[Applause]
thanks was taking around my name is an
easy I'm one of the co-founders at
argent and today actually I would not be
speaking about our agenda will be
speaking about hopper which is an
open-source privacy research that we did
develop early actually this most of this
work was done by believe and big enough
community this is going to be
today I'm going to blow my face
so that should be better so I was saying
we're going to be speaking about Arjun
but about copper which is what was most
innovative and irregular proteins of the
credit goes to him and if you have any
deep technical question you should also
ask em to it on Twitter so I just said
I'm going to be speaking about logic but
I think there is some value in briefly
describing what logic is because it
gives some context of why we started
working on the privacy it sir
so Arjun is the smart contract base what
else we a lot of cool features we have
seen this recovery you can block for the
transaction you can freeze your account
there's no obstruction of gas or the
transaction fees and we used as an ESS
all so so basically what we try to do is
abstract most of the complexity of the
blockchain and enable an experience
similar to once again on the best mobile
banking application today but in a fully
no mr. Devaney and the vision for that
is that we wanna enable actually people
which are outside
to access the blockchain and so just it
is not to build our you financial system
for people that actually I'm not really
tech savvy there's some kind of
expectation of what that system or the
feature that that system should provide
for example people assume that if you
transact that doesn't give the person
who transacting with access to your
theory for example I mean future Runge's
making a transaction to my insurer I
mean not P okay for my church that I
just visited an oncologist two weeks ago
this kind of information should not be
disclosed that should be private of
course a material which is a public
nature with full transparency you donate
these properties this also economical
argument for privacy is the fact that
you money or token to be fungible if I
send you one eater you want that eater
to be worth one either now if you know
where that either comes from actually
you will believe that it has this value
because it can be tainted for example it
comes from an exchanging act that token
may be worse miss they're actually one
either
so these properties are very important
so if you want to be inspirational you
can say that privacy is necessary for an
open society in the electronic age if
you're a bit more pragmatic we actually
allow users saying that they were not
they were feeling uncomfortable by
thinking about the one end of which they
had a lot of funds with their hard to
buy and actually this is seven quote is
really the use as we try to solve so we
really ask a question can we actually
invest
I use case a user wants to find his
heart and wallet which has no fun and
send it from our wallet and can we do
that search tab and two addresses are
between the process is pulling on this
video it is mobile friendly and actually
this point has driven developed chosen
to design Locker and of course it has to
be economically viable in terms of gas
if you transfer one either but you click
on find either in class to make that
transaction happen this is not practical
fortunately there are solution to
address that use case and as you
probably all know ZJ snarks can be quite
useful for that we didn't start from
scratch so we should also give some
credit to the team of very white line in
which a that was a little bit earlier
that done a great work and it's not miss
amiss and now semaphore and so which
what basically we we're trying to extend
what they are at dump it on top of what
they're done but really customize it and
make it practical for our target new
skills so others upper or be serious
words it's that basically if I want to
send an aunt to someone I will a secret
which is a leaf in a vertical three and
the person that wants to reach for that
town needs to prove that it knows the
secret behind one of the count and then
this common hasn't been spent yet so the
principle is is quite simple
in practice always water work because we
do have an iOS application that you guys
should try which is in alpha now but it
exists it's a good way to see what it
does
so basically the client using the the
opera application will generate the
leaves so we just do a char 250c of a
secret and the destination reference
using your hardware model to make a
deposit to the mixer contract and you
attach as a family
of course other people will do the same
and each transfer is of identical value
as you will see this is critical and I'm
reserved basically in a sea of identical
transfer of course the motivate the more
people will deposit either of the mixer
contract and the more you'll need et set
increases I put in a stir it's because
it is not as simple as that but it
provides me the intuition are we getting
finally after a certain time the person
wants to be true the comment again using
the Opera can tell the mixer to send the
fun to the destination and you do that
by sending a a proof the mixer comes
back you verify the proof and if the
proof is correct we'll send this one to
the destination address for example that
might be that sequence complete transfer
and correct you received one eternal
quality so this one when the user
experience is actually quite simple know
what is in working practice so not good
it because the CGA smart framework for
mixers but basically you want to prove
that you know secret
three Weatherly to the sha-256 of the
secret in a destination address you
wanna prove that that common hasn't been
spent it so actually you can translate
that automatic mathematical equation and
that will give you circuits so in your
case these are the the set of equations
that we want to solve this is the secret
inputs that we want to prove we know we
don't be reading them and of course
there is some public inputs so using
this you can actually build your circle
and have your verify your approver using
a library such as that in terms of small
contractor small contracts is quite
simple at first example is API we have
two main method commits when you deposit
your funds and you attach your leaf as
data at individual function where you
specify the cubic input data so the
destination only fire which proves that
there's no double span and then you're
the proof that you are constructed using
the Zika slug framework so that's kind
of the general framework as I mentioned
we are similar to all the mixers but
it's all about the choices that you make
for implementation so in the case of
hopper we use Minzy for the Asha
function of the work of three which
stands for minimal multiplicative
complexity the intuition for that is
that in the Zeke is knox remark you get
your equation you translate that into a
circle with addition and
yes and actually the number of
constraints that you will health depends
of the reputation is that you have so if
you actually function with minimum
multiplicative complexities that means
less constraint that means generating
approve will be easier of chain and that
means that it is more mobile-friendly so
we've made that choice so that you could
actually generate the proof of a mobile
within five six seconds of course
there's a few drawbacks of using MCs
I've always in engineering is a question
of compromises if you mean C's there are
more expensive but um because there is
no pre-compile to exceed as we will see
there is an NP for that but that's all
for now maybe see some changes quite
expensive so actually when you deposit a
leave you need to update your worker 3
and that requires gas and also in see
them invested and if you are a is
presentation this morning that I landed
that eternal Foundation is funding
research on MCS for specific events so
to mitigate the risk associated with
disease we are actually using Shan 256
for the leaf of the tree we're not going
to the cryptography behind it but the
intuition is that even it means he turns
out to be non primitive resistant it
will still as privacy assuming that
means he of one half of the the inputs
is pretty much resistance the problem is
that using sha-256
means more secret constraint and so
again we've increased the generation of
the proof
so as an Israeli in our in our use case
we want people being able to transfer
one deed from Hardware wallet to a
larger one it that has not been funded
yet so that comes the question is called
as the person we joined the money will
pay there's no heat they cannot pay for
the gas and so again it is to use the
layers and so in our case we have deploy
along B layer there's work been done by
the simapro team of the gas network
station to actually use a network of
layers and yet if then the relay will be
made that we drove transaction on your
behalf
and we will be repaid the gas that used
by taking a small cut on the deposit as
we discussed on the panel there is
somebody to tell me there's some risk as
using layers because of course you're
using a centralized may not be
centralized but using system we love it
yes we're making Lydia cause that means
that people can use your ID address to
kind of reduce your anonymity so there's
no consideration to to take into that in
one possible solution is to have a
really a market with victim talk another
important question with mixer is one to
betray your funds because of course if
you deposit your funds that you return
immediately then it completely break
their anonymity if you deposit your
funds but you always return em up to 24
hours it's the same people naturally
tend to to a pattern and so this is
something that needs to be mitigated by
actually the UX of building mixer all do
you incentivize users to actually behave
correctly or in a smart way the problem
is that yeah whatever anonymity you use
for example in our we just illustrate
the number of other lives that I've been
deposit since we deposited so that can
be represented unanimity said but again
this is not
admittedly because say there is any 17
maybe 16 our other deposit they come
from the same person which is actually
trying to target so it's been tricky to
to find from the privacy matrix and so
the next person of opera yet is to
basically only enable you to betray your
fans after a certain time so that all
usually positive depositing within what
they will be incentivized to be true
more or less at the same time so again
you you cannot increase energy so I
mentioned that will enable transfer of
1e again this makes sense we let people
deposit point 77 either for example and
then someone will close point 77 this is
a good probability that these two people
are actually connected again you've
recreated a thing that we try to break
so yeah it is to fix the amount that
people can deposit so they become
indistinguishable now the one
improvement that we can do because of
course if there is only the positive one
it is quite kind of limiting so again is
that it would make the contract for 1e
contract attendee contract for unworthy
but the promise that you split your
enemy tea set and again this is no
ability there are a solution and this is
something that we work a new future or
that you want people to work on is the
possibility to use jumps encircled
so basically yet is that you always
deposit multiple of one key and then one
you want to be true you can actually
combine two these into one and so you
can for example we grow 100 100 without
breaking it
another limitation of upper is that this
body around 32,000 leaf per contract and
the reason is that you have an Oracle 3
and the more then you want to America 3
the more expensive it is in terms of gas
and seen you wanted to keep this and
there are billions of the deposit
individuals it's kind of leaving the
number of level that you can aid in
America 3 and so the number at the level
of us believe that you can deposit so we
have fixed a 15 which is the gasser on a
medium the problem is that once you fill
up your 3 to deploy new culture
so I'm talking about some of the
limitations or upper fortunately there's
a lot of areas for improvement
one is a lot optimization so you could
attach the public input into one which
would reduce the number of cars raining
you can optimize the contract for the
moment the contract is in plain solidity
there's some step that will be written
in assembly that would reduce
consumption by fifteen to twenty percent
and again that enables you to increase
the depth of your three and so the the
possible deposit that can be of a single
contract and there is work on you VIP
1108 well yes d which is a pre compiled
form in c so that we really reduce the
gas computing it sees that means
updating the Merkel three women shippers
again we can use a much bigger tree
another functional improvement that is
part of the next iteration offer is to
store a buffer of the reason mercury
moves because now when you want when you
want to create your your proof you need
to have a miracle tab to delete that one
the problem is that by the time you
completely approve that we take five six
seconds and then you submit your
transaction to the blockchain
yeah admitted fifteen thirty or one
minute to be mine it is possible that
someone deposits a new leaf in between
which will update you three and
absolutely or broken path is no longer
valid so by keeping the mystery of three
four five work routes actually you can
improve the number of people that will
succeed
as I mentioned the klo pistol Patrol
using just bleep and then we can work on
a clear market so that's it that was
kind of brief but I you guys enjoy if
you want if you interested by upper you
can check us on kita the project is
fully open source and the idea for us is
be the tool for the communities and this
is not to be other projects or feel free
to contribute if you have question you
can think us on Twitter or telegram and
if you interested by arthritic and on
wallet right now let's keep the waiting
list using the link that is there I
don't know if you guys have any
questions
how much gas does it cost so we blew it
into other millions for millions of the
positive lol
yes expertly to make the proof that we
combine to Merkel Eve into one so say I
believe a secret College has won either
another one that that's one eater I do
John Smith and suddenly everybody's
perfect so either and once that is done
and so if I meet will be tuned
interested in the end I can actually
flow different because it's a different
amount
yes different circle but again you came
from line the Jung's beat with the rope
so that actually in his basement
you can Janice see like that but we need
your needs to belabor customers because
we still need to know the secret be a
nice town so it's more like a transfer
with someone else unless you will
transfer in the second period is more to
the yellow to Charles
[Applause]