BlockBorrow

Borrow a dollar-pegged stablecoin against your productive cryptoassets (starting with xSUSHI) 🚀

Contract System

USDZ

• Dollar-stable token, minted against collateral.

• Mint/burn managed by Controller.

Controller

• Central system manager.

• Keeps records of users' collateralized positions, ratios, etc.

• Keeps track of USDZ and xSUSHI prices using SushiSwap TWAP.

• Has ability to liquidate undercollateralized positions.

Protocol Plan V1

MVP version, for educational purposes. Not intended for real financial use.

    Protocol Parameters:

• 3% annual interest on all borrowings

• Collateral will be xSUSHI to start

• Stablecoin (dollar-pegged) is called USDZ

• Can borrow USDZ against collateral up to 150% collateralization ratio

• At 150% col. ratio or lower, positions can be liquidated for the amount that would bring it back to 150% col. ratio.

• Can only withdraw collateral if col. ratio over 200%. Can't withdraw collateral that would make col. ratio < 200%

      Liquidation:
  

• To keep things simple, liquidation will market sell the entire xSUSHI collateral via SushiSwap for USDC. USDC will then be redeemable 1:1 with USDZ. This should keep USDZ approx dollar-pegged even if it has very little trade volume.

• liquidator executes liquidate or batchLiquidate on address(es) with debt position(s)

• when liquidating a position, 10% of the xSUSHI is diverted as a liquidation fee, and the remaining 90% is swapped for USDC.

• Of the 10% liquidation fee: 2% goes to liquidator, 8% to protocol treasury.

          Borrowing:
  

• Delay of 10 blocks between depositing collateral and borrowing (to prevent Flash Loan attacks, as USDZ will likely be very illiquid at the start). #The Lend-Borrow Accounting Process

The Lend-Borrow Accounting Process

• User deposits xSUSHI by approving, then calling deposit()

--stores amount of xSUSHI deposited, as collateral

--emits Deposit event

• User can then call borrow(), passing amount to borrow

--calculates USDC value of user's xSUSHI collateral (xSushiPrice) via SushiSwap

--calculates compound interest user owes on any outstanding debt from lastBorrowed to now (using time, not blocks)

--calculates collateral ratio (colRatio) of user, given current debt + interest

--if colRatio <= 200%, reverts with "not enough collateral"

--if colRatio > 200%, user can borrow up to a 200% colRatio

--calculates borrowable as

--xSushiPrice * ( colRatio - 200% )

--if amount > borrowable, reverts with "amount too high"

--sets user debt to prev debt + interest + amount borrowed

--sets user's lastBorrowed to now (to restart interest compounding from the new total debt figure)

--emits Borrow event

• Anyone can call liquidate(), passing an address that has a position

--checks if address has a position, if not reverts with "address has no position"

--calculates totalDebt amount for address as debt + interest on the debt since lastBorrowed. This is a USDZ figure.

--calculates USDC value of user's xSUSHI collateral (xSushiPrice) via SushiSwap.

--calculates the colRatio of the address as ( xSushiPrice * collateral ) / totalDebt

--if colRatio > 150%, reverts with "collateral ratio still safe"

--if colRatio <= 150%, liquidation process starts

--90% of xSUSHI is swapped for USDC on SushiSwap

--8% of xSUSHI is transferred internally to protocol

--2% of xSUSHI is transferred internally to liquidater

--sets user debt and collateral to 0

--emits a Liquidation event

Protocol Plan V2

-Gasless function calls

-More yield-bearing collateral assets

-Gov token that owns treasury, directs development of protocol

-Airdrop of gov token

-Borrowing earns gov tokens

-Transferring earns gov tokens

-Liquidating earns gov tokens

Resources

Abracadabra Docs | GitHub Aave Docs | GitHub Maker Liquidation 2.0 Module Uniswap V2 Prices, Swaps