Design a Blockchain-Based System

Functional Requirements

1. Decentralization:
   • The system should operate on a decentralized network, ensuring no single point of control.
2. Data Integrity:
   • Ensure that once data is recorded in the blockchain, it cannot be altered retroactively.
3. Consensus Mechanism:
   • Implement a consensus algorithm (e.g., Proof of Work, Proof of Stake) to validate transactions and add new blocks.
4. Transaction Processing:
   • Allow users to initiate, validate, and confirm transactions.
5. Smart Contracts:
   • Support the creation and execution of smart contracts for automated and self-executing agreements.
6. Node Communication:
   • Enable nodes to communicate and synchronize with each other to maintain a consistent state across the network.
7. Security:
   • Implement cryptographic techniques to secure transactions and user data.
8. Scalability:
   • Design the system to handle an increasing number of transactions and nodes efficiently.
9. User Authentication:
   • Provide mechanisms for user identity verification and access control.
10. Data Storage:
    • Efficiently store blockchain data, including transaction history and smart contract states.

Non-Functional Requirements

1. Performance:
   • Ensure low latency in transaction processing and block validation.
2. Reliability:
   • The system should be resilient to node failures and network partitions.
3. Scalability:
   • Support a growing number of users and transactions without significant performance degradation.
4. Security:
   • Protect against common blockchain attacks such as 51% attacks, double-spending, and Sybil attacks.
5. Interoperability:
   • Allow integration with other blockchain networks and legacy systems.
6. Availability:
   • Ensure high availability and uptime, even in the presence of network disruptions.
7. Data Consistency:
   • Maintain data consistency across all nodes in the network.
8. Extensibility:
   • Design the system to accommodate future enhancements and new features.
9. Energy Efficiency:
   • Optimize the system to minimize energy consumption, especially if using energy-intensive consensus mechanisms.
10. Privacy:
    • Implement privacy-preserving techniques to protect user data and transaction details.