sequence-diagram-simplified.puml

@startuml
actor Client
participant "Espresso\nConfirmation Layer" as Esp
participant Rollup as L2
participant "Light Client\nContract" as LC
participant "Rollup\nContract" as L2_L1

Client -> L2 : L2 transaction
note right
1.
end note

L2 -> L2: L2 Block
note right
2.
end note

Client <-- L2 : New <i>trusted</i> state
note left
Clients that trust a rollup server
can get the updated state without
waiting for the state update proof
or confirmation from Espresso.
end note

L2 -> Esp : Espresso transaction:\nL2 Block, Rollup ID
note right
3.
end note

Esp -> Esp : Consensus orders\nEspresso transactions\ninto Espresso blocks

par Interested parties process block

Client <-- Esp : Block
Client -> Client : Execute block
note left
Optionally, clients can check for
confirmations themselves to quickly
know about new L2 blocks confirmed
by Espresso.
end note

else

Esp -> L2 : Block
note right
4.
end note
L2 -> L2 : Execute block

else

Esp -> LC : Block Commitment +\nProof of consensus
note right
5.
end note
LC -> LC: Validate Proof of consensus\nStore commitmenet

end

par Interested parties process new state

Client <-- Esp : Block Commitment +\nProof of consensus
Client -> Client : Validate Proof of consensus
Client <-- L2 : New State\nProof
Client -> Client : Validate proof\nagainst commitment
note left
Optionally, clients can check
proofs themselves to quickly
get the updated state without
trusting a full node or
executing a whole block.
end note


else

L2 -> L2_L1 : New state\nProof
note right
6.
end note
L2_L1 -> LC : Read sequence
L2_L1 <-- LC: Commitments
note right
7.
end note
L2_L1 -> L2_L1 : Validate proof\nagainst sequence
Client <-- L2_L1 : New <i>certified</i> state
note left
With some latency, clients receive
the latest state with no trust <i>or</i>
computation, from the L1.
end note

end
@enduml