SnmpKit v0.4.0 Release Notes

🎉 Major Release: Complete SNMPv3 Support

Release Date: December 2024
Version: 0.4.0
Previous Version: 0.3.7

🚀 Overview

This is a major milestone release that introduces complete SNMPv3 support with the User Security Model (USM), achieving 100% test coverage with 1,271 passing tests. This release transforms SnmpKit into a production-ready, enterprise-grade SNMP toolkit with full protocol compliance.

✨ Major New Features

🔐 Complete SNMPv3 User Security Model (USM)

  • Full message encoding/decoding for all SNMPv3 security levels
  • Discovery message support for engine ID discovery
  • Time synchronization capabilities
  • Security parameter processing with proper validation

🔒 Authentication Protocols

  • MD5 (RFC 3414) - Legacy support
  • SHA-1 (RFC 3414) - Legacy support
  • SHA-224 (RFC 7860) - Modern security
  • SHA-256 (RFC 7860) - Recommended
  • SHA-384 (RFC 7860) - High security
  • SHA-512 (RFC 7860) - Maximum security

🛡️ Privacy (Encryption) Protocols

  • DES (RFC 3414) - Legacy support
  • AES-128 (RFC 3826) - Standard encryption
  • AES-192 (RFC 3826) - Enhanced security
  • AES-256 (RFC 3826) - Maximum encryption

🔧 Security Levels

  • noAuthNoPriv - No authentication, no encryption
  • authNoPriv - Authentication only
  • authPriv - Authentication + encryption

🏗️ Technical Improvements

Message Processing

  • V3 message encoder/decoder with complete ASN.1 support
  • Scoped PDU handling for context-aware operations
  • Message flags processing for security level control
  • Security parameter encoding/decoding

Key Management

  • Key derivation functions following RFC specifications
  • Password-based key generation with proper localization
  • Engine ID-based key localization
  • Key size validation for all protocols

Error Handling

  • Comprehensive error codes with descriptive messages
  • Authentication mismatch detection
  • Graceful degradation for unsupported features
  • Input validation with security considerations

📊 Quality Achievements

Testing Excellence

  • 1,271 total tests with 0 failures (100% pass rate)
  • Comprehensive edge case coverage including:
    • Large message handling (1000+ byte payloads)
    • Protocol compliance with RFC limits
    • Authentication/encryption round-trips
    • Malformed message handling
    • Memory and performance edge cases

RFC Compliance

  • RFC 3412 - Message Processing and Dispatching
  • RFC 3414 - User-based Security Model (USM)
  • RFC 3826 - Advanced Encryption Standard (AES) Ciphersuites
  • RFC 7860 - HMAC-SHA-2 Authentication Protocols

🔧 API Enhancements

New Modules

# V3 Message Processing
SnmpKit.SnmpLib.PDU.V3Encoder

# Security Components
SnmpKit.SnmpLib.Security.Auth
SnmpKit.SnmpLib.Security.Priv
SnmpKit.SnmpLib.Security.Keys
SnmpKit.SnmpLib.Security.USM

Usage Examples

# Create SNMPv3 user
user = %{
  security_name: "myuser",
  auth_protocol: :sha256,
  auth_key: "my_auth_password",
  priv_protocol: :aes128,
  priv_key: "my_priv_password",
  engine_id: "discovered_engine_id"
}

# Create authenticated + encrypted message
message = %{
  version: 3,
  msg_id: 12345,
  msg_flags: %{auth: true, priv: true, reportable: true},
  msg_security_model: 3,
  msg_data: %{
    context_engine_id: user.engine_id,
    context_name: "",
    pdu: your_pdu
  }
}

# Encode message
{:ok, encoded} = V3Encoder.encode_message(message, user)

# Decode message
{:ok, decoded} = V3Encoder.decode_message(encoded, user)

🐛 Bug Fixes

  • Fixed ASN.1 length encoding for large messages
  • Resolved authentication mismatch issues in auth+priv scenarios
  • Corrected message data format handling for different security levels
  • Fixed key size validation for all encryption protocols
  • Improved error code consistency across security components

📈 Performance Improvements

  • Optimized message encoding/decoding with efficient ASN.1 processing
  • Streamlined security parameter handling
  • Reduced memory allocation in cryptographic operations
  • Faster key derivation with cached computations

🔄 Breaking Changes

None for existing SNMPv1/v2c users

  • All existing SNMPv1/v2c functionality remains fully backward compatible
  • SNMPv3 is an additive feature that doesn't affect existing code

For users upgrading from pre-release SNMPv3 code

  • Error codes harmonized - some authentication errors now return :authentication_mismatch instead of :authentication_failed
  • Key validation improved - more strict validation for protocol-specific requirements

🛠️ Development Improvements

  • Enhanced test suite with comprehensive SNMPv3 scenarios
  • Integration tests for end-to-end message processing
  • Edge case testing for protocol compliance
  • Performance benchmarks for cryptographic operations

📚 Documentation

  • Complete API documentation for all SNMPv3 components
  • Usage examples for each security level
  • Protocol compliance notes with RFC references
  • Security best practices guide

🚀 Migration Guide

For new SNMPv3 users

  1. Define your security requirements (auth-only vs auth+priv)
  2. Choose appropriate protocols (SHA-256 + AES-128 recommended)
  3. Implement key management using the Keys module
  4. Use V3Encoder for message processing

For existing users

  • No changes required - SNMPv1/v2c functionality unchanged
  • SNMPv3 available as additional capability when needed

🔮 What's Next

  • SNMPv3 engine discovery automation
  • Certificate-based authentication exploration
  • Performance optimizations for high-throughput scenarios
  • Extended MIB support for SNMPv3-specific objects

🙏 Acknowledgments

This release represents a significant engineering effort to bring enterprise-grade SNMPv3 support to the Elixir ecosystem. Special thanks to the community for testing and feedback during development.

📋 Full Changelog

For a complete list of changes, see the Git commit history.


Ready for Production: This release is production-ready with complete test coverage and RFC compliance. Perfect for enterprise SNMP applications requiring strong security.