Add Merkle-proof-based reputation verification

[dDevAhmed]

📚 Overview

Contracts currently trust backend/oracle reputation values without verification.

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🌊 Drips Context

This violates a core Web3 principle: trust minimization.

Reputation must be cryptographically verifiable.

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❗ Problem

• Direct oracle reads
• No proof validation

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✅ Expected Behavior

• Backend submits Merkle root
• Users provide proof when voting
• Contract verifies inclusion

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🧠 Implementation Guidelines

• Add root storage
• Add proof verification function
• Modify vote function to require proof

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✅ Acceptance Criteria

• Valid proofs pass
• Invalid proofs revert
• Root updates handled safely

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⏳ Complexity

High

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🏷 Labels

audit, protocol, high-priority, drips-wave