NSA Communications Spying by Powerlines by JeremiahProphet


									                                               UNCLASSIFIED                             Cryptologic Quarterly

                      Data Communications Via Powerlines
                                           I                      I                          (b) (3)-P.L.        86-36

    The author is a member ofNSA Cohort 11 at           bine, such as in nuclear- or coal-powered electric
the Joint Military Intelligence College. Many of        power plants, or a low-speed turbine, such as is
the ideas presented in this paper were developed        used in hydroelectric power plants). The power is
as a class research paper at the Joint Military         transferred to the transmission system via a volt-
Intelligence College.                                   age step-up transformer. 3 Typical voltages in this
    The views expressed in this paper are those of      stage range from 138 kV to 500 kV or more. Bulk
the author and do not reflect the official policy       power is delivered from the generating plants via
or position of the Department ofDefense or the          this intercity transmission system (which can
u.s. government.                                        span several states) to the transmission substa-
                                                        tions where the power is transferred to a sub-
    The hunger for increased bandwidth is driv-         transmission system whose voltages range from
ing individuals, corporations, and organizations        38 kV to 138 kV; power transference is made via
to seek new methods for delivering Internet serv-       a step-down transformer. The subtransmission
ice to customers. Many of these methods are well        system delivers the high voltage throughout a city
known: radio-frequency (or wireless) communi-           or large region. Power is delivered to the con-
cations (such as the IEEE 802.11 Wireless LAN,          sumers via the distribution system. Transference
Bluetooth, and the HomeRF and SWAP                      from the subtransmission system to the distribu-
Protocols), infrared communications (IrDA),             tion system is made within regions called distri-
fiber-optic channels, high-speed telephone con-         bution substations, likewise using step-down
nections (such as DSL and ISDN or the more              transformers. Output cables from the distribution
modern Home Phoneline Networking Alliance               substations are typically called feeders.
(HomePNA) system).l One approach that is still
receiving a cool reception in the United States is a        In the United States, the distribution system
highly discussed option in Europe and the rest of       is subdivided into two components: the primary
the world using the power grid as a delivery con-       distribution system (the voltages of which run
duit for high-speed data communications. This           from 4.6 kV to 12.47 kV)4 and the secondary dis-
paper provides a brief introduction to High-            tribution system (the voltages of which are the
Speed Powerline Communications (HSPLC): the             typical 120/240/208 voltages in houses and
technologies, politi,al struggles, and future look.     offices). Power from the primary distribution sys-
                                                        tem to the secondary distribution system is trans-
The Electric Power Grid Design                          ferred via the distribution transformers common-
                                                        ly seen on top of power poles or in large metal
    Before discussing HSPLC, it is informative to       boxes near offices and apartment complexes. A
outline the construction of the power delivery sys-     typical arrangement for suburban power connec-
tems in the United States and Europe. In the            tions has four houses connected in a secondary
United States, electric power is transferred from       distribution system, being served by a single dis-
the power producer to the power user via a three-       tribution transformer. At best, a secondary distri-
stage delivery system. Electric power is generated      bution system in the U.S. services only a few
at a moderately high voltage (typically around          apartments with a single transformer.
4.16 - 13.8 kilovolts (kV); 1 kV = 1000 volts)2 at
the power plant (using either a high-speed tur-

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    Europe and most of the rest of the world use a         XlO,7 the granddaddy of powerline protocols,
single layer distribution system. Output voltages      uses amplitude modulation to send binary infor-
from the subtransmission substations range from        mation from a controller/transmitter to XlO
200 to 300 volts, depending on the country. The        modules that are plugged into a standard electri-
reasons for the differing philosophies are not         cal outlet. The control pulses consist of 120 kHz
important to this paper, but it is important to rec-   bursts with a 1ms envelope: the presence of a
ognize that in the United States usually only a        burst signals a logical "1" while the absence of a
handful of consumers connected are in a single         burst is a logical "0.,,8 A single bit is transmitted
(secondary) distribution system while in the rest      twice (for reliability)9 on each cycle of the 60 Hz
of the world hundreds of consumers can be con-         AC power sine-wave; the bursts are synchronized
nected in a single distribution system. As will be     to within 200ms of the zero-voltage crossing
seen later, these facts partially answer the ques-     point of the AC power sine-wave. As a result, its
tion of why HSPLC is of great interest in Europe       transmission rate is limited to 60 bits per second
but of only mild interest in the U.S.                  (bps). Further, a complete X-lO command con-
                                                       sists of two packets, each containing two identical
Low-speed Powerline Communications                     messages of 11 bits (voltage cycles); each packet is
Protocols                                              separated by a 3-cycle gaplO (again, redundancy
                                                       for reliability). The result is that a single X-lO
     Using the electric powerline to send informa-     command takes approximately 47 cycles of the 60
tion is not a new idea. Sweden has used its elec-      Hz signal or 0.8 seconds to send.
tric power grid for telephone communications for
many years. Further, electric power lines have             The developers of the CEBus standard (EIA-
been used throughout the world for low-frequen-        600) state that they use spread-spectrum tech-
cy communications by the electric power indus-         nology to transmit data. l l However, unlike tradi-
try, for baby monitors, or simple control func-        tional spread-spectrum techniques such as fre-
tions, using protocols such as XlO@ Home               quency-hopping or direct-sequence spreading,
Automation, Intellon CEBus@, Echelon                   the spread-spectrum of CEBus sweeps the signal
LONWorks@, or Intelogis PLUG-IN@.5 These               frequency from 100 Hz to 400 Hz for each bit.
proprietary protocols are low speed and are used       According to the developers, this overcomes some
solely for controlling consumer systems, such as       of the inherent noise problems associated with
lights, appliances or simple electronics. In addi-     higher speed powerline communications. Like
tion to these consumer-oriented protocols, the         XlO, CEBus has two fundamental components: a
power industry has a separate protocol for using       transceiver and a microcontroller. Unlike XlO,
powerlines to communicate system control               CEBus is not restricted to powerline communica-
(SCADA) data. In the past, signals used by the         tions but can use any communication media,
electric utilities for controlling signal powerline    including RF. 12 At its higher level, CEBus uses
communication have been analog. Data are trans-        its own Common Application Language (CAL) to
mitted using either amplitude modulation (either       ensure that CEBus compliant systems made by
double-sideband or single-sideband) or frequen-        different manufacturers can exchange commands
cy-shift (ON-OFF) keying on carrier frequencies        and status requests. 13 CAL creates device "con-
from 30 kHz to 500 kHz in the U.S. and from 10         texts" and object classes to communicate a
kHz to 490 kHz in Canada. 6 Because the power          given command to the appropriate device. 14 The
industry worldwide is changing its protocols for       CEBus protocol is similar to Ethernet in that
all SCADA communications, this report does not         (a) it is peer-to-peer and (b) it uses a Carrier
examine the power utility protocols.                   Sense Multiple Access/Collision Detection and
                                                       Resolution (CSMA/CDCR) protocol to avoid data

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collisions. 15 This protocol requires a network       client/server operation) or the CEBus Generic
node to wait until the line is clear so that there    Common Application Language (CAL, for peer-
will be no simultaneous transmission on the line.     to-peer operation); at the Network, Transport,
Data are transmitted at the rate of approximately     and Data Link Layers, PLUG-IN defines the
10 kilobits per second (kbps). Standard EIA 709.2     Power Line Exchange (PLX) Protocol while at the
defines the specifications to use either CEBus for    Physical Layer PLUG-IN uses the Digital Power
sending data over two- and three-phase electrical     Line (DPL) Protocol. Using DPL, PLUG-IN
powerlines. The standard restricts the powerline      boasts data transmission rates of up to 350 kbps
channel to a spectral bandwidth from 125 kHz to       using a single channel frequency. PLUG-IN uses
140 kHz and specifies data communication rates        Frequency-Shift-Keying (FSK) to encode the data
of 5.65 kbps while providing a narrow-band            onto the signal carrier. A proposed version of
power line signaling technology that meets North      PLUG-IN DPL (for Digital Power Line) is to use
American and European regulations. 16                 multiple signal channels to produce speeds of
                                                      over 1 Mbps. Bit error rates for DPL are in the
    LONWorks 17 (ANSI/EIA 701.9-A-1999) is            range of 10- 9 with 80 dB of dynamic range. The
similar to CEBus: it works as either a peer-to-peer   FSK scheme encodes the digital data onto the
or a master-slave data communication system; it       power line by using two or more separate fre-
uses spread spectrum technology to transmit           quencies that are in a fairly narrow frequency
data; and it uses a CSMA technique for data colli-    band. Like the other low-speed powerline com-
sion avoidance. Additionally, LONWorks also           munications protocols, PLUG-IN is intended for
supports many communication media including           control system communication signals. However,
twisted pair, power line, fiber-optics, coaxial       the success of DPL has led other companies to
cable, radio frequency, and infrared!8 Unlike         attempt to modify it for carrying high-speed data
CEBus, LONWorks supports higher data rates:           communications over powerlines.
from 610 bps up to 1.25 Mbps 19 and is a propri-
etary protocol, requiring a license for operation.    High-speed Powerline Communications
However, if used for data transmission over           Protocols
powerlines, LONWorks is restricted by EIA
709.2, just like CEBus. The LONWorks standard             There are many difficulties in using power-
implements a control system communication             lines for High Speed Powerline Communications
network using an open communications protocol,        (HSPLC), including the wide variation in the line
LONTalk, and LONWorks Network Services                impedance as a function of frequency, the high
(LNS), in addition to a proprietary MAC protocol      attenuation and interference problems, and the
to provide the peer-to-peer networking layer. A       signal reflections caused by signal mismatches. 21
key feature of LONworks is the LNS, which pro-        Each developer of HSPLC products has attempt-
vides an object-oriented method to connect net-       ed to solve these difficulties by proposing differ-
worked control devices. LNS clients can run on        ent protocols. While many companies and organ-
any platform (PC, MAC, UNIX, embedded, etc.).         izations have been (and still are) pushing their
LNS Server supports both LONTALK and TCP/IP           concept, only four primary protocols are actively
protocols at the transport layer.                     competing to become THE protocol for HSPLC.
                                                      These are Intellon's PowerPacket™ protocol,
    PLUG-IN 20 is based on the Open System            Intelogis' Plug-In PLX™, Digital Powerline M
Interconnection (OS!) model and defines several       (DPL), and Adaptive Networks' AN1000 Power
protocols: at the Application Layer, PLUG-IN          Line Communication system.
uses either the proprietary Intelogis Common
Application Layer (iCAL) Protocol (for

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    The HomePlug (Powerline) Alliance consists                  and modulate each carrier by a separate low-rate
of over forty members who are major manufac-                    data stream. However, where FDMA allocates
turers of computers and data communication                      each subchannel (which are typically 10 kHz to 30
equipment, including 3Com, CISCO, Compaq,                       kHz wide) to separate users, OFDM uses all the
Intel, Motorola, Panasonic, Radio Shack and                     subchannels (OFDM typically has 100-1000 sub-
Texas Instruments. On June 5, 2000,                             channels, each around 1 kHz wide)26 to broadcast
PowerPacket was selected by the HomePlug                        a single message, thus allowing more data to be
Alliance to become the basis for an industrial                  transmitted faster with a lower symbol rate than
specification in home powerline networking. 22                  in FDMA. Figure 1 is a graph of a typical
As a result, most of the manufacturers who were                 OFDM/FDMA spectrum. Coded Orthogonal
developing the other protocols (with the excep-                 Frequency Division Multiplexing (COFDM) is the
tion ofAdaptive Networks) are moving away from                  same as OFDM except that forward error correc-
their original developments and turning their                   tion is applied to the signal before transmission.
attention to creating products that will conform
to the new HomePlug standard.                                       One problem encountered with power line
                                                                communications is aliasing (distortion of a signal
                                                                due to the interference of the signals from adja-
                                                                cent channels). As data rates increase and chan-
                                                                nel bandwidths narrow, aliasing increases. In
                                                                order to prevent aliasing, guard frequency bands
                                                                are included in each subchannel. This means that
                                                                a portion of the spectrum allocated to each sub-
                                                                channel is a "dead zone" of no signal. The guard
                                                                bands in FDMA are large (typically up to 50 per-
                                                                cent of the total spectrum),27 whereas in OFDM
                                                                the guard bands are much smaller resulting in the
                                                                spacing between channels being closer in OFDM
                                                                than in FDMA. By setting all the subcarriers
                                                                orthogonal to each (hence, the definition of
                                                                Orthogonal Frequency Division Multiplexing),
                                                                interference is reduced between the closely
          Fig. 1. Time-Ftequency Spectt<l ofOFDM                spaced carriers.
                 From l.4wtey, Chapted.
    PowerPacket, now referred to as
HomePlug 1.0, uses Orthogonal                                                                          Bwding

Frequency Division Multiplexing
(OFDM) technology to transmit data
at up to 5 Megabits per second                 OblltlUCti an
(MbpS)23 in the 4- to 20-MHz fre-              to line   oc _
quency band of the powerline. 24               si.!!paI palh

OFDM is a multicarrier transmission
technique, similar to Frequency
Division Multiple Access (FDMA).25
Both of these techniques divide the                                   Fig. 2. Multipath Interference
available spectrum into many carriers                                    From l.4wtey. Chaptet 1.

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           Another of the problems with HSPLC is that                            Because of their low symbol rates, ODFM sig-
       of multipath reflections. Figure 2 below indicates                    nals are highly resistant to multipath interfer-
       the concept of multipath reflections in the case of                   ence. 28 Additionally, a time domain guard period,
       radio communications.                                                 shown in figure 3, is added to reduce the possibil-
                                                                             ity of interference due to the symbol spreading
           Multipath interference, also called "ghosting,"                   caused by the multiple paths. 29
       results when a signal travels from a transmitter to
       a receiver via multiple possible signal paths. Since                       Theoretically, the OFDM protocol should be
       the time required for a signal to travel a finite dis-                able to operate at up to 100 Mbps, although most
       tance varies directly with the distance, a signal                     devices operate at around 14 Mbps.30 Since the
       that travels over multiple paths will result in a                     RF characteristics of a powerline vary as a func-
       multitude of signals being presented at the                           tion of frequency, using different modulations
       receiver, each received signal slightly time-shifted                  would allow the channel efficiency to be opti-
       with respect to each other (i.e., having phase                        mized to its maximum potential. 31 Because the
       shifts with respect to each other). These multiple                    subchannel carriers are orthogonal to each other,
       paths can be created by reflections (in a power-                      each subcarrier in OFDM can be modulated with
       line, reflections are the result of impedance mis-                    a separate modulation scheme such as any com-
       matches between the transmission line and the                         bination of coherent or differential, phase or
       loads attached to the line) or diffractions around                    amplitude modulation schemes, including BPSK,
       obstacles (in a powerline, diffractions are caused                    QPSK, 8PSK, 16QAM, 64QAM or others.
       by imperfections, such as "kinks" or cracks in the                    Normally, this is not done, but the same modula-
       transmission line). For powerline communica-                          tion scheme is used on all subchannels for the
       tions, multipath distortion results in digital inter-                 sake of economy of design. The choice of the
       symbol interference. Like aliasing, multipath                         modulation scheme depends on how much noise
       interference increases with frequency.                                is in the channel.32

                                                                                 While the HomePlug Alliance has chosen
                       OFDM signal with half zero guard period
                                                                             ODFM to be the standard powerline communica-
                                                                             tion protocol, not everyone agrees that it is the
                                                                             best. Michael Propp, president of rival Adaptive
                                                                             Networks Inc., claims that the HomePlug proto-
                                                                             col "enables a PC-centric, point-to-point unicast-
                                                                             ing network" and that such a network is "not a
                                                                             usable home network.,,33 A rival consortium, the
                                                                             Consumer ElectroniCs Association (CEA) R7.3
                                                                             Committee, argues that, for it to be applicable for
                                                                             home use, a powerline network must be able to
                                                                             support a large number of nodes and "simultane-
                                                                             ous entertainment activities such as streaming
                                                                             audio and video, plus provisions for multicasting
                 2.4      2.6     2.8      3      3.2    3.4       3.6       and broadcasting," something PowerPacket does
                                        Samples                  x 104       not provide. 34 However, an interesting feature of
                                                                             the 14 Mbps PowerPacket chips currently being
              Fig. 3. OFDM Sig041 With GU4rq Pericxl                         produced by Intellon (INT5130) is that they come
                       From L4wrey, Ch4pter 1.                               equipped with real-time 56-bit DES encryption of

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data packets,35 a feature that has been identified            The other major HSPLC technologies, Plug-In
as a major need in powerline communications               PLX and Digital Powerline, are similar in techni-
but has not been stressed in design circles.              cal content and were discussed earlier in the low-
                                                          frequency protocols. They both operate around 1-
    Propp argues that home networks need a                2 Mbps and use frequency-shift key (FSK) tech-
wideband spread-spectrum transmission and                 niques.
adaptive equalization to ensure that some portion
of the transmitted spectrum is received without           Regulatory Issues ofPowerline
distortion due to "the multiple peaks and valleys         Communications
of the power line transfer function."36 As shown
in figure 4,37 the transmission line attenuation              There is a spirited debate raging in Europe
(the dark line) is not constant but varies with fre-      over HSPLC (the topic is hot in Europe, since the
quency. A narrowband spread-spectrum signal               technology there is capable of being cost effective.
                                                          In the U.S., the market has yet to develop so the
                                                          issue is not as hotly pursued.) The debate centers
                                                          mostly on the electromagnetic compatibility/
                                                          electromagnetic interference (EMC/EMI) issues
                                                          associated with HSPLC. Key players in this arena
                                                          are the International Powerline Communications
                                                          Forum (IPCF), the European Telecommunica-
                                                          tions Standards Institute (ETSI), the
                                                          International Telecommunication Union (ITU),
                                                          the European Radiocommunications Office
                                                          (ERa), a subcommittee of the European
      60 kHz                              <160kHz         Conference of Postal and Telecommunications
                                                          Administrations (CEPT) (ERa coordinates
 Fig. 4. Powetllne Attenuation and Spread Spechum.        radiofrequency spectrum allocations in
              From Adaptive Netwotks.                     Europe) ,38 the European Committee for
                                                          Electrotechnical Standardization (CENELEC),39
(shown with the light colored line) may not pass          and the ComiM Internationale Special des
some frequencies while a wideband spread-spec-            Perturbations Radioelectrotechnique (CISPR), a
trum signal (the medium colored line) will allow          committee of the International Electrotechnical
some portion ofthe signal to pass. However, since         Commission (IEC) dealing with the technical
the attenuation vanes with frequency (as well as          issues of EMC and other related matters. The IEC
time and distance between the source and the              itself is the worldwide standards-setting institu-
receiver), the receiver must adapt to the changing        tion concerned with all aspects of electrical tech-
conditions.                                               nology (CENELEC is the European member of
                                                          the IEC, just like the ISO is the U.S. member of
    Propp's own corporation, Adaptive Networks,           the IEC).
Inc., just happens to manufacture a product that
provides these features: the AN1000 Power line                In a nutshell, the problem is that HSPLC radi-
Communication system. Adaptive Network's pro-             ates electromagnetic energy off the power trans-
tocol, which is being considered by the CEA R7.3          mission lines. Depending on the data rate, signal
Committee for its specification, pushes wide-             frequencies of HSPLC can vary from 100 kHz to
band spread spectrum and adaptive control ofthe           30 MHz, a band of frequencies that is highly used
receiver.                                                 for mobile, marine and aeronautical distress and

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                                             UNCLASSIFIED                              Cryptologic Quarterly

calling, for time signals used by radio                the UDPITCPlIP suite. New products and new
astronomers, by airports for civil defense com-        concepts are constantly being added.
munications - in short, a wide variety of critical
communications. Currently, spectral usage in this          That said, there are many critics of the entire
area is set by ERa and the radiation limits are        concept of powerline data transmission, particu-
established by CISpR,40 The IPCF has been lob-         larly high-speed powerline communications
bying the IEC to change the standards for radia-       (HSPLC). Some of the problems and criticisms to
tion in the frequency bands. Needless to say, the      be resolved are as follows:
massive amount of coordination between the
ETSI/ITU, CISPR/IEC, ERO/CEPT and CEN-                     HSPLC is unfeasible and inefficient for data
ELEC is slowing the regulatory aspects of HSPLC        transmission. This argument is losing ground as
adoption. Additionally, there is massive resist-       practical devices capable of operating at tens of
ance by the current users of the proposed fre-         megabits per second are appearing. Tests have
quency band (coming from civil defense organi-         shown that the new devices have overcome some
zations, military, scientific (astronomy) organiza-    of the limitations inherent in older HSPLC
tions - everyone who has a stake in the outcome).      designs and that high data rates with low bit-
However, the current state of HSPLC regulation         error rates are possible.
is a declaration by the IEC that there WILL be a
revision of the frequency band and EMC limits in           HSPLC is impractical, especially in the
order to accommodate HSPLC. 41 ETSI and CEN-           United States, due to signal blockage by the
ELEC are jointly developing a new standard to          power transformers. As discussed earlier, only a
accommodate everyone, but there will be much           few consumers are linked together in the U.S. by
effort before everyone is satisfied. 42                the power distribution system while many con-
                                                       sumers are linked together by the distribution
Summary                                                system in the rest of the world. These power
                                                       transformers in the U.S. distribution system thus
      The growing digital revolution is creating an    inhibit potential Internet communication.
ever-increasing demand for bandwidth. Many             Supporters have countered by noting two areas
products and services are being introduced to ful-     HSPLC can serve: as a local area network within
fill this demand, one of which is the use of power-    a home, building, or small office (where being
lines to transport data, whether by low-speed or       able to plug-and-play a device using a standard
high-speed data transmission. Many companies           power plug is a great attraction for the consumer)
are working to create what they consider to be the     and as a bulk carrier between regions (using the
ideal approach to using powerlines for data trans-     transmission grid of the power industry).
mission. In the low~speed powerline communica-         Further, the supporters have argued that contem-
tions arena, used primarily for simple functions       porary systems are just as impractical: the cost of
such as simple system control and low-frequency        laying optical fiber to the door of each consumer
communications (e.g., baby monitors), propri-          makes that option unlikely; that DSL doesn't
etary protocols still dominate. These systems are      reach every home, particularly in the U.S.; that
well established, and the only new innovations         telephone modems rely on multiplexing in order
are to add more products to the line. On the other     to extend access to more persons (i.e., technology
hand, high-speed powerline communications is           used in telecommunications today can be easily
just entering the respectability phase of product      and cheaply adapted to HSPLC at the distribution
design. The signaling characteristics of the differ-   transformer to multiplex the users onto the rest of
ing protocols are proprietary, but the higher-level    the network); and that all telecommunication
communications protocols are proposed to be of

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options suffer degradation as the number of users               5. Feng.
increases.                                                      6. IEEE Guide for Power-Line Carrier
                                                            Applications, Draft #6 (New York: Institute of
    The biggest headache is the regulatory limits           Electrical and Electronics Engineers, Inc., July 2000),
imposed by EMC/EMI considerations. There are                22.
many opponents to HSPLC as a result of this                     7. Feng.
issue. However, regulations change, and the more                8. Amitava Dutta-Roy, "Networks for Homes,"
that industry desires the introduction of HSPLC,            IEEE Spectrum 36, No. 12, December 1999, 30. Cited
the more likely the existing regulations will be            hereafter as Dutta-Roy.
modified.                                                       9. Feng.
                                                                10. Feng.
    Security issues have been little addressed.                 11. About CEBus Standard,
There is a growing recognition that HSPLC has a             http://www.exp-math.uni-essen.de/-vinck/plc/
serious security vulnerability, particularly in             cebus_main.htm (24. July 2001).
Europe, due to the interconnectedness of the net-               12. Feng.
work and the open protocols (UDP ITCPlIP)                       13. Feng.
being proposed. Industry is starting to address                 14. Dutta-Roy, 30.
these issues, but caveat emptor.                                15. Feng.
                                                                16. "EIA-709.2 Control Network Power Line (PL)
    Powerline carrier communications is here to             Channel Specification,"
stay. It may be limited to a local area network             http://www.exp-math.uni-essen.de/-vinck/plc/ eia-
within the home or office, or it may become                 709.htm (24 July 2001). Cited hereafter as EIA-709.2.
another medium like telephone modem commu-                      17. Feng.
nications, but it will be used in the future. The               18. EIA-709.2.
only real obstacle to its full development is the               19. "Existing Powerline Communications
lack of a standard around which the entire indus-           Standards," Powerline Communications,
try can rally. The future holds the answer.                 http://www.exp-math.uni-essen.dej -vinck/plc/
                                                            cwt-faq.htm (24 July 2001).
Notes                                                           20. Feng.
    1. Xinhua Feng, 14 November 1999, Home                      21. Dutta-Roy, 30.
Networking, http://www.exp-math.uni-essen.de/                   22. "HomePlug Select Intellon's PowerPacket
-vinckjplcjhomenetworking.htm (24 July 2001).               Technology," 5 June 2000, Powerline World - News
Cited hereafter as Feng.                                    Headlines, http://www.powerlineworld.com (24 April
    2. Theodore R. Bosela, Introduction to Electrical       200l).
Power System Technology (Upper Saddle River, NJ:                23. HomePlug 1.0, www.homeplug.org (24 April
Prentice Hall, 1997), 81. Cited hereafter as Bosela.        2001).
    3. A transformer is essentially a large block of iron       24. Margaret Quan, "Sparks Fly as Power Line
whose purpose is to "transform" the voltages and cur-       Networks Surge Ahead," EE Times, 9 June 2000, 204.
rents from one system to another. A "Step-up" trans-            25. Eric Lawrey, Chapter 1 - Introduction, 24
former means that the output voltages of the trans-         October 2000, http://www.eng.jcu.edu.au/eric/ the-
former are higher than the input voltages. A "Step-         sis/MultiuserOFDM/multiuserOFDM.html (31 July
down" transformer means that the output voltages of         2001). Cited hereafter as Lawrey, Chapter 1.
the transformer are lower than the input voltages.              26. Lawrey, Chapter 1.
Transformers have great impact on data communica-               27. Lawrey, Chapter 1.
tions.                                                          28. Eric LaWTey, "Multiuser OFDM Paper,"
    4. Bosela, 89.                                          http://www.eng.jcu.edu.au/eric/thesis/

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     MultiuserOFDM/multiuserOFDM.htm (31 July                  Adaptive Networks, The Powerline As a
     2001). Cited hereafter as LaWTey, "Multiuser OFDM."   Reliable High-Speed Communication Medium.
          29. LaWTey, Chapter 1.                           http://www.adaptivenetworks.com/prsprint.pdf
          30. Margaret Quan, "Intellon Rolls HomePlug      (24 July 2001).
     Silicon As Field Trials Conclude," EE Times, 8 May
     2001.http://www.eetimes.com/story/                       Bosela, Theodore R. Introduction to
     OEG20010507S0047 (24 July 2001). Cited hereafter      Electrical Power System Technology. Upper
     as Quan, "Field Trials."                              Saddle River, NJ: Prentice Hall, 1997.
          31. LaWTey, "Multiuser OFDM."
          32. LaWTey, "Multiuser OFDM."                        Dutta-Roy, Amitava. "Networks for Homes."
          33. Margaret Quan, "HomePlug Completes           IEEE Spectrum 36, No. 12, December 1999,26 -
     Powerline Network Spec," EE Times, 28 June 2001,      33.
     (31 July 2001). Cited hereafter as Quan, "Powerline       "EIA-709.2 Control Network Power Line (PL)
     Spec."                                                Channel Specification."
          34. Quan, "Powerline Spec."                      http://www.exp-math.uni-essen.de/-vinck/
          35. Quan, "Field Trials."                        plc/eia-709.htm (24 July 2001).
          36. Michael Propp, "Power Line Protocols Back
     Multimedia Use," EETimes, October 11,1999,                "Existing   Powerline   Communications
     http://content.techweb.com/se/                        Standards."    Powerline    Communications.
     directlink.cgi?EETI9991011S0066 (24 July 2001).       http://www.exp-math.uni-essen.de/-vinck/plc/
          37. Adaptive Networks, The Powerline As a        cwt-faq.htm (24 July 2001).
     Reliable High-Speed Communication Medium,
     http://www.adaptivenetworks.com/prsprint.pdf (24          Feng, Xinhua. 14 November 1999. Home
     July 2001). Cited hereafter as Adaptive Networks.     Networking.
          38. http://www.cept.org/ (7 August 2001).        http://www.exp-math.uni-essen.de/-vinck/
          39. "Info - About CENELEC",                      plc/homenetworking.htm (24 July 2001).
     http://www.cenelec.org/Info/about.htm (7 August
     2001).                                                    Greimel, Hans. "Companies Unveil New
          40. http://www.emclab.umr.edu/cispr.html (7      Technology That Turns Electric Sockets into
     August 2001).                                         Phone Jacks." 22 March 2001. TBO.com's
          41. John Newbury, IEEE representative to the     Weather Center.
     ITU, in a public address at the 2001 IEEE Summer      http://ap.tbo.com/ap/breaking/
     Power Meeting, Vancou'(er, BC, 15 - 19 July 2001.     MGANH7T2NKC.html (23 March 2001).
          42. John Newbury,' "Regulatory Requirements
     for Power Communications Systems Operating in the        HomePlug 1.0. www.homeplug.org (24 Apr!
     High Frequency Band," Proceedings of the              2001).
     5th International Symposium on Power-Line
     Communications and Its Applications (ISPLC) ,             "HomePlug Select Intellon's PowerPacket
     Malmo, Sweden, 4-6 April 2001, 305-310.               Technology." 5 June 2000. Power/ine World -
                                                           News Headlines.
     References                                            http://www.powerlineworld.com (24 April
        About CEBus Standard.
     http://www.exp-math.uni-essen.de/                          http://www.cept.org/ (7 August 2001).
     -vinck/plc/cebus_main.htm (24 July 2001).

                                                 UNCLASSIFIED                                         Page 61

Cryptologic Quarterly                         UNCLASSIFIED

   http://www.emclab.umr.edu/cispr.html (7              Propp, Michael. "Power Line Protocols Back
August 2001).                                       Multimedia Use." EETimes.com, October 11,
   IEEE Guide for Power-Line Carrier                http://content.techweb.com/se/
Applications, Draft #6 (New York: Institute of      directlink.cgi?EET19991011S0066 (24 July
Electrical and Electronics Engineers, Inc., July    2001).
                                                        Quan, Margaret. "Intellon Rolls HomePlug
    "Info - About CENELEC."                         Silicon As Field Trials Conclude." 8 May 2001.
http://www.cenelec.org/Info/about.htm               EETimes.com. http://www.eetimes.com/story/
(7 August 2001).                                    OEG20010507S0047 (24 July 2001).

    Lawrey, Eric. "Chapter 1 - Introduction." 24       Quan, Margaret. "Sparks Fly as Power Line
October 2000.                                       Networks Surge Ahead." Electronic Engineering
http://www.eng.jcu.edu.au/eric/thesis/              Times, 9 June 2000: 204-205.
MultiuserOFDM/multiuserOFDM.html (31 July

   Lawrey, Eric. "Multiuser OFDM Paper."
MultiuserOFDM/multiuserOFDM.html (31 July

   Newbury, John. IEEE representative to the
lTD, in a public address at the 2001 IEEE
Summer Power Meeting, Vancouver, BC, 15 - 19
July 2001.

    Newbury, John. "Regulatory Requirements
for Power Communications Systems Operating in
the High Frequency Band." Proceedings of the
5th International Symposium on Power-Line
Communications and Its Applications (ISPLC),
Malmo, Sweden, 4 - 6 April 2001, 305-310.

Page 62                                       UNCLASSIFIED
                                          eONFiDENTIAL",>E1                                   Cryptologic Quarterly

                                                 .................................. /i I1\\    {b{ (3)-P.L.

          ~                   lisase~i~r Engineer/TechnologyVulnerabilityAnalyst in
        C311, a position he has held since 10 August 1998~
           (U//FOUO) He was an NSA Cooperative Educationenlployee
        from 1974 to 1977, and he has worked as a/rocketplulJ}.m~e~~I!:':::iii-iiii~                     ----,
        diagnostics engineer for Sverdrup Technologies,/198
    i   1982; as a sonar/underwater magnetics/engine.er f()r the
        Naval Coastal Systems Center, 1983; as a /nlunitions
    J   design engineer for Sandia National laboratories, 1984-
    I   1987; as a research engineer for the Georgia Tech
        Research Institute, 1988-1990; and as an assistant
        professor of engineering at John BrOwn University,
           (U//FOUO~                        //

          (U//FOUO)         Js a member of the Institute of Electrical and Electronics
        Enaineers and the American Society of Enaineerina Educators.

           (Uh'!"'OUO}1       !was certified as a Cryptologic Engineer by NSA in 1977.
        He is an NSA adjunct faculty member.

                                                                                                      /  (b) (6)

I   I

                                         CONPIO!N'fIALfflE1                                                Page 63

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