WirelessHART employs robust security measures to ensure the network and data are protected at all times. This includes message confidentiality (end-to-end encryption), message integrity checking, authentication (message and device), and secure procedures for devices joining the network. Industry standard techniques are used to provide authentication and encryption.

Wireless Security

• Confidentiality - End-to end data encryption is employed to prevent sensitive data from being intercepted.
  • Encryption of data prevents an attacker from changing the data
  • Mathematically scrambles the message (AES-128)
  • Statistically very difficult to break
  • All sensor traffic is encrypted, even during the “Join” process
  • Same technology used by banks
    
• Verification -Message Integrity Code (MIC) is generated to sign the data end-to-end
  • WirelessHART devices generate a 2nd MIC that signs the entire packet on a per-hop basis
  • An encrypted nonce (message counter) makes replay attacks much more difficult
    
• Robust Operation -Denial-of-service attacks are mitigated with channel hopping and redundant paths provided by the mesh infrastructure.
  • Prevent jamming (noise injection) between the device and gateway by changing the frequency of communication across a band of frequencies (frequency hopping)
  • Redundant path routing also helps sidestep noise sources, whether malicious or not
  • Real world testing shows reliability levels equal to or better than wired systems. Refer to Appendix B for more information on network co-existence.
  • Message acknowledgement confirms to successful transmission of data to the sender which could trigger a message retry or use of a redundant path
    
• Key Management—Password protection (secure keys) is used to prevent unauthorized devices from joining the network and communicating on the network.
  • Rotating the encryption keys makes them extremely difficult to exploit
  • Separate Join and Network Keys provides additional protection levels
  • Complexity of rotating keys is seamlessly handled during normal operation
    
• Authentication—The use of individual encryption codes and passwords on a point to point basis limits the consequences of any individual device being compromised.
  • A Network Manager won’t allow new devices onto the network without prior authentication
  • Uses a joining process that is secure and simple
  • The Network Manager is responsible to maintain a “good” users list (white list), others fall into the Rogue category and are denied access
  • Monitoring: Radical changes in the sensor network topology are detected and MAY be the result of unauthorized activity