Hands On System Design Course - Code Everyday

Hands On System Design Course - Code Everyday

Day 65: Field-Level Encryption for Sensitive Log Data

Module 3: Advanced Log Processing Features | Week 10: Security and Compliance

System Design Course's avatar
System Design Course
Jul 15, 2025
∙ Paid
3
2
Share

Building Production-Grade Data Protection for Distributed Log Processing Systems

What We'll Build Today

Today you'll create a production-grade field-level encryption system that automatically protects sensitive data in your logs while keeping operational information readable. Here's what we're building:

Core System Components:

  • Intelligent PII detection engine that spots emails, phone numbers, and sensitive field names

  • AES-256-GCM encryption engine with automatic key rotation

  • Processing pipeline that encrypts only sensitive fields

  • Real-time web dashboard for monitoring and testing

  • Comprehensive audit system for compliance tracking

Key Capabilities:

  • Process 50+ logs per second with encryption overhead under 5ms

  • Automatically detect and encrypt PII while preserving debug data

  • Rotate encryption keys every 30 days for security

  • Provide complete audit trails for GDPR/HIPAA compliance

  • Integrate seamlessly with existing log processing infrastructure


Understanding the Challenge

Yesterday you implemented role-based access control that determines who can access logs. Today, we're solving an equally critical challenge: protecting sensitive data within those logs through field-level encryption.

Consider this scenario: Your e-commerce platform processes millions of transactions daily, generating logs containing user emails, phone numbers, and payment references. Compliance teams demand PII protection, but engineering teams need logs for debugging. Traditional all-or-nothing encryption makes logs useless for analysis.

Field-level encryption solves this elegantly - encrypting only sensitive fields while leaving operational data readable for debugging and monitoring.

This post is for paid subscribers

Already a paid subscriber? Sign in
© 2025 System Design Course
Privacy ∙ Terms ∙ Collection notice
Start writingGet the app
Substack is the home for great culture