DWELL: Pay your rent with a yield-bearing stablecoin

.gitmodules

@@ -1,3 +1,10 @@
+[submodule "rent/lib/forge-std"]
+	path = dwell/lib/forge-std
+	url = https://github.com/foundry-rs/forge-std
+[submodule "rent/lib/openzeppelin-contracts"]
+	path = dwell/lib/openzeppelin-contracts
+	url = https://github.com/OpenZeppelin/openzeppelin-contracts
+
 [submodule "riff/lib/forge-std"]
 	path = riff/lib/forge-std
 	url = https://github.com/foundry-rs/forge-std

README.md

@@ -4,27 +4,26 @@ Welcome to the **Seismic** blockchain's **Prototypes** repository! This repo is
 
 ## Purpose
 
- This repository exists for:
+This repository exists for:
 
-- **Reference & Examples:** Developers looking to understand the Seismic blockchain or seeking best practices can explore these prototypes as real-world examples.  
-- **Collaboration:** We encourage contributions, feedback, and discussions about all things Seismic. 
+- **Reference & Examples:** Developers looking to understand the Seismic blockchain or seeking best practices can explore these prototypes as real-world examples.
+- **Collaboration:** We encourage contributions, feedback, and discussions about all things Seismic.
 
 Each project in this repo lives in its own directory and includes a dedicated README that provides more details.
 
 ## Projects Overview
 
 Below is a quick summary of each prototype currently available in this repository:
 
-1. **`Riff`**  
-   A bonding curve that you can hear.
-2. **`Project 2 here`**  
-   Description here.
-
+1. **`RIFF`**  
+   Listen to a bonding curve.
+1. **`DWELL`**  
+   Pay your rent with a yield-bearing stablecoin.
 
 ## Contributing
 
-1. **Fork** this repository.  
-2. **Create** a new branch for your prototype or feature.  
+1. **Fork** this repository.
+2. **Create** a new branch for your prototype or feature.
 3. **Add** your prototype in a new directory, including a `README.md` with setup instructions and information on your project. Additionally, include a 1-2 sentence summary of the project in this top-level `README.md`.
 4. **Open** a pull request describing your changes and why they're valuable.
 
@@ -34,7 +33,7 @@ We're excited to see what you build and look forward to collaborating on the fut
 
 ## Get in Touch
 
-- **Website:** [Seismic Blockchain](https://www.seismic.systems)  
-- **Twitter:** [@SeismicSys](https://x.com/SeismicSys) 
+- **Website:** [Seismic Blockchain](https://www.seismic.systems)
+- **Twitter:** [@SeismicSys](https://x.com/SeismicSys)
 
-If you have any questions or want to propose a new idea, please open an issue or reach out on our official channels. Thank you for being an early part of the Seismic ecosystem!
+If you have any questions or want to propose a new idea, please open an issue or reach out on our official channels. Thank you for being an early part of the Seismic ecosystem!

dwell/.gitignore

@@ -0,0 +1,4 @@
+.env
+broadcast/
+cache/
+out/

dwell/README.md

@@ -0,0 +1,20 @@
+# Privacy-Preserving/Yield-Bearing Tokens
+
+## Overview
+
+**Problem**: Traditional rent payments are antiquated, requiring manual processing, offering no yield on deposits, and exposing sensitive financial information. This creates inefficiencies for both tenants and landlords while leaving value on the table.
+
+**Insight**: Since rental markets operate on predictable payment schedules, there's an opportunity to optimize capital efficiency through automated payments and yield generation. Privacy-preserving mechanisms can protect sensitive financial data while maintaining transparency where needed.
+
+**Solution**: USDY (USD Yield) implements a privacy-preserving token system for rental payments that generates yield during deposit periods while protecting transaction privacy. Tenants can earn returns on their deposits until rent is due, landlords receive guaranteed on-time payments, and all parties maintain financial privacy through shielded transactions. The system uses a shares-based accounting mechanism to distribute yield fairly among all participants.
+
+## Architecture
+
+- `SRC20.sol`: Base privacy-preserving ERC20 implementation using shielded types
+- `ISRC20.sol`: Interface for shielded ERC20 functionality
+- `USDY.sol`: Yield-bearing USD stablecoin with privacy features
+- Comprehensive test suite in `test/` directory
+
+## License
+
+AGPL-3.0-only

dwell/foundry.toml

@@ -0,0 +1,6 @@
+[profile.default]
+src = "src"
+out = "out"
+libs = ["lib"]
+
+# See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options

dwell/src/ISRC20.sol

@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+pragma solidity ^0.8.20;
+
+/**
+ * @dev Interface of the ERC-20 standard as defined in the ERC, modified for shielded types.
+ */
+interface ISRC20 {
+    /**
+     * @dev Function to emit when tokens are moved from one account to another.
+     * Must be overridden by implementing contracts to define event emission behavior.
+     * Default implementation is no-op for privacy.
+     * 
+     * @param from The sender address
+     * @param to The recipient address
+     * @param value The transfer amount
+     */
+    function emitTransfer(address from, address to, uint256 value) external;
+
+    /**
+     * @dev Function to emit when allowance is modified.
+     * Must be overridden by implementing contracts to define event emission behavior.
+     * Default implementation is no-op for privacy.
+     * 
+     * @param owner The token owner
+     * @param spender The approved spender
+     * @param value The approved amount
+     */
+    function emitApproval(address owner, address spender, uint256 value) external;
+
+    /**
+     * @dev Returns the value of tokens in existence.
+     */
+    function totalSupply() external view returns (uint256);
+
+    /**
+     * @dev Returns the value of tokens owned by `account`.
+     * For privacy reasons, returns actual balance only if caller is the account owner,
+     * otherwise reverts.
+     */
+    function balanceOf(saddress account) external view returns (uint256);
+
+    /**
+     * @dev Moves a shielded `value` amount of tokens from the caller's account to `to`.
+     *
+     * Returns a boolean value indicating whether the operation succeeded,
+     * otherwise reverts.
+     *
+     * Expected that implementation calls emitTransfer.
+     */
+    function transfer(saddress to, suint256 value) external returns (bool);
+
+    /**
+     * @dev Returns the remaining number of tokens that `spender` will be
+     * allowed to spend on behalf of `owner` through {transferFrom}. This is
+     * zero by default.
+     *
+     * This value changes when {approve} or {transferFrom} are called.
+     * For privacy reasons, returns actual allowance only if caller is either owner or spender,
+     * otherwise reverts.
+     */
+    function allowance(saddress owner, saddress spender) external view returns (uint256);
+
+    /**
+     * @dev Sets a shielded `value` amount of tokens as the allowance of a shielded `spender` over the
+     * caller's tokens.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Expected that implementation calls emitApproval.
+     */
+    function approve(saddress spender, suint256 value) external returns (bool);
+
+    /**
+     * @dev Moves a shielded `value` amount of tokens from a shielded `from` address to a shielded `to` address using the
+     * allowance mechanism. `value` is then deducted from the caller's
+     * allowance.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Expected that implementation calls emitTransfer.
+     */
+    function transferFrom(saddress from, saddress to, suint256 value) external returns (bool);
+}

dwell/src/ISRC20Metadata.sol

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+pragma solidity ^0.8.20;
+
+import {ISRC20} from "./ISRC20.sol";
+
+/**
+ * @dev Interface for the optional metadata functions from the ERC-20 standard.
+ */
+interface ISRC20Metadata is ISRC20 {
+    /**
+     * @dev Returns the name of the token.
+     */
+    function name() external view returns (string memory);
+
+    /**
+     * @dev Returns the symbol of the token.
+     */
+    function symbol() external view returns (string memory);
+
+    /**
+     * @dev Returns the decimals places of the token.
+     */
+    function decimals() external view returns (uint8);
+}