Basic radio frequency
communications - 2
Session 1
Contents
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Basic security concepts
Attacks against wireless networks
Wireless technologies
Classification according to the range
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Basic security concepts
• Vulnerability
– An inherent weakness in the design, configuration,
implementation of a network or system
– This can take any form and can be intentional,
accidental, or simply an act of nature
• Threat
– Any possible event that can disrupt the operation,
functioning, integrity, or availability of a network
or system
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Basic security concepts
• Attack
– A specific technique used to exploit a vulnerability
• Example
– A threat could be a denial of service
– A vulnerability is in the design of a communication
system
– An attack could be jamming
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Basic security concepts
• Confidentiality
– Providing confidentiality means hiding the
information from an unauthorized third party
• Integrity
– Ensuring data integrity means protecting data
from being modified without authorization
• Availability
– The wireless network should be always available
to be used
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Basic security concepts
• Privacy
– Ensuring privacy means hiding the user identity,
location or service usage
• Authentication
– Process that ensures that only legitimate users
(possessing certain credentials) can access the
wireless network
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Basic security concepts
• Access Control
– Process that grants a legitimate user access to
certain information that he/she is allowed to
access
• Non-repudiation
– Activities that prevent users from denying the use
of wireless networks
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Attacks against wireless networks
• Passive attacks (1)
– Channel eavesdropping
• An attacker can place an antenna to hear the
information between the victim transmitter and
receiver
– Channel overuse
• The radio spectrum is a shared resource
• A wireless operator or a user may make an excessive
use of the radio spectrum and prevent others from
accessing it
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Attacks against wireless networks
• Passive attacks (2)
– Traffic analysis
• An analysis that shows characteristics of the traffic, e.g.
how frequently the communication takes place
• Active attacks (1)
– Channel jamming
• Part of denial of service attacks
• Performed by transmitting at the same time in the
same communication channel as the victim
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Attacks against wireless networks
• Active attacks (2)
– Identity cheat
• An attacker impersonates a legitimate user in the
wireless networks
– Spoofing
• An attacker retrieves data and sends other data to the
victim user
– Data alteration
• An attacker modifies the content of the information
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Attacks against wireless networks
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Attacks against wireless networks
• Specific vulnerabilities of wireless networks
regarding mobility, i.e. the fact that a device
can roam across different wireless networks
and network operators (1)
– Privacy of a user is threatened
– Mobile device is small
• Limited storage, computing power and energy
• Strong protection measures (e.g. strong cryptography)
are difficult to implement
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Attacks against wireless networks
• Specific vulnerabilities of wireless networks
regarding mobility, i.e. the fact that a device
can roam across different wireless networks
and network operators (2)
– Mobile device can be easily stolen
• This may lead to misuse and reverse engineering
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Wireless technologies
• RFID
• Personal networks
– Bluetooth (IEEE 802.15.1)
– ZigBee (IEEE 802.15.4)
• Wireless LAN (IEEE 802.11)
• Cellular networks
– GSM
– UMTS (3G)
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Wireless technologies
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Wireless mesh networks
Mobile ad hoc networks
Hybrid ad hoc networks
Vehicular networks
Sensor networks
Integrated networks
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RFID
• RFID (Radio Frequency Identification)
– Serves for automatic and secure reading of an IDnumber
– There are also RFID devices capable of storing
data – wireless memory (e.g. electronic passports)
• Applications (http://www1.nrk.no/nett-tv/klipp/164552)
– Logistics
– Ticketing
– Transport (e.g. Autopass), etc.
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RFID
• Operation
– An RFID tag is mounted on the object to be
identified
• The tag consists of a chip and an antenna
• Energy needed for operation of the tag is (usually)
received from the reader – a radio transmitter
– When the tag finds itself in the field of the
reader’s radio signal, it transmits an echo
– The echo is checked in the reader’s database and
thus the object is identified.
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Personal networks
• Bluetooth
– A short-range communications system intended to
replace the cables connecting portable and/or
fixed electronic devices.
– The system offers services that enable the
connection of devices and the exchange of data
between these devices.
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Personal networks
• Bluetooth
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Personal networks
• ZigBee
– A short-range communication system intended to
facilitate communication between various
technical devices, tipically home appliances.
– Simpler messages than Bluetooth
– More scalable than Bluetooth
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Wireless LAN
• Wireless LAN enables connectivity of
computing devices (PCs, laptop, printers, etc.)
by means of a radio link
• Such a connection is transparent for the users
– There is no logical difference between a wired and
a wireless connection.
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Wireless LAN
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Cellular networks
• Cellular network
– A radio network made up of a number of radio
cells, each served by a fixed transmitter, known as
a base station.
– These cells are used to cover different areas in
order to provide radio coverage over a wider area
than the area of one cell
• Example
– Mobile telephony networks (GPS, UMTS)
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Cellular networks
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Cellular networks
• Abbreviations (1)
– SIM – Subscriber Identity Module
– MS – Mobile Station
– USIM – Universal Subscriber Identity Module
– ME – Mobile Equipment
– TE – Terminal Equipment
– UE – User Equipment
– BTS – Base Transceiver Station
– BSC – Base Station Controller
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Cellular networks
• Abbreviations (2)
– Node B – Analogue to BTS in UMTS
– RNC – Radio Network Controller
– BSS – Base Station Subsystem
– RNS – Radio Network Subsystem
– MSC – Mobile Switching Center
– GMSC – Gateway MSC
– SGSN – Serving GPRS Support Node
– GGSN – Gateway GPRS Support Node
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Cellular networks
• Abbreviations (3)
– VLR – Visitor Location Register
– HLR – Home Location Register
– EIR – Equipment Identity Register
– AuC – Authentication Center
– PSTN – Public Switched Telephone Network
– PLMN – Public Land Mobile Network
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Wireless mesh networks
• Mesh network
– Data communication through fixed nodes
– The connectivity allows continued communication
even if some of the nodes in the network stop
functioning
• Wireless mesh network
– Communication between the nodes is wireless
– Similar to mobile ad hoc networks, but the nodes
are in general not mobile.
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Mobile ad hoc networks (MANETs)
• A self-configuring network of mobile routers
(and associated hosts) connected by wireless
links
• Together, they form an arbitrary topology
• The routers are free to move randomly and
organize themselves arbitrarily
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Mobile ad hoc networks (MANETs)
• The network's wireless topology may change
rapidly and unpredictably
• Such a network may operate in a standalone
fashion, or may be connected to a larger
Internet
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Mobile ad hoc networks (MANETs)
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Hybrid ad hoc networks
• A structure-based network that is extended
using multi-hop communications
• The existence of a communication link
between the mobile station and the base
station is not required
– A mobile station that has no direct connection
with a base station can use other mobile stations
as relays.
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Hybrid ad hoc networks
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Vehicular networks (VANETs)
• A form of MANET
– Intended to provide communication among
nearby vehicles and between vehicles and nearby
fixed equipment (roadside equipment)
• The main goal
– providing safety and comfort for passengers
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Vehicular networks (VANETs)
• A special electronic device is placed inside
each vehicle
– Provides ad hoc network connectivity for the
passengers
• This network tends to operate without any
infrastructure
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Vehicular networks (VANETs)
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Wireless sensor networks
• Spatially distributed autonomous devices
– Use sensors to cooperatively monitor physical or
environmental conditions (temperature, sound,
vibration, pressure, motion, pollutants, etc.) at
different locations.
• In addition to one or more sensors, each node
in a sensor network is equipped with a radio
transceiver, a small microcontroller, and an
energy source, usually a battery.
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Wireless sensor networks
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Integrated networks
• Modern networks often integrate many types
of networks, including various types of
wireless networks
• Example
– Sensor networks and ad hoc networks are often
integrated to make a single network
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Integrated networks
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Classification according to range
• According to the range, wireless networks are
classified in the following way
– Short-range
• Bluetooth, ZigBee
– Medium-range
• WLAN
– Medium long-range
• Cellular
– Long-range
• Satellite global area networks
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Classification according to range
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