Collateral

Both NodeRegistry and AppRegistry implement the ILock interface — a single-asset vault with a time-locked withdrawal mechanism. Node operators and app builders post YELLOW tokens as a mandatory functional security deposit, initiate an unlock, wait for the period to elapse, then withdraw.

Node operators post collateral to register and operate clearnode infrastructure on the Yellow Network using Layer3 Fintech Ltd.'s open-source software. App builders post collateral on the AppRegistry as a service quality guarantee for applications registered on the network.

State Machine

        lock(target, amount)       unlock()            withdraw(destination)
  Idle ──────────────────► Locked ──────────► Unlocking ─────────────────► Idle
                              │                   │
                        lock() top-up          relock()
                        (stays Locked)     (back to Locked)

States

State	Value	Description
Idle	0	No locked balance
Locked	1	Tokens are locked as collateral
Unlocking	2	Countdown started, waiting for unlock period

Functions

lock(target, amount)

Deposits amount YELLOW tokens into the vault, crediting target. The caller must have approved the registry to spend their tokens. Can be called multiple times to top up while in the Locked state.

• Reverts if target is in Unlocking state (AlreadyUnlocking)
• Reverts if amount is zero (InvalidAmount)
• Anyone can lock tokens on behalf of another address

unlock()

Starts the withdrawal countdown for the caller's full balance. The unlock period is set at deployment (default 14 days).

• Reverts if caller has no locked balance (NotLocked)
• Reverts if already unlocking (AlreadyUnlocking)
• NodeRegistry: immediately removes the operator's collateral weight from parameter administration

relock()

Cancels an in-progress unlock and returns to the Locked state.

• Reverts if not in Unlocking state (NotUnlocking)
• NodeRegistry: immediately restores the operator's collateral weight

withdraw(destination)

Transfers the caller's full locked balance to destination after the unlock period has elapsed.

• Reverts if not in Unlocking state (NotUnlocking)
• Reverts if countdown hasn't finished (UnlockPeriodNotElapsed)
• Resets state to Idle

View Functions

Function	Returns	Description
asset()	address	YELLOW token address
UNLOCK_PERIOD()	uint256	Withdrawal delay in seconds
lockStateOf(address)	LockState	Current state (0/1/2)
balanceOf(address)	uint256	Locked balance
unlockTimestampOf(address)	uint256	When withdrawal becomes available (0 if not unlocking)

NodeRegistry vs AppRegistry

Feature	NodeRegistry	AppRegistry
Purpose	Node operator security deposit	App builder service quality guarantee
Parameter admin weight	Yes (OZ Votes)	No
Auto-self-delegation	Yes (on first lock)	N/A
Delegation	Yes (delegate(address))	N/A
Slashing	No	Yes (ADJUDICATOR_ROLE)
Slash cooldown	N/A	Yes (setSlashCooldown)
Access control	Open	AccessControl (admin + adjudicator roles)

Events

Event	Parameters	When
Locked	user, deposited, newBalance	Tokens locked as collateral
UnlockInitiated	user, balance, availableAt	Unlock started
Relocked	user, balance	Unlock cancelled
Withdrawn	user, balance	Tokens withdrawn