Features of LendingV2

# Features of LendingV2 [TOC] ## Notice: - Gas consumption - Library version (To verify later) ## Steps: 1. Cooperate with product team to confirm features and design implementation 2. Implementation + Verify 3. Formal Verification + Audit 4. Testnet Launch + Bounty Programs 5. Mainnet Alpha Launch ## Features - General Lending ### Isolation Mode * isolated collateral asset with limited set of borrowing assets and debt ceiling. - [x] Borrowers supplying an isolated asset as collateral cannot supply other assets as collateral (though they can still supply to capture yield), and can borrow permitted stablecoins up to a specified debt ceiling. - [x] Uers can exit isolation mode at any time by disabling the isalated asset as collateral. * Criterions - [ ] Only allows asset as isolated mode simultaneously while adding it to markets. - [ ] Disallows existing assets entering isolated mode. - [x] Always allows enabling new assets borrowable in isolated mode. - [ ] Disallows disabling borrowable assets in isolated mode. - [x] All isolated assets share the same borrowable assets list. [Skyge 04-14] Q1. For borrowable assets in isolation mode, it can change from unborrowable to borrowable, so can it change from borrowable to unborrowable? - [ ] Option1: No. - [ ] Option2: Yes, it seems like does not affect the equity of users, but for the front-end, maybe need to do more to show borrowed assets that are unborrowable in isolation mode. - [x] Q2. How to calculate current debt amount? 可以考虑直接用可被借资产的数量计量，这里已经假定了可借资产都是稳定币，并且不考虑价格（即：假定价格都为$1） [Skyge 04-07] eg: Under the isolation mode, one asset should behave like following (Assuming Arb Token and OP Token are isolated assets, `debtCeiling = 500` , and only USDC, DAI can be borrowed): *debtCeiling means total borrowed amount in the isolation mode, but it is yet to be confirmed.* - Alice supplies 100 Arb Token, and then she sets Arb Token as collateral (enter markets), so now she enters the solation mode, and she can only borrow USDC, DAI. - Alice supplies ETH, but it can not be used as collateral. - Alice supplies OP Token, cause she has enterred the solation mode, so OP Token can not be used as collateral. - Alice disables Arb Token as collateral(exist markets), now, she exists the solation mode，so she can set any token as collateral. - Alice sets ETH as collateral, cause she has a non-isolated asset as collateral, so she will never enter the solation mode. **TODO:** - [ ] When add new parameters in struct Market, should not generate storage collision(04-07). ### Efficient Mode - [x] Allow borrowers to extract the highest borrowing power out of their collateral by certain categories. - [x] User is only allowed to enter one category simultaneously. - [x] User is still allowed to supply other assets and to use them as collateral, but only collateral belonging to the same E-Mode category chosen by the user will have enhanced risk parameters. - [x] In certain e-mode, only specific assets within the same category can be borrowed. * Criterions - [ ] An asset is only allowed in one E-Mode category and cannot appear in more than one category. - [ ] Once one asset joins a category, it will be disallowed to exit. - [x] Assets belonging to one category share the same risk parameters defined by the category, such as: collateral factor, liquidation threshold, liquidation bonus, close factor, etc. [Skyge 04-24] Q1: Should eMode risk parameters always increase? - [ ] Option1: Yes - [ ] Option2: No, e.g. eMode.ltv 97% -> 98% -> 97%. When decrease some parameters, it may decrease users' equity at the same time, although it is not a good idea, but owner can do like this. ~~Q2: An asset can appear in more than one category at now.~~ ~~- [x] Option1: Yes~~ [Skyge:04-11] - [x] Can set a new oracle in e-mode? [A] According to the current requirement, it's not required. ### Liquidation Threshold * seperate LTV and liquidation threshold, LTV/LT(liquidation threshold) per collaterals ### Variable liquidation close factor * ~~gradual liquidation close-factor per loan assets, up to 100%.~~ ### Withdraw&Borrow Timelock 1. **requirements** * Single borrow / withdraw limit set, for example, * letgo limit * 1 block limit * multi-blocks limit * assets limit, for example, * daily volumes limit * whitelist strategies, for example, * flag to enable/disable whitelists * allow accounts in the whitelists having their own limit, for example tx limits and daily volumes limits. 2. **reference structure** {accounts}{assets}[tx-limits][delay-blocks] {accounts}{assets}[dailyVolume-limits][delay-blocks] ### Repay with deposits * The feature looks like "ability to do external call before the end of redeeming", so users can exchange the redeems for borrows to repay the loans. This is so-called "repay with deposits". * With the help of this feature, users can do lots of stuff, for example "switch your deposits". ### Permissionless Pool * tools set to set up lending pool automatically * parameters / oracle / web / api ### Action Conditions(newly added conditions) Notes: in following cases, the actions will be disallowed. | enableIsolated | enableCollaterals | disableIsolated | enableEMode | disableEMode | Borrow | Liquidate | | -------------- | ----------------- | --------------- | --------------------------- | ------------ | ---------------------------------- | ----------------------------- | | hasCollaterals | inIsolatedMode | - | inEMode | - | borrowsExcluedIsolated | solventByLiquidationThreshold | | - | - | - | borrowsExcluedEModeCategory | - | borrowsExceededDebtCeilingIsolated | - | | - | - | - | - | - | borrowsExcluedEModeCategory | - | ### Process(Skyge) Current process is in the notion: https://www.notion.so/dforce/Technical-Design-Spec-b6804f4014a94055bcc0b469721bd693?pvs=4 --- --- ## Features - Hybrid NFT Lending ### Support ERC-721 * NFT as collateral and instant borrowing power, build-in feature in general lending * tokenize NFT deposit, act as social right of portrait * oracle with ability of boosting "rare" portraits * liquidation of NFT, auction and liquidity protection * instance 'buy' leveraged by borrowing power as low as zero-downpayment * instance 'sell' leverage by collaterl listing(repay & pay) ### Risk Framework * THE very question: which type of Loan is really required by NFT holders? Peer-to-Pool OR Peer-to-Peer. * Loan types: variable/fix rate, fix-term loans ## Reference ### AAVE V3 > [Key Features](https://hackmd.io/@0xSn0w/H1pPv-hX5) ### Euler > [Key Features](https://hackmd.io/@0xSn0w/BJJppfvg3) ### ParaSpace > [Key Features](https://hackmd.io/@0xSn0w/ByA1Azvg2) ### BendDao > [Key Features](https://hackmd.io/@0xSn0w/rJKZd4Fl2) ### Zharta > [Key Features](https://hackmd.io/@0xSn0w/B1zAlkjl2)