<s>
TorChat	B-Protocol
was	O
a	O
peer-to-peer	O
anonymous	O
instant	B-Application
messenger	I-Application
that	O
used	O
Tor	B-Application
onion	I-Application
services	O
as	O
its	O
underlying	O
network	O
.	O
</s>
<s>
The	O
characteristics	O
of	O
Tor	B-Application
's	O
onion	O
services	O
ensure	O
that	O
all	O
traffic	O
between	O
the	O
clients	O
is	O
encrypted	O
and	O
that	O
it	O
is	O
very	O
difficult	O
to	O
tell	O
who	O
is	O
communicating	O
with	O
whom	O
and	O
where	O
a	O
given	O
client	B-Protocol
is	O
physically	O
located	O
.	O
</s>
<s>
TorChat	B-Protocol
is	O
free	O
software	O
licensed	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
.	O
</s>
<s>
In	O
TorChat	B-Protocol
every	O
user	O
has	O
a	O
unique	O
alphanumeric	O
ID	O
consisting	O
of	O
16	O
characters	O
.	O
</s>
<s>
This	O
ID	O
will	O
be	O
randomly	O
created	O
by	O
Tor	B-Application
when	O
the	O
client	B-Protocol
is	O
started	O
the	O
first	O
time	O
,	O
it	O
is	O
basically	O
the	O
.onion	O
address	O
of	O
an	O
onion	O
service	O
.	O
</s>
<s>
TorChat	B-Protocol
clients	O
communicate	O
with	O
each	O
other	O
by	O
using	O
Tor	B-Application
to	O
contact	O
the	O
other	O
's	O
onion	O
service	O
(	O
derived	O
from	O
their	O
ID	O
)	O
and	O
exchanging	O
status	O
information	O
,	O
chat	O
messages	O
and	O
other	O
data	O
over	O
this	O
connection	O
.	O
</s>
<s>
Since	O
onion	O
services	O
can	O
receive	O
incoming	O
connections	O
even	O
if	O
they	O
are	O
behind	O
a	O
router	O
doing	O
network	B-Protocol
address	I-Protocol
translation	I-Protocol
(	O
NAT	O
)	O
,	O
TorChat	B-Protocol
does	O
not	O
need	O
any	O
port	B-Protocol
forwarding	I-Protocol
to	O
work	O
.	O
</s>
<s>
The	O
first	O
public	O
version	O
of	O
TorChat	B-Protocol
was	O
released	O
in	O
November	O
2007	O
by	O
Bernd	O
Kreuss	O
(	O
prof7bit	O
)	O
.	O
</s>
<s>
It	O
is	O
written	O
in	O
Python	B-Language
and	O
used	O
the	O
cross-platform	O
widget	O
toolkit	O
wxPython	B-Language
which	O
made	O
it	O
possible	O
to	O
support	O
a	O
wide	O
range	O
of	O
platforms	B-Device
and	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
older	O
Windows	O
versions	O
of	O
TorChat	B-Protocol
were	O
built	O
with	O
py2exe	B-Application
(	O
since	O
0.9.9.292	O
replaced	O
with	O
pyinstaller	O
)	O
and	O
came	O
bundled	O
with	O
a	O
copy	O
of	O
Tor	B-Application
readily	O
configured	O
so	O
that	O
it	O
could	O
be	O
run	O
as	O
a	O
portable	B-Application
application	I-Application
right	O
off	O
a	O
USB	O
flash	O
drive	O
without	O
any	O
installation	O
,	O
configuration	O
or	O
account	O
creation	O
.	O
</s>
<s>
Between	O
2008	O
and	O
2010	O
were	O
n't	O
any	O
updated	O
packages	O
,	O
resulting	O
in	O
the	O
bundled	O
version	O
of	O
Tor	B-Application
becoming	O
obsolete	O
and	O
unable	O
to	O
connect	O
to	O
the	O
Tor	B-Application
network	I-Application
,	O
which	O
was	O
the	O
reason	O
for	O
the	O
appearance	O
of	O
forks	O
that	O
basically	O
just	O
replaced	O
the	O
bundled	O
Tor.exe	O
with	O
a	O
current	O
one	O
.	O
</s>
<s>
In	O
December	O
2010	O
,	O
an	O
official	O
update	O
finally	O
became	O
available	O
that	O
,	O
among	O
some	O
minor	O
bugfixes	O
,	O
also	O
again	O
included	O
an	O
up-to-date	O
Tor.exe	O
.	O
</s>
<s>
After	O
2014	O
,	O
all	O
development	O
activity	O
stopped	O
and	O
TorChat	B-Protocol
has	O
not	O
received	O
any	O
further	O
updates	O
.	O
</s>
<s>
The	O
binary	O
(	O
a	O
Cocoa	O
application	O
)	O
and	O
source-code	O
(	O
Objective-C	O
)	O
bundled	O
in	O
a	O
Xcode	B-Operating_System
7	O
project	O
can	O
be	O
downloaded	O
on	O
SourceMac	O
.	O
</s>
<s>
A	O
rewrite	O
of	O
the	O
TorChat	B-Protocol
protocol	O
in	O
Java	B-Language
was	O
created	O
in	O
the	O
beginning	O
of	O
2012	O
,	O
called	O
jTorChat	O
on	O
Google	B-Protocol
Code	I-Protocol
.	O
</s>
<s>
Containing	O
the	O
latest	O
Tor.exe	O
,	O
it	O
is	O
meant	O
to	O
emulate	O
all	O
the	O
features	O
of	O
the	O
original	O
TorChat	B-Protocol
protocol	O
,	O
as	O
well	O
as	O
extending	O
the	O
protocols	O
for	O
jTorChat-specific	O
features	O
.	O
</s>
<s>
Filesharing	O
,	O
while	O
implemented	O
in	O
the	O
original	O
TorChat	B-Protocol
,	O
is	O
not	O
yet	O
implemented	O
in	O
jTorChat	O
.	O
</s>
<s>
At	O
this	O
stage	O
jTorChat	O
is	O
designed	O
to	O
work	O
effectively	O
on	O
Windows	O
without	O
any	O
configuration	O
,	O
however	O
since	O
its	O
written	O
in	O
Java	B-Language
,	O
it	O
can	O
run	O
on	O
any	O
platform	O
supported	O
by	O
both	O
,	O
Tor	B-Application
and	O
Java	B-Language
itself	O
,	O
making	O
it	O
very	O
portable	O
.	O
</s>
<s>
The	O
project	O
is	O
actively	O
seeking	O
Java	B-Language
contributors	O
,	O
especially	O
to	O
help	O
debug	O
the	O
GUI	O
interface	O
.	O
</s>
<s>
In	O
February	O
2012	O
,	O
developer	O
Prof7bit	O
moved	O
TorChat	B-Protocol
to	O
GitHub	B-Application
,	O
as	O
a	O
protest	O
against	O
Google	O
selectively	O
censoring	O
access	O
to	O
TorChat	B-Protocol
download	O
to	O
certain	O
countries	O
.	O
</s>
<s>
Prof7bit	O
has	O
switched	O
to	O
working	O
on	O
torchat2	B-Protocol
,	O
which	O
is	O
a	O
rewrite	O
from	O
scratch	O
,	O
using	O
Lazarus	B-Language
and	O
Free	B-Operating_System
Pascal	I-Operating_System
.	O
</s>
<s>
In	O
2015	O
security	O
analysis	O
of	O
TorChat	B-Protocol
protocol	O
and	O
its	O
Python	B-Language
implementation	O
was	O
conducted	O
.	O
</s>
<s>
It	O
was	O
found	O
that	O
although	O
the	O
design	O
of	O
TorChat	B-Protocol
is	O
sound	O
,	O
its	O
implementation	O
has	O
several	O
flaws	O
,	O
which	O
make	O
TorChat	B-Protocol
users	O
vulnerable	O
to	O
impersonation	O
,	O
</s>
<s>
Despite	O
the	O
flaws	O
found	O
,	O
the	O
use	O
of	O
TorChat	B-Protocol
might	O
still	O
be	O
secure	O
in	O
a	O
scenario	O
where	O
the	O
peer	O
's	O
onion	O
address	O
does	O
not	O
become	O
known	O
to	O
an	O
adversary	O
interested	O
in	O
attacking	O
the	O
person	O
behind	O
the	O
TorChat	B-Protocol
address	O
.	O
</s>
