Lipa Brown Bag
07.09.2023
Eltoo
Gabriel Comte
Eltoo
Ever heard of it?
Naming
Layer 2
L2
eltoo
New update mechanism
- Replacement for the penalty TX
- Concept phase, not implemented yet
- Paper by Decker, Russell, Osuntokun
New update mechanism
Bitcoin Timelocks
nLockTime: TX is only valid after block X
nSequence: TX is only valid X blocks after parent confirmed
CLTV: Enforces compatible nLockTime on spending TX
CSV: Enforces compatible nSequence on spending TX
Setup
Channel state 1
Channel state 1
Channel state 2
Close channel
Close channel
Allowed ordering
Prevented ordering
Malicious attempt
Attack prevention
Eltoo advantages
- Removed security issue: Publish old state
- Symmetric channel states
- Knowing last channel state suffices
SIGHASH_ANYPREVOUT
Draft: BIP 118
Previously SIGHASH_NO_INPUT
Requires a soft fork
... community is not in consensus about it
No penalty
Attempting to cheat becomes essentially free
Questions?
