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ADR-0010: Session Token Storage Strategy for SPIKE Nexus


  • Status: accepted
  • Date: 2024-11-03
  • Tags: Security, Sessions, Memory Management, Scalability

Context

SPIKE Nexus requires storage of session tokens for admin authentication. We need to evaluate the option of storing these tokens in-memory (as opposed to storing them in a database).

Key considerations:

  • SPIKE Nexus is primarily used by administrators, not end-users
  • Session persistence across server restarts is not a critical requirement
  • Security is a primary concern for the SPIKE ecosystem
  • User scale is limited (admin-focused tool)
  • Memory consumption for session tokens is minimal

Decision

We will implement in-memory storage for session tokens in SPIKE Nexus instead of storing them in the database.

Rationale

Why In-Memory Storage:

Enhanced Security

  • Eliminates risks associated with persistent storage
  • Reduces attack surface by removing database attack vectors
  • Automatic token invalidation on server restart provides security benefit
  • Aligns with SPIKE’s security-first approach

Performance

  • Faster token validation due to in-memory access
  • Eliminates encryption/decryption overhead
  • Reduces database load

Simplicity

  • Simpler implementation and maintenance
  • No need for token cleanup mechanisms
  • Reduces complexity in encryption management

Scale Considerations

  • Limited admin users means memory impact is negligible
  • Session tokens are small in size
  • Vertical scaling is sufficient for admin-focused tool

Why Not Database Storage

  1. Session persistence across restarts is not a requirement
  2. Additional security exposure through database is unnecessary
  3. Encryption/decryption overhead is not justified
  4. Database cleanup complexity can be avoided

Consequences

Positive:

  1. Improved security posture
  2. Simplified implementation
  3. Better performance
  4. Reduced maintenance overhead

Negative:

  1. Sessions will be lost on server restart/crash
  2. No persistent audit trail of sessions
  3. Potential minor increase in memory usage
  4. May complicate future horizontal scaling if needed

Mitigations:

  1. Clear documentation that sessions require re-authentication after server restart
  2. Implement proper logging for security events to compensate for lack of session history
  3. Monitor memory usage in production
  4. Consider distributed caching solutions if horizontal scaling becomes necessary

Implementation Notes

  1. Use thread-safe in-memory data structure for token storage
  2. Implement session timeout mechanism
  3. Add monitoring for memory usage
  4. Include proper logging for security-relevant events