Optimism,
a
leading
layer-2
blockchain,
aims
to
help
Ethereum
users
transact
quickly
and
for
lower
fees.
Its
tech
serves
as
the
foundation
for
some
of
the
biggest
names
in
blockchain,
including
the
Coinbase
exchange’s
popular
Base
blockchain
and
Worldcoin’s
World
Chain–from
OpenAI
founder
Sam
Altman.
But
for
years,
Optimism
had
a
problem.
All
of
the
blockchains
that
used
Optimism’s
technology
were
built
according
to
a
core
underlying
premise:
They
“borrowed”
Ethereum’s
security
apparatus.
In
reality,
however,
that
wasn’t
the
case.
Until
now,
Optimism
has
been
missing
a
core
feature
at
the
heart
of
its
security
design:
“Fault
proofs.”
On
Monday,
that
long-promised
tech
is
finally
coming
to
Optimism’s
mainnet.
Fault-proofs
are
meant
to
keep
Optimism-based
layer-2
chains
honest.
They
help
prevent
operators
of
a
layer-2
chain
from
passing
inaccurate
transaction
data
down
to
Ethereum’s
layer-1
transaction
ledger,
and
they
power
the
layer-2
chain’s
“decentralized”
withdrawal
mechanism.
Similar
“proof”
technology
is
used
by
all
layer-2
rollup
networks,
including
Optimism
competitors
like
Arbitrum.
It’s
meant
to
ensure
that
a
rollup’s
users–be
they
NFT
traders,
retail
investors,
or
big-name
financial
institutions–can
trust
Ethereum’s
sprawling
operator
network,
rather
than
the
rollup’s
own
internal
systems,
to
record
their
transactions
and
withdrawals
accurately.
As
layer-2
chains
like
Arbitrum
baked
proofs
their
systems,
Optimism
lagged
behind.
For
years,
this
made
Optimism
the
butt
of
criticism
from
peers
who
claimed
their
own
technology
was
safer
and
more
advanced.
Now
that
fault
proofs
are
finally
coming
to
Optimism’s
mainnet,
the
network’s
developers–and
the
growing
ecosystem
of
other
teams
that
use
its
technology–hope
to
put
their
past
behind
them.
How
do
‘Fault
Proofs’
work?
Over
the
past
two
years,
layer-2
rollup
networks
like
Optimism
have
become
the
go-to
method
for
operating
on
the
notoriously
expensive
Ethereum
blockchain.
When
a
user
submits
a
transaction
to
a
rollup
network,
it
is
bundled
with
transactions
from
other
users
before
it
is
passed
down
to
Ethereum.
Those
bundles
are
written
to
Ethereum’s
transaction
ledger
all
at
once,
a
setup
that
lets
users
transact
faster
and
for
just
a
fraction
of
the
fees.
In
theory,
rollup
transactions
are
secured
by
“proofs,”
which
are
cryptographic
methods
that
allow
observers
on
Ethereum
to
check
whether
transaction
details
have
been
recorded
accurately.
This
is
most
relevant
in
the
context
of
withdrawals,
allowing
users
to
trust
Ethereum–rather
than
the
rollup
network–to
pull
their
funds
out
of
the
layer-2
chain.
Without
fault
proofs,
users
who
deposited
their
funds
into
Optimism
needed
to
trust
the
rollup’s
“security
council”
to
return
their
funds–a
system
that
exposed
the
rollup
to
potential
human
error
or
bias.
With
fault
proofs,
those
users
should
only
need
to
trust
Ethereum.
Optimism
derives
name
from
its
“optimistic”
proof
system,
and
it
launched
a
version
of
the
tech
when
it
first
released
in
2021
before
quickly
scrapping
it
after
finding
issues.
“We
literally
deleted
the
entire
system
essentially,
re-architected
it,
and
rewrote
the
entire
thing,”
Karl
Floersch,
the
CEO
of
OP
Labs,
said
in
an
interview
with
CoinDesk.
“That
was
brutal,
but
absolutely
the
correct
decision.”
The
Optimism
team
previously
shared
in
March
that
it
was
testing
its
fault
proofs
system
on
their
Sepolia
testnet.
Since
then,
they
had
an
audit
conducted
by
blockchain
security
firm
Sherlock,
and
found
a
few
bugs
that
they
were
able
to
patch
out.
“So
we
fixed
everything
that
we
did
find,
and
we
got
a
lot
of
confidence
in
the
actual
implementation
being
ready
for
prime
time,”
Floersch
said.
Starting
this
week,
the
network
will
again
rely
on
a
fault-proof
system
to
power
withdrawals,
but
it
will
still
retain
“training
wheels”
meant
to
ensure
that
things
run
smoothly.
The
Security
Council
will
remain
intact
and
can
intervene
in
the
event
that
the
fault-proof
system
goes
down.
This
combination
of
the
two
entities
is
what
Optimism
is
calling
“Stage
1
decentralization.”
The
goal
is
to
eventually
reach
Stage
2
decentralization,
where
the
network
will
not
have
to
rely
on
the
Security
Council
at
all.
“Stage
2
is
a
multiple
fault
proof
system,
sufficient
such
that
it
is
possible
to
run
the
system
in
some
ways,
like
on
autopilot.
There’s
no
ability
for
the
Security
Council
to
intervene
at
the
last
moment,”
Floersch
said.
Floersch
added
that
the
team
is
hard
at
work
to
reach
its
Stage
2
goals,
but
he
didn’t
give
a
timeline
for
when
that
ultimate
vision
would
be
reached.
With
fault
proofs
finally
shipping
to
Optimism’s
mainnet,
other
chains
that
use
Optimism’s
OP
Stack
will
gain
access
to
the
tech
as
well.
(According
to
DefiLlama,
Two
blockchains
that
use
Optimism’s
OP
Stack,
Blast
and
Base,
currently
surpass
Optimism’s
mainnet
in
terms
of
total
value
locked.)
“We’re
going
to
start
with
OP
mainnet
for
this
upgrade,
it’s
a
decently
large
upgrade,”
Floersch
told
CoinDesk.
“However,
it
should
not
be
too
long”
for
Coinbase’s
Base
chain
to
implement
the
fault
proof
system,
too,
Floersch
added.
