	O
data	B-General_Concept
loss	I-General_Concept
for	O
backup	B-Protocol
policies	O
in	O
the	O
event	O
that	O
the	O
computer	O
being	O
backed-up	O
becomes	O
infected	O
with	O
ransomware	O
capable	O
of	O
deleting	O
or	O
encrypting	O
the	O
victim	O
's	O
backups	B-Protocol
.	O
</s>
<s>
Secret	O
key	O
encryption	O
is	O
sometimes	O
referred	O
to	O
as	O
zero	B-Protocol
knowledge	I-Protocol
,	O
meaning	O
that	O
only	O
the	O
user	O
has	O
the	O
encryption	O
key	O
needed	O
to	O
decrypt	O
the	O
data	O
.	O
</s>
<s>
To	O
be	O
truly	O
zero	B-Protocol
knowledge	I-Protocol
,	O
the	O
file	B-Application
hosting	I-Application
service	I-Application
must	O
not	O
be	O
able	O
to	O
store	O
the	O
user	O
's	O
passwords	O
or	O
see	O
their	O
data	O
even	O
with	O
physical	O
access	O
to	O
the	O
servers	O
.	O
</s>
<s>
This	O
form	O
of	O
encryption	O
is	O
rapidly	O
gaining	O
popularity	O
,	O
with	O
companies	O
such	O
as	O
MEGA	O
(	O
previously	O
Megaupload	B-Application
)	O
and	O
SpiderOak	B-Operating_System
being	O
entirely	O
zero	B-Protocol
knowledge	I-Protocol
file	O
storage	O
and	O
sharing	O
.	O
</s>
<s>
Since	O
secret	O
key	O
encryption	O
results	O
in	O
unique	O
files	O
,	O
it	O
makes	O
data	B-General_Concept
deduplication	I-General_Concept
impossible	O
and	O
therefore	O
may	O
use	O
more	O
storage	O
space	O
.	O
</s>
<s>
This	O
enables	O
the	O
cloud	O
storage	O
provider	O
to	O
de-duplicate	B-General_Concept
data	O
blocks	O
,	O
meaning	O
only	O
one	O
instance	O
of	O
a	O
unique	O
file	O
(	O
such	O
as	O
a	O
document	O
,	O
photo	O
,	O
music	O
or	O
movie	O
file	O
)	O
is	O
actually	O
stored	O
on	O
the	O
cloud	O
servers	O
but	O
made	O
accessible	O
to	O
all	O
uploaders	B-Application
.	O
</s>
<s>
A	O
third	O
party	O
who	O
gained	O
access	O
to	O
the	O
encrypted	O
files	O
could	O
thus	O
easily	O
determine	O
if	O
a	O
user	O
has	O
uploaded	B-Application
a	O
particular	O
file	O
simply	O
by	O
encrypting	O
it	O
themselves	O
and	O
comparing	O
the	O
outputs	O
.	O
</s>
