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[Music]
and please give a warm Round of Applause
for Roger
[Applause]
dingledine okay hi everybody is the
microphone working sounds like it is
excellent how many people here know how
tour works or uh have Run tour tour
browser awesome great how many people
here know words like Bridges and
pluggable transports bunch of hands also
perfect okay so I'm going to talk a
little bit uh about the intro to tour
for those who didn't raise their hands
I'll try to get through that quickly and
then I'm going to talk about uh intro
DET tour and censorship and try to get
through that quickly and then talk about
what has happened in Russia over the
past few years what's happened in Iran
uh last year and what's happened in
turkistan this year and then we'll talk
about uh policy uh and political
questions that come from that okay so
tour is a free software project tour is
a nonprofit uh one of the fun things
about tour is the community of people
all around the world uh any City you go
to these days has a university where
professors are doing uh tore research
and there are grad students interested
in this uh we have somewhere between 2
million and 8 million daily users it's
an anonymity system so it's a bit hard
to tell exactly how many we have and
we're part of larger ecosystems the
internet Freedom world the free software
World censorship research anonymity
research so big picture we've got Alice
here she's trying to get to some website
like Bob and do it safely uh there are a
bunch of places the attacker can be
maybe the attacker watching Alice's
local network uh maybe it's Starbucks or
somebody running the Wi-Fi here uh
they're trying to learn what Alice is
doing or maybe the attacker uh is inside
the network deuts Telecom NSA something
like that uh and they're trying to learn
which alyses went to which Bobs or maybe
the attacker is on The Bob side maybe
it's CNN and they want to know who their
users are uh or maybe it's somebody
watching Wikileaks trying to figure out
who's connecting to it so these are all
the the the types of attacks that we
think about uh in terms of an anonymity
system um and encryption is important
you should use encryption but even when
you're using encryption people watching
you get to learn uh who you talk to how
how long you talk uh when you talk
things like that uh when the CIA tries
to attack things they're not trying to
break the encryption these days they
build the social graph of uh this person
talks to this person so let's break into
his house and uh install something on
his laptop so encryption is good but
it's not enough and another way of
looking at that is Communications
metadata not too many years ago there
was creepy NSA dude with his phrase we
kill people based on metadata so the the
the goal of tour is to uh protect not
just the contents of your Communications
but the metadata of your Communications
as well so another way of looking at
that I actually only use the word
anonymity when I'm talking to other
researchers when I'm talking to my
parents I tell them I'm working on a
privacy system anonymity I'm not sure
but privacy is an important thing for
the world to have when I'm talking to
companies I work on communication
security because they don't care about
privacy privacy is dead but
communication security is important to
have and when I'm talking to governments
I work on traffic analysis resistant
communication networks and again it's
the same system but telling governments
you got an anonymity system they don't
want that privacy why would we want that
security we've got lots of that oh
traffic analysis resistance yes we we do
need that so part of the the fun of this
is to get all those us users into the
same anonymity set so you have the
Egyptian activist and the German BN guy
and uh the cancer survivor all in the
same uh anonymity set so they blend
together and then there's another
category we're going to talk a lot about
today which is the reachability side for
human rights where I want to reach BBC
and my local network doesn't let me do
it okay so how do you build one of these
the easy answer is a big centralized
system like a VPN where all the
connections come in and then they get
proxied to somewhere else and the first
problem there is what happens if that
Central Point is evil and they're
actually turns out they do log turns out
they do uh give their logs out who knows
it's hard to hard to tell these things
in a centralized system but it's worse
than that what if the centralized system
is completely honest it's still one
point where a bunch of connections come
in bunch of connections come out so if
you can do traffic analysis on that to
match up this Alice to that Bob that's
bad news so the goal of tour is to
distribute the trust over multiple
relays so there's no single point in the
system that knows which Alice talked to
which Bob so it isn't about privacy by
promise I know who you I know what
you're doing but I promise I won't tell
it's about privacy by Design or privacy
by by construction where the actual
system separates who gets to know what
about what's going on
and we've been growing in terms of
bandwidth over the past many years and
the graph looks like this every time
just with different dates at the bottom
uh another piece that's important uh
which we'll we can talk about afterwards
tour itself is the anonymity layer I was
talking about it tries to hide your IP
address but there's another layer the
application layer uh where cookies and
fonts and uh application versions and
all the stuff inside browsers we need to
deal with that also so tour browser
takes care of the second half of the
Privacy uh piece and then the last point
to think about uh is the transparency we
are a free software project uh of course
we give you design documents and
specifications and source code and uh to
explain this is what we meant to build
this is why we built it that way this is
what we built uh and also we say uh hi
I'm Roger I wrote Tor uh we are publicly
identified people and that uh
transparency is important for building
communities uh and of course every time
I say that there's somebody who says uh
oh haha the anonymity people are talking
about transparency haha uh the point is
privacy is about choice and we choose to
be transparent in order to have you uh
understand what the tour Community is
and be part of the tour community and
that's how we build
trust okay so that was crash course on
tour uh for the next side Let's uh give
you the crash course on censorship
resistance and uh the pluggable
transport where
okay so the first arms race cat and
mouse game we're in uh the tour network
is made up of 8,000 relays around the
world and those IP addresses are
publicly listed so at the beginning
China could just grab the whole list
block them it's done you can't get to
tour uh so the fix for this is what we
call Bridge relays where they're not in
a big public list and then the the arms
race becomes how do we give out Bridges
to the people who need them one at a
time without letting the adversary learn
all of them so that turns out to be a
hard problem but it's at least better
than the first one and the other piece
of this is not just finding IP addresses
and blocking them but blocking by
protocol by by using deep packet
inspection to learn uh I'm not going to
allow bit torrent I'm not going to allow
https uh whatever the sensor chooses to
block by protocol so the fix that we
have for that uh originally Tor tried to
look like uh Firefox talking to aache we
are doing encrypted web browsing
everybody should allow encrypted web
browsing uh turns out looking exactly
like that is really hard so uh we tried
that to to fine-tune things for a while
but eventually we ended up with uh let's
modularize this so we've got a bunch of
different transports that take care of
blending in and making you not get
blocked and then the transports deal
with reachability and tour deals with
the anonymity privacy uh traffic
analysis resistance side of
things so there are a couple of
pluggable transports that have worked
pretty well over the past few years and
I'll talk more about them uh in action
in a bit the first one is obs4 so
basically it just adds another layer of
encryption on top of whatever the
protocol is so there are no recognizable
headers and the idea is that when you're
running your protocol
classifier it pops out bit torrent htps
uh web RTC video W get whatever it pops
out and for OBS 4 it pops out I don't
know and the goal of this is the sensor
needs to decide for all of the I don't
knows do I block them all because
there's going to be a long tail of weird
protocols and allowing that long tail
means that we go through and blocking
that long tail means that you block
whatever protocol the new startup made
last week um and in this case this works
really well in places like China because
when you block the long tail of
unclassifiable things the firewall help
desk actually gets a lot of phone calls
saying hey my thing stopped working can
you fix it so that's that's one One
Transport that's been working another
one that's been working is called
snowflake the idea for snowflake is to
transform your traffic into web RTC the
idea is you'll look like video chat uh
and a lot of places allow video chat
through so the other cool thing about
snowflake because it uses web RTC
browsers can do web RTC natively so
snowflake extensions in Firefox and
chrome and brave and so on uh let you
become a snowflake volunteer just by
adding something to your browser you
don't have to apt get install tour and
then know how to edit a text file and so
on uh so that uh variety of volunteers
that we get means first of all we have a
lot of them so we can uh change how we
give them out but also they change a lot
because your browser is on a different
IP address today than it was yesterday
okay another plugable transport that has
been useful in the past is based on
domain fronting how many people here
know the word domain fronting I see uh
some hands but me many fewer hands than
I saw before great okay so the idea for
domain fronting is I want to connect to
some uh hugely popular cloud service
like uh Google cloud or Azure or
something like that and I'm going to do
a an https connection and on the outside
in the server name indicator I will list
a very popular uh domain that they'll
hopefully they will not be willing to
block once I've done the TLs connection
inside the encryption then I send a host
header for a different domain and all of
these uh Cloud providers up until
recently uh allowed you to do that where
you you're you're using encryption to
get to one domain but you're actually
reaching a different website underneath
and that means from the sensors
perspective they see you talking to uh
stack exchange or something like that
which they are willing to let through uh
and then underneath that you're talking
to a tour proxy that sends your traffic
into the tour Network so one downside
here is uh if you're actually using
Google Google cloud or Amazon Cloud they
charge you way too much uh so we don't
want to put all of the tour traffic
through this but you can use it as a
signaling Channel or as a last option uh
but the basic idea is there's a domain
that is too big to fail and hopefully
they won't block it and we can act like
that
that okay and then some other uh the
last thing you need to know about the
censorship side of things is how do we
match up users to Bridges and there's a
service called Bridge DB that breaks
bridges into different buckets and each
bucket makes you exercise some new
scarce resource like you have to come up
with from a new uh sl16 on the Internet
or a new gmail address or solve a Capa
uh and the goal of this is to separate
these so if China gets really good at
having a lot of addresses that's not
enough they also have to have a lot of
Gmail addresses and be good at solving
captas and so on so the part of the goal
of that is to to to have a way to give
Bridge addresses to the users who need
them without letting the the adversary
easily learn all of them and snowflake
has something similar to bridg DB called
the broker where the clients uh Connect
using domain fronting to the broker and
the volunteer snowflakes also connect to
the broker and it pairs uh users who are
censored with volunteers who want to
help them get into tour so far so
good
great okay so that was uh the crash
course on everything I'm talking about
here let's talk about uh what's happened
over the past couple of years so our
story starts uh at the end of December
2021 in Russia where in the same day
Russia ended up blocking all of the
public relays by IP address they ended
up blocking the Azure domain fronting
mechanism that we had they ended up
blocking a bunch of the OBS Four Bridges
the ones that were easiest to find uh
they blocked some other ones that were
harder to find and they blocked
snowflake by protocol and they rolled
all of this out uh basically in the same
day and we uh we had to piece together
what was actually happening a couple of
days after that they sent us a letter to
hetner in Russian basically saying your
website is evil and we're going to block
it and we didn't really know what to do
with that so after a while they blocked
it
so that's the beginning of the story and
you can see the graph of uh number of
people connecting uh directly to relays
without using Bridges or plugable
transports uh and over the course of uh
a day or so uh quite a few people uh
stopped being able to use tour but
there's a corresponding graph of over
that same time period uh many people
were able to switch over to using
Bridges uh in order to continue using
torque in terms of how they block
snowflake in particular it was a
protocol it was a DPI level block where
uh we were sending a certain TLS
extension in both directions and
actually uh normal places that do TLS
only send that extension uh from the the
client's side not the server side so
that was something that you could see in
the TLs handshake and they decided to
block that we actually figured that one
out pretty quickly rolled out a fix uh
and because it was a fix just on the
server side the clients didn't have to
change it all
uh and over the course of a couple of
days uh many people were able to switch
back to using snowflake from inside
Russia the domain fronting one was a bit
more exciting so at first I was thinking
okay we've got this domain it's like
Ajax do aspn CDN natur or something it's
someplace that serves a lot of
JavaScript to the world and it's too big
to fail there's no way they'd be willing
to block that so I was trying to figure
out how did they like did they actually
decide to block that domain what's going
on uh and it turn out the answer is no
they blocked the IP address they blocked
Azure by IP address so this is my no
[ __ ] let me tell you that time we got
Russia to block Azure for a day story
and did they know they were doing it and
they thought it was acceptable I don't
know uh somebody in Azure noticed and
after a day or so and rotated to a new
IP address and uh and the block didn't
follow so it wasn't just us that they
were blocking they were blocking Skype
login they were blocking everything that
Azure has because Azure does geodns so
everything that is azure goes to that
one IP address from all of that region
of the world so that was kind of
exciting and the answer was at first we
were thinking okay let let's switch to a
new domain front let's find something
that's even bigger that they'll not that
they won't block uh but they blocked all
of azure which solved that uh arms race
right
there and then azra solved it for us
after wordss so the the other uh fun
piece of this we put up a forum post
right after that explaining uh here's
how uh if you are blocked here's what
you should do here's how the blocking
Works here's how you can get a bridge uh
here's how snowflake works and because
we had recently set up our Forum on
forum. tour pro.net because we were not
running it uh the the services that we
run are on tour project.org the external
thirdparty services are on tour
project.net tour project.net never never
got blocked so our Forum worked just
fine the whole time uh we got a great
opportunity to interact with hundreds of
thousands of people who were coming
there to learn all about how to get
around these things so there's there's
some lesson in there
somewhere uh in terms of long-term we've
lost maybe uh 2third of the people who
were connecting directly uh over uh
using tour directly to to relays uh but
at the same time we've had quite a quite
a few people coming back the fun thing
here is most people in Russia are using
OBS 4 to get around the censorship and
we'll see in a few more slides that a
lot of people are using snowflake in
Iran I think both of them work in both
places so it's it's more of a social
thing uh which one gets used where so I
should also say here I am showing you uh
200,000 users lost and 40,000 users
gained so we didn't it's not a one for
one map but it's worse than that these
user estimates are extremely uh uh uh
variable extremely vague extremely
ambiguous and the reason for this is uh
those counts are assuming most users are
online all day each day and if you're a
user in Iran or Egypt or Russia or
whatever you go to the Internet cafe for
an hour you leave then we're way way way
under counting so here's some way to
visualize that uh if we assumed all of
the users that we're seeing are on on
line only for an hour a day it's up in
the green line up at 20 million some
users if we assume that every user is
online all the time we're the red line
down there and the blue line is the one
that we actually show for these graphs
so when I'm showing you these graphs uh
it may the numbers might be higher by a
factor of 10 uh we really don't know
what the what the using of tour behavior
is by various populations around the
world it's a privacy system um we can
talk about that later
also okay so another Bridge distribution
mechanism that we worked on when this
Russia thing happened was uh giving out
Bridges by telegram so part of the goal
there was we want to have some easy way
for people to interact with us shouldn't
be a website everybody's using telegram
telegram has worked hard on not being
blocked so we set up a a bot an auto
responder where you ask us for Bridges
and we send you some bridges and you
could imagine the Russian sensors would
do this too so turns out telegram
accounts are assigned numerically so if
I see your telegram name I know how long
ago your account was made so the hack is
if the telegram account is older than a
certain amount give them these Bridges
and if it's newer than a certain amount
give them these Bridges
[Applause]
so so this means that the Russian
censorship Ministry uh very eagerly got
a bunch of new telegram accounts and
signed up and I got all of our bridges
and said we are satisfied we have found
all the telegram Bridges but the reality
is uh there are a bunch of I'll get the
reality is there are a bunch of bridges
like this that uh saw hundreds of users
and were happily proxying uh many
megabytes a second for a while until
eventually somebody leaks them and they
get blocked and we go to another one and
also I should mention uh the importance
of having people on the inside who want
to tell you what's going on we got some
interesting Communications from folks
who run who work in the censorship
Ministry in Russia and I don't want to
write any yes CL
excellent and I don't want to write any
of the words up there because I don't
want somebody using stylometry or
something to guess uh which employee
that was but they were telling us
interesting stor stories like uh my job
is to uh download tour browser and get
Bridges each day and when I get a bridge
I put it in a uh an Excel spreadsheet
and I email it to the sensors so this is
that's the world that they are living in
if you're imagining some sort of
high-tech automated thing uh that was
not what was going on in 2021 2022 uh in
Russia and I think that's still the
case Okay so some other fun parts of
this uh we actually got contacted I'll
give you the English version of this so
you can uh read the non-russian we
actually got contacted by a an NGO
inside Russia who said you know I think
they're blocking your website illegally
like there's a way that they're allowed
to decide to block your domain and they
didn't follow their own law we want to
sue them inside Russia and I'm
thinking okay I mean sure if you want
to
and in particular I'm thinking I I don't
think you're going to succeed at this
but I want to empower you to change your
country from the inside because that I
mean you're an NGO we're an NGO if you
if this is what you want to spend your
time on uh go for it so we we signed a
thing saying they represent us inside
Russia uh and they
[Applause]
won
so that was the good news they ended up
uh convincing some judge that indeed the
the censorship Ministry had not followed
its own laws and it was important for
them to to remove the blocking so that
was the good news here's the not quite
so good news the the orange stuff is
when it didn't work the green stuff is
after the judicial conclusion and then
of course the censorship Ministry said
sounds good we'll we'll follow our laws
this time and block you the appropriate
way which makes sense to me but the good
news that comes after
that is they started off blocking star.
tour project.org
afterwards they blocked
www.torproject.org
so bridges. tour project.org works
forum. Tour all the other websites are
not blocked in Russia uh as a result of
that internal lawsuit so uh go them for
succeeding internally uh and there's a
lesson there about uh letting people
fight their own fights in their
country another fun thing to think about
on the Russia side uh a bunch of people
broke into the censorship Ministry and
took a bunch of documents and put them
on the Internet so if you're interested
in uh looking at sketchy dodgy documents
that may or may not have been planted by
the Russian censorship Ministry I'm not
sure uh so look at them very carefully
if you do but you're the right crowd for
doing that um I think the amnesty folks
have been trying to look at them and
maybe the citizen lab folks have been
trying to look at them uh so their
details about uh what they block how
they go about blocking uh what they spy
on things like that and I think this was
the first dump but there was another
much bigger dump that happened uh like
earlier this year so uh the censorship
Ministry is uh has has a bunch of
interesting details about what it does
and we this group should learn about
that as well okay so where is Russia
these days uh they still sometimes crawl
a bunch of bridges and block them but
mostly bridges last for days or weeks or
more um and a lot of people are using
OBS 4 with telegram uh or maybe other
Bridge distribution strategies or maybe
they they tell their friends uh and
Snowflake and meek also continue to work
so the Russia story is doing pretty well
except Russia in general there are some
other problems going on uh there were
some stories that came out recently
about how the Russian government is
asking the Russian Banks to check if
you've paid for something that looks
like a VPN and if you have then they
call you up and you say what what's
going on why do you need VPN why why
what do you have to hide so the bank is
doing the enforcement to try to
discourage people uh and part of the
goal of something like tour is we don't
charge it's free software it's open
source it's freely available uh so that
you don't have to deal with the fact
that your bank suddenly turns into the
Secret Service uh
on on the government's
[Applause]
behalf okay so that was the Russia story
I'll talk a little bit more about Russia
at the end but let's talk about what
happened in September 2022 in Iran so
here's the graph of uh people using tour
directly in Iran they don't need Bridges
or pluggable transports or things like
that so while there were protests in the
street there were a lot of people mostly
on non-mobile uh networks who were
trying to to be safe to reach Facebook
or whatever they were trying to reach
that was otherwise blocked so that was
the good good version of the story so
remember uh the previous graphs that I
had where I'm like woohoo check out
these like we had 6,000 people using
snowflake in Russia so that that was
awesome but that was that little corner
over there with 6,000 people and we were
like cool 6,000 uh and here we have
hundreds of thousands of people using
snowflake so that was a a pretty big uh
bump and the important thing there is we
found a bunch of bottlenecks while
people were trying to ramp up to 6,000
that we fixed that made us ready for
when the Iran thing happened and
suddenly 100,000 more people wanted to
use it uh and because we had worked on
scaling we were ready for them so that
was a pretty cool uh coincidence that
happened
part of the reason why a lot of people
were using snowflake at the time was uh
Word of Mouth Community inside Iran
saying hey use this thing this thing
works to get around the censorship and
it's safe so we had a lot of folks uh
telling their friends to be able to do
that safely and uh a fun day in I think
October 1 of 2022 we were the number one
app in the app store in Iran and and we
were the number two app in the app store
in Iran for that
[Applause]
day now to be fair that was just one day
and uh and and things changed after that
and I'll tell you a little bit more
about uh how those things changed but
part of the reason why we were ready in
terms of the snowflake scalability was
you can see the the campaigns that we
did in 2022 to try to get more more
volunteers running snowflake uh and then
when that happened towards the in
October 2022 we were uh ready to grow
even further and at this point we have
uh 100,000 or more people running uh
volunteer snowflake uh Bridges as either
extensions in their browser or if you
have an actual computer that's not
behind a net that's much more useful
there's a go Standalone version of
snowflake uh please install it and run
it and help uh help be uh part of this
graph the Standalone ones are the green
ones down there that are the most
important and they are far fewer than
125,000 okay so that was the good news
here's the the more interesting uh the
the debugging side of things so at some
point uh around October 5 we notice hey
we're we're handling less snowflake
traffic than we were before uh what's
going on did they did they block us is
there a bug is there like a scaling
thing did something fall over uh so the
first fix was uh we went to go look at
the logs on on the snowflake server side
and it's giving us a bunch of too many
open files so we're like okay there's a
bug we fixed it sounds good uh but then
we fixed it and it didn't actually solve
the problem The Next Step was Well it
can't be Iran specific because uh we
lost 70% of our users in Iran but uh but
also we lost like 60% of our users in
the US so it must be something about the
snowflake infrastructure it can't be an
Iran specific block because we lost
users in a lot of different countries uh
and then we were thinking okay this
looks like a pretty steep drop like
something something specific happened
here it isn't just like an overload or a
a system isn't able to keep up with
things there's there's a particular like
10-minute period where all the bandwidth
fell off and then we were looking more
and we realized even before that
blocking event there's correlation
between number of users in Iran and
number of users in the US and number of
users in Germany and it's a goip issue
our goip database uh thinks that these
Iranian users are in the US and Germany
because goip databases are especially
bad for uh countries that aren't going
to buy televisions or do e-commerce and
so on so uh so the reality was yes it
was users in Iran that were falling off
but we spent a couple of days uh being
convinced that it couldn't be because uh
look it's happening to a lot of
countries so at that point we were
talking to people in Country and one of
them said uh I could connect from my PC
but not my Mac so there's something
going there's something going on there
and uh and that that that got got us
started on trying to figure it out so at
that point uh some nice person gave us
root on his uban Ubuntu computer in Iran
and we were testing things to browser
Linux Works to browser Android Works
Orbot Works Orbot doesn't work wait
what's going on here uh sometimes it
works sometimes it doesn't work uh and
the answer we finally figured out uh it
inside the uh TLS handshake decision for
snowflake doing domain fronting to talk
to the broker uh it looks at whether
you've got AES acceleration support and
if it does it uses a different set of
flags that are visible in the TLs
handshake and the reason why we we had
yes and and no was on the Ubunto
computer where we ran our Android
emulator it had a real CPU so it had AES
acceleration so it worked for us but on
an actual uh crappy Android system that
doesn't have uh a good kind of CPU it
ends up uh not having AES acceleration
and thus it looks different from the
outside so the reality uh if you had a
newer version of go it also worked but
if you had the old version of go and no
AES acceleration uh that's what got
blocked so that took us longer than it
should have to figure out uh but on the
the other hand wow that was a weird
choice for them to choose in terms of
deep packet inspection in terms of of
how to distinguish whether it was
snowflake or not that they were blocking
uh so the fix was uh there's a library
called utls for go that uh tries to make
your TLS connection look like a wide
variety of different uh types of
protocols so it knows how to look like
Chrome it knows how to look like Firefox
and so on so we integrated utls into
snowflake so that it could do domain
conf fronting to talk to the broker in a
way that really Blends in we put out a
new version of Orbot uh and then the
person replies I can confirm this works
in Iran so woohoo great we fixed it but
also it took us about a week to fix it
because we we had to get the Ubuntu
system and so on and during that week a
lot was happening in Iran that we were
not a part of so fast forward to that
that that was a problem that happened in
October
2022 a new problem happened in September
member 2023 just a few months ago uh and
it wasn't a censorship event but it was
just as bad so the domain front that we
picked we were using fastly uh we were
using uh uh part of Stack exchange as
our domain that's too big to fail that
domain switched from fastly to Cloud
flare and so all the snowflake users
were showing up at fastly being like I'm
talking to stack exchange can you let me
through and fast is like they're they're
not even here anymore what do you why
are you asking for that so so it was
because the domain we had picked uh
ended up not being where we thought it
was going to be we were unable to all of
those users were unable to connect to
the snowflake broker so at that point we
lost uh some number of users and um they
haven't come back yet so there's another
lesson to be had there so good news in
the sense that snowflake Works in Iran
OBS 4 Works in Iran there are tens of
thousands of people who are using it uh
but it's not it's not entirely good news
and one way to think about that is
thinking about usability in terms of how
this uh arms race Works uh in ter so
every time the sensor does something and
we fix something and they do something
and we fix something that's another step
that the users have to deal with they
have to understand how the system works
they have to say oh I need a bridge oh
snowflake doesn't work let me let me try
snowflake next week so every time we're
doing that we're adding a burden to the
user so yes uh we see a bunch of users
switching from direct relay connections
to using Bridges but it's not as many
users so each of these steps we lose uh
some people and that means that we need
to slow down the arms race not just keep
on taking steps and having it be a cat
and mouse
game okay so that was the Iran side uh
let's talk about the turkistan side and
uh uh and then the bigger picture so
these countries that I've been talking
about so far Russia and Iran they they
the censorship game that we're used to
it's the collateral damage game it's the
one where uh they're not going to block
all of Google because uh too many people
would get upset so they're not willing
to block certain things Turkmenistan on
the other hand blocks most IP addresses
they block uh hetner they block digital
ocean they block ovh they block uh uh
like Amazon Cloud they block most Cloud
things uh they block most destination
ports so like the the default stun
servers that snowflake uses like the
standard stun servers that everybody
uses to do video chat they don't work in
Turkmenistan they're blocked by
destination Port so they they're playing
a fundamentally different game we've
been doing a couple things to try to to
help anyway one of them is we found that
residential addresses tend not to be
blocked so if you set up an obs4 bridge
on port 8080 on a like Comcast or
something uh then tends to work so
that's a start but uh though that
community of people that we're working
with uh is big enough that they tell
some other people and eventually uh that
bridge gets noticed uh Meek works on
domain fronting works on Azure uh but it
doesn't scale but it's at least
something for the users right now U the
real challenge there so we we were
trying to like understand what's going
on in the country and as far as we can
tell the censorship Ministry has a
person there
who's pleased to accept payments for you
to have a real internet connection and
this means that their job is to make
things so shitty that if you can pay you
will and that's a that's not a technical
thing like that's not a thing where
they're going to do a DPI thing and I'm
going to change some protocol stuff
that's a fundamental corruption issue
where they're not only are they willing
to accept collateral damage but they
want it they want to to make things
terrible so that if you have the money
to pay the bribe you'll use it so that's
a that's not a technical problem that's
a policy problem I don't know what the
fix is do we ask the dictator in
Turkmenistan to assign a new person in
charge of the censorship Ministry who
will take bribes differently um we'll
we'll talk a bit about sanctions so
that's uh a start another example uh
that's similar in a not so technical not
so intentional censorship vein China is
getting harder and harder to use
circumvention tools not because they're
blocking the circumvention tools or the
vpns and so on it's because China is
building more and more bandwidth inside
the country compared to bandwidth
outside the country and that means that
if you're trying to talk outside the
country you end up with 20% packet loss
and that's that's just a normal thing
and it causes people to say well Google
can't run a good website buo is solid
and fast and easy and Google is I don't
know is just so flaky I just I don't
even try to use it anymore so that's
it's a it's a it's a form of censorship
but not in the way that we're used to
okay so let's talk about uh some of the
other uh things that have made me upset
or concerned uh while I was thinking
about the Russia Iran uh Turkmenistan
side of things one of them was uh rt.com
ended up censored in Europe I'll talk
more about that in a bit and that means
because a lot of the tour exit relays
are in Europe Europe you can't read
rt.com over tour either because you pop
out of some place in Germany or France
or something and it's blocked for you
there so that's that's kind of a a weird
surprising thing another weird
surprising thing here's a a heat map of
where in the world the snowfake
volunteers were in July 2022 so we see a
lot of them in the US woohoo we see a
lot of them in Germany thank you uh we
see a lot of them in Russia and Iran and
the what I think is happening there is
people in those countries here install
Snowflake and then you'll get around
censorship so then they go and install
the wrong component of snowflake they
become a snowflake volunteer it's not
helping them get around censorship uh
it's probably not helping other people
get around censorship because uh they
would have a tough time reaching the
rest of the tour network from them so
this is a a usability thing to think
about I think we partially fixed this by
changing the snowflake. Tour project.org
website to be very clear if if you're
censored do this if you want to be a
helpful person do this they are not the
same thing but this is uh one of the
lessons we learned along the way another
fun mystery here's a graph of the number
of people connecting into the tour
network uh during that week that Ukraine
was in the news what the heck is going
on uh maybe it's a goip issue and those
are actually people in Russia uh maybe
those are people uh following some
instructions on the internet to install
Torah and try to dos the Russian
websites um I don't know it's a lot of
it's a lot of torque
lines speaking of that uh one of the one
of the things that happened uh in the US
and Europe soon after the Russia
invasion of Ukraine is a lot of places
in the US are like I'm I'm the telephone
company but I'm going to turn off
connections to Russia that'll show them
we're going to sanction them uh and the
reality is uh Hing connectivity for such
uh for such situations uh ends up not
doing what you want so uh a brief aside
Iran had the same sort of situation so
Iran wants to build their own Halal
internet their own internal internet
where you don't have to go to Google
because we have uh an Iranian Google you
don't have to go to Facebook we have an
Iranian Facebook everything you need is
is inside and for a while there they
would block Google and people would get
upset and they would say you blocked
Google [ __ ] you and then Trump called up
Google and said hey could you like turn
off connectivity for all the people who
speak farsy and a bunch of uh Western
companies essentially blocked people
from Iran voluntarily and that changed
it to uh you blocked Google I don't like
you to well Google doesn't want me
anyway and the result of that is when
they next block Google nobody is upset
very much so we're going to see the same
thing in Russia where the Telos the like
the AT&T's and deuts telecoms and so on
like we're going to we're going to uh
turn off service for Russia and all
they're doing is helping Russia build
its own uh isolated internet out of this
okay so that was the beginning of the
sanctions
rant I ended up talking to a guy in uh
from Germany who was in Berlin helping
to write the the censorship uh document
that the EU requested so the EU ended up
asking all of the countries in the EU to
block rt.com Russia today.com and I
don't mind blocking television channels
sounds good but blocking internet
websites like I thought the people who
block things are the bad guys and the
people who allow freedom of speech are
the good guys uh what's going on here in
terms of uh of Europe being excited to
also Implement their own censorship
regime so I I've been trying to figure
out how to communicate this properly and
I was so I was talking to him and I'm
I'm like so why do you like censorship
so much and he's like no no no they're
sanctions and I'm thinking okay well
whatever word we're using like why why
why is it that you're so excited to be
rolling out the censorship and then I
was talking to somebody from uni from
the uh open Observatory of network
interference and he was saying yeah
Romania looked at this EU document and
said oh we're supposed to block all
misinformation websites so they built a
multi megabyte list of URLs that they
wanted to block and their reasoning was
EU asked us us to do this censorship so
that and it ended up blocking a like a
software update website and so on uh
that's not not what was supposed to
happen and then I was I was uh trying to
figure out more details and he's like no
no no don't don't worry it's a six-month
experiment and in six months we're going
to reassess whether we should maintain
the sanctions and I'm thinking okay so
you asked people to buy install
configure roll out censorship
infrastructure and what in 6 months
they're going to unroll it out that's
not how this works so I'd like your help
trying to figure out how to communicate
this to people uh why is the EU so
excited to make sure that all of your
countries here have censorship
infrastructure also and how do we
communicate that this is not it's not
sanctions it's censorship why do you
like to censor so
[Applause]
much
okay and as a last couple of thoughts uh
one of the one of the weird things about
the Russia story our story started in
December the news started talking about
Russia invading Ukraine in like February
so there were months in between where
Russia knew they were doing it we knew
something weird was going on so looking
at censorship of tour from a Global
Perspective uh is an an interesting way
to to try to figure out what going on in
the world and what's going to be
happening later so uh some things that
you can do to help please run Bridges
OBS 4 Bridges snowflakes public relays
the eff is running a campaign right now
to get relays in universities in
particular so I would love to talk to
you afterwards if you're connected to a
university uh it doesn't have to be an
exit relay whatever you can do uh one
big policy question why I'm in the
ethics track is how do we deal with
situations like Turkmenistan where it's
not a cat Mouse technical game it's a
like a nation state level corruption
game and there's uh uh research there's
a conference in Bristol this coming July
the called pets or folky uh on
censorship and anonymity um and also
tomorrow day three we have three
different tour meetups the first one is
a general Meetup I think there will be
two people who are doing uh little
lectures on cool stuff they've been
doing in tour and we'll be around to
talk to you and answer questions uh
after that there's a Relay operator
Meetup in the room next door so if you
uh if you run a relay or you ran a relay
or you want to run a relay or you don't
yet know you want to run a relay we want
to talk to you and uh and help answer
whatever your questions are and show you
that there's a community uh and then
after that the folks who run the tour
servers.net relay Association uh want to
talk to other relay associations and
people who want to help uh the German
community rebuild their uh zel Funda and
and other groups like that um we would
love to chat with you and uh and that's
the end of my way too many slides and I
still have some time for questions so
thank
you and we see already two people
knowing how it works with the
microphones you queue up behind the
microphones and then I call out the
microphone number
and you can also ask questions via the
Internet so while people are moving
around to queue up behind the
microphones we will have the question
from the internet first yeah thank you
uh first question from the internet are
you aware of any legal actions or
Violence Against tour users in Russia
Iran
turkistan and can these users maybe get
fingerprinted yeah so in General most
people seem to be successfully using
tour in these countries and they're
doing fine like the US and Germany there
are too many laws in these countries and
some of them are vague a lot of the
countries have laws but they don't use
them but they could use them so it it's
hard to to feel confident about that
there were some cases in Russia where uh
some people ran tour relays and they
ended up attracting attention and uh and
it worked out for them in the end but it
took a while of of legal fighting but in
General using tools like tour or vpns uh
everybody's doing it and the fact that
everybody's doing it is part of the
safety of being able to do it so we'll
see over the next year or two as Russia
tries to crack down on vpn's even more
are they going to make it even weirder
to be the sort of person who wants a an
actually free internet I'm not sure but
but for now everybody's doing it which
is which is why maybe it's okay and we
have lots of questions so keep them
short and no comments and no follow-up
questions microphone number two please
hi um do you know if that sudden spike
in Iran has something to do with like a
failure of another way to circumvent
censorship CU a lot of people used to
use siphon
there uh so you're wondering if the
spike in users in Iran is because some
other circumvention tool failed and they
all switch I think there are enough
people in Iran trying to use the
internet that there's enough to go
around on all cases I it is the case
that there are other circum vention
tools and some of them did get blocked
right about then uh but I think it was
more there are a lot of people and
mostly they don't do this and when they
need to they do whatever they did last
time and some of them did siphon last
time some of them did tour last time and
now a lot of people know about snowflake
which means the next time something
happens a lot of them are going to turn
to Snowflake and then we have a question
from microphone number one uh you had uh
commented that a h on on the whole new
user group do you have an additional
explanation except for installing the
wrong plug-in side of things yeah well I
talked to somebody from Ukraine who was
convinced that uh that these are that
people in Russia are reasonable and a
lot of Russia isn't blocked their isps
don't choose to follow the censorship
requests so it could be that there are
many people in Russia who said this is
important I want to help my fellow
people uh the ones who are on the back
kind of networks I need to help them get
around censorship so it's so nothing
from the state there or something like
that trying to try stuff I guess yep
hard to know and then we're going to
hear what the internet wants to
know yeah second question from the
internet uh specific to one of your
slides on the graphs regarding to the
number of slow snake Snowflake and obf
as two users what happened exactly in
the beginning of
2023 yeah um so when we were fixing some
so so the the question is uh the
snowflake users were going up everything
was going great and then at the
beginning of 2023 the snowflake users in
Russia disappeared and then they came
back a while later and at the end of
2022 with the Iran thing we were trying
to fix even more scaling issues because
we were uh the snowflake bridges are
handling many gigabits per second of
traffic and we had so much traffic that
we were trying to figure out ways to
scale better and we accidentally added a
bug that made it scale worse and uh and
we noticed it after a couple of weeks
and fixed it but that was the result uh
but as a result there were users who who
used something else for that and then we
have a question from microphone number
three yes I have the question um there
was a journalist called Yasha Lin and he
was criticizing you and how do you feel
about that like concerning Government
funding like always erors possible the
like useful idiots thing like with the
opposition on Hong Kong overly relying
on technology also I think he suggested
that you have had an internship at the
NSA
um and also um some Security
Professionals suggest that you shouldn't
use tour browser you should use like
tour plus plus Chrome how do you feel
about that oo and that that the third
one is
easy um so let me try to answer all of
them in brief uh we as an organization
are transparent we do get funding from
governments we've got funding from the
US government the Swedish government for
a little while we had funding from the
German foreign Ministry uh all of that
you can find in the tour financials
which we publish each here so part of
the goal of that is to be transparent
about where not just where the money
comes from but what we do with it to say
say these are the projects that we have
these are the outputs and to do all of
that in public so that it isn't a
question of of why did they want to to
give us money this is a complicated uh
topic that I can't answer in just 20
seconds uh but the answer to all of that
is transparency for the third one don't
use tour browser use your hacked
together tour Plus Chrome uh that is a
terrible terrible idea because of all
the fixes inside tour browser at the
application layer so afterwards I would
be happy to tell you a bunch of uh we
would call them zero days using tour and
chrome but they're not zero days they're
like 10 years where everybody has known
about them uh and they're they're
basically Pro proxy bypass issues where
if you use Tor and chrome you'll end up
sending traffic out directly on your
local network bypassing the tour proxy
because chrome doesn't care so that's
that's the very short version of that
and then we have question from
microphone number two hi uh great talk
uh I have a question have any of these
countries tried sabotaging uh tour from
the inside for example running dogy
relays or overloading in with danial
service yes um running Dody relays from
Russia and Iran and so on we have not
seen as far as we know there is a
strange arms race going on at the edges
where uh some somebody somewhere is
trying to run some bad relays in terms
of denial of service who boy that's been
a big topic over the past few years
because as far as we can tell there are
Russian underground Mobsters uh trying
to sell drugs or whatever on the
internet and there are other Russian
underground Mobsters also trying to do
it and they're beating on each other and
the collateral damage is the tour
Network so we've seen a bunch of Dos
issues but I think they're unrelated to
the government level policy thing that
we're seeing here I think they're more
related to people who are being
sanctioned to the point that they want
to make US Dollars somehow and this is
that's how they've picked then we have a
question from microphone number four um
thank you for the great talk um this may
be an off-topic question but since you
work on privacy which messenger would
you recommend to use which messenger
would I recommend to use the answer used
to be Ricochet back in the day when
there was Ricochet development um I use
signal for a bunch of things because a
lot of people use signal for a bunch of
things so that's a pretty good answer
and we know the signal people we talked
earlier about the importance of
transparency and community so uh that
depends on the person and what they're
trying to do but use the ones that your
friends want to talk to you on is is not
a bad first start as long as it's and
encrypted yeah use the safe one that
your friends want to talk to you on
thank you the internet has a question
yes the internet would like to know um
do you plan to support some sort of
Transport via DNS for example if
everything else than DNS is blocked yes
there is a pluggable transport people
are working on called
dnst uh it's a it's a pluggable
transport that makes DNS requests and
tunnels your uh your signal traffic or
your tour traffic uh as though it looks
like DNS and one of the cool outcomes of
that is uh maybe we can all use tour
uh on our trains or airplanes or
something where DNS works but other
things don't uh so there yes that's
that's something that's under
development uh and as things like OBS 4
and snowflake stop being the right
answer then things like dnst might start
being the right answer and then we have
a question from microphone number one um
so do you have any proposals when it
comes to uh circumventing like this exit
Noe uh censorship because I guess that
like when it comes to exit notes most of
them like um runs in AU or us or
something and is what we see now in the
case of au that if they try to
collectively just want to ban things is
there a kind of a yeah so that's that's
a tough one uh I've been talking here
about censorship of people trying to
reach the tour network but what you're
talking about is censorship of people
trying to use tour to reach websites and
the websites don't want to hear from
tour users or there's something in
between that's that's making it hard to
do and at the beginning we said oh well
let's just not let relays be exits in
countries that have too much censorship
uh and that that line gets blurry very
quickly maybe you end up with all of
your network in Iceland or something uh
that probably doesn't scale one there
have been people working on exit Bridges
so it's a it's a it's a bunch of proxy
addresses that you can use to be able to
reach websites without them knowing
knowing that it's tour uh there's a
campaign that we've been hoping to start
sometime to go talk to Cloud flare and
aami and all the the big CDN to teach
them why privacy is important uh there
was a study that aami did years ago
where they looked at all the people
connecting over tour to macy's.com like
the place where you buy clothing and
they found that the uh the average
connection was more likely to be
malicious because there are people doing
spam attacks or something but the chance
that they would buy something was the
same over tour as not over tour so
actually those are real users that maybe
you want to have and that was
interesting for aami to say so I think
there's there's something to be done
there but we need to that's like a 10
person for five-year campaign to to make
relationships and uh educational
materials and so on uh so yeah that's a
hard problem and a a one that is growing
in importance thank good and we have
more questions than we have minutes left
so microphone number two uh during the
IR part you promoted the running of
snowflake service on computers that are
not behind Nat under which conditions
should one run a snowflake server and
when should one run should one run an OB
an Ops 4 Bridge uh for instance on a
non-residential IP
address OBS 4 bridges are easier to run
technically because uh they're in Debian
and you you edit text files and they
work pretty well uh but if you're
comfortable like compiling snowflake
from go or you're comfortable running a
Docker image for snowflake uh snowflakes
tend to use more bandwidth than OBS 4
Bridges uh because they'll scale up to
as much as you can uh for OBS 4 you need
to be reachable from the outside so you
need to do like TCP port forwarding for
a snowflake it's best if you like
forward entire blocks of UDP ports so
that web RTC can work uh behind whatever
firewall you have so they're both useful
do whichever you like uh don't do both
of them on one IP address because then
whichever one is weaker gets you blocked
and then we have question for microphone
number
three um why wouldn't a proliferation of
snowflake bridges in uh Russia and Iran
um indicate enumeration of snowflake
users
H so you're saying maybe the sensors
want to learn who the user are and so
they're signing up snowflakes in their
country in order and because they're in
the country they're probably run by the
government so the the flaw in the logic
is that it's easier to get something on
hetner than it is to run something
inside Iran even if you're the Iranian
government so that that if I were Iran
and I wanted to do that I'd run a bunch
of snowflakes elsewhere uh and the other
the the other answer to the question of
uh how bad would that be is that bad uh
the goal of Torah is to prevent the the
adversary from learning that this user
went to that destination just learning
that they're trying to use snowflake
goes back to the earlier question we
were talking about of uh this is an
ordinary thing to do the fact that the
average user in Iran is using tour to
reach Facebook to look at their cat
pictures is a security property it needs
to be ordinary that you're using tour or
you're right things go bad we only have
time for one more question and that will
be from the that thank you um if we look
back into the year
2013 uh when the Snowden topic came up
tour played a very important role and
the NSA thought literally that tour
stinks um do you have any indication
that it still just stinks or whether or
not the NSA is taking active counter
measures against T yeah this is a great
question and uh and the real answer is
that we need a new Ed every week or two
coming out with a new set of documents
for uh what they've been up to lately in
terms of what they learned and even back
then uh the documents that we got Ed
tried to bring as much as he could about
Tor out the documents that we saw showed
the NSA didn't know what they were doing
but that doesn't mean there's not an
analyst down the hall that did know what
they were doing and didn't get their
documents leaked so it's hard to know
what to conclude here uh I've talked to
people in the n say who say that they
use and rely on tour and it's got the
right design and uh and it's hard for
them to break that doesn't mean that
much either um in terms of uh what we
should be worried about in the future
one of the things we're worried about is
uh netf flow based traffic analysis
where a growing number of countries and
companies are uh collecting logs of uh
when you're connected for how long how
many bites got sent and uh and a growing
data retention Trend around the world uh
makes me nervous because maybe you have
a data set here and you call up the
Spanish Telco and they have a
corresponding data set over here and hey
maybe these do match up uh so I I would
worry about that but uh if you want to
help on the traffic analysis research
side we'd love to have your help and
pets coming up in July is the right
place for that good give Roger a big
round of applause thank
[Applause]
you
[Music]
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