# Smart Contract & Platform Security Report

This report outlines the verified security controls, audit parameters, and technical architecture implemented across the BlockBridge platform and smart contracts.

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## 🛡️ Smart Contract Architecture & Security Controls

BlockBridge's contract system leverages the **EIP-2535 Diamond Standard** to ensure upgradeability, compartmentalization, and gas efficiency.

### 1. Upgrade Timelock & Multi-Step Governance
- **Genesis Lock**: All code upgrades are disabled at genesis. Upgrades must be proposed via a governance-controlled timelock.
- **proposeUpgrade**: Any changes to facets (add, replace, or remove functions) require a proposal transaction.
- **Execution Delay**: A mandatory delay of **172,800 seconds (48 hours)** must elapse before any proposed upgrade can be executed via `executeUpgrade`.
- **Stray ETH Rejecter**: The diamond governance layout rejects any direct/accidental transfer of ETH to prevent stuck funds.

### 2. Escalated Escrow Protection
- **Milestone-Based releases**: Escrows hold startup funding on-chain. Capital is disbursed only when milestone proofs are submitted and verified by lead mentors/investor consensus.
- **Signature verification**: All off-chain metadata (KYC statuses, ratings, and certifications) is cryptographically signed using the issuer's private key (`DID_ISSUER_PRIVATE_KEY`) and validated on-chain to ensure zero data tampering.

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## ⚙️ Application & Server-Side Security

Beyond the blockchain layer, the Next.js API layer is protected by standard web app security controls:

### 1. Web3 Identity & Session Security
- **NextAuth + DID Guard**: User sessions are tied to verified Web3 wallets. Sensitive operations verify signatures locally or check for active DID credentials.
- **Rate-Limiting**: High-risk routes (e.g. quote retrieval, payment initialization) are rate-limited via a sliding-window algorithm on Redis.
- **Signature Webhooks**: Payment gateway webhooks (such as Yellow Card or Crossmint callbacks) verify signatures using secret HMAC keys before triggering on-chain escrow operations.

### 2. Compliance & PII Protection
- **Symmetric Encryption**: User passport data (government IDs, full names) is encrypted using AES-256-GCM before storage.
- **PII Scrubbing**: Server logs automatically redact credit cards, bank account details, and full names via regex pattern scrubbers.

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## 🧪 Test Verification Suite

All contract code and application routes are fully validated by automated test runner blocks:
- **Foundry**: Governance, ownership transition, timelocks, and diamond cuts are covered by `DiamondGovernance.t.sol` tests.
- **Hardhat**: Milestone escrows, SBT reputational scoring, and signature validation are covered by standard contract mocha test suites.
- **Jest**: Webhook routing, quote calculations, and API security guards are covered by backend Jest integration test suites.