steffen peter, oliver stecklina, peter langend ö rfer
DESCRIPTION
An Engineering Approach for Secure and Safe Wireless Sensor and Actuator Networks for Industrial Automation Systems. Steffen Peter, Oliver Stecklina, Peter Langend ö rfer. Outline. Motivation Introduction development flow System analysis Mapping process Conclusions. - PowerPoint PPT PresentationTRANSCRIPT
IHPIm Technologiepark 2515236 Frankfurt (Oder)
Germany
IHP Im Technologiepark 25 15236 Frankfurt (Oder) Germany www.ihp-microelectronics.com © 2009 - All rights reserved
An Engineering Approach for Secure and SafeWireless Sensor and Actuator Networks
for Industrial Automation Systems
Steffen Peter, Oliver Stecklina, Peter Langendörfer
IHP Im Technologiepark 25 15236 Frankfurt (Oder) Germany www.ihp-microelectronics.com © 2009- All rights reserved
Outline
• Motivation
• Introduction development flow
• System analysis
• Mapping process
• Conclusions
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Realflex project (2008-2010)
Water works Biogas facility Roboter cell
wireless architecture for industrial automation
large distance,public networks
Small latency, dependability
Standards, existent architecture
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Waterworks scenario
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Today’s way of handling security
• Shield network and define that it is secure
not realistic in wireless networks• Enable “sort of miracle” security layer
mostly not right solution• Patch security where a hole is assumed
often not efficient
all threads considered?• Proper design of security solutions
expensive and time-consuming
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Proposed development flow
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System Analysis
• Break it down-Find atomic flows of information Data flow graph with dependencies
• Analyze each processing step separately-What are the requirements for this step?-Ignore dependencies at this stage
• Resolve dependencies-Requirements resolve over data flow
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Example
• Control pumps based on measured flow and pressure values–Uplink
-Sensors on the field PLC-Wireless connection to the Ethernet access point
–Downlink-PLCpumps-Wireless connection to the Ethernet access point-High integrity requirement
sensor AP PLC AP pump
U p l i n k D o w n l i n k
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Security properties
• Concealment / Secrecy• Integrity• Availability• Authentication• Authorization• Accountability• Non-Repudiation
Security requirements
vector
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Security Metric
Security class Attacker Attacker tools Budget
0 No security attack can be succeed 'by accident'
1 curious hacker common tools < 10,000$
2organized attacker (academic, crime)
special tools< 100,000$
3large organized attacker(crime, government)
highly specialized tools, laboratory
> 100,000$
An algorithm belongs to class c if it resists all attacks from attacker groups smaller than c.
Requirement Vector = <(0…3)7>
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Proposed development flow
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Mapping Process
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What to do if drawer is empty?
• Find a solution from scratch–State of the art–Good solution–Not efficient
• Look in neighborhood–Find close solutions–Analyze & solve the differences
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Waterworks Example
• Security: –Strong integrity
• Environment: –open field, short range wireless (802.15.4)–One message every 30 seconds
• Dependability: –node life time min. one month400mJ/operation
-Information integrity >99.9999% 1/1 million
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Waterworks Example (2)
• Assumed no direct solution found • Neighborhood: wired environment
–Security requirements fulfilled by protected environment–Information integrity realized with CRC
we have no protected environment, but CRC is fine
adapt dependencies (information integrity solved)• How to realize protected environment
–Mapping tells us AES OFB is solution (message integrity due to pair-wise shared keys)
Test against other requirements: too high energy consumption
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Waterworks Example (3)
• Problem message overhead–16 bit message + 20 bit CRC encrypted with 128 bit AES
• Solution: take one AES key for 3 messages40 bit ciphertext
Still security of 128 bit AES OFB Information integrity as in wired environment Dependency requirements fulfilled
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Conclusions
• Suitable security and safety needs consideration of–Environment–Dependability requirements–Security requirementsHuge complexity, expensive development flow
• Proposed semi-formal engineering methodology is a first answer–Requirements and potential solutions are cataloged
as result of a formal analysis processAllows reproducible problems and reusability of answers–Mapping process as efficient way to integrate applications
• Fuzzy requirements (environment) still biggest challenge for a full automatic integration process
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Thank You
Questions?