# Smart Contract Architecture

## **Neovestor Smart Contract Architecture**

*Tokenizing Real-World Assets (RWAs) on Solana*

***

### **Core Programs**

#### **`neovestor_token` (SPL Token-2022 Extension)**

**Purpose**: Mint and manage tokenized RWAs (e.g., real estate, private credit).\
**Key Features**:

* **Transfer Hooks**: Enforce compliance checks (e.g., KYC/AML) before transfers.
* **Metadata**: Store RWA details (e.g., asset type, valuation, legal docs) using Token-2022 metadata extensions.
* **Mint Freeze Authority**: Pause token transfers during emergencies via DAO governance.

```rust
// Pseudocode (Anchor Framework)  
#[derive(Accounts)]  
pub struct MintRwa<'info> {  
    #[account(init, payer = authority, space = 8 + 64)]  
    pub rwa_mint: Account<'info, Mint>,  
    #[account(mut)]  
    pub authority: Signer<'info>,  
    pub token_program: Program<'info, Token2022>,  
    pub system_program: Program<'info, System>,  
}  
```

***

#### **`neovestor_compliance` (Custom Program)**

**Purpose**: Validate investor eligibility and enforce regulatory rules.\
**Key Features**:

* **KYC/AML Checks**: Integrate with Fractal ID or Circle’s API to verify identities.
* **Geoblocking**: Restrict transfers to/from OFAC-sanctioned regions.
* **Whitelists**: Allow only approved wallets to hold tokenized RWAs.

```rust
#[instruction(allowed_countries: Vec<String>)]  
pub fn enforce_kyc(ctx: Context<EnforceKyc>) -> Result<()> {  
    let country = get_investor_country(&ctx.accounts.investor.key())?;  
    require!(allowed_countries.contains(&country), NeovestorError::BlockedRegion);  
    Ok(())  
}  
```

***

#### **`neovestor_governance` (Custom DAO Program)**

**Purpose**: Manage protocol upgrades, fees, and asset onboarding via decentralized governance.\
**Key Features**:

* **Proposal System**: Stake $NEO tokens to propose changes (e.g., adjust reserve ratios).
* **Quadratic Voting**: Prevent whale dominance using vote weighting.
* **Time Locks**: Delay execution of critical proposals (e.g., 72 hours).

```rust
#[account]  
pub struct Proposal {  
    pub id: u64,  
    pub description: String,  
    pub votes_for: u64,  
    pub votes_against: u64,  
    pub executed: bool,  
}  
```

***

#### **`neovestor_liquidity` (SPL Token + Custom Logic)**

**Purpose**: Manage liquidity reserves and redemptions.\
**Key Features**:

* **Reserve Pool**: Automatically hold 10% of deposits in USDC for instant withdrawals.
* **Staking Vaults**: Allow users to stake RWA tokens for yield (e.g., 5% APY in USDC).
* **Oracle Pricing**: Fetch real-time RWA valuations via Pyth Network.

```rust
pub fn calculate_redemption(ctx: Context<CalculateRedemption>, amount: u64) -> Result<()> {  
    let nav = PythOracle::get_price(&ctx.accounts.rwa_mint)?;  
    let usdc_value = amount.checked_mul(nav).ok_or(NeovestorError::MathError)?;  
    ctx.accounts.investor.usdc_balance += usdc_value;  
    Ok(())  
}  
```

***

#### **`neovestor_vault` (Squads Multi-Sig Integration)**

**Purpose**: Securely manage treasury and asset collateral.\
**Key Features**:

* **Multi-Sig Approvals**: Require 3/5 signers for withdrawals (via Squads Protocol).
* **Collateralization**: Over-collateralize loans (125% LTV) to mitigate defaults.

```rust
// Squads-compatible instruction  
pub fn withdraw_from_vault(ctx: Context<WithdrawVault>, amount: u64) -> Result<()> {  
    require!(ctx.accounts.squad.has_quorum(3), NeovestorError::InsufficientApprovals);  
    // Transfer funds  
    Ok(())  
}  
```

***

### **Key Solana Native Integrations**

* **SPL Token-2022**:
  * Use [Token-2022](https://spl.solana.com/token-2022) for transfer hooks, metadata, and interest-bearing tokens.
* **BPF Loader**:
  * Deploy upgradeable programs using Solana’s [BPF loader](https://docs.solana.com/developing/on-chain-programs/overview#berkeley-packet-filter-bpf).
* **Cross-Program Invocation (CPI)**:
  * Securely call SPL Token, Pyth Oracle, and Squads programs via CPI.

***

### **Security Practices**

* **Audits**:
  * Third-party audits for custom programs.
* **Anchor Framework**:
  * Use [Anchor](https://www.anchor-lang.com/) for Rust-based safety (type-safe accounts, input validation).
* **Transfer Hooks**:
  * Enforce compliance checks via Token-2022’s [transfer-hook interface](https://spl.solana.com/token-2022/extensions#transfer-hook).

***

### **Example Workflow: Tokenizing Real Estate**

1. **Asset Onboarding**:
   * DAO approves a new real estate asset via `neovestor_governance`.
2. **Mint Tokens**:
   * `neovestor_token` mints 1M tokens representing 10% ownership of a $50M property.
3. **Investor Purchase**:
   * User deposits USDC, passes `neovestor_compliance` checks, and receives tokens.
4. **Income Distribution**:
   * Rental income converted to USDC and distributed via `neovestor_liquidity`.
5. **Redemption**:
   * Investor burns tokens to redeem USDC from `neovestor_vault`.

***

### **Future Upgrades**

* **Cross-Chain RWAs**:
  * Use [Wormhole](https://wormhole.com/) to bridge assets to Ethereum/Polygon.
* **Dynamic NFTs**:
  * Represent asset ownership tiers via [Metaplex](https://www.metaplex.com/).

***

This architecture leverages Solana’s speed, low costs, and native token standards to deliver a compliant, scalable platform for institutional RWAs. For implementation guidance, refer to the [Solana Program Library](https://spl.solana.com/) and [Anchor Documentation](https://www.anchor-lang.com/docs).