Blockchain for Tokenized Money

Install Node.js, a code editor (e.g., VS Code), and the MetaMask browser extension.

Set up a local Ethereum development environment using Hardhat.

Create and manage Ethereum accounts using MetaMask and Hardhat's local accounts.

Acquire test ETH from a faucet and send a transaction on an Ethereum testnet.

Inspect a transaction on a block explorer to understand its components (sender, receiver, value, gas).

Interact with a Hardhat project using basic CLI tasks like `compile` and `test`.

Write a simple smart contract with state variables, a constructor, and functions.

Distinguish between value types (uint, bool, address) and reference types (arrays, structs, mappings).

Use visibility specifiers (public, private, internal, external) to control function and variable access.

Implement conditional logic and bounded loops, considering gas cost implications.

Use mappings and arrays for efficient data storage and retrieval.

Define and emit events to log contract activities on-chain.

Compile a contract with Hardhat and deploy it to a local network.

Describe the structure of a test file using ethers.js and a testing framework (Mocha/Chai).

Write a setup routine to deploy a fresh contract instance before each test.

Write unit tests for a contract's functions, asserting expected outcomes using ethers.js.

Test for expected reverts on failed conditions using `revertedWith`.

Test for correct event emissions and validate their arguments.

Simulate transactions from different accounts to test multi-user interactions and access control.

Use `console.log` from within Solidity for debugging purposes in a Hardhat environment.

Implement contract inheritance and use abstract contracts and interfaces.

Use structs and enums to model complex, domain-specific data.

Handle errors effectively using `require`, `revert`, and custom errors.

Distinguish between `storage`, `memory`, and `calldata` data locations to optimize for gas.

Write and apply function modifiers for reusable checks, such as access control.

Describe the reentrancy vulnerability and prevent it using the checks-effects-interactions pattern.

Use OpenZeppelin's `ReentrancyGuard` as a practical defense against reentrancy attacks.

Explain how Solidity v0.8+ built-in checks protect against integer overflow/underflow.

Explain the purpose and function signatures of the ERC-20 standard.

Use OpenZeppelin's ERC-20 base contract to create a custom token with a fixed supply.

Write tests to verify the initial state (name, symbol, total supply) upon deployment.

Write tests for successful and failed token transfers, checking balances and events.

Write tests for the `approve` and `transferFrom` allowance mechanism.

Deploy an ERC-20 token to a testnet and interact with it using MetaMask.

Implement role-based access control using OpenZeppelin's `AccessControl` contract.

Explain the transparent proxy pattern for enabling smart contract upgrades.

Deploy an upgradeable smart contract using Hardhat and OpenZeppelin's Upgrades Plugins.

Perform a contract upgrade on a testnet while preserving state.

Explain the security considerations and trade-offs of using upgradeable contracts and centralized admin roles.

Compare the design of fiat-backed, crypto-collateralized, and algorithmic stablecoins.

Implement a stablecoin contract by extending OpenZeppelin's ERC-20, adding mint and burn functions.

Restrict minting and burning capabilities to an authorized administrator role.

Integrate OpenZeppelin's `Pausable` utility to allow an emergency stop of all token transfers.

Write unit tests for the minting, burning, and pausing functionalities, including access control checks.

Deploy the upgradeable stablecoin to a testnet and demonstrate minting, transferring, and pausing.

Explain how tokenized securities differ from utility tokens, focusing on regulatory requirements.

Analyze the ERC-3643 (T-REX) standard's components for managing identity and compliance.

Design a simplified on-chain identity system using a mapping of addresses to investor tiers.

Design a transfer restriction mechanism that checks sender and receiver eligibility against the identity system.

Implement an interface for an external identity registry contract.

Implement a basic, on-chain allowlist as a simplified identity registry.

Build a security token contract that inherits from ERC-20 and uses `AccessControl`.

Override the `_beforeTokenTransfer` hook to enforce transfer restrictions based on the allowlist.

Implement a function to allow a compliance administrator to freeze and unfreeze specific accounts.

Implement a forced transfer function for an administrator to move tokens for legal or recovery purposes.

Design a dividend distribution model using the pull-over-push pattern to enhance security.

Implement `depositDividends` and `withdrawDividends` functions, secured with `ReentrancyGuard`.

Write tests to validate issuance logic and role-based access control for minting and administration.

Write tests to simulate and validate compliant token transfers between eligible, allowlisted investors.

Write tests to ensure transfers are correctly reverted when violating compliance rules (e.g., non-allowlisted user).

Write tests for the account freezing and forced transfer functionalities.

Write tests for the dividend distribution mechanism, covering deposits and successful/failed withdrawals.

Build a Node.js script using ethers.js to connect to a deployed smart contract.

Write a script to programmatically execute token minting and transfer transactions.

Use a script to query on-chain data, such as token balances, total supply, and administrative roles.

Write a script to listen for and process real-time token transfer events, decoding event logs.

Implement a deployment script with environment-specific configuration using Hardhat.

Verify and publish smart contract source code on a block explorer like Etherscan.

Describe the role of multisig wallets (e.g., Gnosis Safe) in securely managing admin keys for production contracts.

Explain the role of oracles like Chainlink for providing external data to smart contracts.

Explain the role of indexing protocols like The Graph for efficiently querying on-chain data for analytics.

Perform a final security review of the token contracts using a standard checklist approach.