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Cryptographic Protocols for a Secure and Privat...

Cryptographic Protocols for a Secure and Private IoT

Mrinal Wadhwa

April 19, 2021
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  1. Implicit trust in network boundaries Lack of mutual authentication Lack

    of end-to-end data integrity and confidentiality Poor management of keys and credentials
  2. Implicit trust in network boundaries Lack of mutual authentication Lack

    of end-to-end data integrity and confidentiality Poor management of keys and credentials
  3. The phone may not be online all the time so

    the service also caches this data to deliver it later … Heart Rate Monitor Heart Rate Service 80 bpm Heart Rate Application
  4. Initiator Responder Shared Secret Shared Secret M1 M2 M3 The

    shared secret is then used as a key in Symmetric Key Cryptography to maintain con fi dentiality and integrity of application data. Application Data - Authenticated Encryption The entities involved use Public Key Cryptography to authenticate each other and agree on a shared secret. Authenticated Key Exchange D Secure Channel
  5. Coming back to our heart rate solution, for secure communication

    … Heart Rate Monitor Heart Rate Service Heart Rate Application
  6. Heart Rate Monitor Heart Rate Service Secure Channel We setup

    a secure channel between the monitor and the service. Heart Rate Application
  7. Heart Rate Monitor Heart Rate Service Secure Channel Secure Channel

    And another secure channel between the phone and the service. Heart Rate Application
  8. Heart Rate Monitor Heart Rate Service Transport Layer Security Transport

    Layer Security Since these devices have direct access to the internet, with TLS … Heart Rate Application
  9. Heart Rate Monitor Heart Rate Service 80 bpm Transport Layer

    Security Transport Layer Security Heart Rate Application
  10. Heart Rate Monitor Heart Rate Service 80 bpm 0x217c5111… Transport

    Layer Security Transport Layer Security Heart Rate Application
  11. Heart Rate Monitor Heart Rate Service 80 bpm 0x217c5111… 80

    bpm Transport Layer Security Transport Layer Security Heart Rate Application
  12. Heart Rate Monitor Heart Rate Service 80 bpm 0x217c5111… 80

    bpm 0x8621f842… Transport Layer Security Transport Layer Security Heart Rate Application
  13. Heart Rate Monitor Heart Rate Service 80 bpm 0x217c5111… 80

    bpm 0x8621f842… 80 bpm This type of setup is industry best practice. Transport Layer Security Transport Layer Security Heart Rate Application
  14. Heart Rate Monitor Heart Rate Service 80 bpm 0x217c5111… 80

    bpm 0x8621f842… 80 bpm But even when we manage to setup the channels correctly the data is still exposed to the service. 
 The service doesn’t need to know the contents of the message to route and cache messages (its primary job). Transport Layer Security Transport Layer Security Heart Rate Application
  15. Least Privilege. Principle of Every program and every privileged user

    of the system should operate using the least amount of privilege necessary to complete the job.” — Jerome Saltzer, Communications of the ACM, 1974
  16. Route/Cache sensor data, alerts and videos. Camera Door Bell Camera

    Door Bell Application Camera Door Bell Service
  17. Gateway Flood Warning Sensor Multiple transport protocols in the path

    of one message. TCP TCP Flood Monitoring System Sensors Vendor’s Service LPWAN
  18. Gateway Flood Warning Sensor Flood Monitoring System Sensors Vendor’s Service

    Various protocols have various different secure channel designs. TLS TLS LPWAN
  19. Gateway Flood Warning Sensor A secure channel that is decoupled

    from the transport layer connections. 
 The gateway and sensor vendor shouldn’t be exposed to application data. Flood Monitoring System Sensors Vendor’s Service
  20. D D D … Devices … … Gateways … Lighting

    HVAC Water Monitoring Elevators Access Control Fire Safety Waste Parking … Vendor IoT Backends … System Integrator 1 Building Management System … SI IoT Backends … System Integrator 2 G G D D D D D D D D D D D D D D D D D D D D D G G G G G G G G G G G G G G Complexity & attack surfaces grow to be unmanageable. Proprietary data is leaked. Security becomes untenable.
  21. D D D … Devices … … Gateways … Lighting

    HVAC Water Monitoring Elevators Access
  22. Implicit trust in network boundaries Lack of mutual authentication Lack

    of end-to-end data integrity and confidentiality Poor management of keys and credentials