rBNB, a decentralized DeFi product produced by StaFi that solves the liquidity problem of staked BNB on Binance Chain mainnet.
rBNB token is a synthetic staking derivative issued by StaFi when they stake BNB through the StaFi rBNB App. rBNB tokens are anchored to the staked BNB assets and the corresponding staking rewards. rBNB tokens can be transferred and traded at any time.
rBNB App can help BNB stakers solve two major issues:
1) There will be no need to wait for 7 days to unbond the staked BNB assets. Users can transfer, mortgage, and trade rBNB assets at any time to liberate liquidity and hedge price risks.
2) There is no need to learn the complicated Binance Chain’s Tendermint BFT consensus mechanism or staking reward calculation rules if you want to maximize staking rewards. With the rBNB App, users only need to follow a few steps to deposit BNB into the rBNB contract, which will automatically select the best validator for delegation by the rewards maximization strategy.
When a user deposits BNB into the rBNB contract, StaFi will calculate the amount of rBNB to issue to the user based on the current exchange rate between BNB and rBNB. When a user holds rBNB, StaFi will calculate the amount of redeemable BNB based on the real-time BNB staking reward.
The rBNB exchange rate Ci grows with the increase in staking income. It is determined by the total number of BNB locked in the staking contract Qstk, the total number of redeemed BNB Qred, the number of staking rewards Qrew, the number of slashes Qslh, the commission rate Rcom, the total number of rBNB issued M, and the total number of burnt rBNB N. The calculation formula is as follows:
Through rBNB, StaFi solves the following problems for BNB holders:
1) There is no need to worry about the liquidity of staked BNB. Users can trade rBNB on Pancake, or mortgage on lending protocols to liberate liquidity at any time in the future.
2) The rBNB contract integrates a strategy for maximizing staking rewards, which automatically selects a group of Original Validators with the highest rewards on the chain for staking.
3) The rBNB contracts will automatically collect the staking rewards to restake. So stakers have no need to withdraw the staking rewards manually and then restake to generate the compound interest like before.
rBNB App serves to solve the liquidity of BNB staking. The core participants are as follows:
Stake BNB through StaFi rBNB App.
Original Validator (OV)
StaFi Special Validator (SSV)
The validator who controls the asset relationship in the staking Contract is called SSV. SSV mechanism adopts a distributed key management solution with the panel rotated on the chain. For details, please refer to StaFi WhitePaper SSV.
Based on Binance Chain’s Tendermint BFT consensus mechanism and the influencing factors of staking rewards, the rBNB App adopts the following staking rewards maximization strategy:
1) Diversified delegation
The BNB tokens deposited by the users will be distributed to several(N) mini staking pools. N will be based on the scale of the deposit. Each staking pool will then select several (M) validators for delegation by the profit maximization strategy, so as to reduce the slashing occurrence probability of a single node.
2) Strictly select Original Validators candidates
The rBNB App will evaluate the performance data of original validator candidates from the metrics including online duration, slashing record, self-bond ratio, node identity, commission ratio, etc., to ensure that excellent validators with relatively low commission are selected.
3) An automatic delegation strategy that maximizes staking rewards
The solution monitors OV’s on-chain data in real-time, such as commission ratio changes, commission volume ranking, slashing, off-line rate, and other indicators. This ensures that in each Epoch, the system selects the best OVs for delegation while simultaneously reinvesting profits.
4) A strategy that minimizes the potential loss
When the system detects that the node is slashed or the online rate is lower than the standard, the rBNB staking contract will automatically initiate the redelegation and re-select other qualified validators for delegation.
Users could redeem the staked BNB and corresponding rewards at any time through rBNB App. After receiving the request of redemption, rBNB contracts will automatically unstake and withdraw BNBs from the BNB staking contract deployed on BC, then send the BNB tokens to the user’s BSC address after around 14 days.
Please note that the unbonding period of rBNB App is 14 days, though that of BNB staking on BSC is 7 days. This is because the staking module of BNB staking on BC only supports to unbond once every 7 days. Therefore, if more than one user unbond through StaFi rBNB App, StaFi contract have to collect all the redemption asks in the first 7 days, then unbond from the BC chain in the next 7 days.
When users redeem the BNBs, there will be a redemption fee charged at 0.2%, of which the details are listed in rBNB Charge chapter.
Since the Binance Chain uses the Tendermint consensus engine to develop PoS mechanism, the slashing risk minimization strategy will be the same as the rATOM App.
Through rBNB, StaFi can help users avoid slashing in the following ways:
1) Staking Contract favors those validators who do not have slashing history to become official OVs.
2) Validators with a higher proportion of self-bond will be preferred for OVs so that OVs are motivated to avoid slash.
3) Staking contracts will select several OVs for each nomination so that a certain slashed OV will not have a huge impact on user funds if it gets slashed. Therefore, even if an OV is slashed (the probability very low), staking rewards will not be affected.
4) When slashing is detected on a delegated node, the rBNB contract will immediately execute the redelegation on the above node to minimize the loss.
Users do not need to claim staking rewards when using rBNB App, and the on-chain staking contract will automatically re-stake the rewards to generate the higher APR.
When minting rBNB, users have to pay the gas for cross-chain relayers who are monitoring the Binance Chain BNB staking module in real-time and paying related cross-chain fees. Therefore, the cross-chain fees in minting rBNB can be calculated through this formula: N * (StaFi chain Gas Fee + BNB Staking Gas Fee), and the payment is made by FIS, StaFi mainnet native token.
N is a flexible parameter and it will be set lower than 1 at the start to lower down the total staking expense of BNB stakers.
The rBNB App will charge part of staker’s staking rewards as the commission, which includes the commissions charged both by the validator and StaFi. The commission collected by StaFi and Original Validators will not exceed 20% of staking total rewards.
When a user redeems staking assets, s/he only needs to apply for redemption on StaFi’s staking dashboard. The redemption process is mainly divided into two steps:
Step 1: Enter the amount of rBNB , which can’t exceed your rBNB balance.
Step 2: Confirm and apply. The system will burn the rBNB token you applied for, and calculate the amount of redeemable BNB by the exchange rate. The balance, after deducting the service charge, will be sent to the user’s wallet address.
The service charge (Feered) is determined by the users’ applied quantity for redemption M, the current rBNB/BNB exchange rate Rc, and the redemption rate Rr :
Rr is currently set at 0.2% in the initial stage.
StaFi will create rich, multi-level circulation scenarios that stretch across different chains for rBNB holders:
1) When the rBNB App is launched, rBridge will at the same time support rBNB two-way cross-chain bridge function from StaFi chain to BSC, so that users can have access to DeFi applications on BSC by using rBridge product.
2) In the near future, StaFi will list rBNB tokens on DEXes such as Pancake, and launch liquidity mining incentive campaigns to ensure the liquidity of the pairs.