hash-of-wisdom/docs/IMPLEMENTATION.md

Word of Wisdom Server - Implementation Plan

Phase 1: Proof of Work Package Implementation

Goal: Create standalone, testable PoW package with HMAC-signed stateless challenges

• Project Setup

  • Initialize Go module and basic project structure
  • Create PoW challenge structure and types
  • Set up testing framework and utilities

• Challenge Generation & HMAC Security

  • Implement HMAC-signed challenge generation (stateless)
  • Create challenge authenticity verification
  • Add timestamp validation for replay protection (5 minutes TTL)
  • Implement canonical challenge field ordering for HMAC
  • Add Base64URL encoding for HMAC signatures (JSON handles this)
  • Implement challenge string construction (quotes:timestamp:difficulty:random)

• PoW Algorithm Implementation

  • Implement SHA-256 based PoW solution algorithm
  • Implement leading zero bit counting for difficulty
  • Create nonce iteration and solution finding
  • Add difficulty scaling (3-10 bits range)
  • Create challenge string format: quotes:timestamp:difficulty:random:nonce
  • Implement hash verification for submitted solutions

• Verification & Validation

  • Create challenge verification logic with HMAC validation
  • Add solution validation against original challenge
  • Test HMAC tamper detection and validation
  • Add difficulty adjustment mechanisms (config-based)

• Testing & Performance

  • Unit tests for challenge generation and verification
  • Unit tests for HMAC signing and validation
  • Unit tests for PoW solution finding and verification
  • Benchmark tests for different difficulty levels
  • Test edge cases (expired challenges, invalid HMAC, wrong difficulty)
  • Performance tests for concurrent challenge operations

Phase 2: Quote Handler

Goal: Simple quote service with public API using resty

• Add resty dependency to go.mod
• Create quote service package
• Implement quote fetching with HTTP client
• Add basic error handling

Phase 3: Service Layer Implementation

Goal: Complete service layer with DI for handling requests (untied from TCP presentation)

• Create service layer interfaces and contracts
• Implement quote request service workflow
• Integrate PoW challenge generation and verification
• Set up simple dependency wiring
• Implement full request-response cycle
• Add comprehensive service layer tests
• Add error handling and validation
• Create public concrete WisdomService type
• Add workflow tests with real PoW implementations
• Add unsuccessful flow tests for invalid solutions

Phase 4: Binary Protocol Implementation

• Implement binary message protocol codec with Reader/Writer abstraction
• Create protocol message types and structures
• Add message serialization/deserialization (JSON)
• Implement protocol parsing with proper error handling
• Create message validation and bounds checking
• Write unit tests for protocol components

Phase 5: Binary Protocol Reworking & Application Layer Integration

• Refactor protocol codec into streaming MessageDecoder
• Implement streaming message processing with io.Reader
• Create request/response encoding and decoding methods
• Add comprehensive round-trip testing for protocol validation
• Update application layer to use streaming Message interface
• Fix application tests for new protocol design

Phase 6: TCP Server & Connection Management

• Implement TCP server with connection handling
• Add dual timeout protection:
  • Connection timeout (max total connection time)
  • Read timeout (max idle time between bytes - slowloris protection)
• Implement proper connection lifecycle management
• Create protocol state machine for request/response flow
• Add graceful connection cleanup and error handling
• Add slog structured logging to TCP server
• Implement functional options pattern for server configuration
• Update cmd/server to use new TCP server with logging

Phase 7: Client Implementation

• Create client application structure
• Implement PoW solver algorithm on client side
• Create client-side protocol implementation
• Add retry logic and error handling
• Implement connection management
• Create CLI interface for client
• Write client integration tests for slowloris protection

Phase 8: Basic Server Architecture

• Set up metrics collection (prometheus)
• Create configuration management
• Integrate all components into server architecture

Phase 9: Advanced Server Features

• Add connection pooling and advanced connection management
• Implement graceful shutdown mechanism
• Add health check endpoints
• Add request/response logging middleware
• Create health check endpoints
• Write integration tests for server core

Phase 10: DDOS Protection & Rate Limiting

• Implement IP-based connection limiting
• Create rate limiting service with time windows
• Add automatic difficulty adjustment based on load
• Implement temporary IP blacklisting
• Create circuit breaker for overload protection
• Add monitoring for attack detection
• Write tests for protection mechanisms

Phase 11: Observability & Monitoring

• Add structured logging throughout application
• Implement metrics for key performance indicators:
  • Active connections count
  • Challenge generation rate
  • Solution verification rate
  • Success/failure ratios
  • Response time histograms
• Create logging middleware for request tracing
• Add error categorization and reporting
• Implement health check endpoints

Phase 12: Configuration & Environment Setup

• Create configuration structure with validation
• Support environment variables and config files
• Add configuration for different environments (dev/prod)
• Implement feature flags for protection levels
• Create deployment configuration templates
• Add configuration validation and defaults

Phase 13: Docker & Deployment

• Create multi-stage Dockerfile for server
• Create Dockerfile for client
• Create docker-compose.yml for local development
• Add docker-compose for production deployment
• Create health check scripts for containers
• Add environment-specific configurations
• Create deployment documentation

Phase 14: Testing & Quality Assurance

• Write comprehensive unit tests (>80% coverage):
  • PoW algorithm tests
  • Protocol handler tests
  • Rate limiting tests
  • Quote service tests
  • Configuration tests
• Create integration tests:
  • End-to-end client-server communication
  • Load testing scenarios
  • Failure recovery tests
  • DDOS protection validation
• Add benchmark tests for performance validation
• Create stress testing scenarios

Phase 15: Documentation & Final Polish

• Write comprehensive README with setup instructions
• Create API documentation for all interfaces
• Add inline code documentation
• Create deployment guide
• Write troubleshooting guide
• Add performance tuning recommendations
• Create monitoring and alerting guide

Phase 16: Production Readiness Checklist

• Security audit of all components
• Performance benchmarking and optimization
• Memory leak detection and prevention
• Resource cleanup validation
• Error handling coverage review
• Logging security (no sensitive data exposure)
• Configuration security (secrets management)
• Container security hardening

Directory Structure

/
├── cmd/
│   ├── server/          # Server application entry point
│   └── client/          # Client application entry point
├── internal/
│   ├── server/          # Server core logic
│   ├── protocol/        # Protocol implementation
│   ├── pow/             # Proof of Work implementation
│   ├── quotes/          # Quote management
│   ├── ratelimit/       # Rate limiting & DDOS protection
│   ├── config/          # Configuration management
│   ├── metrics/         # Metrics collection
│   └── logger/          # Structured logging
├── pkg/                 # Public packages
├── test/                # Integration tests
├── docker/              # Docker configurations
├── deployments/         # Deployment configurations
└── docs/                # Additional documentation

Success Criteria

• Server handles 1000+ concurrent connections
• PoW protection prevents DDOS attacks effectively
• All tests pass with >80% code coverage
• Docker containers build and run successfully
• Client successfully solves challenges and receives quotes
• Comprehensive logging and metrics in place
• Production-ready error handling and recovery
• Clear documentation for deployment and operation