foreign
[Music]
I'm going to talk a bit about scaling
but I want to start first just with a
very quick apology in case you were here
to hear about multi-dimensional resource
pricing I had a bit of a hard time to
make up my mind which of the two talks I
wanted to give so for a while on the
website both titles were on there so if
you're really into multimeter resource
pricing which you should be I can only
recommend I gave a talk earlier this
year about it in the ethereum context
which
um is quite interesting I think and then
also with eip4844 we are about to
introduce a there's an open PR to to
update the fee Market there and
hopefully fingers crossed this will be
the very first time that we start moving
to multi-dimensional Resource pricing in
practice on ethereum like in this case
two-dimensional so do have a look
um but today here I'll talk about
scaling and specifically
um
um Roll-Ups why Roll-Ups
um first one I want to talk more more in
on the theoretical side why really is a
roll up so fundamental to scaling and
then
um bring it back and and talk about
ethereum's uh future place in that world
basically
um so first why why roll ups
um uh and and I want to start by uh with
something that I call execution chains
it's basically just blockchains as you
know them so uh Bitcoin of course was
the very first ever
um special purpose execution chain uh
special purpose just because it's only
for payments and and money uh ethereum
the very first a general purpose
execution chain in general all these
chains of course they want to have
maximum functionality maximum throughput
um but that that's attention with
needing to guarantee security and
decentralization and to illustrate that
kind of the tension
um I created this little uh final graph
so basically uh on the on the
x-axis you have the cost to run a full
node and on the y-axis you have the the
throughput that your network can have
um and with the Bitcoin and ethereum
basically uh you are in this nice Zone
where they're down there where basically
everyone wants to can run their own
chain locally I don't run my own Bitcoin
chain right okay okay so it is Bitcoin
but I could it's just a trust trade-off
that I'm I choose to make
um but that does mean that these chains
are fundamentally Limited in throughput
right by by uh basically the minimum
consumer Hardware capabilities and and
kind of the key Insight you release that
like everyone validating everyone's
transaction doesn't scale
but of course we we don't want to give
up you know security by by kind of
moving beyond this so like the very
first thing you could do and I I picked
Solana just as an example and this is
not meant as a slide at all actually I
think uh in a second you'll uh kind of
see how in a way they're kind of moving
in an interesting Direction here but but
basically what they're doing what their
version of scaling is just to basically
go further up this diagonal
um and that does give you a higher
throughput but of course it means that
now running a full node is it becomes
really expensive so that's one way of
just increasing a throughput the problem
is what if you don't run your own full
node and there's some sort of
disagreement right some some malicious
attack some some chain Fork uh you only
have two choices either you go with a
majority in which case 51 of the network
can always rewrite all the rules take
away your money everything right all the
other the other thing you can of course
do is how Halt and recover via the
social layer but that's
um very slow of course so whether we
want to end up on that graph that's
basically this what I call the Unicorn
Zone up there where everyone could you
know trustlessly validate the network
but we still have like really high
throughput
um so how how can we basically find a
way to to to get there
um and and that's basically where roll
ups come in and why do Roll-Ups come in
there um to explain that as you might be
aware you probably are aware there are
like two different flavors of Roll-Ups
optimistic and ZK Roll-Ups the easier to
explain in this context is optimistic
rollups so uh to talk basically to to
kind of get any tuition for for how
optimistic will have solve this this
kind of this dilemma here and we can
look look again at the at the Savannah
case and as I was talking about right if
if there's a disagreement and even if
you don't run your own full node you
always have the of the option to just
Halt and recover by the social layer and
the optimistic roll-up kind of idea here
is what if we could just massively speed
that up right instead of running that
kind of
um this this fallback mechanism on human
brains where whenever something goes
wrong you have to actually go on Twitter
and whatnot what if we basically just
automate that right like we replace the
human brain with uh with software and in
particular with fraud proofs and and
um and that's how you how you get
optimistic growth so kind of trying to
keep with my little picture some
symbolism so so their optimistic rollups
are also basically a form of an
execution chain they are their own
blockchains basically
um the way they work is that they apply
the changes optimistically
um and anyone can submit a fraud proof
uh so so the only basically the only
guarantee you need is that there's
someone in the system that notices if
something goes wrong but one of and
honesty assumption is a way way way less
severe restriction than a majority
honesty assumption
um and then these photos they are
automatically resolved on some sort of
settlement platform
um yeah that you need and then the
alternative as I was saying ZK Roll-Ups
they are just cryptographic magic right
so in that case you don't have to to do
this retractive fixing of problems
instead you just have any state update
come with a cryptographic proof that no
one did anything wrong and again you
need some sort of settlement platform
um where you can where you can resolve
this
um one more a little caveat here is that
um basically with Roll-Ups we're moving
away from this world where like everyone
needs to run their own like full node to
ensure Integrity right like I could
basically only follow the settlement
chain
um and still basically have all the
guarantees about the roll up
um but one additional uh thing thing to
to ensure is that we have to also pay
attention to data if you run your own
full node for a chain data is implied
right because you actually download all
the data and execute it locally but with
follow-ups you don't do that anymore so
now we basically need explicit data
availability mechanisms
um and and that's what I put this little
kind of database symbol there
um yeah and and with that basically once
you have you have like an explicit
settlement system and you have an
explicit data availability system
now basically you you can break out of
this of this kind of graph of of
um of this
um full node uh versus throughput
um uh basically trade-off and uh and how
can you actually use this now to kind of
to build full blockchain systems um
that's kind of what the what the second
part is about like how how do you
actually turn this into into something
useful
um and this is going to be very picture
heavy because I kind of I don't know for
me it's mostly about giving good
intuitions here
um for like I don't know my mental
models around this basically that was
that was my motivation for the talk
um so again this is like an execution
chain I drew a little box around it it's
basically in its own box there it has
its own security
um and that's that's the world as it
used to be the blockchain world we had a
lot of these boxes like a couple years
ago right and now we're adding these
exciting new tools um to the picture we
are we're adding settlement and we're
adding data availability
um and how do they basically change the
picture well first we kind of have to
bundle them in some like we have to kind
of put them into some useful form uh the
way we like to think about it is
bundling them into what we call a
settlement chain which is its own
blockchain there you can see it has its
own security and it's not the only way
to do to do this like if you for example
know Celestia which is a really really
interesting other um kind of project
that that basically works with similar
kind of models and they keep data and
settlement separate
um but for us the the way ethereum kind
of likes to approach these things is by
combining them into into a settlement
chain so now so now we have these these
two separate chains how do we basically
now actually make use of them well the
way to do this is by and that's what the
arrows are for by basically having
turning the execution chain into a roll
up
um it kind of functions as it did before
but now it uses this the settlement
chain for for for data availability and
for um settlements so you need some sort
of fraud-proving mechanism or it needs
some validity proofs attached but other
than that it still feels like a normal
blockchain basically
um the simplest way to do this is what
what we call like an in try and roll up
so in that case you'd have like one
settlement chain and one roll up on top
and it's basically like a one one to one
and really relationship and in a very
simple way you could imagine basically
this process playing out in the
blockchain world is um and I guess that
fits well into this kind of the
multi-chain vision would be where every
every blockchain that wants to basically
go hyper scaling and just adds their own
little settlement chain
um underneath them
um and that would basically bring you to
this to this picture
um with multiple different uh
blockchains
um they are that would all know have
their own settlement chain the the
downside there is
um that for one you have fractured
security right each each settlement
chain has its own valid data set or its
own miners or its own however you you
get your security as your as your chain
um and it basically some some of those
will be higher security some will be
lower security and that also affects
Bridges uh I'm maybe some of you have
seen kind of metallics right up a while
ago about how basically if you bridge
multiple chains you always end up with
the the weaker secure the weakest
security of all of them right if you
basically if you want to use assets of
like 10 different chains
if the security of one of those breaks
like that specific asset just basically
is is broken for you right and if you
have some sort of defense system where
all of this is interconnected basically
everything Can Crash and Burn
um you really don't want this minimum
the worst of all security kind of
situations and also um I guess that's
less of a severe thing but also in this
picture you're kind of duplicating a lot
of complexity
um for each chain so what would be an
alternative Vision how do we think the
future might look like uh that's what we
what we call like a shared a settlement
chain so in this case you have one big
settlement chain and you can have
multiple Roll-Ups on top of course
probably realistically the future will
look some sort like some sort of hybrid
you'll still have some blockchains
that's prefer to do their own settlement
chain but but we predict that like this
will be a big chunk of it basically like
a shared settlement chain and why is
that advantages
um well two main points really
um one is the shared security
um I like to think about it like shared
pools security it's not quite free
security sometimes you hear people talk
about how if you if you turn your chain
into a roll up you just get the the
security of the base chain for free and
that's not quite right I think because
actually if uh say you have 10 Roll-Ups
on top of a settlement chain then they
basically all put additional strain on
top of that settlement chain right like
now the incentive to attack the
settlement chain is 10x as high so you
you don't just get like security doesn't
just you know isn't just created for
free
um but it is pooled right so so now
basically you have to break the entire
combined system instead of just being
able to take the weakest link and what
that also gives you is then because you
have like one shared trust
um trust Zone basically that all the
bridges between those roll ups if
implemented perfectly you know in front
caveat
um it can can be you can be fully secure
um okay so with that kind of bringing it
back to ethereum of course I guess the
last slide they're heavily hinted to
where we want to end up with at but
where where were we in the past where
are we today and how how could we get to
this shared settlement layer future so
kind of starting with ethereum a few
years ago uh in the early days basically
ethereum also was a pure execution chain
we had approved work security robs
weren't yet a thing that was kind of a
happy place to be in for for a couple
years
um at some point of course like ethereum
always wanted to figure out like how do
we actually scale to billions of users
uh it took quite a while quite a few
years of iterations in in iterations
just because I like kind of research
archeology and I would encourage you if
you ever have some free time and nothing
else to do uh go look at all research
posts it's always fun so to basically
just illustrate that a little bit I've
like picked like three that kind of
accompanied our way kind of towards this
this rural Vision the first one is if
you look April 2019 it's it's really
quite amazing kcd Trio phase one and
done is two as a data availability
engine nowadays I think these this
technology like everyone would just nod
and be like yeah sure thanks shouting
but three and a half years ago I think
that was quite visionary
um then uh a year later a year and a
half later we had vitalik for the first
time confusing this term roll-up Centric
roadmap where basically we we finally
realized that yes there is no other way
to scale like you really need this
decoupling of the execution of the
settlement otherwise like you you
basically as I was saying earlier right
you can't break out of this dilemma so
so we really like Roll-Ups are the way
to go here
um and then just uh third is the a fun
little one
um that uh my colleague Matt
um uh wrote a couple weeks after
vitalik's post
um looking back at our early his two
plans and it actually turns out that uh
basically this if you remember the early
chatting plans
um if I just go back a couple slides if
this works uh actually what we what we
were planning back back in the day with
all these different charts was kind of
this picture all along right it was just
that we wanted to have all these charts
be like super enshrined and and at some
point and try and roll ups basically and
then someone we realized it's just much
better if we open this up for for
General Innovation if we if we don't
build or basically if we're the only
parties building Roll-Ups
um and so yeah this this basically just
you know it's a little history kind of
tidbit so so this is kind of how we how
we got to where we wanted to move move
move forward with ethereum so that kind
of brings us to to the kind of the
pre-merge state where we already started
to use the ethereum chain as a as a
settlement chain as well but of course
it still has execution so it's like kind
of like a hybrid chain it's still proof
of work security of course before the
merge uh and as I was saying right
settlement chains need the settlement
aspect which you kind of get for free
when you have a general purpose chain
but then you also need data availability
and data availability on the existing
ethereum chain is really quite expensive
it was never meant to provide data
availability so what it's kind of
basically right now kind of hacked in
you just basically just dump data into
into ethereum transactions and then
never actually use them
um which works but but it's just very
very um expensive as a source of data
availability uh of course we started
having rollups on top
um really exciting if you ask me I think
Roll-Ups have been making a lot of
progress over the last two years
um and then you know pre-merge we had
this this Beacon chain just an empty
little box nothing in it and but much
stronger proof of proof stake security
right and then of course
as of today we ended up you know merging
and now we have have this uh basically
same same situations before but but much
higher security
um and just as a maybe quicker side I I
think I have the time for that uh why
does proof of stake actually give higher
security I always I mean it's not really
kind of part of my talk but just because
I always see a little bit of confusion
about that debate on Twitter and I think
it's it's really quite quite simple
actually like
um the the way I would think about like
moving from working to proof of stake in
terms of security one it's just more
efficient right and that is because you
don't you basically with mining you
actually have to pay for the entire cost
of the operation you have to reimburse
minus for both the mining hardware and
the energy right like they have to make
all of that up with the income whereas
in proof of stake you only have to make
up the lost interest on your money so
basically you can get away with with
paying way if your rewards for this for
the same security uh in in improve stake
and and then the other one it is also
that proof stake security is just
fundamentally more effective so that
means that if ever there were to be a
failure which of course hopefully they
will never be but if they ever were to
be like an attack or something
um the attack is attributable and so you
can you can just you can go in and
selectively punish people improve work
once someone like an attacker has 51 of
the resources you basically just you
know your change is just lost nothing
nothing to be done improve stake it's
really not a big deal actually right
it's a little bit annoying for maybe a
day and then afterwards you're just done
with it and so so that's really really
uh neat I think and then also like I
couldn't couldn't quite help myself
um maybe this one
esoteric maybe but
um another interesting mechanism in
terms of security that I really like is
this um ultrasound uh money one where
basically the idea is when you have an
normal mining rewards that means that we
have
as the asset has this much improved
monetary properties which in long run
might you know might or might not turn
into a higher expected monetary premium
higher total eth market cap and we can
just buy more Security in absolute terms
but again you know this is esoteric
totally fine if you don't buy into this
that the first bullet point is the more
important one here
um okay so this is ethereum today uh
where do we want to go uh how do we
actually get to this full you know
settlement chain uh how do we get full
data availability all of that kind of
thing so first thing is next year
hopefully a fingers crossed
um looking good I have to say uh
prototype starting erp4844 that we've
been really actively working on just
earlier today there was there was a
session on this
um where basically uh we I don't know if
you saw that but like the data pick the
data symbol there just become became way
bigger because you just you know you you
add better data availability to the
ethereum chain for the first time data
availability is an explicit service we
provide it's not just something tucked
on but it's an explicit service and so
it's just more effective
and then of course uh you've you've
probably all heard about that tongue
sharding soon TM afterwards uh that
could be two years from now hopefully
like maybe maybe it'll be three years
but but soon
um uh and and that's really where we get
like Ultra scalable data
um and and and with that we will be for
the basically we will be able to to
um to host multiple of these really high
throughput Roll-Ups so this is kind of
in terms of scalability this is really
the end game
um that that we as ethereum basically
are are aiming for
um and basically kind of with those
pictures in mind I kind of wanted to
then for the for the last part talk a
little bit about where does this leave
us like this I I hope that kind of gave
it like intuition wise like a good idea
of where we're moving and why but but
what implications does that have so the
first first thing I wanted to briefly
talk about what does it mean for the
existing well it one we used to call it
it one chain like basically what now is
the execution chain with within the
beacon chain what's the future of that
and um they are basically multiple
different
um potential future Visions for it that
you could you could you could see the
first one would be that you it basically
stays this hybrid execution settlement
chain or the roll-up settle on top of it
but also still you know it has some
default on it whatever for high value
transaction it can still be used as an
execution chain so that would be kind of
the default case
um then we we could we could have the
scenario where it really turns over time
one more primarily into a pure
settlement chain so that means that
really more and more of the user
activity migrates layer twos and and
layer one is really just becoming more
more just just a rollout management
layer and then the third one it's more
like a fun thought experiment it's not
really kind of planned or anything but
just wanted to kind of illustrate how
this modular architecture is really
lends itself to to all these these
different different ideas what we could
also do is that we could uh it basically
add in an additional separate set of
pure settlement chain to to the beacon
chain and turn is one basically into a
well you would say you could say a roll
up right so in this case if you if you
look at that picture you could just
think of you know like one of those roll
ups being it one so that's again I don't
I don't think that's likely that that
we'll go that way but you know it would
be almost I don't want to say trivially
but it would be very feasible to to go
that route because we now live in this
in this in this modular World
um the other one I briefly want to talk
about was the the future of the evm so
um first I I do want to say is by no
means certain that kind of the future of
high throughput execution chains will be
VM based right I think ethereum as the
settlement layer will will always use
the evm I think it's just good enough uh
for for that and but it's it's not not
yet decided like it could be that you
know I don't know Solana or something
has the Deep dominant uh winning highly
scalable uh VM um uh solution it could
could be could be the evm it could be
some some of these other competing um
new ones this is yet to be seen I mean
we are very optimistic for the evm in in
in that um scenario as well and I think
I do want to point out
um because that sometimes misunderstood
uh the the reason why ethereum only has
the limited to put it has is not the evm
that's not the limiting factor it's
really that we want to keep the resource
requirements for validators low the mom
the moment you are a roll up and you
adopt the evm you can still go far
beyond the throughput constraints of the
base layer and so and there are many
possible evm improvements that we just
never bothered to do on the base layer
because the data is not relevant for us
but that layer twos are very actively
looking into it so I think there's a
very good chance that the evm will turn
out to be to be like the winning or one
of the evening and height throughput VMS
um yeah and and but but of course uh
whether like like the the outcome of all
of this process will have like big
implications that clients will clients
basically say the existing evm clients
will they be primarily settlement
clients only or will they also be used
for Roll-Ups at some point maybe they'll
want to focus on Roll-Ups even
um how does that look like for
programming languages for the evm uh
whatever tooling all these kind of
things right
um so I think this is this is going to
be like one of the the main interesting
kind of technological debates of the
next five years
um and in particular I wanted to briefly
very briefly talk about evm equivalents
because that's just a topic that I I
personally am really interested in so
for these layer two layer Twos for these
Roll-Ups that choose to go with the evm
and the question is do they go with the
the the exact evm or do they just go
with something that looks kind of like
pvm right and if you remember say
optimism for example they started out
with what they call the Optimus
optimism virtual machine or something
OBM which was basically an Adaptive
version of the evm and now they're back
at using basically the EVMS is so the
question is in the long run what what is
the way to go should you go with evm
equivalents or not and so just briefly
basically the pros that I see would be
of course
um standardization right like if if you
use the evm just all the tooling works
out of the box you have multiple
existing client implementations which
again for security having multiple
clients is just really really uh helpful
but also really hard to achieve so this
is like a big win you can you can get
with evm equivalence and this the the
third one is a bit more speculative but
we could definitely imagine in the
future that we have some sort of
specialized settlement functionality
around evm that we offer for Roll-Ups of
course that would not be mandatory right
if you want to run your own like fuel or
Solana or something on top of ethereum
you can do that as well but we would
have special special support for for
these evm based ones and one really
interesting one especially I think in
the last few months people have more
noticed how governments can really be a
liability and and if you actually follow
the evm as is you can just defer to to
layer one um governance and follow their
changes basically and then what are the
what are the cons
um um why might you not want that well
of course one it's just like if you if
you're if you're stuck with the layer
one evm that does come at a cost of
slightly slower iteration speed right we
have to really vet every change that
goes into the VM quite severely to make
sure nothing ever breaks
um you might just need some layer two
specific functionality it's just harder
to add that
um if you really don't want to you know
kind of mess mess with with evm
um and also and I feel like that's the
one that's the most relevant in the
context of my talk here if we expect
layer one and layer 2 to really operate
at quite different scales in terms of
throughput maybe having identical VMS is
just not the the ideal way to to to to
to to go and just as like a potential
promise you or having the Best of Both
Worlds idea to that I want to leave you
with here is one that I think might
actually be quite exciting to explore in
the future
um what if we could maybe get the Best
of Both Worlds by having a dedicated
version of the evm specs for layer twos
that's still standardized across all the
Roll-Ups that want you know to opt in
um but is is able to over time depart
from layer one and really focus on on
optimize for the layer 2K so I think
there's a good chance that we might end
up in that world and and I think that
that might actually you know um be the
be the best way to get us to to High
scalability
um and yeah and I think I hope if I
remember correctly oh I do have a
summary slide so let me briefly go
through that but then then we're done so
you know traditional uh blockchains you
always have the trade-off between
security and scalability uh Rob solve
this ethereum's Vision we want to become
the primary settlement chain we're still
at the very beginning of this
transformation
ethereum well likely this this is the
last point I I had the likely because
who knows right but we we do still with
the evm also have Ambitions for for
execution chains we do not just want to
be to be a settlement chain
yeah and with that
um thanks
[Applause]