so yeah I'm Liz Steinem gir with least
authority I'm going to talk today about
something that we're calling p4 because
we like to play with numbers and letters
and the P the four p's are private
periodic payment protocol and so yeah
just gonna tell you guys about what our
work is with this and why we're doing it
so like I said I'm Liz Steinem girl from
least authority we believe that people
have a right to privacy our mission is
to make security easy to use and
available to everyone we help others to
improve their technologies to be more
secure through security audits of things
like distributed ledger technologies
blockchain projects and related
cryptographic efforts we also build
technical solutions that incorporate
these values using things like privacy
by design empowering users to control
their own data and also minimizing the
access that service providers have to
the user data or personal data data
minimization we also like to participate
with other communities and work together
on particular efforts to these goals -
I'm sorry I just realized my whole slide
is not showing technical problems there
we go okay so we operate a
subscription-based service that's secure
distributed storage product and we call
it s4 again we like our letters and
numbers and s4 stands for simple secure
storage service and it's built using
open source technology and enables
client-side encryption so that the users
can hold the keys to their data not us
one of the projects that it uses that
you'd eliza's is called Tahoe laughs la
FS which stands for at least Authority
file store and Tahoe laughs and our s4
service doesn't operate on access
control lists or ACL or user accounts
but instead works using object
capability model oh cap or key based
access
this is similar to how cryptocurrency
works in a high level it's similar in
the sense that if you have the private
key you have access to the crypto to the
cryptocurrency
and there's no user lists no centralized
party that is kept that's saying that
this particular cryptocurrency belongs
to you personally so we don't have any
personal account information with our
system about this so we don't have any
personal account information about the
ciphertext that we're storing and you
either have the capability to access it
the key or you don't so this brings us
to our problem and why we started this
effort to begin with we have to use fiat
currency with this so anyway so with our
secure storage product we need to
collect these subscription payments this
is our business model with it and in so
however in the world of fiat currency
and online tools this results in us
collecting personal data by using by
using things like stripe and charge B
and we are collecting this personal data
only for the purpose of processing
payments not for operating the service
itself so right now we use stripe and
charge B and only collect this personal
data and not for any account management
because of the o cap model so we didn't
like this so we started talking amongst
ourselves about how we could potentially
use cryptocurrency to help us avoid
using these centralized systems that are
collecting personal data this came about
from discussions about GDP our
compliance which is the general data
protection regulation it's in the EU
about how personal data should be
managed and so amongst ourselves we
figured out that this was a problem and
so we thought okay what could we do with
cryptocurrency so we started looking
around and how we could accept private
payments for the subscription service
and that would also allow us to do and
and privacy for people just like we are
able to offer them end to end encryption
and privacy with the data storage
service itself and so of course this is
a problem
now it's expensive to make things
private and cheap to make them public
unfortunately this seems to be the case
right now and we're trying to work on
making this not the case an expensive is
relative and I think that this issue
could be easily challenged with new
technology so here are the layers of
privacy that we're considering when we
won't say that we want to do something
that's end and private for the user we
need to preserve this customers privacy
at all these levels and these are the
different layers and systems that we
need to have interacting with about
whether or not there's any personal data
that would be leaked or any metadata
that could be correlated with other data
to become personal data the same way
that the same way that like things like
Bitcoin and aetherium the addresses
could be you you know looked at
correlated with other data in order to
figure out people so that figure out
personal identities so that are not true
anonymity but pseudonym anonymity so
starting from the bottom and moving to
the top we decided to use tor for
network layer privacy because it exists
right now and it's usable some of our
team members contribute to the Tor
project which is an anonymity network
that allows users to not reveal personal
data on the network and this protects
against leaking any IP address
information which can be considered
personal data and then Tahoe laughs is
the technology as I mentioned before
that we use with s4 and this offers
storage laver layer privacy with
client-side encryption and lastly we
also use or not not Leslie sorry and
then we have Z cache I think I I missed
that sorry going up I skipped over Z
cache see cache I'll talk more about it
in the next slide but Z cache sue
shielded transactions help us with
financial privacy and then Tahoe laughs
again helps us with the storage layer
privacy and then going at the top we
have the client application which is
grid sync that we're using for ours but
this also applies to the Z cash wallets
and this gives users control over their
payments and all of this is combined
what we need to give us and and privacy
for our subscription customers and why
we particularly like doing it this way
is because these all these things exist
right now and we can put them together
to have this implemented in a short
amount of time so about cryptocurrency
payments cryptocurrencies have some
technical features that could be
utilized including some privacy features
one blockchain that we are familiar with
is the cache our company's share
founders and although there are two
separate companies now so we should also
share mission for privacy for everyone
so we looked at how we could use utilize
D caches privacy features to help us
preserve privacy in our processing of
customer payments and of course Z cache
offers two types of payments one that
our trend transparents transparent
transactions and that which are is more
like Bitcoin and then also the shielded
transactions which utilize a particular
type of zero knowledge proof called ZK
snarks and so this assures so for
subscriptions we need to establish a
relationship between the customer and
the merchant to facilitate payments that
repeat at specific intervals so we went
on to look at subscriptions with
cryptocurrency so when we researched
what was out there and the standards for
doing subscription payments with crypto
currencies what we found was a bit
limiting and didn't quite meet our needs
especially in the case of end-to-end
privacy one current use of ZK shielded
transactions is to have people prepay
for their subscriptions this this works
okay this is not ideal for subscriptions
but this does work for some service
offerings where you can turn off the
service when a payment lapses and then
turn it back on later after new payment
and like for example electricity
payments however in our case because
people are uploading data to be stored
on our storage service this is not an
ideal user experience because if they
stop their server because of the need to
re-upload that data every single time
and so amongst other downsides to this
approach - and then another option is to
do post paid subscriptions but this is
also not ideal and it may
renewal or payment periodicity a
challenge and of course you can use
smart contracts for managing some
aspects of subscriptions but this and
this is an option with aetherium and
other platforms but it doesn't really
offer much in terms of privacy at the
moment and you can't do those on the Z
cash blockchain at the moment and I hope
to see both of those things change soon
too so this meant what this meant is
that we need to do some work on defied
and defining how to preserve privacy
while still establishing the necessary
relationship for these reoccurring
cryptocurrency payments for a
subscription so this is what we came up
with for p4 on the left side there's a
list of basic tasks that we could that
we need to have completed by a
subscription and on the right side you
can see the various pieces that the
various layers the pieces that I
mentioned earlier and they're part in
these different steps and then this is
all done over the Tor network so in the
first step we have the subscription
initiation the customer visits a web
page and completes the subscription
request now because we're not caring for
much personal data this is probably just
a button actually right now it is just a
button we don't have any fields or a
form for them to fill out because we
don't want any more data we just want to
know that they want to do this and so
and then the second step is subscription
creation and invitation and byte code so
we the merchant create Z cash address
and the and an initial database entry to
link the subscription ID to the Z cash
address we generate a special invite
code for the subscription that includes
configuration details to access our
storage servers the capability that I
mentioned before and it also includes
the initial invoice for the service and
in that invoice is a signature so that
they can also verify us in the future
and then the third step is client side
subscription configuration the customers
client a desktop application in our case
grid sync that I mentioned earlier
securely connects to us receives and
receives the invite code and then gets
configured for both managing the data
they will store on our service and also
the invoices they will receive for it
and the fourth step is
payment and server update next the
customer has to actually send their
first payment for the service for the
service per the invoice that they just
received and they need to do this
payment via a Z cash wallet that payment
is processed on the Z cash blockchain
and we consider it a confirmed after a
certain number of blocks are written
that might not take too long maybe about
an hour I think right now we're thinking
about 24 blocks and then this triggers
the publishing of the next invoice so
the fifth step then is the recurring
invoice and payment process from this
point the client monitors the next for
the next invoice displays it to the
customer and continues to do this loop
after subsequent payments are made and
within when they go checked on the
invoice there's we are also utilizing
payment codes to be able to like to
communicate to them the status of the
payment and then also Cigna they can
also verify the signature with each of
these and then if they stop paying then
their service is stopped so privacy is
maintained by pushing many of the
subscription management activities to
the users device into their client
client so client side instead of
gathering the data in a central
repository by a service like stripe or
the equivalent of stripe and this
decentralization of subscription data
along with the Z cache shielded
transactions and use of the Tor network
allow us to not gather personal
information about customers or any
metadata that could be correlated for
suggestions on who the user is so we'll
go into more details this is the invoice
so as for data standards again we looked
around at things that are existing right
now and we didn't see any kind of common
language or agreed-upon protocol for
expressing notions like billing period
due date grace period and late penalties
so we designed a simple invoice
structure to allow us to communicate
this information on the right you see a
basic list of data that we need to have
in our invoices which could be expanded
to include more data for additional
features in the future and on the left
this is what the string of the invoice
data actually looks like in this example
a customer is being asked
point1 Zack by a particular date here
September 4th for the service least
authority s for if the payment is made
by a given deadline then the
subscription will be extended for a
month 2.5 million seconds until October
4th 2018 and I think in the future we
need to include things like you know
trial periods refunds things like that
could be also included in this but this
was just basically the the short list of
data that we need to just process an
invoice for the subscription so yeah to
start to talk about next steps and where
we're at right now
so we're wrapping up the edits to our
paper about this work and the privacy
considerations that we've made in the
designing of it we think that by also
sharing you know these privacy
considerations not just the technical
specifications of what we're doing that
we can help people understand more about
how to do privacy by design or just at
least explain how we're trying to do it
and we'll be publishing that paper soon
and we've already started implementing
this for our s4 service we hope to have
this we hope to have this available to
pay I mean to use ZK shouldered
transactions to pay for our service
subscription sometime in a few weeks and
this includes making updates to our
desktop client grid sync and also yeah
just making sure that the you know
setting up this also includes setting up
a separate tour website for people to
visit and things like that because we
need to force people even from the time
that they're interested they're browsing
trying to figure out if they want to
subscribe to our service to start to use
tor so that we don't get that IP address
that we can correlate later yeah so also
the sapling upgrade to Z cache just
recently happened and that how it helps
for faster to make a Z cache faster
especially as shielded transactions and
then we hope to get lots of feedback
from various communities especially this
community on to help us iterate and
improve this we would like to coordinate
efforts with other people who are
working in the area of subscription
subscription services and management
within with cryptocurrency and all
so people who care about privacy
payments and stuff like that
so for example and then we were also
thinking about all kinds of great things
that we could do in the future with this
for example we could implement a more
robust communication channel for
subscription management via the
encrypted memo field and Z cash
transactions or data can be passed like
where that invoice data could be passed
back and forth as a in-band
communication channel we're also looking
at expanding on features within Tahoe
laughs to create a communication channel
there too and seeing if that would that
would help and looking at improvements
too or integrations with customer
wallets to support this type of
invoicing data and also the advanced
features of things like trial periods
refunds and stuff like that and we'd
like to see the development of merchants
facing payment frameworks to support
subscriptions and management of those
subscriptions for companies that want to
utilize cryptocurrency payments and
lastly we just hope that this inspires
other subscription services to use
cryptocurrency in a privacy-preserving
way while experimenting with tech we
understand that maybe privacy can be
like an afterthought when you're doing
experimentation but if we do want to see
this because that in order for this to
become mass adoption
especially for cryptocurrency for
subscription payments I think that there
needs to be some privacy in those
payments otherwise the world can see
everything that you're subscribing to
and that's not so cool other and also
even if it's not so obvious what that
data is if it's just like metadata or
something with big data analytic capable
it of capable capabilities that are out
there right now people could start to
easily correlate that data to other data
that's out there and figure out more
about you too so any current
pseudonymity pseudo anonymity that we
have right now will be quickly lost and
a major factor in decentralization is
removing such power from big
corporations Central's central
organizations and giving it to us as
individuals to manage our subscriptions
ourselves so usability will be very key
in this too so I look
forward to hearing from people about
these efforts and how we can move
forward thank you
thanks yeah we have about four minutes
for questions does anyone have any hi is
there any anything that's in that's
stored in the data that allows me to if
I was a user to get any kind of proof
that says my data is being stored and
and is retrievable if I'm subscribed to
a service like this yeah so in Tahoe
laughs if there's proof of storage I
don't think so right now I think that
there's yeah there's maybe some other
ways to do it but not not in the sense
that there yeah
not in the sense of the other projects
that have that right now which I'm sorry
Oh merchant networks so we're the
merchants right now in this case in this
use case where the merchants and this is
just how we're going to handle it as a
merchant in terms of integrating with
other merchant networks that would be
something that we could talk about is
like a future possibility and you mean
other companies other merchants like
Netflix or something like that thank you
like any of this subscription providers
have they shown interest into using this
kind of like anonymous payments into
their service well yeah so other so
other companies have said that they want
to do subscription payments with
cryptocurrency so like I said you could
do right now subscription payments right
now we're kind of difficult there's some
workarounds that we have but we need to
make those easier to use for
cryptocurrency in general and then when
it comes to the angle of privacy I think
that well it might be okay to not be so
worried about the personal data that's
being leaked in the experimental phase
in the short term that if we want to see
in the long term if we want to see mass
adoption I think we need to have some
privacy preserving features in these
subscription management services whether
or not that's true anonymity that's a
difficult thing but um yeah I just I
think that it I think that most people
out there just will not want to do
subscriptions if they think everybody
else in the world knows what they're
doing what they're subscribed into that
I think that we would want to keep that
information to ourselves and only share
it with who we want to share it with
have you had a chance to connect with
Kevin from who's doing VIP 13:37 I just
talked to him quickly about this last
night and yeah well we're gonna connect
some more and talk about it some more
I'd love to see us like coordinate
efforts on that oh I see you're here too
awesome yeah I'd want us to coordinate
efforts on that because I think that it
would be really good to talk to make
sure that like you know we're being
consistent on how we define things like
invoices structure and stuff like that
and yeah see if we can help with privacy
on the etherium Network - any other
questions so one question uh you say you
comply with gdpr but how about AML anti
money laundering
you're opposed to monitor transactions
if it's recurring payments if it's over
fifty thousand how can you do that with
uh if you don't know your customers yes
okay I see AML stuff will I didn't sure
there's yet like you said you mentioned
fifty thousand in this case like to
subscribe to our data storage service
it's definitely not fifty thousand it's
much cheaper than that so I think for
like the day to day subscriptions that
shouldn't be a problem but I can tell
you once we implement this and we start
actually receiving these these payments
for our service in that way our business
will definitely and before that - but
I'll know a lot more about how this is
actually going to be handled by the
regulator's at least in Germany but
right now it doesn't we don't foresee
any major problems about that because
again kyc AML is more
about like large quantities of money as
far as I understand you're shaking your
head no though no not that's not my area
of expertise but I think that that's
definitely something that we should
explore but I also think it's
unrealistic to do the opposite thing
which is to have all of this personal
data floating around in public too so we
have to I think we have to find some
sort of like common ground between
offering more privacy for subscription
payments you with cryptocurrency and
adhering to laws and regulations
you