Underwater Acoustic Communication Security Team 185 · Acoustic Communication Security Team 185...

Underwater Acoustic

Communication Security

Team 185

Sponsor: Prof. Shengli Zhou

Outline •  Modems and Modulation types

•  AquaSent (OFDM) •  Benthos(FSK) •  EvoLogics (S2C) •  Linkquest (DSSS)

•  UAN physical layer security •  Types of jammers •  Types of Attack •  Jamming setup

•  Project Specification

•  Project Schedule

AquaSeNT OFDM

Multiplexing: OFDM •  OFDM may use either PSK or QAM modulation

•  An example of a parallel transmission system. •  Each sub carrier only occupies a small portion of

total bandwidth

•  Has the advantage of reducing frequency selective channel fading by employing frequency diversity.

•  OFDM suffers less from cross talk than an FDM system would

•  OFDM requires strict signal synchronization.

OFDM: Advantages •  3x to 10x greater data transmission rates; possibly

higher over short ranges

•  Insensitive to “multipath:” echoes, reflected signals that arrive with a delay time

•  Benefits to the user

•  More robust communication link: fewer errors or severed links

•  3x – 10x increase in quantity of data in an application

•  Multi-node networks are now possible: •  Assets over an area of the sea floor can be wirelessly

networked together •  Signal hopping networks can transmit data over long

ranges

OFDM: Current Uses •  IEEE 802.11a, g, n and HIPERLAN/2.

•  The wireless personal area network (PAN) ultra-wideband (UWB) IEEE 802.15.3a implementation

•  Used in several 4G and pre-4G cellular networks and mobile broadband standards:

•  The mobility mode of the wireless MAN/broadband wireless access (BWA) standard IEEE 802.16e (or Mobile-WiMAX).

•  The mobile broadband wireless access (MBWA) standard IEEE 802.20.

•  the downlink of the 3GPP Long Term Evolution (LTE) fourth generation mobile broadband standard. The radio interface was formerly named High Speed OFDM Packet Access (HSOPA), now named Evolved UMTS Terrestrial Radio Access (E-UTRA).

•  Underwater Acoustic Communications

AquaSeNT Background •  Aquatic Sensor Network Technology

(AquaSeNT) has pioneered orthogonal frequency division multiplexing (OFDM) technology for subsea communication.

•  AquaSeNT’s OFDM technology has the capacity to deliver more information using a narrower bandwidth than competing technologies.

•  Founders: •  Dr. Jun-Hong Cui - networking theory •  Dr. Shengli Zhou- digital signal processing •  Dr. Jerry Shi - low power, embedded system

design

AquaSeNT Technology & Product Development Status •  8 years of technology / concept development (academic &

commercial research)

•  Core technology is patented; 2 additional patents pending

•  Thousands of hours of lab and lake tests

•  Prototype testing, Fall, 2011 •  - Validated 3100 bps / 5 km range / horizontal communication

channel •  - High “multipath” environment where other systems fail

•  6 months continuous service, Chesapeake Bay NOAA application

•  Commercial launch: October 2012

•  AquaSeNT technology: adapted OFDM modulation techniques from WIFI and the telecommunications industry to underwater communication; data is transmitted in parallel, not in series, delivering significant benefits to the user

Benthos Frequency-Shift Keying (FSK) Underwater Acoustic Communication

Benthos Background

•  Founded: 1962 by Samuel O. Raymond in North Falmouth, Mass.

•  During the first thirty years: focused on supplying underwater equipment to military and government markets esp. the scientific community

•  2006: Acquired by Teledyne Technologies Incorporated (Now known as Teledyne Benthos)

History Highlights •  1985 Benthos imaging and

acoustic equipment used by Woods Hole Oceanographic Institution team to discover the remains of the Titanic

•  1989 Benthos deep sea cameras were used by a team led by Dr. Robert Ballard to capture images of the German WWII battleship Bismarck

•  2000 First e-mail sent from a submarine traveling at speed and depth was sent to the surface using Benthos modems Bismarck Wreckage

http://www.wrecksite.eu/docbrowser.aspx?87

Teledyne Benthos Underwater Acoustic Modems

•  Used around the world to transmit data wirelessly in underwater applications.

•  Benefits include: •  Cost saving over expensive

underwater cabling •  Extending the reach of cabled

networks (by using a set of sensor nodes that can transfer data back to the cabled networks)

•  Variety of modems available rated for different depths and operation in both shallow or deep water

ATM-885 Acoustic Telemetry Modem

Wireless Underwater Communications System

•  Modems provide wireless bidirectional communication between a “local host” and a “remote host”

•  Local/remote hosts connect to the local/remote modems respectively over serial interfaces

•  Both local modems will be ATM-885 Series

•  Local and remote hosts can also both be PCs or instruments

Wireless Underwater Communication System Block Diagram

General Types of Communication

1)  Commands •  Output by the local host

processor to the local modem over the serial interface

•  Executed either by this modem or transmitted over the acoustic link to be executed by the remote modem

2)  Data •  Output either by the

local host processor to the local modem, the reverse respectively, or both

•  Exchanged freely and bidirectionally between the two hosts over the acoustic link

The operating mode of the modem determines the type of communication

Modulation Techniques

•  Phase Shift Keying (PSK) •  Allows modems to operate at up to 15,360 bits/sec •  High bandwidth efficiency •  Primarily used when multipath interference is at a minimum •  ATM-885 Module can transmit data using PSK, but receives

data using MFSK only

•  Multiple Frequency Shift Keying (MFSK) •  Spread spectrum modulation process that transmits multiple

tones simultaneously •  Maximum bit rate of 2400 bits/sec. •  Reliability even in a high multipath environment

Methods for Increasing Reliability

•  Convolutional Coding •  Uses error correcting algorithms determined

from the data being transmitted •  Most effective for increasing reliability

•  Multipath Guard Period •  Used only with MFSK modulation •  Provides a short delay between data frames,

allowing for the dispersion of multipath signals

•  Data Redundancy (AKA frequency diversity) •  Repeats the transmission of a series of data bits

S2C Technology

Sweep Spread Carrier Technology

Sweep Spread Carrier Technology

Behind the Technology

•  S2C = Sweep Spread Carrier Technology

•  Hydro-acoustics communications mimic dolphin’s sound pattern •  dolphins chirp and sing across broad frequency

bandwidths

•  This technology spreads the signal energy over a wide range of frequencies and adapt the signal structure so that multipath components don’t interfere with each other

Behind the Technology

•  At the receiver end, advanced signal processing collects the energy and converts the signals into narrow band signals •  This achieves significant depression of

disturbances and substantial system gain •  Enables successful decoding of signals in crucial

environments even when the environments are heavily masked by noise

Background

•  Evologics is a German company founded in 2000 by leading international scientists

•  They work to develop innovative key technologies for the aerospace, maritime, and offshore industries through engineering and life sciences

•  Improving engineering by learning from nature

R-Series Underwater Acoustic Modems

Configuration Options

•  Housing: Derlin (high-grade plastic), aluminum-magnesium alloy, stainless steel

•  Interface: RS-232 (RS-485 optional) and/or Ethernet

•  Wake Up Module to save battery power •  Wakes up device only when needed

•  External power supply or internal rechargeable battery pack

Reasons to choose S2C •  When implementing an acoustic

underwater communication system, multipath propagation of acoustic waves is the biggest challenge •  Path delays that are larger than the period

lengths of the signals involved are the result of sound traveling at 1500 m/s in water

•  (Propagation – multiplication or increase) •  (Multipath propagation – production of more

paths) •  Additional signal processing must be used to

actually gain phase info out of the different path signals adding up at the receiver hydrophone

Fighting Multipath Propagation

•  Consequences of S2C modulated signal arriving at the receiver: •  It is presumed that all transmitter-receiver paths

have their own path delays and sweep time is larger than the channel delay spread. •  Sweep time is larger than the delay difference

between the longest and shortest paths •  Because of this, every signal arriving at the

receiver is located on its own instant frequency •  It is then possible to identify the different path

arrivals in the frequency domain

Fighting Multipath Propagation

•  Despreading of the received signal: •  Using the S2C carrier synchronized on the

transmitter-receiver path containing the most energy (main multipath) instead of the constant frequency carrier to get the baseband representation of the received signal

•  Problems:

•  Signal is heavily distorted by different multipath so it is crucial to filter out all distorting path arrivals before you can estimate the transmitted symbol using a matched filter

Multipath to single path systems

•  S2C is used to fix the problems encountered when fighting multipath propagation. (distortion) •  It transforms the communication system from a

multipath system to a single path system •  Every multipath arrival has its own frequency

sweep at the receiver. After despreading, the sweeps disappear and different arrivals are now on their own constant frequency with the main multipath arrival situated at 0Hz.

•  Applying a lowpass filter with a cutoff frequency, it is now possible to filter out all distorting multipaths, which isolates the main energy arrival.

DSP Comm : AquaComm Modem

High Reliability of Communications

•  Designed for highly reliable underwater communications •  Works in virtually any real world sea state where

others have failed •  Dramatically reduces operational risks and

maintenance costs

•  Major organizations have tested and proven the reliability of this modem through commercial use •  Brings certainty and confidence that your

application will work

Low Power Consumption

•  This modem uses 10 – 20 times less power than competing modems •  Lower maintenance requirements and total cost

of ownership •  Broadens the applications the modem can be

used for

Small Form and Lightweight Less than half the size of competing modems

Broadens the types of applications the modem can be used for

Ease of Integration

•  Small form factor, lightweight •  Quick and low-cost integration

•  Transparent command modes •  Lower total cost of ownership

•  Command structure that is easy to understand

•  Can quickly and successfully integrate with numerous products

Small Form and Lightweight

•  Less than half the size of competing modems •  Broadens the types of applications the modem

can be used for

Linkquest: Direct Sequence Spread Spectrum

(DSSS)

Introduction

History

•  In 1941, Hollywood actress Hedy Lamarr and pianist George Antheil described a secure radio link to control torpedoes and received U.S. patent #2.292.387.

•  In 1981, U.S. Army started using this technology and has become increasingly popular for applications that involve radio links in hostile environments.

Process

Benefits •  Resistance to intended or unintended jamming

•  Sharing of a single channel among multiple

•  Reduced signal noise level

Uses •  GPS (Navigation Systems)

•  DS-CDMA (Verizon, Sprint)

•  IEEE 802.11 (Wi-Fi)

•  Radio-Controlled model Vehicles

Modem used for the Project

UAN Physical Layer Security

Challenges to UAN Security

•  Long Propagation Delays

•  Narrow Bandwidth

•  Mutlipath Effects

•  Cannot directly apply existing terrestrial security schemes to UAN’s (Underwater Acoustic Networks)

•  Difficult to model an aqueous environment accurately

[1] Michael Zuba, Zhijie Shi, Zheng Peng, Jun-Hong Cui, Shengli Zhou, Vulnerabilities of underwater acoustic networks to denial-of-service jaming attacks, Security and Communication Networks DOI: 10.1002/sec.507 ed. , Wiley Online Library, 2012.

UAN Threats attacks and defenses

[3] Yanping Cong, Guang Yang, Zhiqiang Wei, Wei Zhou, Security in Underwater Sensor Network, College of Information Science and Engineering ed. , Qingdao, China: Ocean University of China, 2010.

Availability ensures that the network must be robust enough to be able to provide services even when the system is attacked.

However, there are some especial constraints of UWSN. We summarize these constraints below: a) Limited in energy, computation and storage. Because nodes are deployed in underwater environment, UWSN nodes can’t use solar power-charged batteries. Energy is the vital issue to consider in designing. b) Unreliable communication channel. Due to the characteristic of underwater channel such as long propagation delay, narrow bandwidth, multipath effect, selectively absorption and ambient noise, underwater channel is unreliable. c) Physical security. UWSN nodes could be deployed in enemy territory, so we cannot guarantee all nodes’ safety. d) Highly dynamic network topology. Majority of underwater sensor nodes are mobile due to water currents. From empirical observations, under-water objects may move at the speed of or 3-6 kilometers per hour in a typical underwater condition [1]. The variation of network topology can cause seriously multipath effect.

Due to the especial constraints, UWSN are vuln-erable to various attacks. We analyze these attacks in next section.

3. Threats, attacks and defenses in UWSN

Figure1. Security issues, attacks and defenses

Figure 1 depicts the protocol stack of UWSN and security issues and the various attacks that can be launched at different layers and corresponding defense technologies. The security issues mainly include: key management [3], trust model, intrusion detection, secure localization, secure synchronization [4], secure data aggregation and encryption techniques. There are a large number of threats and attacks to which UWSN are susceptible. They can be classified as data security attacks, DoS (denial of service) attacks, impersonation attacks, replication attacks and physical attacks.

Among these attacks, due to the special features of UWSN, DoS attack is more destructive than others. Even if UWSN is well protected by encryption algorithm, it is still threatened with DoS attack. DoS attack can disrupt communication and cooperation between nodes and decrease availability of the whole network, what’s more waste precious power. Dos attack is low cost, deadly and hard to detect [5]. Malicious adversary can cause great damage with very low cost. Malicious adversary impersonates a legal node to deceive neighbor nodes. In the power exhaust-tion attack, an attacker imposes a particularly complex task to a sensor node in order to shorten its battery life.

Figure 1 lists various DoS attacks that each layer is vulnerable to, and the different solutions available for its defense [6]. Some attacks crosscut multiple layers or exploit interactions between them. These types of attacks are more dangerous and destructive. Hence, we detailed analyze DoS attacks in different layers of UWSN protocol stack below. 1. Physical Layer

Underwater nodes use acoustics communication because RF radio does not propagate well. There are several kinds of attacks carried out in physical layer: jamming and tampering. 1) Jamming

Jamming is the primary DoS attack in physical layer. In a jamming attack, a malicious attacker constantly emits noises or meaningless signals, thus

163

Availability ensures that the network must be robust enough to be able to provide services even when the system is attacked.

However, there are some especial constraints of UWSN. We summarize these constraints below: a) Limited in energy, computation and storage. Because nodes are deployed in underwater environment, UWSN nodes can’t use solar power-charged batteries. Energy is the vital issue to consider in designing. b) Unreliable communication channel. Due to the characteristic of underwater channel such as long propagation delay, narrow bandwidth, multipath effect, selectively absorption and ambient noise, underwater channel is unreliable. c) Physical security. UWSN nodes could be deployed in enemy territory, so we cannot guarantee all nodes’ safety. d) Highly dynamic network topology. Majority of underwater sensor nodes are mobile due to water currents. From empirical observations, under-water objects may move at the speed of or 3-6 kilometers per hour in a typical underwater condition [1]. The variation of network topology can cause seriously multipath effect.

Due to the especial constraints, UWSN are vuln-erable to various attacks. We analyze these attacks in next section.

3. Threats, attacks and defenses in UWSN

Figure1. Security issues, attacks and defenses

Figure 1 depicts the protocol stack of UWSN and security issues and the various attacks that can be launched at different layers and corresponding defense technologies. The security issues mainly include: key management [3], trust model, intrusion detection, secure localization, secure synchronization [4], secure data aggregation and encryption techniques. There are a large number of threats and attacks to which UWSN are susceptible. They can be classified as data security attacks, DoS (denial of service) attacks, impersonation attacks, replication attacks and physical attacks.

Among these attacks, due to the special features of UWSN, DoS attack is more destructive than others. Even if UWSN is well protected by encryption algorithm, it is still threatened with DoS attack. DoS attack can disrupt communication and cooperation between nodes and decrease availability of the whole network, what’s more waste precious power. Dos attack is low cost, deadly and hard to detect [5]. Malicious adversary can cause great damage with very low cost. Malicious adversary impersonates a legal node to deceive neighbor nodes. In the power exhaust-tion attack, an attacker imposes a particularly complex task to a sensor node in order to shorten its battery life.

Figure 1 lists various DoS attacks that each layer is vulnerable to, and the different solutions available for its defense [6]. Some attacks crosscut multiple layers or exploit interactions between them. These types of attacks are more dangerous and destructive. Hence, we detailed analyze DoS attacks in different layers of UWSN protocol stack below. 1. Physical Layer

Underwater nodes use acoustics communication because RF radio does not propagate well. There are several kinds of attacks carried out in physical layer: jamming and tampering. 1) Jamming

Jamming is the primary DoS attack in physical layer. In a jamming attack, a malicious attacker constantly emits noises or meaningless signals, thus

163

Types of Attack

•  Denial of Service (DoS) Attack

•  Dummy (signal) Jammer

•  Smart (Deceptive) Attack


Dummy (Signal) Attack

•  Knows nothing about the protocols of the network

•  Generates noise to corrupt packets

•  UAN’s exist in an open environment and are particularly vulnerable.


Smart (Deceptive) Attack

•  Knows some information about the network protocols

•  Generally does not follow the MAC (medium access control protocol)

•  Uses legitimate control or data packets to corrupt the channel

•  This type of jammer will pretend to be a legitimate node.


Modes of Attack

•  Constant Attack – Continually injects signals (noise or regular packets) into the communications channel.

•  Random Attack – Will alternate between attacking and sleeping in a pseudo-random fashion.

•  Reactive Attack – When network activity is sensed the jammer will start attempting to jam the network. This is considered to be more advanced.


Jammer

•  ITC 1032 with a 12V supply


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Initial testing Setup

Transmit Receive

Jamm

Acoustic Modem

ITC-1032

Signal Coordination

Effective Jamming

•  Preamble is the most effective attacking point

•  Effective scheme requires three phases: •  Detection of transmission (1) •  Starting jamming transmission (2) •  Period of jamming transmission (3) •  Signal Propagation Time (4)


Preamble

1 2 3 4

Team 185 Schedule

IMPORTANT)DATES

School&Event&

JULY AUGUST Design&Deliverible

M T W T F S S M T W T F S S Team&Meeting

1 2 3 4 5 6 7 1 2 3 4

8 9 10 11 12 13 14 5 6 7 8 9 10 11 26@Aug First&day&of&Class

15 16 17 18 19 20 21 12 13 14 15 16 17 18 9@Sep Last&day&to&drop&without&W

22 23 24 25 26 27 28 19 20 21 22 23 24 25 23@Sep Project-Statement-Due

29 30 31 26 27 28 29 30 31 30@Sep Project-Specfication-Due

9@Oct Presentation

11@Oct First&Tank&test/Lab&Familiarization&

SEPTEMBER OCTOBER 25@Oct Last&Pool&Test

M T W T F S S M T W T F S S 28@Oct Last&day&to&drop&a&course

1 1 2 3 4 5 6 30@Oct Project-Proposal-Due2 3 4 5 6 7 8 7 8 9 10 11 12 13 1@Nov First&Pool&Test

9 10 11 12 13 14 15 14 15 16 17 18 19 20 22@Nov Last&Pool&Test

16 17 18 19 20 21 22 21 22 23 24 25 26 27 24@Nov Thankgiving&Break

23 24 25 26 27 28 29 28 29 30 31 30@Nov End&Thanksgiving&Break

30 9@Dec Final-Report-Due!!!

9@Dec Final&Exams

NOVEMBER DECEMBER 15@Dec End&Final&Exams

M T W T F S S M T W T F S S

1 2 3 1

4 5 6 7 8 9 10 2 3 4 5 6 7 8 Team&185

11 12 13 14 15 16 17 9 10 11 12 13 14 15 Meet&every&Friday&12:15

18 19 20 21 22 23 24 16 17 18 19 20 21 22

25 26 27 28 29 30 23 24 25 26 27 28 29

30 31

2013

Project Specifications

•  Team 185 Project Specification on Google Docs

Underwater Acoustic Communication Security Team 185 · Acoustic Communication Security Team 185...

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