okay good morning everyone now everyone
can definitely hear me let's see if I
can okay here we go okay yeah so I know
the gadget will be okay
yeah so the finale gadgets and research
we've been looking into to use the
beacon chain from eath 2.0 to enhance
the security of the thwa net chain so
here I will explain what it is you might
have heard of it in like a lot of
different contexts so we'll just kind of
go through it I'll try and show you why
we want it hopefully there's like some
fun reasons then we'll talk quickly
about how we get it and yeah then we'll
wrap up by seeing how you can help so
yeah this is like super high level TLDR
like like I said using the purpose take
beacon chain from eighth to O to enhance
the security of the pre-work chain we
have today so you're like well what's
going on there's now there's more block
chains like how does this work here's
this little picture so again because
this is gonna like couple these two
systems together there's like a lot
going on so I try to be clear like
there's this 100 block chain right so
this is like the perfora chain we have
there's a - a beacon chain and I'll
explain a little bit more what that is
exactly and then this will become clear
later but essentially this this is like
showing finality extending from the to
go chain to the 100 chain will go into a
lot more detail on that so I'm sure
you've seen this like a thousand times
by this point very briefly we'll break
down each row there's a beacon chain
it's a proof of stake blockchain
completely new chain from the existing
one and it's gonna build out this new
shorter system that will have very soon
the way we do that is we have this
beacon chain which is like sort of the
system chain it operates and manages
validators in the system then from there
we have all these chart chains which are
these little circles let's say there's
like a thousand of them that's where
user level transactions will happen and
ultimately we'll have phase two then we
have like all
fund apps we know and love on these
chart chains hopefully with like much
great much greater scalability so yeah
then the question is always okay this is
great
you might have noticed I keep saying
phase phase zero phase one phase two
because the system so complicated we're
like breaking this out in two phases so
it's just easier to get right to have
like discrete chunks we can kind of go
and deploy one at a time
then of course Sharon is like okay well
when is this happening the short answer
is like when it's ready we don't want to
like rush anything and there's a lot to
get right there's a lot to get wrong so
in the meantime you can ask okay what
about the chain we have today and we
have this whole bundle of initiatives to
the theorem called etherium 1x again
you've also probably heard a lot about
this over the past couple days it's so
like bundle of features to improve the
theorem we have today keep it going
so like Alexa has been looking at state
management and like state growth on the
chain and like deploying some sort of
state fees to help with the growth there
updates to the VM so this for example
would be like the point II wasn't free
compiles to accelerate certain parts of
computation on chain protocol economics
you probably heard of a IP 1559 which is
changing how transaction fee markets
work so that they're less volatile and
things and then finally another one is
the finality gadget which will okay now
okay quick diversion we're gonna talk
about the final gadget the rest of the
talk but I just want to take a moment to
like communicate that we can actually
get tangible value out of each phase of
this eath to deployment with phase zero
we can do the finale gadget which we'll
look at soon with phase one we can
actually think about using the shard
chains is this like data layer for the
existing chain and that lets us do cool
things like plasmas UK roll-ups zk zk
roll-ups which is an idea Vitalik had
anyways all these like cool layer to
scaling ideas that we can leverage these
char data chains for once they're
deployed then finally phase 2 again
there are a lot of ideas around how to
like move eath one into eath two
and yeah the main point the main
takeaway here is that you know it's it's
not that this all the school stuff is
like far many years away with each step
of this deployment we can like get
something really cool on the theorem two
day okay so back to the finality gadget
like I said we're gonna have the two a
chain there's this process of the
consensus on the beacon chain called
Casper part of Casper is finality and
finality are essentially the set of
rules that say once validators in the
system have made so many statements of a
certain form basically you can't like
fork the blockchain from will call a
finalized block without burning like a
ton of the validators bonds and that's
how you keep the system secure so like
in theory you could like make these
bonds arbitrarily high so you get
arbitrarily high security we then want
to say okay let's use this security on
the the perf working find out yet so
like breaking it down there's like two
key pieces or like mechanisms right so
we'll call it the finality engine which
is like how we get this finality in
first place then hopefully I made it
clear like these systems are like very
uncoupled and so you know finality is
happening here and unless this part
learns about this part and there's no
way to finalize this stuff it's like
whatever is up here could be finalized
and then it's just like kind of floating
on space we need to that we need a way
to learn about the youth one chain
that's why I'm a bigger by eath one data
so the first bit is the finality engine
so we'll quickly goes to this finality
thing again here's a blockchain doesn't
really matter which one proves big
blockchain you know blocks blocks have
links to their previous block so the
idea here is that these arrows are
indicating that the previous dick
validators in this system are like
making these these messages these a
statistician as test Asians is the term
you may have heard they're like yeah I
think like this is the next block in the
chain
and that's kind of one of their main
duties in life as a validator is to like
make these messages because as we'll see
in a second we can kind of look at these
messages and figure out if we hit our
like security thresholds or not so the
the next bit of finality is this process
called justification and these are these
thresholds I was just talking about so
what we're gonna say is that you know
let's say there's like you know a group
of validators if two-thirds of them all
make an attestation or this you know
this claim that this next block is in
the main chain and if two-thirds of them
do that then we're going to say that
it's justified and that's why I'm
indicating here by those gold arrow you
see down here this one's still blue so
like maybe we're at the head of the
chain and the others are working on it
but not everyone has like made their
attestation yet right so we're not quite
there something also to note is that you
can actually like you know skip box here
so like this would actually suggest
there are no messages made no matter
stations and that's okay you can just
keep going as you see now we get to the
fun part finality there's like this very
special rule that you just have to learn
and basically it's the rule is if I
justify on top of something justified
then this first one is finalized and
this is just the pattern that you have
to like apply and I'll show you in a
second how we get security out of this
but essentially you know so we can say
okay justification on top of this one
this is finalized justification so thing
is it's not justification sort of in
sequence but like direct sequence
meaning this this block is not finalized
because there was not like a direct
descendant of this that was justified
then we see down here we like skip some
blocks maybe there is like just
somewhere to never claim to see right
and then we keep going so then this
block was justified
from back here we justified directly on
top of it so this one's actually
finalized and then we have the situation
where like we're trying to build
finality on the head of the chain down
here now we get to the bit where the
security comes in you've probably heard
of these slashing conditions and these
are rules that basically enforce really
this here what it's saying is that as
long as some my conditions hold in terms
of like these patterns of justifications
and voting's you can't finalize two
conflicting blocks so let's let's say
there's a fork here right
these blocks are at the same height you
can't finalize two conflicting blocks
without either well really without at
least a third of the validators losing
their sake so that's why I'm trying to
show over here we like burned a third of
the eath that was validating not good
and we can actually prove this there
have been met like mathematical proofs
there's working sort of formal
verification of these systems all this
good stuff and really yeah just like
sketch the intuition here like as long
as we haven't had one of these attacks
we haven't you know had one these events
where all these validations are slash
then we have sort of one single history
and like here we see this is like what's
supposed to happen even if there was a
fork sort of broadcast on the network
what still happens is that you know 2/3
majority of the validators went down
this work they did not go down this work
and so as long as you know who the
validators are you can actually
determine this based on the messages on
the network and figure out the true
chain
and to give you some sense a healthy
amount of eath that might be validating
in each toe is say 10 million so then
for when his attacks to be successful
right that's a third of the youth has
been burned 3.3 million based on numbers
yesterday that's over 630 million
dollars and this is sort of per attack
so quite expensive okay that was a very
compressed explanation of finality well
now talk about how the beacon chain
learns about eath one data and then
we're gonna do is as we finalize the
beacon chain which learns about this
eighth one data will end up finalizing
the one chain hopefully that's clear so
how this works in practice is that will
apply this beacon chain they'll also be
what's called the deposit contract and
with the deposit contract the idea is
that anyone can then make a deposit of
ether
this smart contract on the eighth one
chain the two chain is then essentially
a light client of this contract and is
watching this contract and that's how
values enter the system so you know it's
sort of trustless in this way you don't
have to like go to three morgue and like
sign up to be a validator anyone can
sort of permissionless Li join the
system yeah and there's a key part of
this any validator in the new system
then to for example make a valid beacon
block has to include sort of their
latest view of the eath one chain and
that's how you get this light client
functionality so here are some diagrams
to that effect basically what I want to
show is like there's a proportion right
up here
beacon changes up here the systems
operational it's going and all this
basically in some block we have some
data right so like this block has a
block hash there just like an address to
this deposit contract there's a root of
all said deposits that have been made to
become a validator and then essentially
to enter into the batter's set here you
can make proofs against this right so
I've already claimed that we're
essentially a light client of this
contract what that means then is that we
know sort of this special route in the
contract
we can and usually make Markel proofs to
figure out okay was this deposit
included or not so what that says oh
great so yeah so then really this ties
it all together I'm just gonna kind of
keep moving so we can ask questions at
the end hopefully I realized this is a
lot quickly but basically what we then
have right is beacon chain learns about
eath one blocks as we finalize the
beacon chain we implicitly finalize
these eath one blocks right so for
example it's like you know by this block
we said hey the head of the eath one
chain was this block then as we finalize
this beacon block because essentially
you know this block hash is written here
and it's finalized we know that via
reference this is now finalized and then
because of the chain nature anything
before it is finalized so then we'll
like keep increasing suffixes of this
chain as we finalize more and more
beacon blocks and then just a you know
belabor the point but that then means is
that you'd have to have one of these
huge burnings of all this ability neath
to actually have for example or a
version on the 100 chain okay yeah why
do we want it essentially again I'm
trimming some argument for better
security there's this quote I've usually
heard attributed to Vlad which is like
with the proof of stake attack it's as
if you're a sick farm burned down with
every attack and what this means is that
you know let's say we're on the fork
chain if I were to attack you I just
have to get like a bunch of hardware
right and I just like they're all let's
hash borrow your chain and then suddenly
there's like a competing fork the only
way to really like stop you if I don't
know where you are is to change our work
right which we know can be tricky so
with proof of stake you can actually
because you have this like reference in
the protocol
like representation in the protocol of
this like consensus object you can
basically just say hey we're gonna like
coordinate as a community to say delete
this part that's attacking us and you
can just keep doing this you know as you
need
I mean you're on time so I'm going to
speed through some of this bit again
security security security this is
another when people early into is that
we can actually reduce issuance right
because with the security of the beacon
chain leverage to the eath one chain we
actually don't need to like we don't
need as high of mining subsidy and yeah
takeaway eath one loves eath two we can
like do a lot of cool stuff wait before
we have this like nice shiny awesome
like future execution environment system
and again a lot could go wrong
it's coupling these two systems in like
a very intimate way and so we definitely
need a lot of like research into like
what could go wrong and how before we
like kind of move ahead so that's about
where we are now we had like there's a
working group we had like our first call
some time ago there's this link here
I'll show this on the internet later a
current kind of open question is that a
lot of the beacon chain like comment
infrastructures kind of been delayed to
phase one so that I made like defer when
and how we can do stuff here again
there's like active research into that
at the moment
here's link to the working group on
teeth magicians there's a telegram group
and I want to get to questions so I'll
speed through this yeah this is me on
any platform just our Alex Stokes and I
have more writing on this stuff yeah we
have maybe one minute for questions
yep
sorry guys best hey hey thanks Alex can
you canoe walk us through what would
happen if the eath one state is
finalized on the eath to beacon node and
then there's a really neat one
if the so we finalized an eighth one
block so that I'm certain certain each
one block is finalized on the beacon
chain but then all of a sudden in eighth
one world that block is no right so yeah
so I actually didn't make this clear but
part of the the goal here is not just to
like have the beacon chain do this thing
and like for sort of finalize block
caches but we'd actually want to go one
step further and have the privilege it's
actual consensus to respect the finality
and so I'm gonna kind of register on
time but that's where I like merging the
systems like it's tricky cuz like you're
actually changing the per for consensus
to say okay if a block has been
finalized we can't revert so then it's
like four choices go to the finalize tie
to the preferred chain then proof work
from there right related to this so you
talked about how like if you have the
finality gadget you might be able to
reduce the mining subsidy one thing I
don't understand about that is it feels
like the mining subsidy is like most
useful for the most recent blocks
because you don't have like really deep
reorg and there will have to be like a
delay from the beacon chain to finalize
each one
so can we actually reduce the my name
subsidy significantly and and why is
that secure last question so that's
actually a good question
I had this again this wasn't clear from
my little diagrams but basically there's
effectively effectively like a follow
distance between what the beacon chain
considers an eighth one block and the
actual head of the eighth one chain and
it's actually quite big right now the
idea is like if we can deploy all this
stuff and it all is happy it makes sense
then we can actually shorten that a lot
so the questions like yeah how how short
can we make this follow distance it
could go I mean theoretically just a few
blocks behind the head and then it's
much more clear like yeah we can
probably lower the subsidy okay right of
time thanks to everyone I know is early
hopeful
[Applause]
you