<s>
Freenet	B-Protocol
is	O
a	O
peer-to-peer	O
platform	O
for	O
censorship-resistant	O
,	O
anonymous	O
communication	O
.	O
</s>
<s>
It	O
uses	O
a	O
decentralized	O
distributed	O
data	O
store	O
to	O
keep	O
and	O
deliver	O
information	O
,	O
and	O
has	O
a	O
suite	O
of	O
free	B-Application
software	I-Application
for	O
publishing	O
and	O
communicating	O
on	O
the	O
Web	O
without	O
fear	O
of	O
censorship	O
.	O
</s>
<s>
Both	O
Freenet	B-Protocol
and	O
some	O
of	O
its	O
associated	O
tools	O
were	O
originally	O
designed	O
by	O
Ian	O
Clarke	O
,	O
who	O
defined	O
Freenet	B-Protocol
's	O
goal	O
as	O
providing	O
freedom	O
of	O
speech	O
on	O
the	O
Internet	O
with	O
strong	O
anonymity	O
protection	O
.	O
</s>
<s>
The	O
distributed	O
data	O
store	O
of	O
Freenet	B-Protocol
is	O
used	O
by	O
many	O
third-party	O
programs	O
and	O
plugins	O
to	O
provide	O
microblogging	B-Application
and	O
media	O
sharing	O
,	O
anonymous	O
and	O
decentralised	O
version	O
tracking	O
,	O
blogging	O
,	O
a	O
generic	O
web	O
of	O
trust	O
for	O
decentralized	O
spam	O
resistance	O
,	O
Shoeshop	O
for	O
using	O
Freenet	B-Protocol
over	O
sneakernet	O
,	O
and	O
many	O
more	O
.	O
</s>
<s>
The	O
origin	O
of	O
Freenet	B-Protocol
can	O
be	O
traced	O
to	O
Ian	O
Clarke	O
's	O
student	O
project	O
at	O
the	O
University	O
of	O
Edinburgh	O
,	O
which	O
he	O
completed	O
as	O
a	O
graduation	O
requirement	O
in	O
the	O
summer	O
of	O
1999	O
.	O
</s>
<s>
Ian	O
Clarke	O
's	O
resulting	O
unpublished	O
report	O
"	O
A	O
distributed	O
decentralized	O
information	O
storage	O
and	O
retrieval	O
system	O
"	O
(	O
1999	O
)	O
provided	O
foundation	O
for	O
the	O
seminal	O
paper	O
written	O
in	O
collaboration	O
with	O
other	O
researchers	O
,	O
"	O
Freenet	B-Protocol
:	O
A	O
Distributed	O
Anonymous	O
Information	O
Storage	O
and	O
Retrieval	O
System	O
"	O
(	O
2001	O
)	O
.	O
</s>
<s>
According	O
to	O
CiteSeer	B-Application
,	O
it	O
became	O
one	O
of	O
the	O
most	O
frequently	O
cited	O
computer	B-General_Concept
science	I-General_Concept
articles	O
in	O
2002	O
.	O
</s>
<s>
Freenet	B-Protocol
can	O
provide	O
anonymity	O
on	O
the	O
Internet	O
by	O
storing	O
small	O
encrypted	O
snippets	O
of	O
content	O
distributed	O
on	O
the	O
computers	O
of	O
its	O
users	O
and	O
connecting	O
only	O
through	O
intermediate	O
computers	O
which	O
pass	O
on	O
requests	O
for	O
content	O
and	O
sending	O
them	O
back	O
without	O
knowing	O
the	O
contents	O
of	O
the	O
full	O
file	O
.	O
</s>
<s>
This	O
is	O
similar	O
to	O
how	O
routers	B-Protocol
on	O
the	O
Internet	O
route	O
packets	B-Protocol
without	O
knowing	O
anything	O
about	O
files	O
—	O
except	O
Freenet	B-Protocol
has	O
caching	O
,	O
a	O
layer	O
of	O
strong	O
encryption	O
,	O
and	O
no	O
reliance	O
on	O
centralized	B-General_Concept
structures	I-General_Concept
.	O
</s>
<s>
Freenet	B-Protocol
has	O
been	O
under	O
continuous	O
development	O
since	O
2000	O
.	O
</s>
<s>
Freenet	B-Protocol
0.7	O
,	O
released	O
on	O
8	O
May	O
2008	O
,	O
is	O
a	O
major	O
re-write	O
incorporating	O
a	O
number	O
of	O
fundamental	O
changes	O
.	O
</s>
<s>
The	O
most	O
fundamental	O
change	O
is	O
support	O
for	O
darknet	B-Operating_System
operation	O
.	O
</s>
<s>
Version	O
0.7	O
offered	O
two	O
modes	O
of	O
operation	O
:	O
a	O
mode	O
in	O
which	O
it	O
connects	O
only	O
to	O
friends	O
,	O
and	O
an	O
opennet-mode	O
in	O
which	O
it	O
connects	O
to	O
any	O
other	O
Freenet	B-Protocol
user	O
.	O
</s>
<s>
When	O
a	O
user	O
switches	O
to	O
pure	O
darknet	B-Operating_System
operation	O
,	O
Freenet	B-Protocol
becomes	O
very	O
difficult	O
to	O
detect	O
from	O
the	O
outside	O
.	O
</s>
<s>
The	O
transport	B-Architecture
layer	I-Architecture
created	O
for	O
the	O
darknet	B-Operating_System
mode	O
allows	O
communication	O
over	O
restricted	O
routes	O
as	O
commonly	O
found	O
in	O
mesh	B-Architecture
networks	I-Architecture
,	O
as	O
long	O
as	O
these	O
connections	O
follow	O
a	O
small-world	O
structure	O
.	O
</s>
<s>
Other	O
modifications	O
include	O
switching	O
from	O
TCP	B-Protocol
to	O
UDP	B-Protocol
,	O
which	O
allows	O
UDP	B-Protocol
hole	O
punching	O
along	O
with	O
faster	O
transmission	O
of	O
messages	O
between	O
peers	O
in	O
the	O
network	B-Architecture
.	O
</s>
<s>
Freenet	B-Protocol
0.7.5	O
,	O
released	O
on	O
12	O
June	O
2009	O
,	O
offers	O
a	O
variety	O
of	O
improvements	O
over	O
0.7	O
.	O
</s>
<s>
As	O
of	O
build	O
1226	O
,	O
released	O
on	O
30	O
July	O
2009	O
,	O
features	O
that	O
have	O
been	O
written	O
include	O
significant	O
security	O
improvements	O
against	O
both	O
attackers	O
acting	O
on	O
the	O
network	B-Architecture
and	O
physical	O
seizure	O
of	O
the	O
computer	O
running	O
the	O
node	O
.	O
</s>
<s>
As	O
of	O
build	O
1468	O
,	O
released	O
on	O
11	O
July	O
2015	O
,	O
the	O
Freenet	B-Protocol
core	O
stopped	O
using	O
the	O
db4o	B-Language
database	O
and	O
laid	O
the	O
foundation	O
for	O
an	O
efficient	O
interface	O
to	O
the	O
Web	O
of	O
Trust	O
plugin	O
which	O
provides	O
spam	O
resistance	O
.	O
</s>
<s>
Freenet	B-Protocol
has	O
always	O
been	O
free	B-Application
software	I-Application
,	O
but	O
until	O
2011	O
it	O
required	O
users	O
to	O
install	O
Java	B-Device
.	O
</s>
<s>
This	O
problem	O
was	O
solved	O
by	O
making	O
Freenet	B-Protocol
compatible	O
with	O
OpenJDK	B-Language
,	O
a	O
free	O
and	O
open	O
source	O
implementation	O
of	O
the	O
Java	B-Device
Platform	I-Device
.	O
</s>
<s>
On	O
11	O
February	O
2015	O
,	O
Freenet	B-Protocol
received	O
the	O
SUMA-Award	O
for	O
"	O
protection	O
against	O
total	O
surveillance	O
"	O
.	O
</s>
<s>
Freenet	B-Protocol
served	O
as	O
the	O
model	O
for	O
the	O
Japanese	O
peer	O
to	O
peer	O
file-sharing	O
programs	O
Winny	B-Protocol
,	O
Share	B-Application
and	O
Perfect	B-Application
Dark	I-Application
,	O
but	O
this	O
model	O
differs	O
from	O
p2p	O
networks	O
such	O
as	O
Bittorrent	B-Protocol
and	O
emule	B-Protocol
.	O
</s>
<s>
Freenet	B-Protocol
separates	O
the	O
underlying	O
network	B-Architecture
structure	O
and	O
protocol	O
from	O
how	O
users	O
interact	O
with	O
the	O
network	B-Architecture
;	O
as	O
a	O
result	O
,	O
there	O
are	O
a	O
variety	O
of	O
ways	O
to	O
access	O
content	O
on	O
the	O
Freenet	B-Protocol
network	B-Architecture
.	O
</s>
<s>
The	O
simplest	O
is	O
via	O
FProxy	O
,	O
which	O
is	O
integrated	O
with	O
the	O
node	O
software	O
and	O
provides	O
a	O
web	O
interface	O
to	O
content	O
on	O
the	O
network	B-Architecture
.	O
</s>
<s>
Using	O
FProxy	O
,	O
a	O
user	O
can	O
browse	O
freesites	O
(	O
websites	O
that	O
use	O
normal	O
HTML	B-Language
and	O
related	O
tools	O
,	O
but	O
whose	O
content	O
is	O
stored	O
within	O
Freenet	B-Protocol
rather	O
than	O
on	O
a	O
traditional	O
web	O
server	O
)	O
.	O
</s>
<s>
Through	O
the	O
use	O
of	O
separate	O
applications	O
or	O
plugins	O
loaded	O
into	O
the	O
node	O
software	O
,	O
users	O
can	O
interact	O
with	O
the	O
network	B-Architecture
in	O
other	O
ways	O
,	O
such	O
as	O
forums	O
similar	O
to	O
web	B-Application
forums	I-Application
or	O
Usenet	O
or	O
interfaces	O
more	O
similar	O
to	O
traditional	O
P2P	O
"	O
filesharing	O
"	O
interfaces	O
.	O
</s>
<s>
While	O
Freenet	B-Protocol
provides	O
an	O
HTTP	B-Protocol
interface	O
for	O
browsing	O
freesites	O
,	O
it	O
is	O
not	O
a	O
proxy	B-Application
for	O
the	O
World	O
Wide	O
Web	O
;	O
Freenet	B-Protocol
can	O
be	O
used	O
to	O
access	O
only	O
the	O
content	O
that	O
has	O
been	O
previously	O
inserted	O
into	O
the	O
Freenet	B-Protocol
network	B-Architecture
.	O
</s>
<s>
In	O
this	O
way	O
,	O
it	O
is	O
more	O
similar	O
to	O
Tor	B-Application
's	O
onion	O
services	O
than	O
to	O
anonymous	O
proxy	B-Application
software	O
like	O
Tor	B-Application
's	I-Application
proxy	I-Application
.	O
</s>
<s>
Freenet	B-Protocol
's	O
focus	O
lies	O
on	O
free	O
speech	O
and	O
anonymity	O
.	O
</s>
<s>
Because	O
of	O
that	O
,	O
Freenet	B-Protocol
acts	O
differently	O
at	O
certain	O
points	O
that	O
are	O
(	O
directly	O
or	O
indirectly	O
)	O
related	O
to	O
the	O
anonymity	O
part	O
.	O
</s>
<s>
Freenet	B-Protocol
attempts	O
to	O
protect	O
the	O
anonymity	O
of	O
both	O
people	O
inserting	O
data	O
into	O
the	O
network	B-Architecture
(	O
uploading	O
)	O
and	O
those	O
retrieving	O
data	O
from	O
the	O
network	B-Architecture
(	O
downloading	O
)	O
.	O
</s>
<s>
Unlike	O
file	O
sharing	O
systems	O
,	O
there	O
is	O
no	O
need	O
for	O
the	O
uploader	O
to	O
remain	O
on	O
the	O
network	B-Architecture
after	O
uploading	O
a	O
file	O
or	O
group	O
of	O
files	O
.	O
</s>
<s>
Instead	O
,	O
during	O
the	O
upload	O
process	O
,	O
the	O
files	O
are	O
broken	O
into	O
chunks	O
and	O
stored	O
on	O
a	O
variety	O
of	O
other	O
computers	O
on	O
the	O
network	B-Architecture
.	O
</s>
<s>
Every	O
node	O
on	O
the	O
Freenet	B-Protocol
network	B-Architecture
contributes	O
storage	O
space	O
to	O
hold	O
files	O
and	O
bandwidth	O
that	O
it	O
uses	O
to	O
route	O
requests	O
from	O
its	O
peers	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
the	O
total	O
bandwidth	O
required	O
by	O
the	O
network	B-Architecture
to	O
transfer	O
a	O
file	O
is	O
higher	O
than	O
in	O
other	O
systems	O
,	O
which	O
can	O
result	O
in	O
slower	O
transfers	O
,	O
especially	O
for	O
infrequently	O
accessed	O
content	O
.	O
</s>
<s>
Since	O
version	O
0.7	O
,	O
Freenet	B-Protocol
offers	O
two	O
different	O
levels	O
of	O
security	O
:	O
opennet	O
and	O
darknet	B-Operating_System
.	O
</s>
<s>
With	O
darknet	B-Operating_System
,	O
users	O
connect	O
only	O
to	O
"	O
friends	O
"	O
with	O
whom	O
they	O
previously	O
exchanged	O
public	B-Application
keys	I-Application
,	O
named	O
node-references	O
.	O
</s>
<s>
Freenet	B-Protocol
's	O
founders	O
argue	O
that	O
true	O
freedom	O
of	O
speech	O
comes	O
only	O
with	O
true	O
anonymity	O
and	O
that	O
the	O
beneficial	O
uses	O
of	O
Freenet	B-Protocol
outweigh	O
its	O
negative	O
uses	O
.	O
</s>
<s>
Freenet	B-Protocol
attempts	O
to	O
remove	O
the	O
possibility	O
of	O
any	O
group	O
imposing	O
its	O
beliefs	O
or	O
values	O
on	O
any	O
data	O
.	O
</s>
<s>
Although	O
many	O
states	O
censor	O
communications	O
to	O
different	O
extents	O
,	O
they	O
all	O
share	B-Application
one	O
commonality	O
in	O
that	O
a	O
body	O
must	O
decide	O
what	O
information	O
to	O
censor	O
and	O
what	O
information	O
to	O
allow	O
.	O
</s>
<s>
In	O
essence	O
,	O
the	O
purpose	O
of	O
Freenet	B-Protocol
is	O
to	O
ensure	O
that	O
no	O
one	O
is	O
allowed	O
to	O
decide	O
what	O
is	O
acceptable	O
.	O
</s>
<s>
Reports	O
of	O
Freenet	B-Protocol
's	O
use	O
in	O
authoritarian	O
nations	O
is	O
difficult	O
to	O
track	O
due	O
to	O
the	O
very	O
nature	O
of	O
Freenet	B-Protocol
's	O
goals	O
.	O
</s>
<s>
One	O
group	O
,	O
Freenet	B-Protocol
China	O
,	O
used	O
to	O
introduce	O
the	O
Freenet	B-Protocol
software	O
to	O
Chinese	O
users	O
starting	O
from	O
2001	O
and	O
distribute	O
it	O
within	O
China	O
through	O
e-mails	O
and	O
on	O
disks	O
after	O
the	O
group	O
's	O
website	O
was	O
blocked	O
by	O
the	O
Chinese	O
authorities	O
on	O
the	O
mainland	O
.	O
</s>
<s>
It	O
was	O
reported	O
that	O
in	O
2002	O
Freenet	B-Protocol
China	O
had	O
several	O
thousand	O
dedicated	O
users	O
.	O
</s>
<s>
However	O
,	O
Freenet	B-Protocol
opennet	O
traffic	O
was	O
blocked	O
in	O
China	O
around	O
the	O
2010s	O
.	O
</s>
<s>
The	O
Freenet	B-Protocol
file	O
sharing	O
network	B-Architecture
stores	O
documents	O
and	O
allows	O
them	O
to	O
be	O
retrieved	O
later	O
by	O
an	O
associated	O
key	O
,	O
as	O
is	O
now	O
possible	O
with	O
protocols	O
such	O
as	O
HTTP	B-Protocol
.	I-Protocol
</s>
<s>
The	O
network	B-Architecture
is	O
designed	O
to	O
be	O
highly	O
survivable	O
.	O
</s>
<s>
The	O
system	O
has	O
no	O
central	O
servers	O
and	O
is	O
not	O
subject	O
to	O
the	O
control	O
of	O
any	O
one	O
individual	O
or	O
organization	O
,	O
including	O
the	O
designers	O
of	O
Freenet	B-Protocol
.	O
</s>
<s>
Information	O
stored	O
on	O
Freenet	B-Protocol
is	O
distributed	O
around	O
the	O
network	B-Architecture
and	O
stored	O
on	O
several	O
different	O
nodes	O
.	O
</s>
<s>
Encryption	O
of	O
data	O
and	O
relaying	O
of	O
requests	O
makes	O
it	O
difficult	O
to	O
determine	O
who	O
inserted	O
content	O
into	O
Freenet	B-Protocol
,	O
who	O
requested	O
that	O
content	O
,	O
or	O
where	O
the	O
content	O
was	O
stored	O
.	O
</s>
<s>
This	O
provides	O
plausible	O
deniability	O
;	O
which	O
,	O
in	O
combination	O
with	O
request	O
relaying	O
,	O
means	O
that	O
safe	O
harbor	O
laws	O
that	O
protect	O
service	O
providers	O
may	O
also	O
protect	O
Freenet	B-Protocol
node	O
operators	O
.	O
</s>
<s>
When	O
asked	O
about	O
the	O
topic	O
,	O
Freenet	B-Protocol
developers	O
defer	O
to	O
the	O
EFF	O
discussion	O
which	O
says	O
that	O
not	O
being	O
able	O
to	O
filter	O
anything	O
is	O
a	O
safe	O
choice	O
.	O
</s>
<s>
Like	O
Winny	B-Protocol
,	O
Share	B-Application
and	O
Perfect	B-Application
Dark	I-Application
,	O
Freenet	B-Protocol
not	O
only	O
transmits	O
data	O
between	O
nodes	O
but	O
actually	O
stores	O
them	O
,	O
working	O
as	O
a	O
huge	O
distributed	O
cache	O
.	O
</s>
<s>
Files	O
on	O
Freenet	B-Protocol
are	O
typically	O
split	O
into	O
multiple	O
small	O
blocks	O
,	O
with	O
duplicate	O
blocks	O
created	O
to	O
provide	O
redundancy	B-Error_Name
.	O
</s>
<s>
Information	O
flow	O
in	O
Freenet	B-Protocol
is	O
different	O
from	O
networks	O
like	O
eMule	B-Protocol
or	O
BitTorrent	B-Protocol
;	O
in	O
Freenet	B-Protocol
:	O
</s>
<s>
After	O
"	O
insertion	O
"	O
is	O
finished	O
,	O
the	O
publishing	O
node	O
is	O
free	O
to	O
shut	O
down	O
,	O
because	O
the	O
file	O
is	O
stored	O
in	O
the	O
network	B-Architecture
.	O
</s>
<s>
In	O
this	O
way	O
Freenet	B-Protocol
tends	O
to	O
'	O
forget	O
 '	O
data	O
which	O
is	O
not	O
retrieved	O
regularly	O
(	O
see	O
also	O
Effect	O
)	O
.	O
</s>
<s>
While	O
users	O
can	O
insert	O
data	O
into	O
the	O
network	B-Architecture
,	O
there	O
is	O
no	O
way	O
to	O
delete	O
data	O
.	O
</s>
<s>
Due	O
to	O
Freenet	B-Protocol
's	O
anonymous	O
nature	O
the	O
original	O
publishing	O
node	O
or	O
owner	O
of	O
any	O
piece	O
of	O
data	O
is	O
unknown	O
.	O
</s>
<s>
Typically	O
,	O
a	O
host	O
computer	O
on	O
the	O
network	B-Architecture
runs	O
the	O
software	O
that	O
acts	O
as	O
a	O
node	O
,	O
and	O
it	O
connects	O
to	O
other	O
hosts	O
running	O
that	O
same	O
software	O
to	O
form	O
a	O
large	O
distributed	O
,	O
variable-size	O
network	B-Architecture
of	O
peer	O
nodes	O
.	O
</s>
<s>
This	O
is	O
unlike	O
most	O
other	O
P2P	O
networks	O
where	O
node	O
administrators	O
can	O
employ	O
a	O
ratio	O
system	O
,	O
where	O
users	O
have	O
to	O
share	B-Application
a	O
certain	O
amount	O
of	O
content	O
before	O
they	O
can	O
download	O
.	O
</s>
<s>
Freenet	B-Protocol
may	O
also	O
be	O
considered	O
a	O
small	O
world	O
network	B-Architecture
.	O
</s>
<s>
The	O
Freenet	B-Protocol
protocol	O
is	O
intended	O
to	O
be	O
used	O
on	O
a	O
network	B-Architecture
of	O
complex	O
topology	O
,	O
such	O
as	O
the	O
Internet	O
(	O
Internet	B-Protocol
Protocol	I-Protocol
)	O
.	O
</s>
<s>
Each	O
message	O
is	O
routed	O
through	O
the	O
network	B-Architecture
by	O
passing	O
from	O
neighbor	O
to	O
neighbor	O
until	O
it	O
reaches	O
its	O
destination	O
.	O
</s>
<s>
The	O
Freenet	B-Protocol
protocol	O
uses	O
a	O
key-based	B-Protocol
routing	I-Protocol
protocol	O
,	O
similar	O
to	O
distributed	B-Operating_System
hash	I-Operating_System
tables	I-Operating_System
.	O
</s>
<s>
Prior	O
to	O
version	O
0.7	O
,	O
Freenet	B-Protocol
used	O
a	O
heuristic	B-Protocol
routing	I-Protocol
algorithm	O
where	O
each	O
node	O
had	O
no	O
fixed	O
location	O
,	O
and	O
routing	O
was	O
based	O
on	O
which	O
node	O
had	O
served	O
a	O
key	O
closest	O
to	O
the	O
key	O
being	O
fetched	O
(	O
in	O
version	O
0.3	O
)	O
or	O
which	O
is	O
estimated	O
to	O
serve	O
it	O
faster	O
(	O
in	O
version	O
0.5	O
)	O
.	O
</s>
<s>
The	O
disadvantage	O
of	O
this	O
is	O
that	O
it	O
is	O
very	O
easy	O
for	O
an	O
attacker	O
to	O
find	O
Freenet	B-Protocol
nodes	O
,	O
and	O
connect	O
to	O
them	O
,	O
because	O
every	O
node	O
is	O
continually	O
attempting	O
to	O
find	O
new	O
connections	O
.	O
</s>
<s>
In	O
version	O
0.7	O
,	O
Freenet	B-Protocol
supports	O
both	O
"	O
opennet	O
"	O
(	O
similar	O
to	O
the	O
old	O
algorithms	O
,	O
but	O
simpler	O
)	O
,	O
and	O
"	O
darknet	B-Operating_System
"	O
(	O
all	O
node	O
connections	O
are	O
set	O
up	O
manually	O
,	O
so	O
only	O
your	O
friends	O
know	O
your	O
node	O
's	O
IP	O
address	O
)	O
.	O
</s>
<s>
Darknet	B-Operating_System
is	O
less	O
convenient	O
,	O
but	O
much	O
more	O
secure	O
against	O
a	O
distant	O
attacker	O
.	O
</s>
<s>
If	O
it	O
's	O
not	O
found	O
,	O
the	O
key	O
's	O
hash	B-Error_Name
is	O
turned	O
into	O
another	O
number	O
in	O
the	O
same	O
range	O
,	O
and	O
the	O
request	O
is	O
routed	O
to	O
the	O
node	O
whose	O
location	O
is	O
closest	O
to	O
the	O
key	O
.	O
</s>
<s>
Essentially	O
the	O
same	O
process	O
is	O
used	O
to	O
insert	O
a	O
document	O
into	O
the	O
network	B-Architecture
:	O
the	O
data	O
is	O
routed	O
according	O
to	O
the	O
key	O
until	O
it	O
runs	O
out	O
of	O
hops	O
,	O
and	O
if	O
no	O
existing	O
document	O
is	O
found	O
with	O
the	O
same	O
key	O
,	O
it	O
is	O
stored	O
on	O
each	O
node	O
.	O
</s>
<s>
Freenet	B-Protocol
assumes	O
that	O
the	O
darknet	B-Operating_System
(	O
a	O
subset	O
of	O
the	O
global	O
social	O
network	B-Architecture
)	O
is	O
a	O
small-world	O
network	B-Architecture
,	O
and	O
nodes	O
constantly	O
attempt	O
to	O
swap	O
locations	O
(	O
using	O
the	O
Metropolis	B-Algorithm
–	I-Algorithm
Hastings	I-Algorithm
algorithm	I-Algorithm
)	O
in	O
order	O
to	O
minimize	O
their	O
distance	O
to	O
their	O
neighbors	O
.	O
</s>
<s>
If	O
the	O
network	B-Architecture
actually	O
is	O
a	O
small-world	O
network	B-Architecture
,	O
Freenet	B-Protocol
should	O
find	O
data	O
reasonably	O
quickly	O
;	O
ideally	O
on	O
the	O
order	O
of	O
hops	O
in	O
Big	O
O	O
notation	O
.	O
</s>
<s>
Initially	O
,	O
the	O
locations	O
in	O
darknet	B-Operating_System
are	O
distributed	O
randomly	O
.	O
</s>
<s>
In	O
opennet	O
connections	O
are	O
established	O
by	O
a	O
join	O
request	O
which	O
provides	O
an	O
optimized	O
network	B-Architecture
structure	O
if	O
the	O
existing	O
network	B-Architecture
is	O
already	O
optimized	O
.	O
</s>
<s>
So	O
the	O
data	O
in	O
a	O
newly	O
started	O
Freenet	B-Protocol
will	O
be	O
distributed	O
somewhat	O
randomly	O
.	O
</s>
<s>
As	O
location	O
swapping	O
(	O
on	O
darknet	B-Operating_System
)	O
and	O
path	O
folding	O
(	O
on	O
opennet	O
)	O
progress	O
,	O
nodes	O
which	O
are	O
close	O
to	O
one	O
another	O
will	O
increasingly	O
have	O
close	O
locations	O
,	O
and	O
nodes	O
which	O
are	O
far	O
away	O
will	O
have	O
distant	O
locations	O
.	O
</s>
<s>
The	O
result	O
is	O
that	O
the	O
network	B-Architecture
will	O
self-organize	O
into	O
a	O
distributed	O
,	O
clustered	O
structure	O
where	O
nodes	O
tend	O
to	O
hold	O
data	O
items	O
that	O
are	O
close	O
together	O
in	O
key	O
space	O
.	O
</s>
<s>
There	O
will	O
probably	O
be	O
multiple	O
such	O
clusters	O
throughout	O
the	O
network	B-Architecture
,	O
any	O
given	O
document	O
being	O
replicated	O
numerous	O
times	O
,	O
depending	O
on	O
how	O
much	O
it	O
is	O
used	O
.	O
</s>
<s>
There	O
are	O
forces	O
which	O
tend	O
to	O
cause	O
clustering	O
(	O
shared	O
closeness	O
data	O
spreads	O
throughout	O
the	O
network	B-Architecture
)	O
,	O
and	O
forces	O
that	O
tend	O
to	O
break	O
up	O
clusters	O
(	O
local	O
caching	O
of	O
commonly	O
used	O
data	O
)	O
.	O
</s>
<s>
These	O
forces	O
will	O
be	O
different	O
depending	O
on	O
how	O
often	O
data	O
is	O
used	O
,	O
so	O
that	O
seldom-used	O
data	O
will	O
tend	O
to	O
be	O
on	O
just	O
a	O
few	O
nodes	O
which	O
specialize	O
in	O
providing	O
that	O
data	O
,	O
and	O
frequently	O
used	O
items	O
will	O
be	O
spread	O
widely	O
throughout	O
the	O
network	B-Architecture
.	O
</s>
<s>
This	O
automatic	O
mirroring	O
counteracts	O
the	O
times	O
when	O
web	O
traffic	O
becomes	O
overloaded	O
,	O
and	O
due	O
to	O
a	O
mature	O
network	B-Architecture
's	O
intelligent	O
routing	O
,	O
a	O
network	B-Architecture
of	O
size	O
n	O
should	O
require	O
only	O
log(n )	O
time	O
to	O
retrieve	O
a	O
document	O
on	O
average	O
.	O
</s>
<s>
Keys	O
are	O
hashes	B-Error_Name
:	O
there	O
is	O
no	O
notion	O
of	O
semantic	O
closeness	O
when	O
speaking	O
of	O
key	O
closeness	O
.	O
</s>
<s>
There	O
are	O
two	O
main	O
varieties	O
of	O
keys	O
in	O
use	O
on	O
Freenet	B-Protocol
,	O
the	O
Content	O
Hash	B-Error_Name
Key	O
(	O
CHK	O
)	O
and	O
the	O
Signed	O
Subspace	O
Key	O
(	O
SSK	O
)	O
.	O
</s>
<s>
A	O
CHK	O
is	O
a	O
SHA-256	B-Algorithm
hash	B-Error_Name
of	O
a	O
document	O
(	O
after	O
encryption	O
,	O
which	O
itself	O
depends	O
on	O
the	O
hash	B-Error_Name
of	O
the	O
plaintext	O
)	O
and	O
thus	O
a	O
node	O
can	O
check	O
that	O
the	O
document	O
returned	O
is	O
correct	O
by	O
hashing	O
it	O
and	O
checking	O
the	O
digest	O
against	O
the	O
key	O
.	O
</s>
<s>
This	O
key	O
contains	O
the	O
meat	O
of	O
the	O
data	O
on	O
Freenet	B-Protocol
.	O
</s>
<s>
CHKs	O
also	O
reduce	O
the	O
redundancy	B-Error_Name
of	O
data	O
since	O
the	O
same	O
data	O
will	O
have	O
the	O
same	O
CHK	O
and	O
when	O
multiple	O
sites	O
reference	O
the	O
same	O
large	O
files	O
,	O
they	O
can	O
reference	O
to	O
the	O
same	O
CHK	O
.	O
</s>
<s>
SSKs	O
are	O
based	O
on	O
public-key	B-Application
cryptography	I-Application
.	O
</s>
<s>
Currently	O
Freenet	B-Protocol
uses	O
the	O
DSA	O
algorithm	O
.	O
</s>
<s>
SSKs	O
can	O
be	O
used	O
to	O
establish	O
a	O
verifiable	O
pseudonymous	O
identity	O
on	O
Freenet	B-Protocol
,	O
and	O
allow	O
for	O
multiple	O
documents	O
to	O
be	O
inserted	O
securely	O
by	O
a	O
single	O
person	O
.	O
</s>
<s>
Files	O
inserted	O
with	O
an	O
SSK	O
are	O
effectively	O
immutable	B-Application
,	O
since	O
inserting	O
a	O
second	O
file	O
with	O
the	O
same	O
name	O
can	O
cause	O
collisions	O
.	O
</s>
<s>
Another	O
subtype	O
of	O
the	O
SSK	O
is	O
the	O
Keyword	O
Signed	O
Key	O
,	O
or	O
KSK	O
,	O
in	O
which	O
the	O
key	B-Application
pair	I-Application
is	O
generated	O
in	O
a	O
standard	O
way	O
from	O
a	O
simple	O
human-readable	O
string	O
.	O
</s>
<s>
Inserting	O
a	O
document	O
using	O
a	O
KSK	O
allows	O
the	O
document	O
to	O
be	O
retrieved	O
and	O
decrypted	O
if	O
and	O
only	O
if	O
the	O
requester	O
knows	O
the	O
human-readable	O
string	O
;	O
this	O
allows	O
for	O
more	O
convenient	O
(	O
but	O
less	O
secure	O
)	O
URIs	B-Protocol
for	O
users	O
to	O
refer	O
to	O
.	O
</s>
<s>
A	O
network	B-Architecture
is	O
said	O
to	O
be	O
scalable	O
if	O
its	O
performance	O
does	O
not	O
deteriorate	O
even	O
if	O
the	O
network	B-Architecture
is	O
very	O
large	O
.	O
</s>
<s>
The	O
scalability	O
of	O
Freenet	B-Protocol
is	O
being	O
evaluated	O
,	O
but	O
similar	O
architectures	O
have	O
been	O
shown	O
to	O
scale	O
logarithmically	O
.	O
</s>
<s>
This	O
work	O
indicates	O
that	O
Freenet	B-Protocol
can	O
find	O
data	O
in	O
hops	O
on	O
a	O
small-world	O
network	B-Architecture
(	O
which	O
includes	O
both	O
opennet	O
and	O
darknet	B-Operating_System
style	O
Freenet	B-Protocol
networks	O
)	O
,	O
when	O
ignoring	O
the	O
caching	O
which	O
could	O
improve	O
the	O
scalability	O
for	O
popular	O
content	O
.	O
</s>
<s>
However	O
,	O
this	O
scalability	O
is	O
difficult	O
to	O
test	O
without	O
a	O
very	O
large	O
network	B-Architecture
.	O
</s>
<s>
Furthermore	O
,	O
the	O
security	O
features	O
inherent	O
to	O
Freenet	B-Protocol
make	O
detailed	O
performance	O
analysis	O
(	O
including	O
things	O
as	O
simple	O
as	O
determining	O
the	O
size	O
of	O
the	O
network	B-Architecture
)	O
difficult	O
to	O
do	O
accurately	O
.	O
</s>
<s>
As	O
of	O
now	O
,	O
the	O
scalability	O
of	O
Freenet	B-Protocol
has	O
yet	O
to	O
be	O
tested	O
.	O
</s>
<s>
As	O
of	O
version	O
0.7	O
,	O
Freenet	B-Protocol
supports	O
both	O
"	O
darknet	B-Operating_System
"	O
and	O
"	O
opennet	O
"	O
connections	O
.	O
</s>
<s>
Opennet	O
connections	O
are	O
made	O
automatically	O
by	O
nodes	O
with	O
opennet	O
enabled	O
,	O
while	O
darknet	B-Operating_System
connections	O
are	O
manually	O
established	O
between	O
users	O
that	O
know	O
and	O
trust	O
each	O
other	O
.	O
</s>
<s>
Freenet	B-Protocol
developers	O
describe	O
the	O
trust	O
needed	O
as	O
"	O
will	O
not	O
crack	O
their	O
Freenet	B-Protocol
node	O
"	O
.	O
</s>
<s>
Opennet	O
connections	O
are	O
easy	O
to	O
use	O
,	O
but	O
darknet	B-Operating_System
connections	O
are	O
more	O
secure	O
against	O
attackers	O
on	O
the	O
network	B-Architecture
,	O
and	O
can	O
make	O
it	O
difficult	O
for	O
an	O
attacker	O
(	O
such	O
as	O
an	O
oppressive	O
government	O
)	O
to	O
even	O
determine	O
that	O
a	O
user	O
is	O
running	O
Freenet	B-Protocol
in	O
the	O
first	O
place	O
.	O
</s>
<s>
The	O
core	O
innovation	O
in	O
Freenet	B-Protocol
0.7	O
is	O
to	O
allow	O
a	O
globally	O
scalable	O
darknet	B-Operating_System
,	O
capable	O
(	O
at	O
least	O
in	O
theory	O
)	O
of	O
supporting	O
millions	O
of	O
users	O
.	O
</s>
<s>
Previous	O
darknets	B-Operating_System
,	O
such	O
as	O
WASTE	O
,	O
have	O
been	O
limited	O
to	O
relatively	O
small	O
disconnected	O
networks	O
.	O
</s>
<s>
The	O
scalability	O
of	O
Freenet	B-Protocol
is	O
made	O
possible	O
by	O
the	O
fact	O
that	O
human	O
relationships	O
tend	O
to	O
form	O
small-world	O
networks	O
,	O
a	O
property	O
that	O
can	O
be	O
exploited	O
to	O
find	O
short	O
paths	O
between	O
any	O
two	O
people	O
.	O
</s>
<s>
Furthermore	O
,	O
the	O
routing	O
algorithm	O
is	O
capable	O
of	O
routing	O
over	O
a	O
mixture	O
of	O
opennet	O
and	O
darknet	B-Operating_System
connections	O
,	O
allowing	O
people	O
who	O
have	O
only	O
a	O
few	O
friends	O
using	O
the	O
network	B-Architecture
to	O
get	O
the	O
performance	O
from	O
having	O
sufficient	O
connections	O
while	O
still	O
receiving	O
some	O
of	O
the	O
security	O
benefits	O
of	O
darknet	B-Operating_System
connections	O
.	O
</s>
<s>
This	O
also	O
means	O
that	O
small	O
darknets	B-Operating_System
where	O
some	O
users	O
also	O
have	O
opennet	O
connections	O
are	O
fully	O
integrated	O
into	O
the	O
whole	O
Freenet	B-Protocol
network	B-Architecture
,	O
allowing	O
all	O
users	O
access	O
to	O
all	O
content	O
,	O
whether	O
they	O
run	O
opennet	O
,	O
darknet	B-Operating_System
,	O
or	O
a	O
hybrid	O
of	O
the	O
two	O
,	O
except	O
for	O
darknet	B-Operating_System
pockets	O
connected	O
only	O
by	O
a	O
single	O
hybrid	O
node	O
.	O
</s>
<s>
Unlike	O
many	O
other	O
P2P	O
applications	O
Freenet	B-Protocol
does	O
not	O
provide	O
comprehensive	O
functionality	O
itself	O
.	O
</s>
<s>
Freenet	B-Protocol
is	O
modular	O
and	O
features	O
an	O
API	B-Application
called	O
Freenet	B-Protocol
Client	O
Protocol	O
(	O
FCP	O
)	O
for	O
other	O
programs	O
to	O
use	O
to	O
implement	O
services	O
such	O
as	O
message	B-Application
boards	I-Application
,	O
file	O
sharing	O
,	O
or	O
online	B-Protocol
chat	I-Protocol
.	O
</s>
<s>
FMS	O
is	O
developed	O
anonymously	O
and	O
can	O
be	O
downloaded	O
from	O
the	O
FMS	O
freesite	O
within	O
Freenet	B-Protocol
.	O
</s>
<s>
It	O
is	O
written	O
in	O
C++	B-Language
and	O
is	O
a	O
separate	O
application	O
from	O
Freenet	B-Protocol
which	O
uses	O
the	O
Freenet	B-Protocol
Client	O
Protocol	O
(	O
FCP	O
)	O
to	O
interface	O
with	O
Freenet	B-Protocol
.	O
</s>
<s>
Frost	O
can	O
be	O
downloaded	O
from	O
the	O
Frost	O
home	O
page	O
on	O
SourceForge	O
,	O
or	O
from	O
the	O
Frost	O
freesite	O
within	O
Freenet	B-Protocol
.	O
</s>
<s>
It	O
is	O
not	O
endorsed	O
by	O
the	O
Freenet	B-Protocol
developers	O
.	O
</s>
<s>
Frost	O
is	O
written	O
in	O
Java	B-Device
and	O
is	O
a	O
separate	O
application	O
from	O
Freenet	B-Protocol
.	O
</s>
<s>
It	O
provides	O
an	O
API	B-Application
for	O
control	O
from	O
other	O
programs	O
is	O
also	O
used	O
to	O
implement	O
a	O
comment	O
system	O
for	O
static	O
websites	O
in	O
the	O
regular	O
internet	O
.	O
</s>
<s>
Infocalypse	O
is	O
an	O
extension	O
for	O
the	O
distributed	O
revision	O
control	O
system	O
Mercurial	B-Protocol
.	O
</s>
<s>
It	O
uses	O
an	O
optimized	O
structure	O
to	O
minimize	O
the	O
number	O
of	O
requests	O
to	O
retrieve	O
new	O
data	O
,	O
and	O
allows	O
supporting	O
a	O
repository	O
by	O
securely	O
reuploading	O
most	O
parts	O
of	O
the	O
data	O
without	O
requiring	O
the	O
owner	O
's	O
private	B-Application
keys	I-Application
.	O
</s>
<s>
FCPLib	O
(	O
Freenet	B-Protocol
Client	O
Protocol	O
Library	O
)	O
aims	O
to	O
be	O
a	O
cross-platform	B-Operating_System
natively	O
compiled	B-Language
set	O
of	O
C++	B-Language
-based	O
functions	O
for	O
storing	O
and	O
retrieving	O
information	O
to	O
and	O
from	O
Freenet	B-Protocol
.	O
</s>
<s>
FCPLib	O
supports	O
Windows	O
NT/2K/XP	O
,	O
Debian	O
,	O
BSD	B-Operating_System
,	O
Solaris	B-Application
,	O
and	O
macOS	B-Application
.	O
</s>
<s>
lib-pyFreenet	O
exposes	O
Freenet	B-Protocol
functionality	O
to	O
Python	B-Language
programs	I-Language
.	O
</s>
<s>
Law	O
enforcement	O
agencies	O
have	O
claimed	O
to	O
have	O
successfully	O
infiltrated	O
Freenet	B-Protocol
opennet	O
in	O
order	O
to	O
deanonymize	O
users	O
but	O
no	O
technical	O
details	O
have	O
been	O
given	O
to	O
support	O
these	O
allegations	O
.	O
</s>
<s>
One	O
report	O
stated	O
that	O
,	O
"	O
A	O
child-porn	O
investigation	O
focused	O
on	O
...	O
[	O
the	O
suspect ]	O
when	O
the	O
authorities	O
were	O
monitoring	O
the	O
online	O
network	B-Architecture
,	O
Freenet.	O
"	O
</s>
<s>
A	O
court	O
case	O
in	O
the	O
Peel	O
Region	O
of	O
Ontario	O
,	O
Canada	O
R	O
.	O
v	O
.	O
Owen	O
,	O
2017	O
ONCJ	O
729	O
(	O
CanLII	O
)	O
,	O
illustrated	O
that	O
law	O
enforcement	O
do	O
in	O
fact	O
have	O
a	O
presence	O
,	O
after	O
Peel	O
Regional	O
Police	O
located	O
who	O
had	O
been	O
downloading	O
illegal	O
material	O
on	O
the	O
Freenet	B-Protocol
network	B-Architecture
.	O
</s>
<s>
The	O
court	O
decision	O
indicates	O
that	O
a	O
Canadian	O
Law	O
Enforcement	O
agency	O
operates	O
nodes	O
running	O
modified	O
Freenet	B-Protocol
software	O
in	O
the	O
hope	O
of	O
determining	O
who	O
is	O
requesting	O
illegal	O
material	O
.	O
</s>
<s>
Freenet	B-Protocol
has	O
had	O
significant	O
publicity	O
in	O
the	O
mainstream	O
press	O
,	O
including	O
articles	O
in	O
The	O
New	O
York	O
Times	O
,	O
and	O
coverage	O
on	O
CNN	B-Architecture
,	O
60	O
Minutes	O
II	O
,	O
the	O
BBC	O
,	O
The	O
Guardian	O
,	O
and	O
elsewhere	O
.	O
</s>
<s>
Freenet	B-Protocol
received	O
the	O
SUMA-Award	O
2014	O
for	O
"	O
protection	O
against	O
total	O
surveillance	O
"	O
.	O
</s>
<s>
A	O
"	O
freesite	O
"	O
is	O
a	O
site	O
hosted	O
on	O
the	O
Freenet	B-Protocol
network	B-Architecture
.	O
</s>
<s>
Freesites	O
are	O
coded	O
in	O
HTML	B-Language
and	O
support	O
as	O
many	O
features	O
as	O
the	O
browser	O
viewing	O
the	O
page	O
allows	O
;	O
however	O
,	O
there	O
are	O
some	O
exceptions	O
where	O
the	O
Freenet	B-Protocol
software	O
will	O
remove	O
parts	O
of	O
the	O
code	O
that	O
may	O
be	O
used	O
to	O
reveal	O
the	O
identity	O
of	O
the	O
person	O
viewing	O
the	O
page	O
(	O
making	O
a	O
page	O
access	O
something	O
on	O
the	O
internet	O
,	O
for	O
example	O
)	O
.	O
</s>
