Intrinsically Secure
WirelessHART® Field
Device Networks andthe Industrial Internetof Things (IIoT)
White Paper

Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Introduction
With the growing interest in the Internet of Things,
as well as growing scrutiny of the security ofmanufacturing networks, there are ways to put thepower of IIoT securely to work in your process
plant.

International standards such as ISA/IEC-62443
provide best practices for developing secure
information and operational technology (IT and OT)
networks.

Device connectivity and increased use of wirelessnaturally increase data management requirements
and by association security of that data.

WirelessHART was designed to be intrinsicallysecure. It has been vetted through international
standardization processes government security
audits and – many years of successful usage, withtens of thousands of networks installed.

– PAGE 1 –Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Table of Contents
Who Should Read this White Paper ................................................................................................ 3
Executive Summary ......................................................................................................................... 3
Key Takeaways ................................................................................................................................ 3WirelessHART Basics ...................................................................................................................... 4
Data Security .................................................................................................................................... 4
Strong Key Management ................................................................................................................. 6
Advanced best practices for experienced users and IT professionals ............................................ 7Conclusion ....................................................................................................................................... 7
Glossary ........................................................................................................................................... 8– PAGE 2 –Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Who Should Read this White Paper
This paper will benefit everyone who uses or designs enterprise security as well as those who maintain
WirelessHART networks or interested in learning more about WirelessHART security features.

Executive Summary
This paper provides a discussion of security features and use cases for deploying intrinsically safe
WirelessHART networks.
The paper is organized into the following sections:Introductory information for users who are new to WirelessHART technologyStandard best practices for users



Advanced best practices for experienced users and IT professionals

GlossaryKey Takeaways

WirelessHART was designed with a priority placed on security from day one

The WirelessHART specification provides vendors and end users with numerous levels ofsecurity

All WirelessHART communications are required to be encryptedBest practices recommend a layered approach to security

Security considerations for WirelessHART deployments– PAGE 3 –Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

WirelessHART Basics

 Radio security features including:WirelessHART (IEC 62591) is a wireless fielddevice communication protocol that is part of theHART (Highway Addressable RemoteTransducer) protocol. WirelessHART, a selforganizing mesh network, uses the IEEE
802.15.4 radio standard, which describes lowpower wireless communications.

o spatial diversity

WirelessHART has been designed by industry
experts with security in mind. It is an open,
multivendor, interoperable protocol that issecure out of the box with security always on
and no user configuration needed. This makes
WirelessHART a simple, easy to use protocol
designed primarily for industrial and otherapplications.
WirelessHART keeps your data secure byimplementing strong encryption using AES 128bit multiple encryption keys, based on the FIPS197 standard, a U. S. Government standard forencrypting data. The confidentiality and integrityof your data is ensured as data travels throughthe network. Even though a field device mayroute your data, that field device will not havethe encryption keys and cannot read the data.
WirelessHART (IEC62591) technology, as
designed by leading engineers and scientists
from member companies of the FieldComm
Group, meets or exceeds process industry
security requirements. WirelessHART devices
have been successfully used in NERC CIP
compliant environments, IEC-62443
environments, as well as having beensuccessfully deployed within the NIST
framework.
Major security features of the protocol
 128-bit message encryptiono Encryption protects against
eavesdropping

o time and frequency diversity
o power and coding diversity with DSSS
(direct sequence, spread spectrum)

What is a meshnetwork?

 Protections against replay “man in themiddle”, “sink hole” and other attacks

A mesh is a network
topology that allows all the Verifications that messages haven’t been
tampered by using integrity codes
 Secure join process with all devices
authenticatedo Prevents against unauthorized devices
from joining your network Data confidentiality as it’s routed aroundthe network utilizing keys

nodes (devices) on thenetwork to communicate
with each other.
WirelessHART is
designed as a selforganizing wireless meshnetwork in which each Individual sessions with any two
WirelessHART entities

node acts as a transmitter Protection against non-repudiation

with a gateway and Protection against “denial of service”

and a receiver of data,associated Network
Manager and Security

 Multi-path mesh networking

Manager. Using
algorithms designed into

Data Security
There are three basic parts to keeping your data
secure and usable. First, your data must be
available. Next, your data should be confidential,and finally, your data integrity must be assured.
Your data must be available or it is useless—you get the data, when and how you need it.
Keeping your data confidential means that only
authorized people or systems can understandthe data and use it. Data integrity means thatyou can trust that the data hasn’t been harmed
or changed.

 Multiple encryption keys

– PAGE 4 –each node or device, thenetwork organizes itself
with optimized
transmission pathways sothat data arrives at thegateway in the most timely
manner. The figure below
depicts a WirelessHART
mesh network.

Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Data Availability
Availability is accomplished by specifying IEEE
802.15.4 compliant radios in a wireless meshnetwork configuration employing frequency, orchannel, hopping technology. The protocol
provides for multiple tries, re-routing, and themesh is self-organizing to provide robustness.

with privacy. This prevents eavesdropping byunauthorized devices inside or outside thenetwork. A WirelessHART sensor network
provides end-to-end AES-128-bit encryption at
the network/transport layer from the data source(e.g. WirelessHART instrument) to the data
consumer (e.g WirelessHART Gateway).
Encryption methods include the use of several

What is an encryption
key?

WirelessHART instruments automatically use a
pseudo-random channel hopping sequence toreduce the chance of interference with otherkeys:

An encryption key is arandom string of bits
created explicitly forscrambling andunscrambling data.
Encryption keys aredesigned with algorithms
intended to ensure thatevery key is unpredictableand unique.
The longer the key built inthis manner, the harder itis to crack the encryption
code. An encryption key isused to encrypt, decrypt,
or carry out both functions,based on the sort ofencryption software usedhttps://www.techopedia.co

networks, such as IEEE 802.11b/g (Wi-Fi),
which operates in the same ISM frequency
band. Additionally, each network operates on astrict overall timing schedule and each
instrument on the network is assigned a time tocommunicate based on this schedule.
Together, pseudo-random channel hopping andnetwork scheduling act as strong deterrents tosecurity breaches independent of, and in
addition to, the cryptographic features of theprotocol.

Data Confidentialitym/definition/25403/encrypt
ion-key

Another integrated and automatic capability ofWirelessHART is how confidentiality is
maintained by using security features associated– PAGE 5 –1.

Individual session encryption keys,

2.

A common network encryption key,

3.

A separate network join encryption key.

Each key provides security and ensuresconfidentiality for specific WirelessHART use
cases.

Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Simplifying security forend users
Security is not an option
with WirelessHART. Butwith numerous featuresand methods to implement
security practices simple,robust, and functional
product design is theresponsibility of suppliers.
Many security bestpractices are automaticallymanaged by implementers

Data Integrity and Authentication
Data protection security features associated withintegrity and authentication ensure that data
sent over the wireless sensor network havecome from the correct source and have not been
intentionally or unintentionally tampered with oraltered.
Keyed message integrity codes (MICs) andcyclic redundancy checks (CRCs) are includedin each WirelessHART data packet to ensure
integrity. The receiving devices use these codes
to confirm that the contents of the packet(s)have not been altered. If the received code
doesn’t match the calculated code, then themessage is discarded.
Data authentication involves verifying that thepacket of data has come from the correct sourcein order to ensure the data can be used and canrelied upon. All data communications occur via
end-to-end authenticated, secure sessions. The
establishment of these secure sessions isdiscussed later in this white paper.

Strong Key Management
An extremely important part of WirelessHART
security involves proper encryption key
generation and management. WirelessHART

uses multiple keys at multiple layers to ensure
security, confidentiality, data integrity andauthentication. Join keys, session keys andnetwork keys are used in different ways to protect
your data.

Key Management is Crucial for Security
Just as in the IT world, passwords must be kept ina secure fashion. Similarly, for WirelessHART,keys must be stored and distributed securely toensure their secrecy.
Encryption keys should be randomly generated
and must be protected. The use of strong keys
rather than default keys, makes it nearly
impossible for an attacker to be able to guess avalid key. For this reason, WirelessHART provides
the capability to utilize random strong keys. Somesystems allow users to choose their own joinkeys; in these cases, these join keys should beselected and protected carefully. Some othersystems may automatically support this entire join
key process. All other keys are randomlygenerated by the WirelessHART network system.
If a common join key is being utilized, it should bechanged periodically to increase the overall
integrity of the system. Note: if the network is
configured to use unique join keys, (also known
as an access control list), rotation or changing is– PAGE 6 –of the specification,
making them invisible tousers and greatly
simplifying procedures.

Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Never Use Default Keysor Passwords
In line with the security
best practices, default
keys are not as safe or as
strong as a randomly
generated key. It isstrongly recommended

not required, since each key is generated forthat device. Ensuring all devices are on thenetwork when the join key is changed will makesure devices aren’t orphaned. Some
implementations of WirelessHART support
automatic changing of keys.
The Security Manager, a part of the
WirelessHART system, is usually embedded
within the WirelessHART Gateway andautomatically handles all keys except for the join
key. As a user, this leaves only one type of keyto control. In some cases, the security manager
can also automatically manage this type of key
as well. Implementations which hide all keys
from view reduce the chance of inadvertent
exposure.

that randomly generated
keys be used.

Advanced best practices forexperienced users and IT
professionals
WirelessHART has built in security. For tips,recommendations and best practices for yourspecific system, consult your vendor for
additional information. The IEC 62591
WirelessHART Engineering Systems Guide (linkhere) is also an excellent resource for additional
good design and installation practices.

Device Access Control Lists Using
Unique Join Keys
When designing networks, every network musthave a unique network ID and a join key before
a device can join the network. This join key canbe common for each device on the network or it
can be unique to each device, creating an
Access Control List (ACL). The resulting ACL
identifies devices which are permitted to join thenetwork, also known as a whitelist. By using
such a device access control list, you can block
unknown nodes from joining and/or monitoring
your network.

Physical Security
Physical security adds important protection to
any security program and helps protect systems
and information. Restricting physical access by– PAGE 7 –unauthorized personnel helps to protect end
user assets. This is true not only for
WirelessHART systems, but all systems usedwithin the facility. Unauthorized personnel canintentionally or unintentionally cause significant
damage to equipment. Access to control systemequipment should only be granted to authorized
personnel.

Conclusion
The WirelessHART protocol has been
specifically designed to provide the highest levelof data security to users of field devices in theprocess industries. Combining the designed-in
security features of WirelessHART with both
Operational Technology (OT) and Information
Technology (IT) network best practices willproduce a high performance wireless fielddevice network that maximizes data availability,
confidentiality, and integrity, while dependably
delivering process data in the industrial industry.
Work with your vendor to better understandspecifics.

Intrinsically Secure WirelessHART® Field Device Networks and the Industrial Internet of Things (IIoT)

Glossary

FieldComm Group is a
global standards-based

AES 128-bit encryption: Advanced Encryption Standard using a 128-bit block.
Encryption Key: a security measure that turns data into an unreadable cipher.

non-profit member
organization consisting ofleading process end

Field Device: Valve, Transmitter or other device with WirelessHART enabled.

users, manufacturers,

FieldComm Group: the organization that owns the HART and WirelessHART, Foundation Fieldbus
and FDI specifications.

universities and research

Gateway: the connection from the WirelessHART field devices to the control system.

organizations that work
together to direct thedevelopment,

HART: Highway Addressable Remote Transducer protocol for wired and wireless communication
between field devices and a control system

incorporation andIEEE 802.11 b/g: WiFi

communication

implementation oftechnologies for theIEEE 802.15.4 mesh network standard for wireless devices

process industries.

IT: Information Technology (as opposed to OT)
MIC: Message Integrity Check, a field in the data designed to indicate that the data hasn’t been
tampered with or changed.
Mesh Network: A network composed of nodes that can communicate with every node on thenetwork. A wireless mesh network can be self-organizing and provide optimization for communicationfrom each node.
Network Manager: software that controls the mesh network
OT: Operations Technology, IT for the plant floor (as opposed to IT)
Security Manager: software that provides the security features of a WirelessHART network
Whitelist: a list of all the trusted devices on the network.

For More Information, contact:
FieldComm Group9430 Research Blvd., Suite 1-120 Austin, TX
78759 US
Tel: 512.792.2300
www.fieldcommgroup.org
June 2017©2017 FieldComm Group– PAGE 8 –