Mina swap is a ZK rollup based constant product AMM decentralised exchange. Mina swap provides a non-custodial, scalable platform for trustlessly exchanging tokens.
Mina swap is a L2 scaling solution that utilises a ZK rollup architecture. In this architecture funds are held and maintained in an on-chain smart contract. Computation of transactions and state transitions happens off-chain. This is achieved by combining transactions into a block for which a ZK rollup proof is generated to attest to the integrity of the applied state transitions. The state deltas and associated ZK rollup proof are then posted to the on-chain smart contract. Due to the achitecture of this solution the system achieves the following properties:
- non-custodial and therefore rollup operators can not steal funds
- scalable as transactions are processed off-chain
- based on validity proofs and therefore a quick withdrawal time
- escape hatch provided to withdraw funds from on-chain contract if operator stops cooperating
Mina swap has two core data structres that constitutes its state, these are:
- Account merkle tree
- Pair merkle tree
The account merkle tree is used to store balances associated with a user account. The account merkle tree has a depth of 24 providing capacity for 16777216 accounts. The balances merkle tree has a depth of 10 providing capacity for 1024 token balances per user acccount. The table below illustrates the account model.
| Name | Type |
|---|---|
| publicKey | PublicKey |
| nonce | UInt32 |
| balances | KeyedMerkleTree<TokenId, UInt64> |
The pair merkle tree is used to store information associated with swap pairs. The pair merkle tree has a depth of 16 providing capacity for 65536 pairs. The table below illustrates the pair model.
| Name | Type |
|---|---|
| pairId | UInt32 |
| token0Id | UInt32 |
| token1Id | UInt32 |
| reserve0 | UInt64 |
| reserve1 | UInt64 |
| lpTokenId | UInt32 |
| lpTotalAmount | UInt64 |
Mina swap is a liqudity pool based constant product automated market maker decentralised exchange. That is to say that the liqudity pool satisfies the invariant
(x_1 - 0.003*x_in) * y_1 >= x_0*y_0
where x_0, y_0 are the initial reserve balances of asset X and Y respsectively,
x_in is the amount of asset X that the user would like to swap, x_1 and y_1
are the final reserve balances of asset X and Y respectively.
Mina swap has three core branches / methods. These are:
- swap
- mint
- burn
The swap branch allows users to swap one token for another. An industry standard 0.3% protocol fee is charged per swap. Of the 0.3%, liqudity providers receive 0.25% and the operator receives 0.05%.
npm run buildnpm run test
npm run testw # watch modenpm run coverage