Triple-nonce System
The LooksRare Protocol implements a triple-nonce system which enables for advanced cancellation features. Nonces are used to check orders validity, to keep track of executed orders and are specific to each user; but they also enable features, like specific or global orders cancellation.
The three nonce are:
Global nonce (globalNonce)
Each user address is mapped to one ask nonce and one bid nonce. The nonce on the maker order struct must match the signer's value on the chain. This can be used for canceling all pending maker bids or/and pending maker asks.
- There are 2 global nonces per user: bid nonce (when
quoteType = 0) and ask nonce (whenquoteType = 1). - They are used to cancel all the bids and/or all the asks for a user.
- For an order, if its order nonce value equals the signer's global nonce value, then the order is valid. Else, it is not executable.
- Users can increment their bid and/or ask global nonces to cancel all/part of their orders.
User 0x54BE3a794282C030b15E43aE2bB182E14c409C5e has a globalNonce (Ask) = 2.
The user has a signed MakerAsk with a orderNonce = 1 → This order is invalid
The user has a signed MakerAsk with a orderNonce = 2 → This order is valid
The user has a signed MakerAsk with a orderNonce = 3 → This order is invalid
Order nonce (orderNonce)
The order nonce is used to know whether an order can be filled, is being filled, or has been filled/cancelled. If an order has started "partial filling", it is impossible to execute other orders sharing this order nonce. The order nonce also allows the implementation of OCO orders.
A user can invalidate a order nonce (or a list of order nonces) manually in order to cancel the orders associated with these nonces.
In the context of strategies that enable partial fills, if the transaction does not fill fully the maker order, the user’s order nonce gets mapped to the order hash.
- The order nonce is mapped with a bytes32 value.
- Each order nonce is mapped to
bytes32(0)by default. - When a maker order with the nonce is fully executed, the order nonce gets mapped to
keccak256("ORDER_NONCE_EXECUTED"). - Each order object signed by the user has to contain an order nonce.
User 0x54BE3a794282C030b15E43aE2bB182E14c409C5e creates two maker orders with the same orderNonce = 2. The first order can be partially filled.
The orderNonce 2 is by default mapped to bytes32(0) → Both orders are valid
The first order gets partially filled, the orderNonce 2 is mapped to the first order’s hash → The second order that shares the same order nonce cannot be executed.
Subset nonce (subsetNonce)
Subsets nonces are part of the order object signed by the user. They come in addition to the order nonce, and serve a different purpose. They are used to group a set of arbitrary orders under the same subset nonce.
Each order is assigned a subset nonce. A subset nonce can only be cancelled manually. When a subset nonce is invalidated, all the orders sharing this subset nonce become invalid. Subset nonces can be shared across MakerAsk and MakerBid.
The protocol is agnostic of how orders are grouped together with subset nonces. It can be enforced at the application level, for example, to group all the user’s orders from a single collection under the same subset nonce. Or it can be customized by the user to create custom subsets.
User 0x54BE3a794282C030b15E43aE2bB182E14c409C5e creates 10 orders, all with the same subsetNonce = 2.
If 1 order is executed → All the other 9 orders remain valid.
User invalidates the subsetNonce 2 → All the 10 orders become invalid.