<s>
Tox	B-Protocol
is	O
a	O
peer-to-peer	O
instant-messaging	O
and	O
video-calling	O
protocol	O
that	O
offers	O
end-to-end	O
encryption	O
.	O
</s>
<s>
A	O
reference	O
implementation	O
of	O
the	O
protocol	O
is	O
published	O
as	O
free	B-License
and	I-License
open-source	I-License
software	I-License
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
GPL-3.0-or-later	I-License
.	O
</s>
<s>
The	O
initial	O
commit	O
to	O
GitHub	B-Application
was	O
pushed	O
on	O
June	O
23	O
,	O
2013	O
,	O
by	O
a	O
user	O
named	O
irungentoo	O
.	O
</s>
<s>
On	O
July	O
12	O
,	O
2014	O
,	O
Tox	B-Protocol
entered	O
an	O
alpha	O
stage	O
in	O
development	O
and	O
a	O
redesigned	O
download	O
page	O
was	O
created	O
for	O
the	O
occasion	O
.	O
</s>
<s>
Users	O
are	O
assigned	O
a	O
public	O
and	O
private	O
key	O
,	O
and	O
they	O
connect	O
to	O
each	O
other	O
directly	O
in	O
a	O
fully	O
distributed	B-Operating_System
,	O
peer-to-peer	O
network	O
.	O
</s>
<s>
All	O
traffic	O
over	O
Tox	B-Protocol
is	O
end-to-end	O
encrypted	O
using	O
the	O
NaCl	B-Application
library	O
,	O
which	O
provides	O
authenticated	B-Algorithm
encryption	I-Algorithm
and	O
perfect	O
forward	O
secrecy	O
.	O
</s>
<s>
Tox	B-Protocol
clients	O
aim	O
to	O
provide	O
support	O
for	O
various	O
secure	O
and	O
anonymised	O
communication	O
features	O
;	O
while	O
every	O
client	O
supports	O
messaging	B-Application
,	O
additional	O
features	O
like	O
group	O
messaging	B-Application
,	O
voice	B-Application
and	I-Application
video	I-Application
calling	I-Application
,	O
voice	B-Application
and	I-Application
video	I-Application
conferencing	I-Application
,	O
typing	O
indicators	O
,	O
message	B-Operating_System
read-receipts	I-Operating_System
,	O
file	O
sharing	O
,	O
profile	O
encryption	O
,	O
and	O
desktop	B-Device
streaming	I-Device
are	O
supported	O
to	O
various	O
degrees	O
by	O
mobile	O
and	O
desktop	O
clients	O
.	O
</s>
<s>
Client	O
developers	O
are	O
strongly	O
encouraged	O
to	O
adhere	O
to	O
the	O
Tox	B-Protocol
Client	O
Standard	O
in	O
order	O
to	O
maintain	O
cross-client	O
compatibility	O
and	O
uphold	O
best	O
security	O
practices	O
.	O
</s>
<s>
Though	O
several	O
apps	O
that	O
use	O
the	O
Tox	B-Protocol
protocol	O
seem	O
similar	O
in	O
function	O
to	O
regular	O
instant	B-Application
messaging	I-Application
apps	O
,	O
the	O
lack	O
of	O
central	O
servers	O
similar	O
to	O
XMPP	B-Protocol
or	O
Matrix	B-Protocol
currently	O
has	O
the	O
consequence	O
that	O
both	O
parties	O
of	O
the	O
chat	O
need	O
to	O
be	O
online	O
for	O
the	O
message	O
to	O
be	O
sent	O
and	O
received	O
.	O
</s>
<s>
The	O
Tox	B-Protocol
enabled	O
messengers	O
deal	O
with	O
this	O
in	O
separate	O
ways	O
,	O
some	O
prevent	O
the	O
user	O
from	O
sending	O
the	O
message	O
if	O
the	O
other	O
party	O
has	O
disconnected	O
while	O
others	O
show	O
the	O
message	O
as	O
being	O
sent	O
when	O
in	O
reality	O
it	O
is	O
stored	O
in	O
the	O
sender	O
's	O
phone	O
waiting	O
to	O
be	O
delivered	O
when	O
the	O
receiving	O
party	O
reconnects	O
to	O
the	O
network	O
.	O
</s>
<s>
The	O
Tox	B-Protocol
core	O
is	O
a	O
library	O
establishing	O
the	O
protocol	O
and	O
API	O
.	O
</s>
<s>
The	O
core	O
of	O
Tox	B-Protocol
is	O
an	O
implementation	O
of	O
the	O
Tox	B-Protocol
protocol	O
,	O
an	O
example	O
of	O
the	O
application	O
layer	O
of	O
the	O
OSI	O
model	O
and	O
arguably	O
the	O
presentation	O
layer	O
.	O
</s>
<s>
Implementations	O
of	O
the	O
Tox	B-Protocol
protocol	O
not	O
done	O
by	O
the	O
project	O
exist	O
.	O
</s>
<s>
Tox	B-Protocol
uses	O
the	O
Opus	B-Algorithm
audio	I-Algorithm
format	I-Algorithm
for	O
audio	O
streaming	O
and	O
the	O
VP8	B-Algorithm
video	I-Algorithm
compression	I-Algorithm
format	I-Algorithm
for	O
video	O
streaming	O
.	O
</s>
<s>
Tox	B-Protocol
uses	O
the	O
cryptographic	O
primitives	O
present	O
in	O
the	O
NaCl	B-Application
crypto	I-Application
library	I-Application
,	O
via	O
libsodium	O
.	O
</s>
<s>
Specifically	O
,	O
Tox	B-Protocol
employs	O
Curve25519	O
for	O
its	O
key	O
exchanges	O
,	O
xsalsa20	O
for	O
symmetric	O
encryption	O
,	O
and	O
Poly1305	B-Algorithm
for	O
MACs	O
.	O
</s>
<s>
Because	O
the	O
tox	B-Protocol
protocol	O
can	O
be	O
used	O
by	O
many	O
different	O
applications	O
,	O
and	O
because	O
the	O
tox	B-Protocol
network	O
broadcasts	O
the	O
used	O
client	O
,	O
it	O
is	O
also	O
possible	O
for	O
clients	O
to	O
use	O
additional	O
encryption	O
when	O
sending	O
to	O
clients	O
which	O
support	O
the	O
same	O
features	O
.	O
</s>
<s>
A	O
client	O
is	O
a	O
program	O
that	O
uses	O
the	O
Tox	B-Protocol
core	O
library	O
to	O
communicate	O
with	O
other	O
users	O
of	O
the	O
Tox	B-Protocol
protocol	O
.	O
</s>
<s>
There	O
are	O
also	O
Tox	B-Protocol
protocol	O
plugins	O
for	O
Pidgin	B-Protocol
(	O
abandoned	O
since	O
2017	O
,	O
one	O
of	O
the	O
forks	O
was	O
maintained	O
until	O
2020	O
)	O
and	O
Miranda	B-Protocol
NG	I-Protocol
(	O
last	O
updated	O
in	O
2021	O
)	O
.	O
</s>
<s>
At	O
July	O
11	O
,	O
2015	O
,	O
Tox	B-Protocol
developers	O
officially	O
announced	O
their	O
disassociation	O
with	O
Tox	B-Protocol
Foundation	O
,	O
due	O
to	O
"	O
a	O
dispute	O
over	O
the	O
misuse	O
of	O
donated	O
funds	O
"	O
by	O
Tox	B-Protocol
Foundation	O
head	O
and	O
CEO	O
,	O
according	O
to	O
LWN.net	O
.	O
</s>
<s>
Due	O
to	O
domains	O
being	O
in	O
control	O
of	O
the	O
Tox	B-Protocol
Foundation	O
,	O
main	O
development	O
of	O
the	O
project	O
was	O
transferred	O
to	O
a	O
new	O
infrastructure	O
,	O
servers	O
,	O
and	O
new	O
domain	O
.	O
</s>
<s>
Tox	B-Protocol
received	O
some	O
significant	O
publicity	O
in	O
its	O
early	O
conceptual	O
stage	O
,	O
catching	O
the	O
attention	O
of	O
global	O
online	O
tech	O
news	O
sites	O
.	O
</s>
<s>
On	O
August	O
15	O
,	O
2013	O
,	O
Tox	B-Protocol
was	O
number	O
five	O
on	O
GitHub	B-Application
's	O
top	O
trending	O
list	O
.	O
</s>
<s>
Concerns	O
about	O
metadata	O
leaks	O
were	O
raised	O
,	O
and	O
developers	O
responded	O
by	O
implementing	O
Onion	B-Protocol
routing	I-Protocol
for	O
the	O
friend-finding	O
process	O
.	O
</s>
<s>
Tox	B-Protocol
was	O
accepted	O
into	O
the	O
Google	B-Application
Summer	I-Application
of	I-Application
Code	I-Application
as	O
a	O
Mentoring	O
Organization	O
in	O
2014	O
and	O
2015	O
.	O
</s>
