Protocol overview

Securd is a Compound-style lending protocol deployed on XRPL EVM. Users interact with it from the XRPL Ledger: each action is an XRPL payment that Axelar relays to XRPL EVM, where it is executed on the user's proxy contract.

Architecture

XRPL wallet
     │  XRPL payment carrying the action
     ▼
Axelar
     │  token transfer (supply, repay) or message (other actions)
     ▼
User proxy on XRPL EVM
     │  holds the user's supplies and debt
     ▼
Securd markets (Comptroller, sTokens, price oracle)

• User proxy. Each XRPL account has one proxy contract on XRPL EVM, created on its first action at an address derived from the r-address. All positions belong to the proxy. Only the bridge adapter can instruct it, and only with an action that originates from the owning XRPL account.
• Axelar. Supply and repay move tokens through Axelar's Interchain Token Service. Borrow, withdraw, and collateral changes are Axelar messages. Borrowed and withdrawn tokens are delivered back to the XRPL wallet through the same bridge.
• Markets. One market per asset, each with its sToken (for example sXRP for XRP). Supplying mints sTokens that represent a share of the market. Borrowing draws from the market's available liquidity. The list of markets is read from the protocol; new markets appear in the app as they are listed.

Intents

Smart contracts cannot verify XRPL signatures. Before a wallet signs an action, the Securd backend issues an intent: a signed description of the action (market, action type, amount, XRPL account, sequence number, deadline). The XRPL payment carries the intent in its memo. On XRPL EVM, the bridge adapter verifies the intent and executes exactly that action on the user's proxy.

Two independent conditions protect funds:

• the intent must be signed by the registered signer, and
• the message must originate from the user's own XRPL account, as reported by Axelar.

The backend key alone cannot move funds, and a wallet cannot execute an action the backend has not signed. Borrowed and withdrawn tokens are always delivered to the XRPL account that sent the action. Before signing, the backend checks the action against the protocol's current state (registration, market status, amount bounds, borrow limit, available liquidity).

Action types

Action	Payment content	Tracker steps
Supply, Repay	Tokens and the relay fee	XRPL payment → Axelar relay → Executed on XRPL EVM
Borrow, Withdraw	Relay fee only	The three steps above, then Delivered to your XRPL wallet
Enable or disable collateral	Relay fee only	XRPL payment → Axelar relay → Executed on XRPL EVM

See Transactions.

Concurrency

One action per account is open at a time. While an action is open, all action buttons display Transaction in progress…. An action that has executed on XRPL EVM and is delivering tokens back to XRPL no longer blocks the next action.

Interest

Interest accrues every block on both supplies and borrows. Rates follow each market's utilization rate:

Utilization = Total borrowed ÷ (Available liquidity + Total borrowed − Reserves)

Each market has an interest rate model with a kink. Below the kink, the borrow rate rises linearly with utilization; above it, the rate rises steeply to bring utilization back down. The supply rate is the borrow rate times utilization, minus the reserve factor. The APYs displayed in the app are the current per-block rates annualized, without compounding. See Market details and Parameters and limits.

The exchange rate between an sToken and its underlying asset increases as interest accrues.

Prices

Each market has an oracle price in USD.

Asset	Source	Maximum age
XRP, USDC.axl	Band price feeds, read on-chain	1 hour
LP tokens	Computed from the AMM pool and published by Securd	15 minutes

A price older than its maximum age reads as zero. If a price reads zero for a market the account holds, the protocol cannot evaluate the account: the app displays Price not available yet, and borrowing, withdrawing collateral and liquidation are paused for that account until a valid price is available. See Health factor and liquidations and LP Prices.

Governance and safeguards

Control	Description
Collateral factor changes	Executed through a timelock with a minimum delay of 48 hours and an execution window of 7 days
Other parameters	Reserve factors, interest rate models, close factor, liquidation incentive, borrow caps and oracle settings are set by the protocol admin without delay
Pause guardian	Can pause supplying and borrowing per market, and sToken transfers and liquidations protocol-wide, immediately. Only the admin can unpause
Bridge adapter	The protocol owner can pause the bridge adapter. While paused, no action from the XRPL is executed, including withdrawals and repayments; positions on XRPL EVM are unchanged
Oracle circuit breaker	The protocol owner can freeze an asset's oracle price at its last value for up to 12 hours during an incident
Supply caps	Enforced off-chain: the protocol monitors each market's supply and may pause supplying when a cap is reached

The protocol has no withdraw pause: a supplied balance can always be redeemed, subject to the borrow limit, the market's available liquidity and the bridge operating. See Withdraw.