<s>
Tor	B-Application
,	O
short	O
for	O
"	O
The	B-Application
Onion	I-Application
Router	I-Application
,	O
"	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
for	O
enabling	O
anonymous	O
communication	O
.	O
</s>
<s>
It	O
directs	O
Internet	O
traffic	O
via	O
a	O
free	O
,	O
worldwide	O
,	O
volunteer	O
overlay	B-Architecture
network	I-Architecture
that	O
consists	O
of	O
more	O
than	O
seven	O
thousand	O
relays	O
.	O
</s>
<s>
Using	O
Tor	B-Application
makes	O
it	O
more	O
difficult	O
to	O
trace	O
a	O
user	O
's	O
Internet	O
activity	O
.	O
</s>
<s>
Tor	B-Application
protects	O
personal	O
privacy	O
by	O
concealing	O
a	O
user	O
's	O
location	O
and	O
usage	O
from	O
anyone	O
performing	O
network	O
surveillance	O
or	O
traffic	O
analysis	O
.	O
</s>
<s>
It	O
protects	O
the	O
user	O
's	O
freedom	O
and	O
ability	O
to	O
communicate	O
confidentially	O
through	O
IP	B-Protocol
address	I-Protocol
anonymity	O
using	O
Tor	B-Application
exit	I-Application
nodes	I-Application
.	O
</s>
<s>
The	O
core	O
principle	O
of	O
Tor	B-Application
,	O
onion	B-Protocol
routing	I-Protocol
,	O
was	O
developed	O
in	O
the	O
mid-1990s	O
by	O
United	O
States	O
Naval	O
Research	O
Laboratory	O
employees	O
,	O
mathematician	O
Paul	O
Syverson	O
,	O
and	O
computer	O
scientists	O
Michael	O
G	O
.	O
Reed	O
and	O
David	O
Goldschlag	O
,	O
to	O
protect	O
American	O
intelligence	O
communications	O
online	O
.	O
</s>
<s>
Onion	B-Protocol
routing	I-Protocol
is	O
implemented	O
by	O
means	O
of	O
encryption	O
in	O
the	O
application	B-Application
layer	I-Application
of	O
the	O
communication	O
protocol	O
stack	O
,	O
nested	O
like	O
the	O
layers	O
of	O
an	O
onion	O
.	O
</s>
<s>
The	O
alpha	O
version	O
of	O
Tor	B-Application
,	O
developed	O
by	O
Syverson	O
and	O
computer	O
scientists	O
Roger	O
Dingledine	O
and	O
Nick	O
Mathewson	O
and	O
then	O
called	O
The	B-Application
Onion	I-Application
Routing	I-Application
project	I-Application
(	O
which	O
was	O
later	O
given	O
the	O
acronym	O
"	O
Tor	B-Application
"	O
)	O
,	O
was	O
launched	O
on	O
20	O
September	O
2002	O
.	O
</s>
<s>
In	O
2004	O
,	O
the	O
Naval	O
Research	O
Laboratory	O
released	O
the	O
code	O
for	O
Tor	B-Application
under	O
a	O
free	O
license	O
,	O
and	O
the	O
Electronic	O
Frontier	O
Foundation	O
(	O
EFF	O
)	O
began	O
funding	O
Dingledine	O
and	O
Mathewson	O
to	O
continue	O
its	O
development	O
.	O
</s>
<s>
In	O
2006	O
,	O
Dingledine	O
,	O
Mathewson	O
,	O
and	O
five	O
others	O
founded	O
The	O
Tor	B-Application
Project	I-Application
,	O
a	O
Massachusetts-based	O
501(c )	O
(	O
3	O
)	O
research-education	O
nonprofit	O
organization	O
responsible	O
for	O
maintaining	O
Tor	B-Application
.	O
</s>
<s>
The	O
EFF	O
acted	O
as	O
The	O
Tor	B-Application
Project	I-Application
's	O
fiscal	O
sponsor	O
in	O
its	O
early	O
years	O
,	O
and	O
early	O
financial	O
supporters	O
included	O
the	O
U.S.	O
Bureau	O
of	O
Democracy	O
,	O
Human	O
Rights	O
,	O
and	O
Labor	O
and	O
International	O
Broadcasting	O
Bureau	O
,	O
Internews	O
,	O
Human	O
Rights	O
Watch	O
,	O
the	O
University	O
of	O
Cambridge	O
,	O
Google	B-Application
,	O
and	O
Netherlands-based	O
Stichting	O
NLnet	O
.	O
</s>
<s>
Over	O
the	O
course	O
of	O
its	O
existence	O
,	O
various	O
Tor	B-Application
weaknesses	O
have	O
been	O
discovered	O
and	O
occasionally	O
exploited	O
.	O
</s>
<s>
Attacks	O
against	O
Tor	B-Application
are	O
an	O
active	O
area	O
of	O
academic	O
research	O
that	O
is	O
welcomed	O
by	O
The	O
Tor	B-Application
Project	I-Application
itself	O
.	O
</s>
<s>
Tor	B-Application
enables	O
its	O
users	O
to	O
surf	O
the	O
Internet	O
,	O
chat	O
and	O
send	O
instant	B-Application
messages	I-Application
anonymously	O
,	O
and	O
is	O
used	O
by	O
a	O
wide	O
variety	O
of	O
people	O
for	O
both	O
licit	O
and	O
illicit	O
purposes	O
.	O
</s>
<s>
Tor	B-Application
has	O
,	O
for	O
example	O
,	O
been	O
used	O
by	O
criminal	O
enterprises	O
,	O
hacktivism	O
groups	O
,	O
and	O
law	O
enforcement	O
agencies	O
at	O
cross	O
purposes	O
,	O
sometimes	O
simultaneously	O
;	O
likewise	O
,	O
agencies	O
within	O
the	O
U.S.	O
government	O
variously	O
fund	O
Tor	B-Application
(	O
the	O
U.S.	O
State	O
Department	O
,	O
the	O
National	O
Science	O
Foundation	O
,	O
and	O
–	O
through	O
the	O
Broadcasting	O
Board	O
of	O
Governors	O
,	O
which	O
itself	O
partially	O
funded	O
Tor	B-Application
until	O
October	O
2012	O
–	O
Radio	O
Free	O
Asia	O
)	O
and	O
seek	O
to	O
subvert	O
it	O
.	O
</s>
<s>
Tor	B-Application
is	O
not	O
meant	O
to	O
completely	O
solve	O
the	O
issue	O
of	O
anonymity	O
on	O
the	O
web	O
.	O
</s>
<s>
Tor	B-Application
is	O
not	O
designed	O
to	O
completely	O
erase	O
tracking	O
but	O
instead	O
to	O
reduce	O
the	O
likelihood	O
for	O
sites	O
to	O
trace	O
actions	O
and	O
data	O
back	O
to	O
the	O
user	O
.	O
</s>
<s>
Tor	B-Application
is	O
also	O
used	O
for	O
illegal	O
activities	O
.	O
</s>
<s>
These	O
can	O
include	O
privacy	O
protection	O
or	O
censorship	B-Application
circumvention	I-Application
,	O
as	O
well	O
as	O
distribution	O
of	O
child	O
abuse	O
content	O
,	O
drug	O
sales	O
,	O
or	O
malware	O
distribution	O
.	O
</s>
<s>
Tor	B-Application
has	O
been	O
described	O
by	O
The	O
Economist	O
,	O
in	O
relation	O
to	O
Bitcoin	B-Protocol
and	O
Silk	O
Road	O
,	O
as	O
being	O
"	O
a	O
dark	O
corner	O
of	O
the	O
web	O
"	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
GCHQ	O
has	O
been	O
using	O
a	O
tool	O
named	O
"	O
Shadowcat	O
"	O
for	O
"	O
end-to-end	O
encrypted	O
access	O
to	O
VPS	O
over	O
SSH	O
using	O
the	O
Tor	B-Application
network	I-Application
"	O
.	O
</s>
<s>
Tor	B-Application
can	O
be	O
used	O
for	O
anonymous	O
defamation	O
,	O
unauthorized	O
news	O
leaks	O
of	O
sensitive	O
information	O
,	O
copyright	O
infringement	O
,	O
distribution	O
of	O
illegal	O
sexual	O
content	O
,	O
selling	O
controlled	O
substances	O
,	O
weapons	O
,	O
and	O
stolen	O
credit	O
card	O
numbers	O
,	O
money	O
laundering	O
,	O
bank	O
fraud	O
,	O
credit	O
card	O
fraud	O
,	O
identity	O
theft	O
and	O
the	O
exchange	O
of	O
counterfeit	O
currency	O
;	O
the	O
black	O
market	O
utilizes	O
the	O
Tor	B-Application
infrastructure	O
,	O
at	O
least	O
in	O
part	O
,	O
in	O
conjunction	O
with	O
Bitcoin	B-Protocol
.	O
</s>
<s>
It	O
has	O
also	O
been	O
used	O
to	O
brick	O
IoT	B-Operating_System
devices	O
.	O
</s>
<s>
In	O
its	O
complaint	O
against	O
Ross	O
William	O
Ulbricht	O
of	O
Silk	O
Road	O
,	O
the	O
US	O
Federal	O
Bureau	O
of	O
Investigation	O
acknowledged	O
that	O
Tor	B-Application
has	O
"	O
known	O
legitimate	O
uses	O
"	O
.	O
</s>
<s>
According	O
to	O
CNET	O
,	O
Tor	B-Application
's	O
anonymity	O
function	O
is	O
"	O
endorsed	O
by	O
the	O
Electronic	O
Frontier	O
Foundation	O
(	O
EFF	O
)	O
and	O
other	O
civil	O
liberties	O
groups	O
as	O
a	O
method	O
for	O
whistleblowers	O
and	O
human	O
rights	O
workers	O
to	O
communicate	O
with	O
journalists	O
"	O
.	O
</s>
<s>
EFF	O
's	O
Surveillance	O
Self-Defense	O
guide	O
includes	O
a	O
description	O
of	O
where	O
Tor	B-Application
fits	O
in	O
a	O
larger	O
strategy	O
for	O
protecting	O
privacy	O
and	O
anonymity	O
.	O
</s>
<s>
In	O
2014	O
,	O
the	O
EFF	O
's	O
Eva	O
Galperin	O
told	O
Businessweek	O
that	O
"	O
Tor	B-Application
's	O
biggest	O
problem	O
is	O
press	O
.	O
</s>
<s>
The	O
Tor	B-Application
Project	I-Application
states	O
that	O
Tor	B-Application
users	O
include	O
"	O
normal	O
people	O
"	O
who	O
wish	O
to	O
keep	O
their	O
Internet	O
activities	O
private	O
from	O
websites	O
and	O
advertisers	O
,	O
people	O
concerned	O
about	O
cyber-spying	O
,	O
and	O
users	O
who	O
are	O
evading	O
censorship	O
such	O
as	O
activists	O
,	O
journalists	O
,	O
and	O
military	O
professionals	O
.	O
</s>
<s>
In	O
November	O
2013	O
,	O
Tor	B-Application
had	O
about	O
four	O
million	O
users	O
.	O
</s>
<s>
According	O
to	O
the	O
Wall	O
Street	O
Journal	O
,	O
in	O
2012	O
about	O
14%	O
of	O
Tor	B-Application
's	O
traffic	O
connected	O
from	O
the	O
United	O
States	O
,	O
with	O
people	O
in	O
"	O
Internet-censoring	O
countries	O
"	O
as	O
its	O
second-largest	O
user	O
base	O
.	O
</s>
<s>
Tor	B-Application
is	O
increasingly	O
used	O
by	O
victims	O
of	O
domestic	O
violence	O
and	O
the	O
social	O
workers	O
and	O
agencies	O
that	O
assist	O
them	O
,	O
even	O
though	O
shelter	O
workers	O
may	O
or	O
may	O
not	O
have	O
had	O
professional	O
training	O
on	O
cyber-security	O
matters	O
.	O
</s>
<s>
Along	O
with	O
SecureDrop	B-Application
,	O
Tor	B-Application
is	O
used	O
by	O
news	O
organizations	O
such	O
as	O
The	O
Guardian	O
,	O
The	O
New	O
Yorker	O
,	O
ProPublica	O
and	O
The	O
Intercept	O
to	O
protect	O
the	O
privacy	O
of	O
whistleblowers	O
.	O
</s>
<s>
The	O
report	O
further	O
noted	O
that	O
Tor	B-Application
"	O
plays	O
only	O
a	O
minor	O
role	O
in	O
the	O
online	O
viewing	O
and	O
distribution	O
of	O
indecent	O
images	O
of	O
children	O
"	O
(	O
due	O
in	O
part	O
to	O
its	O
inherent	O
latency	O
)	O
;	O
its	O
usage	O
by	O
the	O
Internet	O
Watch	O
Foundation	O
,	O
the	O
utility	O
of	O
its	O
onion	O
services	O
for	O
whistleblowers	O
,	O
and	O
its	O
circumvention	O
of	O
the	B-Application
Great	I-Application
Firewall	I-Application
of	I-Application
China	I-Application
were	O
touted	O
.	O
</s>
<s>
Tor	B-Application
's	O
executive	O
director	O
,	O
Andrew	O
Lewman	O
,	O
also	O
said	O
in	O
August	O
2014	O
that	O
agents	O
of	O
the	O
NSA	O
and	O
the	O
GCHQ	O
have	O
anonymously	O
provided	O
Tor	B-Application
with	O
bug	B-Error_Name
reports	O
.	O
</s>
<s>
The	O
Tor	B-Application
Project	I-Application
's	O
FAQ	O
offers	O
supporting	O
reasons	O
for	O
the	O
EFF	O
's	O
endorsement	O
:	O
</s>
<s>
Tor	B-Application
aims	O
to	O
conceal	O
its	O
users	O
 '	O
identities	O
and	O
their	O
online	O
activity	O
from	O
surveillance	O
and	O
traffic	O
analysis	O
by	O
separating	O
identification	O
and	O
routing	O
.	O
</s>
<s>
It	O
is	O
an	O
implementation	O
of	O
onion	B-Protocol
routing	I-Protocol
,	O
which	O
encrypts	O
and	O
then	O
randomly	O
bounces	O
communications	O
through	O
a	O
network	O
of	O
relays	O
run	O
by	O
volunteers	O
around	O
the	O
globe	O
.	O
</s>
<s>
These	O
onion	B-Protocol
routers	I-Protocol
employ	O
encryption	O
in	O
a	O
multi-layered	O
manner	O
(	O
hence	O
the	O
onion	O
metaphor	O
)	O
to	O
ensure	O
perfect	O
forward	O
secrecy	O
between	O
relays	O
,	O
thereby	O
providing	O
users	O
with	O
anonymity	O
in	O
a	O
network	O
location	O
.	O
</s>
<s>
That	O
anonymity	O
extends	O
to	O
the	O
hosting	O
of	O
censorship-resistant	O
content	O
by	O
Tor	B-Application
's	O
anonymous	O
onion	O
service	O
feature	O
.	O
</s>
<s>
Furthermore	O
,	O
by	O
keeping	O
some	O
of	O
the	O
entry	O
relays	O
(	O
bridge	O
relays	O
)	O
secret	O
,	O
users	O
can	O
evade	O
Internet	B-Application
censorship	I-Application
that	O
relies	O
upon	O
blocking	O
public	O
Tor	B-Application
relays	O
.	O
</s>
<s>
Because	O
the	O
IP	B-Protocol
address	I-Protocol
of	O
the	O
sender	O
and	O
the	O
recipient	O
are	O
not	O
both	O
in	O
cleartext	O
at	O
any	O
hop	O
along	O
the	O
way	O
,	O
anyone	O
eavesdropping	O
at	O
any	O
point	O
along	O
the	O
communication	O
channel	O
cannot	O
directly	O
identify	O
both	O
ends	O
.	O
</s>
<s>
Furthermore	O
,	O
to	O
the	O
recipient	O
,	O
it	O
appears	O
that	O
the	O
last	O
Tor	B-Application
node	I-Application
(	O
called	O
the	O
exit	B-Application
node	I-Application
)	O
,	O
rather	O
than	O
the	O
sender	O
,	O
is	O
the	O
originator	O
of	O
the	O
communication	O
.	O
</s>
<s>
A	O
Tor	B-Application
user	O
's	O
SOCKS-aware	O
applications	O
can	O
be	O
configured	O
to	O
direct	O
their	O
network	O
traffic	O
through	O
a	O
Tor	B-Application
instance	O
's	O
SOCKS	B-Application
interface	O
,	O
which	O
is	O
listening	O
on	O
TCP	O
port	O
9050	O
(	O
for	O
standalone	O
Tor	B-Application
)	O
or	O
9150	O
(	O
for	O
Tor	B-Application
Browser	B-Application
bundle	O
)	O
at	O
localhost	B-Protocol
.	O
</s>
<s>
Tor	B-Application
periodically	O
creates	O
virtual	O
circuits	O
through	O
the	O
Tor	B-Application
network	I-Application
through	O
which	O
it	O
can	O
multiplex	B-Architecture
and	O
onion-route	O
that	O
traffic	O
to	O
its	O
destination	O
.	O
</s>
<s>
Once	O
inside	O
a	O
Tor	B-Application
network	I-Application
,	O
the	O
traffic	O
is	O
sent	O
from	O
router	O
to	O
router	O
along	O
the	O
circuit	O
,	O
ultimately	O
reaching	O
an	O
exit	B-Application
node	I-Application
at	O
which	O
point	O
the	O
cleartext	O
packet	O
is	O
available	O
and	O
is	O
forwarded	O
on	O
to	O
its	O
original	O
destination	O
.	O
</s>
<s>
Viewed	O
from	O
the	O
destination	O
,	O
the	O
traffic	O
appears	O
to	O
originate	O
at	O
the	O
Tor	B-Application
exit	I-Application
node	I-Application
.	O
</s>
<s>
Tor	B-Application
's	O
application	O
independence	O
sets	O
it	O
apart	O
from	O
most	O
other	O
anonymity	B-Application
networks	I-Application
:	O
it	O
works	O
at	O
the	O
Transmission	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
(	O
TCP	O
)	O
stream	O
level	O
.	O
</s>
<s>
Applications	O
whose	O
traffic	O
is	O
commonly	O
anonymized	O
using	O
Tor	B-Application
include	O
Internet	B-Protocol
Relay	I-Protocol
Chat	I-Protocol
(	O
IRC	B-Protocol
)	O
,	O
instant	B-Application
messaging	I-Application
,	O
and	O
World	O
Wide	O
Web	O
browsing	O
.	O
</s>
<s>
Tor	B-Application
can	O
also	O
provide	O
anonymity	O
to	O
websites	O
and	O
other	O
servers	O
.	O
</s>
<s>
Servers	O
configured	O
to	O
receive	O
inbound	O
connections	O
only	O
through	O
Tor	B-Application
are	O
called	O
onion	O
services	O
(	O
formerly	O
,	O
hidden	O
services	O
)	O
.	O
</s>
<s>
Rather	O
than	O
revealing	O
a	O
server	O
's	O
IP	B-Protocol
address	I-Protocol
(	O
and	O
thus	O
its	O
network	O
location	O
)	O
,	O
an	O
onion	O
service	O
is	O
accessed	O
through	O
its	O
onion	O
address	O
,	O
usually	O
via	O
the	O
Tor	B-Application
Browser	B-Application
.	O
</s>
<s>
The	O
Tor	B-Application
network	I-Application
understands	O
these	O
addresses	O
by	O
looking	O
up	O
their	O
corresponding	O
public	B-Application
keys	I-Application
and	O
introduction	O
points	O
from	O
a	O
distributed	B-Operating_System
hash	I-Operating_System
table	I-Operating_System
within	O
the	O
network	O
.	O
</s>
<s>
It	O
can	O
route	O
data	O
to	O
and	O
from	O
onion	O
services	O
,	O
even	O
those	O
hosted	O
behind	O
firewalls	B-Application
or	O
network	B-Protocol
address	I-Protocol
translators	I-Protocol
(	O
NAT	O
)	O
,	O
while	O
preserving	O
the	O
anonymity	O
of	O
both	O
parties	O
.	O
</s>
<s>
Tor	B-Application
is	O
necessary	O
to	O
access	O
these	O
onion	O
services	O
.	O
</s>
<s>
Onion	O
services	O
were	O
first	O
specified	O
in	O
2003	O
and	O
have	O
been	O
deployed	O
on	O
the	O
Tor	B-Application
network	I-Application
since	O
2004	O
.	O
</s>
<s>
Other	O
than	O
the	O
database	O
that	O
stores	O
the	O
onion	O
service	O
descriptors	O
,	O
Tor	B-Application
is	O
decentralized	O
by	O
design	O
;	O
there	O
is	O
no	O
direct	O
readable	O
list	O
of	O
all	O
onion	O
services	O
,	O
although	O
a	O
number	O
of	O
onion	O
services	O
catalog	O
publicly	O
known	O
onion	O
addresses	O
.	O
</s>
<s>
TorSearch	O
is	O
an	O
internet	B-Application
search	I-Application
engine	I-Application
that	O
indexes	O
pages	O
to	O
help	O
find	O
content	O
in	O
websites	O
located	O
on	O
the	O
Tor	B-Application
network	I-Application
.	O
</s>
<s>
Because	O
onion	O
services	O
route	O
their	O
traffic	O
entirely	O
through	O
the	O
Tor	B-Application
network	I-Application
,	O
connection	O
to	O
an	O
onion	O
service	O
is	O
encrypted	O
end-to-end	O
and	O
not	O
subject	O
to	O
eavesdropping	O
.	O
</s>
<s>
There	O
are	O
,	O
however	O
,	O
security	O
issues	O
involving	O
Tor	B-Application
onion	I-Application
services	O
.	O
</s>
<s>
For	O
example	O
,	O
services	O
that	O
are	O
reachable	O
through	O
Tor	B-Application
onion	I-Application
services	O
and	O
the	O
public	O
Internet	O
are	O
susceptible	O
to	O
correlation	O
attacks	O
and	O
thus	O
not	O
perfectly	O
hidden	O
.	O
</s>
<s>
The	O
open	B-Application
source	I-Application
OnionScan	O
program	O
,	O
written	O
by	O
independent	O
security	O
researcher	O
Sarah	O
Jamie	O
Lewis	O
,	O
comprehensively	O
examines	O
onion	O
services	O
for	O
numerous	O
flaws	O
and	O
vulnerabilities	O
.	O
</s>
<s>
Onion	O
services	O
can	O
also	O
be	O
accessed	O
from	O
a	O
standard	O
web	B-Application
browser	I-Application
without	O
client-side	B-Operating_System
connection	O
to	O
the	O
Tor	B-Application
network	I-Application
,	O
using	O
services	O
like	O
Tor2web	B-Application
.	O
</s>
<s>
Popular	O
sources	O
of	O
.onion	O
links	O
include	O
Pastebin	O
,	O
Twitter	B-Application
,	O
Reddit	B-Application
,	O
and	O
other	O
Internet	B-Application
forums	I-Application
.	O
</s>
<s>
Like	O
all	O
current	O
low-latency	O
anonymity	B-Application
networks	I-Application
,	O
Tor	B-Application
cannot	O
and	O
does	O
not	O
attempt	O
to	O
protect	O
against	O
monitoring	O
of	O
traffic	O
at	O
the	O
boundaries	O
of	O
the	O
Tor	B-Application
network	I-Application
(	O
i.e.	O
,	O
the	O
traffic	O
entering	O
and	O
exiting	O
the	O
network	O
)	O
.	O
</s>
<s>
While	O
Tor	B-Application
does	O
provide	O
protection	O
against	O
traffic	O
analysis	O
,	O
it	O
cannot	O
prevent	O
traffic	O
confirmation	O
(	O
also	O
called	O
end-to-end	O
correlation	O
)	O
.	O
</s>
<s>
A	O
2009	O
study	O
revealed	O
that	O
Tor	B-Application
and	O
the	O
alternative	O
network	O
system	O
JonDonym	B-Language
(	O
Java	B-Language
Anon	I-Language
Proxy	I-Language
,	O
JAP	O
)	O
are	O
considered	O
more	O
resilient	O
to	O
website	O
fingerprinting	O
techniques	O
than	O
other	O
tunneling	B-Protocol
protocols	I-Protocol
.	O
</s>
<s>
The	O
reason	O
for	O
this	O
is	O
that	O
conventional	O
single-hop	O
VPN	B-Application
protocols	O
do	O
not	O
need	O
to	O
reconstruct	O
packet	O
data	O
nearly	O
as	O
much	O
as	O
a	O
multi-hop	O
service	O
like	O
Tor	B-Application
or	O
JonDonym	B-Language
.	O
</s>
<s>
Website	O
fingerprinting	O
yielded	O
greater	O
than	O
90%	O
accuracy	O
for	O
identifying	O
HTTP	B-Protocol
packets	O
on	O
conventional	O
VPN	B-Application
protocols	O
versus	O
Tor	B-Application
which	O
yielded	O
only	O
2.96	O
%	O
accuracy	O
.	O
</s>
<s>
However	O
,	O
some	O
protocols	O
like	O
OpenSSH	B-Language
and	O
OpenVPN	B-Language
required	O
a	O
large	O
amount	O
of	O
data	O
before	O
HTTP	B-Protocol
packets	O
were	O
identified	O
.	O
</s>
<s>
Researchers	O
from	O
the	O
University	O
of	O
Michigan	O
developed	O
a	O
network	O
scanner	O
allowing	O
identification	O
of	O
86%	O
of	O
live	O
Tor	B-Application
"	O
bridges	O
"	O
with	O
a	O
single	O
scan	O
.	O
</s>
<s>
Like	O
many	O
decentralized	O
systems	O
,	O
Tor	B-Application
relies	O
on	O
a	O
consensus	B-Operating_System
mechanism	I-Operating_System
to	O
periodically	O
update	O
its	O
current	O
operating	O
parameters	O
,	O
which	O
for	O
Tor	B-Application
are	O
network	O
parameters	O
like	O
which	O
nodes	B-Protocol
are	O
good/bad	O
relays	O
,	O
exits	O
,	O
guards	O
,	O
and	O
how	O
much	O
traffic	O
each	O
can	O
handle	O
.	O
</s>
<s>
Tor	B-Application
's	O
architecture	O
for	O
deciding	O
the	O
consensus	O
relies	O
on	O
a	O
small	O
number	O
of	O
directory	O
authority	O
nodes	B-Protocol
voting	O
on	O
current	O
network	O
parameters	O
.	O
</s>
<s>
Currently	O
,	O
there	O
are	O
eight	O
directory	O
authority	O
nodes	B-Protocol
,	O
and	O
their	O
health	O
is	O
publicly	O
monitored	O
.	O
</s>
<s>
The	O
IP	B-Protocol
addresses	I-Protocol
of	O
the	O
authority	O
nodes	B-Protocol
are	O
hard	O
coded	O
into	O
each	O
Tor	B-Application
client	O
.	O
</s>
<s>
The	O
authority	O
nodes	B-Protocol
vote	O
every	O
hour	O
to	O
update	O
the	O
consensus	O
,	O
and	O
clients	O
download	O
the	O
most	O
recent	O
consensus	O
on	O
startup	O
.	O
</s>
<s>
A	O
network	O
congestion	O
attack	O
,	O
such	O
as	O
a	O
DDoS	O
,	O
can	O
prevent	O
the	O
consensus	O
nodes	B-Protocol
from	O
communicating	O
and	O
thus	O
prevent	O
voting	O
to	O
update	O
the	O
consensus	O
.	O
</s>
<s>
If	O
the	O
same	O
autonomous	B-Architecture
system	I-Architecture
(	O
AS	O
)	O
,	O
responsible	O
for	O
routing	O
packets	O
at	O
least	O
partly	O
,	O
is	O
present	O
on	O
both	O
path	O
segments	O
from	O
a	O
client	O
to	O
entry	O
relay	O
and	O
from	O
exit	O
relay	O
to	O
destination	O
,	O
such	O
an	O
AS	O
can	O
statistically	O
correlate	O
traffic	O
on	O
the	O
entry	O
and	O
exit	O
segments	O
of	O
the	O
path	O
(	O
i.e.	O
</s>
<s>
In	O
September	O
2007	O
,	O
Dan	O
Egerstad	O
,	O
a	O
Swedish	O
security	O
consultant	O
,	O
revealed	O
he	O
had	O
intercepted	O
usernames	O
and	O
passwords	O
for	O
email	O
accounts	O
by	O
operating	O
and	O
monitoring	O
Tor	B-Application
exit	I-Application
nodes	I-Application
.	O
</s>
<s>
As	O
Tor	B-Application
cannot	O
encrypt	O
the	O
traffic	O
between	O
an	O
exit	B-Application
node	I-Application
and	O
the	O
target	O
server	O
,	O
any	O
exit	B-Application
node	I-Application
is	O
in	O
a	O
position	O
to	O
capture	O
traffic	O
passing	O
through	O
it	O
that	O
does	O
not	O
use	O
end-to-end	O
encryption	O
such	O
as	O
Secure	B-Protocol
Sockets	I-Protocol
Layer	I-Protocol
(	O
SSL	O
)	O
or	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
.	O
</s>
<s>
While	O
this	O
may	O
not	O
inherently	O
breach	O
the	O
anonymity	O
of	O
the	O
source	O
,	O
traffic	O
intercepted	O
in	O
this	O
way	O
by	O
malicious	O
Tor	B-Application
exit	I-Application
nodes	I-Application
operators	O
can	O
expose	O
information	O
about	O
the	O
source	O
in	O
either	O
or	O
both	O
of	O
payload	O
and	O
protocol	O
data	O
.	O
</s>
<s>
Furthermore	O
,	O
Egerstad	O
is	O
circumspect	O
about	O
the	O
possible	O
subversion	O
of	O
Tor	B-Application
by	O
intelligence	O
agencies	O
:	O
</s>
<s>
In	O
October	O
2019	O
,	O
a	O
Tor	B-Application
researcher	O
revealed	O
that	O
since	O
at	O
least	O
2017	O
,	O
there	O
were	O
hundreds	O
of	O
highly	O
suspicious	O
entry	O
,	O
relay	O
,	O
and	O
exit	B-Application
nodes	I-Application
,	O
run	O
by	O
an	O
unknown	O
group	O
,	O
in	O
an	O
unprecedented	O
scale	O
.	O
</s>
<s>
It	O
was	O
alleged	O
that	O
this	O
number	O
of	O
servers	O
could	O
pose	O
the	O
risk	O
of	O
a	O
sybil	O
attack	O
as	O
it	O
could	O
map	O
Tor	B-Application
users	O
 '	O
routes	O
inside	O
the	O
network	O
,	O
increasing	O
risk	O
of	O
deanonymization	O
.	O
</s>
<s>
At	O
some	O
point	O
there	O
were	O
about	O
900	O
nodes	B-Protocol
running	O
and	O
by	O
November	O
2021	O
about	O
600	O
of	O
them	O
were	O
purged	O
.	O
</s>
<s>
In	O
October	O
2011	O
,	O
a	O
research	O
team	O
from	O
ESIEA	O
claimed	O
to	O
have	O
discovered	O
a	O
way	O
to	O
compromise	O
the	O
Tor	B-Application
network	I-Application
by	O
decrypting	O
communication	O
passing	O
over	O
it	O
.	O
</s>
<s>
The	O
technique	O
they	O
describe	O
requires	O
creating	O
a	O
map	O
of	O
Tor	B-Application
network	I-Application
nodes	B-Protocol
,	O
controlling	O
one-third	O
of	O
them	O
,	O
and	O
then	O
acquiring	O
their	O
encryption	O
keys	O
and	O
algorithm	O
seeds	B-Algorithm
.	O
</s>
<s>
Then	O
,	O
using	O
these	O
known	O
keys	O
and	O
seeds	B-Algorithm
,	O
they	O
claim	O
the	O
ability	O
to	O
decrypt	O
two	O
encryption	O
layers	O
out	O
of	O
three	O
.	O
</s>
<s>
In	O
order	O
to	O
redirect	O
Tor	B-Application
traffic	O
to	O
the	O
nodes	B-Protocol
they	O
controlled	O
,	O
they	O
used	O
a	O
denial-of-service	O
attack	O
.	O
</s>
<s>
A	O
response	O
to	O
this	O
claim	O
has	O
been	O
published	O
on	O
the	O
official	O
Tor	B-Application
Blog	O
stating	O
these	O
rumors	O
of	O
Tor	B-Application
's	O
compromise	O
are	O
greatly	O
exaggerated	O
.	O
</s>
<s>
Steven	O
Murdoch	O
and	O
George	O
Danezis	O
from	O
University	O
of	O
Cambridge	O
presented	O
an	O
article	O
at	O
the	O
2005	O
IEEE	O
Symposium	O
on	O
security	O
and	O
privacy	O
on	O
traffic-analysis	O
techniques	O
that	O
allow	O
adversaries	O
with	O
only	O
a	O
partial	O
view	O
of	O
the	O
network	O
to	O
infer	O
which	O
nodes	B-Protocol
are	O
being	O
used	O
to	O
relay	O
the	O
anonymous	O
streams	O
.	O
</s>
<s>
These	O
techniques	O
greatly	O
reduce	O
the	O
anonymity	O
provided	O
by	O
Tor	B-Application
.	O
</s>
<s>
Murdoch	O
has	O
been	O
working	O
with	O
and	O
has	O
been	O
funded	O
by	O
Tor	B-Application
since	O
2006	O
.	O
</s>
<s>
Operators	O
of	O
Internet	O
sites	O
have	O
the	O
ability	O
to	O
prevent	O
traffic	O
from	O
Tor	B-Application
exit	I-Application
nodes	I-Application
or	O
to	O
offer	O
reduced	O
functionality	O
for	O
Tor	B-Application
users	O
.	O
</s>
<s>
For	O
example	O
,	O
it	O
is	O
not	O
generally	O
possible	O
to	O
edit	O
Wikipedia	O
when	O
using	O
Tor	B-Application
or	O
when	O
using	O
an	O
IP	B-Protocol
address	I-Protocol
also	O
used	O
by	O
a	O
Tor	B-Application
exit	I-Application
node	I-Application
.	O
</s>
<s>
The	O
BBC	O
blocks	O
the	O
IP	B-Protocol
addresses	I-Protocol
of	O
all	O
known	O
Tor	B-Application
exit	I-Application
nodes	I-Application
from	O
its	O
iPlayer	B-Application
service	O
,	O
although	O
non-exit	O
relays	O
and	O
bridges	O
are	O
not	O
blocked	O
.	O
</s>
<s>
In	O
March	O
2011	O
,	O
researchers	O
with	O
the	O
Rocquencourt	O
French	O
Institute	O
for	O
Research	O
in	O
Computer	O
Science	O
and	O
Automation	O
(	O
Institut	O
national	O
de	O
recherche	O
en	O
informatique	O
et	O
en	O
automatique	O
,	O
INRIA	O
)	O
,	O
documented	O
an	O
attack	O
that	O
is	O
capable	O
of	O
revealing	O
the	O
IP	B-Protocol
addresses	I-Protocol
of	O
BitTorrent	B-Protocol
users	O
on	O
the	O
Tor	B-Application
network	I-Application
.	O
</s>
<s>
The	O
"	O
bad	O
apple	O
attack	O
"	O
exploits	O
Tor	B-Application
's	O
design	O
and	O
takes	O
advantage	O
of	O
insecure	O
application	O
used	O
to	O
associate	O
the	O
simultaneous	O
use	O
of	O
a	O
secure	O
application	O
with	O
the	O
IP	B-Protocol
address	I-Protocol
of	O
the	O
Tor	B-Application
user	O
in	O
question	O
.	O
</s>
<s>
One	O
method	O
of	O
attack	O
depends	O
on	O
control	O
of	O
an	O
exit	B-Application
node	I-Application
or	O
hijacking	O
tracker	O
responses	O
,	O
while	O
a	O
secondary	O
attack	O
method	O
is	O
based	O
in	O
part	O
on	O
the	O
statistical	O
exploitation	O
of	O
distributed	B-Operating_System
hash	I-Operating_System
table	I-Operating_System
tracking	O
.	O
</s>
<s>
The	O
results	O
presented	O
in	O
the	O
bad	O
apple	O
attack	O
research	O
paper	O
are	O
based	O
on	O
an	O
attack	O
launched	O
against	O
the	O
Tor	B-Application
network	I-Application
by	O
the	O
authors	O
of	O
the	O
study	O
.	O
</s>
<s>
The	O
attack	O
targeted	O
six	O
exit	B-Application
nodes	I-Application
,	O
lasted	O
for	O
twenty-three	O
days	O
,	O
and	O
revealed	O
a	O
total	O
of	O
10,000	O
IP	B-Protocol
addresses	I-Protocol
of	O
active	O
Tor	B-Application
users	O
.	O
</s>
<s>
This	O
study	O
is	O
significant	O
because	O
it	O
is	O
the	O
first	O
documented	O
attack	O
designed	O
to	O
target	O
P2P	O
file-sharing	O
applications	O
on	O
Tor	B-Application
.	O
</s>
<s>
BitTorrent	B-Protocol
may	O
generate	O
as	O
much	O
as	O
40%	O
of	O
all	O
traffic	O
on	O
Tor	B-Application
.	O
</s>
<s>
Furthermore	O
,	O
the	O
bad	O
apple	O
attack	O
is	O
effective	O
against	O
insecure	O
use	O
of	O
any	O
application	O
over	O
Tor	B-Application
,	O
not	O
just	O
BitTorrent	B-Protocol
.	O
</s>
<s>
Jansen	O
et	O
al	O
..	O
,	O
describes	O
a	O
DDoS	O
attack	O
targeted	O
at	O
the	O
Tor	B-Application
node	I-Application
software	O
,	O
as	O
well	O
as	O
defenses	O
against	O
that	O
attack	O
and	O
its	O
variants	O
.	O
</s>
<s>
The	O
attack	O
works	O
using	O
a	O
colluding	O
client	O
and	O
server	O
,	O
and	O
filling	O
the	O
queues	O
of	O
the	O
exit	B-Application
node	I-Application
until	O
the	O
node	B-Protocol
runs	O
out	O
of	O
memory	O
,	O
and	O
hence	O
can	O
serve	O
no	O
other	O
(	O
genuine	O
)	O
clients	O
.	O
</s>
<s>
By	O
attacking	O
a	O
significant	O
proportion	O
of	O
the	O
exit	B-Application
nodes	I-Application
this	O
way	O
,	O
an	O
attacker	O
can	O
degrade	O
the	O
network	O
and	O
increase	O
the	O
chance	O
of	O
targets	O
using	O
nodes	B-Protocol
controlled	O
by	O
the	O
attacker	O
.	O
</s>
<s>
The	O
Heartbleed	B-Error_Name
OpenSSL	B-Language
bug	B-Error_Name
disrupted	O
the	O
Tor	B-Application
network	I-Application
for	O
several	O
days	O
in	O
April	O
2014	O
while	O
private	B-Application
keys	I-Application
were	O
renewed	O
.	O
</s>
<s>
The	O
Tor	B-Application
Project	I-Application
recommended	O
Tor	B-Application
relay	O
operators	O
and	O
onion	O
service	O
operators	O
revoke	O
and	O
generate	O
fresh	O
keys	O
after	O
patching	O
OpenSSL	B-Language
,	O
but	O
noted	O
Tor	B-Application
relays	O
use	O
two	O
sets	O
of	O
keys	O
and	O
Tor	B-Application
's	O
multi-hop	O
design	O
minimizes	O
the	O
impact	O
of	O
exploiting	O
a	O
single	O
relay	O
.	O
</s>
<s>
Five	O
hundred	O
eighty-six	O
relays	O
,	O
later	O
found	O
to	O
be	O
susceptible	O
to	O
the	O
Heartbleed	B-Error_Name
bug	I-Error_Name
,	O
were	O
taken	O
offline	O
as	O
a	O
precautionary	O
measure	O
.	O
</s>
<s>
On	O
30	O
July	O
2014	O
,	O
the	O
Tor	B-Application
Project	I-Application
issued	O
the	O
security	O
advisory	O
"	O
relay	O
early	O
traffic	O
confirmation	O
attack	O
"	O
in	O
which	O
the	O
project	O
discovered	O
a	O
group	O
of	O
relays	O
that	O
tried	O
to	O
de-anonymize	O
onion	O
service	O
users	O
and	O
operators	O
.	O
</s>
<s>
In	O
summary	O
,	O
the	O
attacking	O
onion	O
service	O
directory	O
node	B-Protocol
changed	O
the	O
headers	O
of	O
cells	O
being	O
relayed	O
tagging	O
them	O
as	O
"	O
relay	O
"	O
or	O
"	O
relay	O
early	O
"	O
cells	O
differently	O
to	O
encode	O
additional	O
information	O
and	O
sent	O
them	O
back	O
to	O
the	O
requesting	O
user/operator	O
.	O
</s>
<s>
If	O
the	O
operator	O
's	O
guard/entry	O
node	B-Protocol
was	O
also	O
part	O
of	O
the	O
attacking	O
relays	O
,	O
the	O
attacking	O
relays	O
might	O
be	O
able	O
to	O
capture	O
the	O
IP	B-Protocol
address	I-Protocol
of	O
the	O
user/operator	O
along	O
with	O
the	O
onion	O
service	O
information	O
that	O
the	O
user/operator	O
was	O
requesting	O
.	O
</s>
<s>
The	O
attacking	O
relays	O
were	O
stable	O
enough	O
to	O
be	O
designated	O
as	O
"	O
suitable	O
as	O
hidden	O
service	O
directory	O
"	O
and	O
"	O
suitable	O
as	O
entry	O
guard	O
"	O
;	O
therefore	O
,	O
both	O
the	O
onion	O
service	O
users	O
and	O
the	O
onion	O
services	O
might	O
have	O
used	O
those	O
relays	O
as	O
guards	O
and	O
hidden	O
service	O
directory	O
nodes	B-Protocol
.	O
</s>
<s>
The	O
attacking	O
nodes	B-Protocol
joined	O
the	O
network	O
early	O
in	O
the	O
year	O
on	O
30	O
January	O
and	O
the	O
project	O
removed	O
them	O
on	O
4	O
July	O
.	O
</s>
<s>
Although	O
the	O
attack	O
's	O
beginning	O
is	O
unclear	O
,	O
the	O
project	O
implied	O
that	O
between	O
February	O
and	O
July	O
,	O
IP	B-Protocol
addresses	I-Protocol
of	O
onion	O
service	O
users	O
and	O
operators	O
might	O
have	O
been	O
exposed	O
.	O
</s>
<s>
reminded	O
users	O
and	O
onion	O
service	O
operators	O
that	O
Tor	B-Application
could	O
not	O
prevent	O
de-anonymization	O
if	O
the	O
attacker	O
controlled	O
or	O
could	O
listen	O
to	O
both	O
ends	O
of	O
the	O
Tor	B-Application
circuit	O
,	O
like	O
in	O
this	O
attack	O
.	O
</s>
<s>
In	O
November	O
2014	O
there	O
was	O
speculation	O
in	O
the	O
aftermath	O
of	O
Operation	O
Onymous	O
,	O
resulting	O
in	O
17	O
arrests	O
internationally	O
,	O
that	O
a	O
Tor	B-Application
weakness	O
had	O
been	O
exploited	O
.	O
</s>
<s>
Andrew	O
Lewman	O
—	O
a	O
Tor	B-Application
Project	I-Application
representative	O
—	O
downplayed	O
this	O
possibility	O
,	O
suggesting	O
that	O
execution	O
of	O
more	O
traditional	O
police	O
work	O
was	O
more	O
likely	O
.	O
</s>
<s>
the	O
search	O
warrant	O
for	O
an	O
administrator	O
of	O
Silkroad	O
2.0	O
indicated	O
that	O
from	O
January	O
2014	O
until	O
July	O
,	O
the	O
FBI	O
received	O
information	O
from	O
a	O
"	O
university-based	O
research	O
institute	O
"	O
with	O
the	O
information	O
being	O
"	O
reliable	O
IP	B-Protocol
addresses	I-Protocol
for	O
Tor	B-Application
and	O
onion	O
services	O
such	O
as	O
SR2	O
"	O
that	O
led	O
to	O
the	O
identification	O
of	O
"	O
at	O
least	O
another	O
seventeen	O
black	O
markets	O
on	O
Tor	B-Application
"	O
and	O
"	O
approximately	O
78	O
IP	B-Protocol
addresses	I-Protocol
that	O
accessed	O
a	O
vendor	O
.onion	O
address.	O
"	O
</s>
<s>
In	O
March	O
2016	O
,	O
a	O
security	O
researcher	O
based	O
in	O
Barcelona	O
demonstrated	O
laboratory	O
techniques	O
using	O
time	O
measurement	O
via	O
JavaScript	B-Language
at	O
the	O
1-millisecond	O
level	O
which	O
could	O
potentially	O
identify	O
and	O
correlate	O
a	O
user	O
's	O
unique	O
mouse	B-Device
movements	O
,	O
provided	O
the	O
user	O
has	O
visited	O
the	O
same	O
"	O
fingerprinting	O
"	O
website	O
with	O
both	O
the	O
Tor	B-Application
browser	B-Application
and	O
a	O
regular	O
browser	B-Application
.	O
</s>
<s>
This	O
proof	O
of	O
concept	O
exploits	O
the	O
"	O
time	O
measurement	O
via	O
JavaScript	B-Language
"	O
issue	O
,	O
which	O
had	O
been	O
an	O
open	O
ticket	O
on	O
the	O
Tor	B-Application
Project	I-Application
for	O
ten	O
months	O
.	O
</s>
<s>
In	O
2015	O
,	O
the	O
administrators	O
of	O
Agora	O
,	O
a	O
darknet	B-Operating_System
market	O
,	O
announced	O
they	O
were	O
taking	O
the	O
site	O
offline	O
in	O
response	O
to	O
a	O
recently	O
discovered	O
security	O
vulnerability	O
in	O
Tor	B-Application
.	O
</s>
<s>
They	O
did	O
not	O
say	O
what	O
the	O
vulnerability	O
was	O
,	O
but	O
Wired	O
speculated	O
it	O
was	O
the	O
"	O
Circuit	O
Fingerprinting	O
Attack	O
"	O
presented	O
at	O
the	O
USENIX	B-Operating_System
security	O
conference	O
.	O
</s>
<s>
The	O
main	O
implementation	O
of	O
Tor	B-Application
is	O
written	O
primarily	O
in	O
C	B-Language
.	O
</s>
<s>
The	O
Tor	B-Application
Browser	B-Application
is	O
a	O
web	B-Application
browser	I-Application
capable	O
of	O
accessing	O
the	O
Tor	B-Application
network	I-Application
.	O
</s>
<s>
It	O
was	O
created	O
as	O
the	O
Tor	B-Application
Browser	B-Application
Bundle	O
by	O
Steven	O
J	O
.	O
Murdoch	O
and	O
announced	O
in	O
January	O
2008	O
.	O
</s>
<s>
The	O
Tor	B-Application
Browser	B-Application
consists	O
of	O
a	O
modified	O
Mozilla	B-Application
Firefox	I-Application
ESR	O
web	B-Application
browser	I-Application
,	O
the	O
TorButton	B-Application
,	O
TorLauncher	O
,	O
NoScript	B-Operating_System
and	O
the	O
Tor	B-Application
proxy	I-Application
.	O
</s>
<s>
Users	O
can	O
run	O
the	O
Tor	B-Application
Browser	B-Application
from	O
removable	B-Device
media	I-Device
.	O
</s>
<s>
It	O
can	O
operate	O
under	O
Microsoft	B-Application
Windows	I-Application
,	O
macOS	B-Application
,	O
Android	B-Application
and	O
Linux	B-Application
.	O
</s>
<s>
The	O
default	O
search	B-Application
engine	I-Application
is	O
DuckDuckGo	B-Application
(	O
until	O
version	O
4.5	O
,	O
Startpage.com	B-Application
was	O
its	O
default	O
)	O
.	O
</s>
<s>
The	O
Tor	B-Application
Browser	B-Application
automatically	O
starts	O
Tor	B-Application
background	O
processes	O
and	O
routes	O
traffic	O
through	O
the	O
Tor	B-Application
network	I-Application
.	O
</s>
<s>
Upon	O
termination	O
of	O
a	O
session	O
the	O
browser	B-Application
deletes	O
privacy-sensitive	O
data	O
such	O
as	O
HTTP	B-Protocol
cookies	O
and	O
the	O
browsing	O
history	O
.	O
</s>
<s>
This	O
is	O
effective	O
in	O
reducing	O
web	B-Application
tracking	I-Application
and	O
canvas	B-Protocol
fingerprinting	I-Protocol
,	O
and	O
it	O
also	O
helps	O
to	O
prevent	O
creation	O
of	O
a	O
filter	B-Algorithm
bubble	I-Algorithm
.	O
</s>
<s>
To	O
allow	O
download	O
from	O
places	O
where	O
accessing	O
the	O
Tor	B-Application
Project	I-Application
URL	O
may	O
be	O
risky	O
or	O
blocked	O
,	O
a	O
GitHub	B-Application
repository	O
is	O
maintained	O
with	O
links	O
for	O
releases	O
hosted	O
in	O
other	O
domains	O
.	O
</s>
<s>
In	O
2011	O
,	O
the	O
Dutch	O
authority	O
investigating	O
child	O
pornography	O
discovered	O
the	O
IP	B-Protocol
address	I-Protocol
of	O
a	O
Tor	B-Application
onion	I-Application
service	O
site	O
called	O
"	O
Pedoboard	O
"	O
from	O
an	O
unprotected	O
administrator	O
's	O
account	O
and	O
gave	O
it	O
to	O
the	O
FBI	O
,	O
who	O
traced	O
it	O
to	O
Aaron	O
McGrath	O
.	O
</s>
<s>
The	O
technique	O
,	O
exploiting	O
a	O
Firefox/Tor	O
browser	B-Application
's	O
vulnerability	O
that	O
had	O
been	O
patched	O
and	O
targeting	O
users	O
that	O
had	O
not	O
updated	O
,	O
had	O
a	O
Flash	B-Operating_System
application	O
pinging	O
a	O
user	O
's	O
IP	B-Protocol
address	I-Protocol
directly	O
back	O
to	O
an	O
FBI	O
server	O
,	O
and	O
resulted	O
in	O
revealing	O
at	O
least	O
25	O
US	O
users	O
as	O
well	O
as	O
numerous	O
users	O
from	O
other	O
countries	O
.	O
</s>
<s>
In	O
August	O
2013	O
it	O
was	O
discovered	O
that	O
the	O
Firefox	B-Application
browsers	I-Application
in	O
many	O
older	O
versions	O
of	O
the	O
Tor	B-Application
Browser	B-Application
Bundle	O
were	O
vulnerable	O
to	O
a	O
JavaScript-deployed	O
shellcode	O
attack	O
,	O
as	O
NoScript	B-Operating_System
was	O
not	O
enabled	O
by	O
default	O
.	O
</s>
<s>
Attackers	O
used	O
this	O
vulnerability	O
to	O
extract	O
users	O
 '	O
MAC	O
and	O
IP	B-Protocol
addresses	I-Protocol
and	O
Windows	O
computer	O
names	O
.	O
</s>
<s>
In	O
2022	O
,	O
Kaspersky	O
researchers	O
found	O
that	O
when	O
looking	O
up	O
"	O
Tor	B-Application
Browser	B-Application
"	O
in	O
Chinese	O
on	O
YouTube	B-General_Concept
,	O
one	O
of	O
the	O
URLs	O
provided	O
under	O
the	O
top-ranked	O
Chinese-language	O
video	O
actually	O
pointed	O
to	O
a	O
malware	O
disguised	O
as	O
Tor	B-Application
Browser	B-Application
.	O
</s>
<s>
Once	O
installed	O
,	O
it	O
saves	O
browsing	O
history	O
and	O
form	O
data	O
that	O
genuine	O
Tor	B-Application
forgot	O
by	O
default	O
,	O
and	O
even	O
downloads	O
malicious	O
components	O
to	O
computers	O
with	O
IP	B-Protocol
addresses	I-Protocol
in	O
China	O
.	O
</s>
<s>
On	O
29	O
October	O
2015	O
,	O
the	O
Tor	B-Application
Project	I-Application
released	O
Tor	B-Application
Messenger	O
Beta	O
,	O
an	O
instant	B-Application
messaging	I-Application
program	O
based	O
on	O
Instantbird	B-Protocol
with	O
Tor	B-Application
and	O
OTR	B-Protocol
built	O
in	O
and	O
used	O
by	O
default	O
.	O
</s>
<s>
Like	O
Pidgin	B-Protocol
and	O
Adium	B-Protocol
,	O
Tor	B-Application
Messenger	O
supports	O
multiple	O
different	O
instant	B-Application
messaging	I-Application
protocols	O
;	O
however	O
,	O
it	O
accomplishes	O
this	O
without	O
relying	O
on	O
libpurple	B-Protocol
,	O
implementing	O
all	O
chat	O
protocols	O
in	O
the	O
memory-safe	O
language	O
JavaScript	B-Language
instead	O
.	O
</s>
<s>
According	O
to	O
Lucian	O
Armasu	O
of	O
Toms	O
Hardware	O
,	O
in	O
April	O
2018	O
,	O
the	O
Tor	B-Application
Project	I-Application
shut	O
down	O
the	O
Tor	B-Application
Messenger	O
project	O
for	O
three	O
reasons	O
:	O
the	O
developers	O
of	O
"	O
Instabird	O
"	O
discontinued	O
support	O
for	O
their	O
own	O
software	O
,	O
limited	O
resources	O
and	O
known	O
metadata	O
problems	O
.	O
</s>
<s>
The	O
Tor	B-Application
Messenger	O
developers	O
explained	O
that	O
overcoming	O
any	O
vulnerabilities	O
discovered	O
in	O
the	O
future	O
would	O
be	O
impossible	O
due	O
to	O
the	O
project	O
relying	O
on	O
outdated	O
software	O
dependencies	O
.	O
</s>
<s>
In	O
2016	O
,	O
Tor	B-Application
developer	O
Mike	O
Perry	O
announced	O
a	O
prototype	O
tor-enabled	O
smartphone	O
bases	O
on	O
CopperheadOS	B-Application
.	O
</s>
<s>
It	O
was	O
meant	O
as	O
a	O
direction	O
for	O
Tor	B-Application
on	O
mobile	O
.	O
</s>
<s>
Using	O
Tor	B-Application
with	O
Orbot	B-Language
and	O
Tor	B-Application
Browser	B-Application
are	O
supported	O
by	O
custom	O
Android	B-Application
operating	I-Application
systems	I-Application
CalyxOS	B-Operating_System
and	O
DivestOS	B-Application
.	O
</s>
<s>
GrapheneOS	B-Operating_System
supports	O
using	O
Orbot	B-Language
VPN	B-Application
but	O
not	O
Tor	B-Application
Browser	B-Application
.	O
</s>
<s>
The	O
Vuze	B-Application
(	O
formerly	O
Azureus	B-Application
)	O
BitTorrent	B-Protocol
client	O
,	O
Bitmessage	B-Application
anonymous	O
messaging	O
system	O
,	O
and	O
TorChat	B-Protocol
instant	B-Application
messenger	I-Application
include	O
Tor	B-Application
support	O
.	O
</s>
<s>
The	O
Briar	B-Protocol
messenger	O
routes	O
all	O
messaging	O
via	O
Tor	B-Application
by	O
default	O
.	O
</s>
<s>
OnionShare	O
allows	O
users	O
to	O
share	O
files	O
using	O
Tor	B-Application
.	O
</s>
<s>
The	B-Application
Guardian	I-Application
Project	I-Application
is	O
actively	O
developing	O
a	O
free	B-License
and	I-License
open-source	I-License
suite	O
of	O
applications	O
and	O
firmware	O
for	O
the	O
Android	B-Application
operating	I-Application
system	I-Application
to	O
improve	O
the	O
security	O
of	O
mobile	O
communications	O
.	O
</s>
<s>
The	O
applications	O
include	O
the	O
ChatSecure	B-Protocol
instant	B-Application
messaging	I-Application
client	O
,	O
Orbot	B-Language
Tor	B-Application
implementation	O
(	O
also	O
available	O
for	O
iOS	B-Application
)	O
,	O
Orweb	O
(	O
discontinued	O
)	O
privacy-enhanced	O
mobile	O
browser	B-Application
,	O
Orfox	O
,	O
the	O
mobile	O
counterpart	O
of	O
the	O
Tor	B-Application
Browser	B-Application
,	O
ProxyMob	O
Firefox	B-Operating_System
add-on	I-Operating_System
,	O
and	O
ObscuraCam	O
.	O
</s>
<s>
Onion	O
Browser	B-Application
is	O
open-source	B-Application
,	O
privacy-enhancing	O
web	B-Application
browser	I-Application
for	O
iOS	B-Application
,	O
which	O
uses	O
Tor	B-Application
.	O
</s>
<s>
It	O
is	O
available	O
in	O
the	O
iOS	B-Application
App	B-Application
Store	I-Application
,	O
and	O
source	O
code	O
is	O
available	O
on	O
GitHub	B-Application
.	O
</s>
<s>
Brave	B-Application
added	O
support	O
for	O
Tor	B-Application
in	O
its	O
desktop	O
browser	B-Application
's	O
private-browsing	B-Protocol
mode	O
.	O
</s>
<s>
Users	O
can	O
switch	O
to	O
Tor-enabled	O
browsing	O
by	O
clicking	O
on	O
the	O
hamburger	O
menu	O
on	O
the	O
top	O
right	O
corner	O
of	O
the	O
browser	B-Application
.	O
</s>
<s>
Several	O
security-focused	O
operating	O
systems	O
make	O
or	O
made	O
extensive	O
use	O
of	O
Tor	B-Application
.	O
</s>
<s>
These	O
include	O
Hardened	O
Linux	B-Application
From	O
Scratch	O
,	O
Incognito	O
,	O
Liberté	O
Linux	B-Application
,	O
Qubes	O
OS	O
,	O
Subgraph	O
,	O
Tails	B-Application
,	O
Tor-ramdisk	O
,	O
and	O
Whonix	O
.	O
</s>
<s>
Tor	B-Application
has	O
been	O
praised	O
for	O
providing	O
privacy	O
and	O
anonymity	O
to	O
vulnerable	O
Internet	O
users	O
such	O
as	O
political	O
activists	O
fearing	O
surveillance	O
and	O
arrest	O
,	O
ordinary	O
web	O
users	O
seeking	O
to	O
circumvent	O
censorship	O
,	O
and	O
people	O
who	O
have	O
been	O
threatened	O
with	O
violence	O
or	O
abuse	O
by	O
stalkers	O
.	O
</s>
<s>
The	O
U.S.	O
National	O
Security	O
Agency	O
(	O
NSA	O
)	O
has	O
called	O
Tor	B-Application
"	O
the	O
king	O
of	O
high-secure	O
,	O
low-latency	O
Internet	O
anonymity	O
"	O
,	O
and	O
BusinessWeek	O
magazine	O
has	O
described	O
it	O
as	O
"	O
perhaps	O
the	O
most	O
effective	O
means	O
of	O
defeating	O
the	O
online	O
surveillance	O
efforts	O
of	O
intelligence	O
agencies	O
around	O
the	O
world	O
"	O
.	O
</s>
<s>
Other	O
media	O
have	O
described	O
Tor	B-Application
as	O
"	O
a	O
sophisticated	O
privacy	O
tool	O
"	O
,	O
"	O
easy	O
to	O
use	O
"	O
and	O
"	O
so	O
secure	O
that	O
even	O
the	O
world	O
's	O
most	O
sophisticated	O
electronic	O
spies	O
have	O
n't	O
figured	O
out	O
how	O
to	O
crack	O
it	O
"	O
.	O
</s>
<s>
Advocates	O
for	O
Tor	B-Application
say	O
it	O
supports	O
freedom	O
of	O
expression	O
,	O
including	O
in	O
countries	O
where	O
the	O
Internet	O
is	O
censored	O
,	O
by	O
protecting	O
the	O
privacy	O
and	O
anonymity	O
of	O
users	O
.	O
</s>
<s>
The	O
mathematical	O
underpinnings	O
of	O
Tor	B-Application
lead	O
it	O
to	O
be	O
characterized	O
as	O
acting	O
"	O
like	O
a	O
piece	O
of	O
infrastructure	O
,	O
and	O
governments	O
naturally	O
fall	O
into	O
paying	O
for	O
infrastructure	O
they	O
want	O
to	O
use	O
"	O
.	O
</s>
<s>
,	O
80%	O
of	O
The	O
Tor	B-Application
Project	I-Application
's	O
$2M	O
annual	O
budget	O
came	O
from	O
the	O
United	O
States	O
government	O
,	O
with	O
the	O
U.S.	O
State	O
Department	O
,	O
the	O
Broadcasting	O
Board	O
of	O
Governors	O
,	O
and	O
the	O
National	O
Science	O
Foundation	O
as	O
major	O
contributors	O
,	O
aiming	O
"	O
to	O
aid	O
democracy	O
advocates	O
in	O
authoritarian	O
states	O
"	O
.	O
</s>
<s>
Some	O
have	O
proposed	O
that	O
the	O
government	O
values	O
Tor	B-Application
's	O
commitment	O
to	O
free	O
speech	O
,	O
and	O
uses	O
the	O
darknet	B-Operating_System
to	O
gather	O
intelligence	O
.	O
</s>
<s>
Tor	B-Application
also	O
receives	O
funding	O
from	O
NGOs	O
including	O
Human	O
Rights	O
Watch	O
,	O
and	O
private	O
sponsors	O
including	O
Reddit	B-Application
and	O
Google	B-Application
.	I-Application
</s>
<s>
Tor	B-Application
executive	O
director	O
Andrew	O
Lewman	O
said	O
that	O
even	O
though	O
it	O
accepts	O
funds	O
from	O
the	O
U.S.	O
federal	O
government	O
,	O
the	O
Tor	B-Application
service	O
did	O
not	O
collaborate	O
with	O
the	O
NSA	O
to	O
reveal	O
identities	O
of	O
users	O
.	O
</s>
<s>
Critics	O
say	O
that	O
Tor	B-Application
is	O
not	O
as	O
secure	O
as	O
it	O
claims	O
,	O
pointing	O
to	O
U.S.	O
law	O
enforcement	O
's	O
investigations	O
and	O
shutdowns	O
of	O
Tor-using	O
sites	O
such	O
as	O
web-hosting	O
company	O
Freedom	O
Hosting	O
and	O
online	O
marketplace	O
Silk	O
Road	O
.	O
</s>
<s>
In	O
October	O
2013	O
,	O
after	O
analyzing	O
documents	O
leaked	O
by	O
Edward	O
Snowden	O
,	O
The	O
Guardian	O
reported	O
that	O
the	O
NSA	O
had	O
repeatedly	O
tried	O
to	O
crack	O
Tor	B-Application
and	O
had	O
failed	O
to	O
break	O
its	O
core	O
security	O
,	O
although	O
it	O
had	O
had	O
some	O
success	O
attacking	O
the	O
computers	O
of	O
individual	O
Tor	B-Application
users	O
.	O
</s>
<s>
The	O
Guardian	O
also	O
published	O
a	O
2012	O
NSA	O
classified	O
slide	O
deck	O
,	O
entitled	O
"	O
Tor	B-Application
Stinks	O
"	O
,	O
which	O
said	O
:	O
"	O
We	O
will	O
never	O
be	O
able	O
to	O
de-anonymize	O
all	O
Tor	B-Application
users	O
all	O
the	O
time	O
"	O
,	O
but	O
"	O
with	O
manual	O
analysis	O
we	O
can	O
de-anonymize	O
a	O
very	O
small	O
fraction	O
of	O
Tor	B-Application
users	O
"	O
.	O
</s>
<s>
When	O
Tor	B-Application
users	O
are	O
arrested	O
,	O
it	O
is	O
typically	O
due	O
to	O
human	O
error	O
,	O
not	O
to	O
the	O
core	O
technology	O
being	O
hacked	O
or	O
cracked	O
.	O
</s>
<s>
A	O
late	O
2014	O
report	O
by	O
Der	O
Spiegel	O
using	O
a	O
new	O
cache	O
of	O
Snowden	O
leaks	O
revealed	O
,	O
however	O
,	O
that	O
the	O
NSA	O
deemed	O
Tor	B-Application
on	O
its	O
own	O
as	O
a	O
"	O
major	O
threat	O
"	O
to	O
its	O
mission	O
,	O
and	O
when	O
used	O
in	O
conjunction	O
with	O
other	O
privacy	O
tools	O
such	O
as	O
OTR	B-Protocol
,	O
Cspace	O
,	O
ZRTP	B-Protocol
,	O
RedPhone	O
,	O
Tails	B-Application
,	O
and	O
TrueCrypt	B-Application
was	O
ranked	O
as	O
"	O
catastrophic	O
,	O
"	O
leading	O
to	O
a	O
"	O
near-total	O
loss/lack	O
of	O
insight	O
to	O
target	O
communications	O
,	O
presence	O
...	O
"	O
</s>
<s>
In	O
March	O
2011	O
,	O
The	O
Tor	B-Application
Project	I-Application
received	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
's	O
2010	O
Award	O
for	O
Projects	O
of	O
Social	O
Benefit	O
.	O
</s>
<s>
The	O
citation	O
read	O
,	O
"	O
Using	O
free	O
software	O
,	O
Tor	B-Application
has	O
enabled	O
roughly	O
36	O
million	O
people	O
around	O
the	O
world	O
to	O
experience	O
freedom	O
of	O
access	O
and	O
expression	O
on	O
the	O
Internet	O
while	O
keeping	O
them	O
in	O
control	O
of	O
their	O
privacy	O
and	O
anonymity	O
.	O
</s>
<s>
Iran	O
tried	O
to	O
block	O
Tor	B-Application
at	O
least	O
twice	O
in	O
2011	O
.	O
</s>
<s>
In	O
2013	O
,	O
Jacob	O
Appelbaum	O
described	O
Tor	B-Application
as	O
a	O
"	O
part	O
of	O
an	O
ecosystem	O
of	O
software	O
that	O
helps	O
people	O
regain	O
and	O
reclaim	O
their	O
autonomy	O
.	O
</s>
<s>
In	O
June	O
2013	O
,	O
whistleblower	O
Edward	O
Snowden	O
used	O
Tor	B-Application
to	O
send	O
information	O
about	O
PRISM	O
to	O
The	O
Washington	O
Post	O
and	O
The	O
Guardian	O
.	O
</s>
<s>
In	O
2014	O
,	O
the	O
Russian	O
government	O
offered	O
a	O
$	O
111,000	O
contract	O
to	O
"	O
study	O
the	O
possibility	O
of	O
obtaining	O
technical	O
information	O
about	O
users	O
and	O
users	O
 '	O
equipment	O
on	O
the	O
Tor	B-Application
anonymous	O
network	O
"	O
.	O
</s>
<s>
In	O
September	O
2014	O
,	O
in	O
response	O
to	O
reports	O
that	O
Comcast	O
had	O
been	O
discouraging	O
customers	O
from	O
using	O
the	O
Tor	B-Application
Browser	B-Application
,	O
Comcast	O
issued	O
a	O
public	O
statement	O
that	O
"	O
We	O
have	O
no	O
policy	O
against	O
Tor	B-Application
,	O
or	O
any	O
other	O
browser	B-Application
or	O
software.	O
"	O
</s>
<s>
In	O
October	O
2014	O
,	O
The	O
Tor	B-Application
Project	I-Application
hired	O
the	O
public	O
relations	O
firm	O
Thomson	O
Communications	O
to	O
improve	O
its	O
public	O
image	O
(	O
particularly	O
regarding	O
the	O
terms	O
"	O
Dark	B-Operating_System
Net	I-Operating_System
"	O
and	O
"	O
hidden	O
services	O
,	O
"	O
which	O
are	O
widely	O
viewed	O
as	O
being	O
problematic	O
)	O
and	O
to	O
educate	O
journalists	O
about	O
the	O
technical	O
aspects	O
of	O
Tor	B-Application
.	O
</s>
<s>
Turkey	O
blocked	O
downloads	O
of	O
Tor	B-Application
Browser	B-Application
from	O
the	O
Tor	B-Application
Project	I-Application
.	O
</s>
<s>
In	O
June	O
2015	O
,	O
the	O
special	O
rapporteur	O
from	O
the	O
United	O
Nations	O
 '	O
Office	O
of	O
the	O
High	O
Commissioner	O
for	O
Human	O
Rights	O
specifically	O
mentioned	O
Tor	B-Application
in	O
the	O
context	O
of	O
the	O
debate	O
in	O
the	O
U.S.	O
about	O
allowing	O
so-called	O
backdoors	O
in	O
encryption	O
programs	O
for	O
law	O
enforcement	O
purposes	O
in	O
an	O
interview	O
for	O
The	O
Washington	O
Post	O
.	O
</s>
<s>
In	O
July	O
2015	O
,	O
the	O
Tor	B-Application
Project	I-Application
announced	O
an	O
alliance	O
with	O
the	O
Library	O
Freedom	O
Project	O
to	O
establish	O
exit	B-Application
nodes	I-Application
in	O
public	O
libraries	O
.	O
</s>
<s>
The	O
pilot	O
program	O
,	O
which	O
established	O
a	O
middle	O
relay	O
running	O
on	O
the	O
excess	O
bandwidth	O
afforded	O
by	O
the	O
Kilton	O
Library	O
in	O
Lebanon	O
,	O
New	O
Hampshire	O
,	O
making	O
it	O
the	O
first	O
library	O
in	O
the	O
U.S.	O
to	O
host	O
a	O
Tor	B-Application
node	I-Application
,	O
was	O
briefly	O
put	O
on	O
hold	O
when	O
the	O
local	O
city	O
manager	O
and	O
deputy	O
sheriff	O
voiced	O
concerns	O
over	O
the	O
cost	O
of	O
defending	O
search	O
warrants	O
for	O
information	O
passed	O
through	O
the	O
Tor	B-Application
exit	I-Application
node	I-Application
.	O
</s>
<s>
Although	O
the	O
Department	O
of	O
Homeland	O
Security	O
(	O
DHS	O
)	O
had	O
alerted	O
New	O
Hampshire	O
authorities	O
to	O
the	O
fact	O
that	O
Tor	B-Application
is	O
sometimes	O
used	O
by	O
criminals	O
,	O
the	O
Lebanon	O
Deputy	O
Police	O
Chief	O
and	O
the	O
Deputy	O
City	O
Manager	O
averred	O
that	O
no	O
pressure	O
to	O
strong-arm	O
the	O
library	O
was	O
applied	O
,	O
and	O
the	O
service	O
was	O
re-established	O
on	O
15	O
September	O
2015	O
.	O
</s>
<s>
U.S.	O
Rep.	O
Zoe	O
Lofgren	O
(	O
D-Calif	O
)	O
released	O
a	O
letter	O
on	O
10	O
December	O
2015	O
,	O
in	O
which	O
she	O
asked	O
the	O
DHS	O
to	O
clarify	O
its	O
procedures	O
,	O
stating	O
that	O
"	O
While	O
the	O
Kilton	O
Public	O
Library	O
's	O
board	O
ultimately	O
voted	O
to	O
restore	O
their	O
Tor	B-Application
relay	O
,	O
I	O
am	O
no	O
less	O
disturbed	O
by	O
the	O
possibility	O
that	O
DHS	O
employees	O
are	O
pressuring	O
or	O
persuading	O
public	O
and	O
private	O
entities	O
to	O
discontinue	O
or	O
degrade	O
services	O
that	O
protect	O
the	O
privacy	O
and	O
anonymity	O
of	O
U.S.	O
</s>
<s>
In	O
a	O
2016	O
interview	O
,	O
Kilton	O
Library	O
IT	O
Manager	O
Chuck	O
McAndrew	O
stressed	O
the	O
importance	O
of	O
getting	O
libraries	O
involved	O
with	O
Tor	B-Application
:	O
"	O
Librarians	O
have	O
always	O
cared	O
deeply	O
about	O
protecting	O
privacy	O
,	O
intellectual	O
freedom	O
,	O
and	O
access	O
to	O
information	O
(	O
the	O
freedom	O
to	O
read	O
)	O
.	O
</s>
<s>
The	O
second	O
library	O
to	O
host	O
a	O
Tor	B-Application
node	I-Application
was	O
the	O
Las	O
Naves	O
Public	O
Library	O
in	O
Valencia	O
,	O
Spain	O
,	O
implemented	O
in	O
the	O
first	O
months	O
of	O
2016	O
.	O
</s>
<s>
In	O
August	O
2015	O
,	O
an	O
IBM	O
security	O
research	O
group	O
,	O
called	O
"	O
X-Force	O
"	O
,	O
put	O
out	O
a	O
quarterly	O
report	O
that	O
advised	O
companies	O
to	O
block	O
Tor	B-Application
on	O
security	O
grounds	O
,	O
citing	O
a	O
"	O
steady	O
increase	O
"	O
in	O
attacks	O
from	O
Tor	B-Application
exit	I-Application
nodes	I-Application
as	O
well	O
as	O
botnet	O
traffic	O
.	O
</s>
<s>
In	O
September	O
2015	O
,	O
Luke	O
Millanta	O
created	O
OnionView	O
(	O
now	O
defunct	O
)	O
,	O
a	O
web	O
service	O
that	O
plots	O
the	O
location	O
of	O
active	O
Tor	B-Application
relay	O
nodes	B-Protocol
onto	O
an	O
interactive	O
map	O
of	O
the	O
world	O
.	O
</s>
<s>
In	O
December	O
2015	O
,	O
Daniel	O
Ellsberg	O
(	O
of	O
the	O
Pentagon	O
Papers	O
)	O
,	O
Cory	O
Doctorow	O
(	O
of	O
Boing	O
Boing	O
)	O
,	O
Edward	O
Snowden	O
,	O
and	O
artist-activist	O
Molly	O
Crabapple	O
,	O
amongst	O
others	O
,	O
announced	O
their	O
support	O
of	O
Tor	B-Application
.	O
</s>
<s>
The	O
bill	O
specifically	O
referenced	O
Tor	B-Application
.	O
</s>
<s>
Also	O
in	O
March	O
2016	O
,	O
the	O
first	O
Tor	B-Application
node	I-Application
,	O
specifically	O
a	O
middle	O
relay	O
,	O
was	O
established	O
at	O
a	O
library	O
in	O
Canada	O
,	O
the	O
Graduate	O
Resource	O
Centre	O
(	O
GRC	O
)	O
in	O
the	O
Faculty	O
of	O
Information	O
and	O
Media	O
Studies	O
(	O
FIMS	O
)	O
at	O
the	O
University	O
of	O
Western	O
Ontario	O
.	O
</s>
<s>
Given	O
that	O
the	O
running	O
of	O
a	O
Tor	B-Application
exit	I-Application
node	I-Application
is	O
an	O
unsettled	O
area	O
of	O
Canadian	O
law	O
,	O
and	O
that	O
in	O
general	O
institutions	O
are	O
more	O
capable	O
than	O
individuals	O
to	O
cope	O
with	O
legal	O
pressures	O
,	O
Alison	O
Macrina	O
of	O
the	O
Library	O
Freedom	O
Project	O
has	O
opined	O
that	O
in	O
some	O
ways	O
she	O
would	O
like	O
to	O
see	O
intelligence	O
agencies	O
and	O
law	O
enforcement	O
attempt	O
to	O
intervene	O
in	O
the	O
event	O
that	O
an	O
exit	B-Application
node	I-Application
were	O
established	O
.	O
</s>
<s>
On	O
16	O
May	O
2016	O
,	O
CNN	B-Architecture
reported	O
on	O
the	O
case	O
of	O
core	O
Tor	B-Application
developer	O
isis	O
agora	O
lovecruft	O
,	O
who	O
had	O
fled	O
to	O
Germany	O
under	O
the	O
threat	O
of	O
a	O
subpoena	O
by	O
the	O
FBI	O
during	O
the	O
Thanksgiving	O
break	O
of	O
the	O
previous	O
year	O
.	O
</s>
<s>
On	O
2	O
December	O
2016	O
,	O
The	O
New	O
Yorker	O
reported	O
on	O
burgeoning	O
digital	O
privacy	O
and	O
security	O
workshops	O
in	O
the	O
San	O
Francisco	O
Bay	O
Area	O
,	O
particularly	O
at	O
the	O
hackerspace	O
Noisebridge	O
,	O
in	O
the	O
wake	O
of	O
the	O
2016	O
United	O
States	O
presidential	O
election	O
;	O
downloading	O
the	O
Tor	B-Application
browser	B-Application
was	O
mentioned	O
.	O
</s>
<s>
Also	O
,	O
in	O
December	O
2016	O
,	O
Turkey	O
has	O
blocked	O
the	O
usage	O
of	O
Tor	B-Application
,	O
together	O
with	O
ten	O
of	O
the	O
most	O
used	O
VPN	B-Application
services	O
in	O
Turkey	O
,	O
which	O
were	O
popular	O
ways	O
of	O
accessing	O
banned	O
social	O
media	O
sites	O
and	O
services	O
.	O
</s>
<s>
Tor	B-Application
(	O
and	O
Bitcoin	B-Protocol
)	O
was	O
fundamental	O
to	O
the	O
operation	O
of	O
the	O
darkweb	O
marketplace	O
AlphaBay	O
,	O
which	O
was	O
taken	O
down	O
in	O
an	O
international	O
law	O
enforcement	O
operation	O
in	O
July	O
2017	O
.	O
</s>
<s>
Despite	O
federal	O
claims	O
that	O
Tor	B-Application
would	O
not	O
shield	O
a	O
user	O
,	O
however	O
,	O
elementary	O
operational	O
security	O
errors	O
outside	O
of	O
the	O
ambit	O
of	O
the	O
Tor	B-Application
network	I-Application
led	O
to	O
the	O
site	O
's	O
downfall	O
.	O
</s>
<s>
In	O
June	O
2017	O
the	O
Democratic	O
Socialists	O
of	O
America	O
recommended	O
intermittent	O
Tor	B-Application
usage	O
.	O
</s>
<s>
And	O
in	O
August	O
2017	O
,	O
according	O
to	O
reportage	O
cybersecurity	O
firms	O
which	O
specialize	O
in	O
monitoring	O
and	O
researching	O
the	O
dark	O
Web	O
(	O
which	O
relies	O
on	O
Tor	B-Application
as	O
its	O
infrastructure	O
)	O
on	O
behalf	O
of	O
banks	O
and	O
retailers	O
routinely	O
share	O
their	O
findings	O
with	O
the	O
FBI	O
and	O
with	O
other	O
law	O
enforcement	O
agencies	O
"	O
when	O
possible	O
and	O
necessary	O
"	O
regarding	O
illegal	O
content	O
.	O
</s>
<s>
In	O
June	O
2018	O
,	O
Venezuela	O
blocked	O
access	O
to	O
the	O
Tor	B-Application
network	I-Application
.	O
</s>
<s>
Tor	B-Application
came	O
out	O
strongly	O
against	O
the	O
raid	O
against	O
its	O
support	O
organization	O
,	O
which	O
provides	O
legal	O
and	O
financial	O
aid	O
for	O
the	O
setting	O
up	O
and	O
maintenance	O
of	O
high-speed	O
relays	O
and	O
exit	B-Application
nodes	I-Application
.	O
</s>
<s>
Since	O
October	O
2018	O
,	O
Chinese	O
online	O
communities	O
within	O
Tor	B-Application
have	O
begun	O
to	O
dwindle	O
due	O
to	O
increased	O
efforts	O
to	O
stop	O
them	O
by	O
the	O
Chinese	O
government	O
.	O
</s>
<s>
In	O
November	O
2019	O
,	O
Edward	O
Snowden	O
called	O
for	O
a	O
full	O
,	O
unabridged	O
simplified	O
Chinese	O
translation	O
of	O
his	O
autobiography	O
,	O
Permanent	O
Record	O
,	O
as	O
the	O
Chinese	O
publisher	O
had	O
violated	O
their	O
agreement	O
by	O
expurgating	O
all	O
mentions	O
of	O
Tor	B-Application
and	O
other	O
matters	O
deemed	O
politically	O
sensitive	O
by	O
the	O
Chinese	O
Communist	O
Party	O
.	O
</s>
<s>
On	O
8	O
December	O
2021	O
,	O
the	O
Russian	O
government	O
agency	O
Roskomnadzor	O
announced	O
it	O
has	O
banned	O
Tor	B-Application
and	O
six	O
VPN	B-Application
services	O
for	O
failing	O
to	O
abide	O
by	O
the	O
Russian	O
Internet	O
blacklist	O
.	O
</s>
<s>
Russian	O
ISPs	O
unsuccessfully	O
attempted	O
to	O
block	O
Tor	B-Application
's	O
main	O
website	O
as	O
well	O
as	O
several	O
bridges	O
beginning	O
on	O
1	O
December	O
2021	O
.	O
</s>
<s>
The	O
Tor	B-Application
Project	I-Application
has	O
appealed	O
to	O
Russian	O
courts	O
over	O
this	O
ban	O
.	O
</s>
<s>
In	O
response	O
to	O
Internet	B-Application
censorship	I-Application
during	O
the	O
Russian	O
invasion	O
of	O
Ukraine	O
,	O
the	O
BBC	O
and	O
VOA	O
have	O
directed	O
Russian	O
audiences	O
to	O
Tor	B-Application
.	O
</s>
<s>
The	O
Russian	O
government	O
increased	O
efforts	O
to	O
block	O
access	O
to	O
Tor	B-Application
through	O
technical	O
and	O
political	O
means	O
,	O
while	O
the	O
network	O
reported	O
an	O
increase	O
in	O
traffic	O
from	O
Russia	O
,	O
and	O
increased	O
Russian	O
use	O
of	O
its	O
anti-censorship	O
Snowflake	B-Application
tool	I-Application
.	O
</s>
<s>
Russian	O
courts	O
temporarily	O
lifted	O
the	O
blockade	O
on	O
Tor	B-Application
's	O
website	O
(	O
but	O
not	O
connections	O
to	O
relays	O
)	O
on	O
May	O
24	O
,	O
2022	O
due	O
to	O
Russian	O
law	O
requiring	O
that	O
the	O
Tor	B-Application
Project	I-Application
be	O
involved	O
in	O
the	O
case	O
.	O
</s>
<s>
Iran	O
implemented	O
rolling	O
internet	O
blackouts	O
during	O
the	O
Mahsa	O
Amini	O
protests	O
,	O
and	O
Tor	B-Application
and	O
Snowflake	B-Application
were	O
used	O
to	O
circumvent	O
them	O
.	O
</s>
<s>
China	O
,	O
with	O
its	O
highly	O
centralized	O
control	O
of	O
its	O
internet	O
,	O
had	O
effectively	O
blocked	O
Tor	B-Application
.	O
</s>
<s>
Tor	B-Application
responded	O
to	O
earlier	O
vulnerabilities	O
listed	O
above	O
by	O
patching	O
them	O
and	O
improving	O
security	O
.	O
</s>
<s>
The	O
Tor	B-Application
Project	I-Application
website	O
provides	O
the	O
best	O
practices	O
(	O
instructions	O
)	O
on	O
how	O
to	O
properly	O
use	O
the	O
Tor	B-Application
browser	B-Application
.	O
</s>
<s>
When	O
improperly	O
used	O
,	O
Tor	B-Application
is	O
not	O
secure	O
.	O
</s>
<s>
For	O
example	O
,	O
Tor	B-Application
warns	O
its	O
users	O
that	O
not	O
all	O
traffic	O
is	O
protected	O
;	O
only	O
the	O
traffic	O
routed	O
through	O
the	O
Tor	B-Application
browser	B-Application
is	O
protected	O
.	O
</s>
<s>
Users	O
are	O
also	O
warned	O
to	O
use	O
HTTPS	B-Protocol
versions	O
of	O
websites	O
,	O
not	O
to	O
torrent	B-Protocol
with	O
Tor	B-Application
,	O
not	O
to	O
enable	O
browser	B-Application
plugins	O
,	O
not	O
to	O
open	O
documents	O
downloaded	O
through	O
Tor	B-Application
while	O
online	O
,	O
and	O
to	O
use	O
safe	O
bridges	O
.	O
</s>
<s>
Users	O
are	O
also	O
warned	O
that	O
they	O
cannot	O
provide	O
their	O
name	O
or	O
other	O
revealing	O
information	O
in	O
web	B-Application
forums	I-Application
over	O
Tor	B-Application
and	O
stay	O
anonymous	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Despite	O
intelligence	O
agencies	O
 '	O
claims	O
that	O
80%	O
of	O
Tor	B-Application
users	O
would	O
be	O
de-anonymized	O
within	O
6	O
months	O
in	O
the	O
year	O
2013	O
,	O
that	O
has	O
still	O
not	O
happened	O
.	O
</s>
<s>
In	O
fact	O
,	O
as	O
late	O
as	O
September	O
2016	O
,	O
the	O
FBI	O
could	O
not	O
locate	O
,	O
de-anonymize	O
and	O
identify	O
the	O
Tor	B-Application
user	O
who	O
hacked	O
into	O
the	O
email	O
account	O
of	O
a	O
staffer	O
on	O
Hillary	O
Clinton	O
's	O
email	O
server	O
.	O
</s>
<s>
The	O
best	O
tactic	O
of	O
law	O
enforcement	O
agencies	O
to	O
de-anonymize	O
users	O
appears	O
to	O
remain	O
with	O
Tor-relay	O
adversaries	O
running	O
poisoned	O
nodes	B-Protocol
,	O
as	O
well	O
as	O
counting	O
on	O
the	O
users	O
themselves	O
using	O
the	O
Tor	B-Application
browser	B-Application
improperly	O
.	O
</s>
<s>
For	O
example	O
,	O
downloading	O
a	O
video	O
through	O
the	O
Tor	B-Application
browser	B-Application
and	O
then	O
opening	O
the	O
same	O
file	O
on	O
an	O
unprotected	O
hard	O
drive	O
while	O
online	O
can	O
make	O
the	O
users	O
 '	O
real	O
IP	B-Protocol
addresses	I-Protocol
available	O
to	O
authorities	O
.	O
</s>
<s>
When	O
properly	O
used	O
,	O
odds	O
of	O
being	O
de-anonymized	O
through	O
Tor	B-Application
are	O
said	O
to	O
be	O
extremely	O
low	O
.	O
</s>
<s>
Tor	B-Application
project	I-Application
's	O
co-founder	O
Nick	O
Mathewson	O
explained	O
that	O
the	O
problem	O
of	O
"	O
Tor-relay	O
adversaries	O
"	O
running	O
poisoned	O
nodes	B-Protocol
means	O
that	O
a	O
theoretical	O
adversary	O
of	O
this	O
kind	O
is	O
not	O
the	O
network	O
's	O
greatest	O
threat	O
:	O
</s>
<s>
Tor	B-Application
does	O
not	O
provide	O
protection	O
against	O
end-to-end	O
timing	O
attacks	O
:	O
if	O
an	O
attacker	O
can	O
watch	O
the	O
traffic	O
coming	O
out	O
of	O
the	O
target	O
computer	O
,	O
and	O
also	O
the	O
traffic	O
arriving	O
at	O
the	O
target	O
's	O
chosen	O
destination	O
(	O
e.g.	O
</s>
<s>
Depending	O
on	O
individual	O
user	O
needs	O
,	O
Tor	B-Application
browser	B-Application
offers	O
three	O
levels	O
of	O
security	O
located	O
under	O
the	O
Security	O
Level	O
(	O
the	O
small	O
gray	O
shield	O
at	O
the	O
top-right	O
of	O
the	O
screen	O
)	O
icon	O
>	O
Advanced	O
Security	O
Settings	O
.	O
</s>
<s>
In	O
addition	O
to	O
encrypting	O
the	O
data	O
,	O
including	O
constantly	O
changing	O
an	O
IP	B-Protocol
address	I-Protocol
through	O
a	O
virtual	O
circuit	O
comprising	O
successive	O
,	O
randomly	O
selected	O
Tor	B-Application
relays	O
,	O
several	O
other	O
layers	O
of	O
security	O
are	O
at	O
a	O
user	O
's	O
disposal	O
:	O
</s>
<s>
Standard	O
(	O
default	O
)	O
–	O
at	O
this	O
security	O
level	O
,	O
all	O
browser	B-Application
features	O
are	O
enabled	O
.	O
</s>
<s>
JavaScript	B-Language
is	O
disabled	O
on	O
non-HTTPS	O
sites	O
.	O
</s>
<s>
On	O
sites	O
where	O
JavaScript	B-Language
is	O
enabled	O
,	O
performance	O
optimizations	O
are	O
disabled	O
.	O
</s>
<s>
JavaScript	B-Language
is	O
disabled	O
by	O
default	O
on	O
all	O
sites	O
.	O
</s>
