Stafi is a defi protocol that frees up the liquidity of pledged assets. Users can mortgage POS tokens (e.g. dot, FIS, etc.) through the stafi mortgage contract, and obtain rtoken (e.g. rdot, RFIs, etc.) as a return. These tokens can be used for trading to hedge against market fluctuations, while still obtaining mortgage income. FIS is a native functional token of the stafi protocol, which is used for the following functions: Mortgage: the verifier in the stafi consensus needs to take a stake in FIS to join the consensus network, and the nominee needs to mortgage FIS to participate. Transaction costs: to avoid system abuse, the initiator of the transaction must pay FIS to access computing resources. In this way, invalid transactions will be eliminated, similar to the functions of other Boca chains. Chain Governance: FIS holders can participate in changing stafi protocol parameters, vote for protocol upgrade and determine the development process. Anyone can make a proposal to the agreement, but only FIS holders can vote for or against the proposal, that is, one FIS account represents one vote. Value acquisition: most of the platform fees (transaction fees and liquidity fees) of the stafi protocol will be used to fund the repurchase and combustion of FIS tokens. According to the governance decision, the distribution of stafi income may change. Stafi releases the liquidity of mortgaged assets through mortgage contracts. The agreement consists of the following main components: rtoken: rtoken is a derivative asset issued by stafi based on mortgage tokens. Holding rtokens means that you can apply for redemption of native mortgage tokens at any time. This also means that the holder of rtoken has the right to receive the proceeds of the mortgage token. Mortgage contract: a set of codes containing the core functions of stafi, such as pledge, redemption and transaction. It also records the mapping relationship between rtoken and the underlying mortgage token. The role of mortg