Exploring the Architecture of Sui Bridge: A Trust-Minimized Solution

Over
recent
months,
significant
efforts
have
been
dedicated
to
developing

Sui
Bridge,
a
native
bridge
for
the
Sui
ecosystem.
This
initiative
enhances
the
accessibility
of
Sui
for
the
broader
community
and
improves
interoperability
with
other
blockchains.

Sui
Bridge
Background

In
the
blockchain
ecosystem,
a
bridge
is
a





protocol
that
enables
interaction
and
communication
between
independent
blockchain
networks.
Bridges
facilitate
the
transfer
of
data
across
boundaries,
allowing
users
to
move
their
assets
from
one
chain
to
another
and
even
perform
more
complex
operations
like
cross-chain
message
passing.

Sui
Bridge
utilizes
a
lock
and
mint
mechanism,
holding
Ethereum-native
assets
within
Ethereum
smart
contracts
while
minting
or
burning
Sui
assets
depending
on
the
direction
of
the
bridge
interaction.
As
a
native
bridge
on
Sui,
it
requires
no
additional
trust.
The
same
entities
that
secure
Sui
also
secure
Sui
Bridge,
and
its
code
is
integrated
into
the
Sui
framework.

Currently
available
on
Testnet,
Sui
Bridge
supports
tokens
such
as
ETH,
WETH,
WBTC,
and
USDT
between
Ethereum
Sepolia
and
Sui
Testnet.
Following
its
Mainnet
release,
support
for
more
assets
will
be
prioritized,
and
future
versions
will
introduce
new
functionalities
like
custom
cross-chain
messaging
and
integration
with
other
blockchains.

High
Level
Architecture

Sui
Bridge
comprises
four
key
components:
the
Sui
Bridge
committee
or
node
network,
the
Sui
Bridge
smart
contracts,
the
full
nodes
operating
on
Ethereum
and
Sui,
and
the
bridge
client.

The
client
acts
as
the
interface
between
the
user
and
the
Sui
Bridge
infrastructure,
coordinating
user
bridging
actions
by
submitting
correctly
formatted
transactions
and
collecting
Sui
Bridge
node
signatures
as
needed.
Full
nodes
on
both
sides
of
the
bridge
submit
transactions,
while
bridge
nodes
also
run
Ethereum
and
Sui
full
nodes
to
listen
for
and
respond
to
bridging
actions.

When
bridging
assets
from
Ethereum
to
Sui,
the
user
deposits
assets
into
the
Sui
Bridge
smart
contract
on
Ethereum.
The
client
observes
this
transaction
and
coordinates
the
process.
The
Sui
Bridge
committee,
operating
Ethereum
full
nodes,
verifies
the
legitimacy
of
the
client’s
request.
After
verification,
the
bridging
action
is
completed
by
minting
bridged
assets
for
the
user
through
the
Sui
Bridge
package
on
Sui.
Currently,
Sui
Validators
subsidize
the
gas
fees
associated
with
bridging
transactions.

When
bridging
from
Sui
to
Ethereum,
the
process
is
similar,
except
users
must
manually
submit
the
claiming
transaction
on
Ethereum.
This
transaction
includes
signature
data
from
the
Sui
Bridge
nodes,
allowing
the
Ethereum
account
to
redeem
the
specified
assets
locked
in
the
bridge
contract.

All
bridging
records
and
approvals
are
stored
in
the
bridge
object
on-chain,
with
governance
actions
controlled
by
the
Sui
Bridge
committee.

Bridge
Messages

Sui
Bridge
constructs
messages
in
a
lightweight
manner
to
ensure
low
gas
costs.
A
common
messaging
format
is
employed
to
ensure
each
chain
can
efficiently
decode
and
verify
messages
and
signatures.
The
structure
is
minimalistic,
containing
only
essential
fields
such
as
message
type,
version,
sequence
number,
source
chain
identifier,
and
payload.

Bridge
Security

Determining
a
bridge’s
trust
model
is
crucial
for
supporting
a
bustling
ecosystem
and
large
flows.
Sui
Bridge
leverages
the
security
of
Sui
to
ensure
both
security
and
decentralization.
The
same
node
operators
that
secure
Sui
also
manage
and
maintain
the
Sui
Bridge
infrastructure.

Sui
Bridge
utilizes
recoverable
ECDSA
signatures,
allowing
public
key
recovery
directly
from
the
signature
itself.
This
streamlines
the
verification
process,
ensuring
only
legitimate
transactions
are
processed.
A
message
is
considered
valid
only
when
the
combined
weight
of
the
signatures
meets
or
exceeds
a
predefined
threshold.

Building
Interoperability

The
Sui
native
bridge
provides
a
secure
and
efficient
means
of
transferring
assets
between
blockchain
networks,
laying
the
groundwork
for
more
advanced
cross-chain
interactions.
By
leveraging
its
robust
trust
model,
incorporating
ECDSA
for
secure
transactions,
and
employing
a
committee-based
signature
verification
process,
Sui
Bridge
ensures
high
security
and
reliability.

As
the
ecosystem
develops,
the
bridge
will
support
a
wider
array
of
assets
and
abilities,
such
as
custom
cross-chain
messaging.
Sui
Bridge
represents
a
significant
step
forward
in
the
landscape
of
Sui
interoperability,
offering
a
seamless
and
highly
secure
solution
for
cross-chain
asset
transfers.

Image
source:
Shutterstock