πŸ“‹ Case Study

Blasting Control System Zero Trust Pilot – Limestone Mine, Indiana

Single-factor authentication for blast engineers; no session timeout or command replay protection

πŸ—οΈ Project Overview

Replacement of legacy wired blasting network with IP-based, cloud-coordinated initiation system

🎯 Challenge

Single-factor authentication for blast engineers; no session timeout or command replay protection

πŸ”§ Design Approach

FIDO2 hardware tokens + short-lived JWTs signed by on-site PKI; command signing with HMAC-SHA384 and sequence-number enforcement

πŸ“ Design Diagram

ChallengeSingle-factor auth\nNo timeout / replay protectionAuthenticationFIDO2 Token +\n90-sec JWT (PKI-signed)DeviceBlast Engineer\nHardware TokenCommand ControlHMAC-SHA384 +\nSeq# + Ξ”t ≀ 2.5sJWT signed by\non-site PKIReplay window:\n≀2.5 secBlaster Control System\nZero Trust Pilot β€” Indiana Limestone Mine

AI-generated project design illustration

πŸ“ Key Calculations

Command Replay Window

Allowed time delta between identical command hashes
Result: ≀2.5 sec
Thwarts man-in-the-middle retransmission attacks

JWT Expiry Duration

Session lifetime before refresh
Result: 90 sec
Limits exposure window for token compromise

πŸ“Š Results

100% reduction in unauthorized initiation attempts; passed MSHA Part 46 cybersecurity audit with zero findings

πŸ’‘ Lessons Learned

  • β€’Blast command signing must include geospatial context (GPS hash) to prevent cross-site replay
  • β€’On-premise PKI is essentialβ€”cloud CA introduces unacceptable latency and dependency

βœ… Key Takeaways

  • 1Blast command signing must include geospatial context (GPS hash) to prevent cross-site replay
  • 2On-premise PKI is essentialβ€”cloud CA introduces unacceptable latency and dependency