Mrs. Linda Koontz

September 9, 2003

FILE-SHARING
PROGRAMS
Users of Peer-to-Peer
Networks Can Readily
Access Child Pornography
Statement of Linda D. Koontz
Director, Information Management Issues
United States General Accounting Office
GAO Testimony
Before the Committee on the Judiciary,
United States Senate
For Release on Delivery
Expected at 2 p.m. EDT
on Tuesday
September 9, 2003
GAO-03-1115T
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Child pornography is easily found and downloaded from peer-to-peer
networks. In one search, using 12 keywords known to be associated with
child pornography on the Internet, GAO identified 1,286 titles and file names,
determining that 543 (about 42 percent) were associated with child
pornography images. Of the remaining, 34 percent were classified as adult
pornography and 24 percent as nonpornographic. In another search using
three keywords, a Customs analyst downloaded 341 images, of which 149
(about 44 percent) contained child pornography (see the figure below).
These results are in accord with increased reports of child pornography on
peer-to-peer networks; since it began tracking these in 2001, the National
Center for Missing and Exploited Children has seen a fourfold increase--
from 156 in 2001 to 757 in 2002. Although the numbers are as yet small by
comparison to those for other sources (26,759 reports of child pornography
on Web sites in 2002), the increase is significant.
Juvenile users of peer-to-peer networks are at significant risk of inadvertent
exposure to pornography, including child pornography. Searches on
innocuous keywords likely to be used by juveniles (such as names of
cartoon characters or celebrities) produced a high proportion of
pornographic images: in our searches, the retrieved images included adult
pornography (34 percent), cartoon pornography (14 percent), child erotica
(7 percent), and child pornography (1 percent).
While federal law enforcement agencies--including the FBI, Justice's Child
Exploitation and Obscenity Section, and Customs--are devoting resources
to combating child exploitation and child pornography in general, these
agencies do not track the resources dedicated to specific technologies used
to access and download child pornography on the Internet. Therefore, GAO
was unable to quantify the resources devoted to investigating cases on peerto-
peer networks. According to law enforcement officials, however, as tips
concerning child pornography on peer-to-peer networks escalate, law
enforcement resources are increasingly being focused on this area.
Classification of Images Downloaded through Peer-to-Peer File-Sharing Program
FILE-SHARING PROGRAMS
Users of Peer-to-Peer Networks Can
Readily Access Child Pornography
http://www.gao.gov/cgi-bin/getrpt?GAO-03-
1115T
To view the full testimony, click on the link
above.
For more information, contact Linda Koontz at
(202) 512-6240 or koontzl@gao.gov.
Highlights of GAO-03-1115T, a testimony
before the Committee on the Judiciary,
United States Senate
September 9, 2003
The availability of child
pornography has dramatically
increased in recent years as it has
migrated from printed material to
the World Wide Web, becoming
accessible through Web sites, chat
rooms, newsgroups, and now the
increasingly popular peer-to-peer
file sharing programs. These
programs enable direct
communication between users,
allowing users to access each
other's files and share digital
music, images, and video.
GAO was requested to determine
the ease of access to child
pornography on peer-to-peer
networks; the risk of inadvertent
exposure of juvenile users of peerto-
peer networks to pornography,
including child pornography; and
the extent of federal law
enforcement resources available
for combating child pornography
on peer-to-peer networks. Today's
testimony is based on GAO's report
on the results of that work (GAO-
03-351),
Because child pornography cannot
be accessed legally other than by
law enforcement agencies, GAO
worked with the Customs Cyber-
Smuggling Center in performing
searches: Customs downloaded
and analyzed image files, and GAO
performed analyses based on
keywords and file names only.
Page 1 GAO-03-1115T
Mr. Chairman and Members of the Committee:
Thank you for inviting us to discuss our work on the availability of child
pornography on peer-to-peer networks. 1
In recent years, child pornography has become increasingly available as it
has migrated from magazines, photographs, and videos to the World Wide
Web. As you know, a great strength of the Internet is that it includes a
wide range of search and retrieval technologies that make finding
information fast and easy. However, this capability also makes it easy to
access, disseminate, and trade pornographic images and videos, including
child pornography. As a result, child pornography has become accessible
through Web sites, chat rooms, newsgroups, and the increasingly popular
peer-to-peer technology, a form of networking that allows direct
communication between computer users so that they can access and share
each other's files (including images, video, and software).
As requested, in my remarks today, I will summarize the results of a
review that we recently conducted to determine
? the ease of access to child pornography on peer-to-peer networks;
? the risk of inadvertent exposure of juvenile users of peer-to-peer networks
to pornography, including child pornography; and
? the extent of federal law enforcement resources available for combating
child pornography on peer-to-peer networks.
We also include an attachment that briefly discusses how peer-to-peer file
sharing works.
Results in Brief
It is easy to access and download child pornography over peer-to-peer
networks. We used KaZaA, a popular peer-to-peer file-sharing program, 2 to
search for image files, using 12 keywords known to be associated with
child pornography on the Internet.3 Of 1,286 items identified in our search,
about 42 percent were associated with child pornography images. The
remaining items included 34 percent classified as adult pornography and
1 U.S. General Accounting Office, File-Sharing Programs: Peer-to-Peer Networks Provide Ready Access
to Child Pornography,
GAO-03-351 (Washington, D.C.: Feb. 20, 2003).
2 Other popular peer-to-peer applications include Gnutella, BearShare, LimeWire, and Morpheus.
3 The U.S. Customs CyberSmuggling Center assisted us in this work. Because child pornography
cannot be accessed legally other than by law enforcement agencies, we relied on Customs to
download and analyze image files. We performed analyses based on titles and file names only.
Page 2 GAO-03-1115T
24 percent as nonpornographic. In another KaZaA search, the Customs
CyberSmuggling Center used three keywords to search for and download
child pornography image files. This search identified 341 image files, of
which about 44 percent were classified as child pornography and 29
percent as adult pornography. The remaining images were classified as
child erotica4 (13 percent) or other (nonpornographic) images (14
percent). These results are consistent with observations of the National
Center for Missing and Exploited Children, which has stated that peer-topeer
technology is increasingly popular for the dissemination of child
pornography. Since 2001, when the center began to track reports of child
pornography on peer-to-peer networks, such reports have increased more
than fourfold--from 156 in 2001 to 757 in 2002.
When searching and downloading images on peer-to-peer networks,
juvenile users can be inadvertently exposed to pornography, including
child pornography. In searches on innocuous keywords likely to be used
by juveniles, we obtained images that included a high proportion of
pornography: in our searches, the retrieved images included adult
pornography (34 percent), cartoon pornography5 (14 percent), and child
pornography (1 percent); another 7 percent of the images were classified
as child erotica.
We could not quantify the extent of federal law enforcement resources
available for combating child pornography on peer-to-peer networks. Law
enforcement agencies that work to combat child exploitation and child
pornography do not track their resource use according to specific Internet
technologies. However, law enforcement officials told us that as they
receive more tips concerning child pornography on peer-to-peer networks,
they are focusing more resources in this area.
Background
Child pornography is prohibited by federal statutes, which provide for civil
and criminal penalties for its production, advertising, possession, receipt,
distribution, and sale.6 Defined by statute as the visual depiction of a
minor--a person under 18 years of age--engaged in sexually explicit
conduct,7 child pornography is unprotected by the First Amendment,8 as it
is intrinsically related to the sexual abuse of children.
4 Erotic images of children that do not depict sexually explicit conduct.
5 Images of cartoon characters depicting sexually explicit conduct.
6 See chapter 110 of Title 18, United States Code.
7 See 18 U.S.C. § 2256(8).
8 See New York v. Ferber, 458 U.S. 747 (1982).
Page 3 GAO-03-1115T
In the Child Pornography Prevention Act of 1996,9 Congress sought to
prohibit images that are or appear to be "of a minor engaging in sexually
explicit conduct" or are "advertised, promoted, presented, described, or
distributed in such a manner that conveys the impression that the material
is or contains a visual depiction of a minor engaging in sexually explicit
conduct." In 2002, the Supreme Court struck down this legislative attempt
to ban "virtual" child pornography10 in Ashcroft v. The Free Speech
Coalition, ruling that the expansion of the act to material that did not
involve and thus harm actual children in its creation is an unconstitutional
violation of free speech rights. According to government officials, this
ruling may increase the difficulty of prosecuting those who produce and
possess child pornography. Defendants may claim that pornographic
images are of "virtual" children, thus requiring the government to establish
that the children shown in these digital images are real. Recently,
Congress enacted the PROTECT Act,11 which attempts to address the
constitutional issues raised in The Free Speech Coalition decision.12
The Internet Has Emerged as the Principal Tool for Exchanging Child Pornography
Historically, pornography, including child pornography, tended to be
found mainly in photographs, magazines, and videos.13 With the advent of
the Internet, however, both the volume and the nature of available child
pornography have changed significantly. The rapid expansion of the
Internet and its technologies, the increased availability of broadband
Internet services, advances in digital imaging technologies, and the
availability of powerful digital graphic programs have led to a proliferation
of child pornography on the Internet.
9 Section 121, P.L. 104-208, 110 Stat. 3009-26.
10 According to the Justice Department, rapidly advancing technology has raised the possibility of
creating images of child pornography without the use of a real child ("virtual" child pornography).
Totally virtual creations would be both time-intensive and, for now, prohibitively costly to produce.
However, the technology has led to a ready defense (the "virtual" porn defense) against prosecution
under laws that are limited to sexually explicit depictions of actual minors. Because the technology
exists today to alter images to disguise the identity of the real child or make the image seem computergenerated,
producers and distributors of child pornography may try to alter depictions of actual
children in slight ways to make them appear to be "virtual" (as well as unidentifiable), thereby
attempting to defeat prosecution. Making such alterations is much easier and cheaper than building an
entirely computer-generated image.
11 Public Law No. 108-21 (Apr. 30, 2003).
12 S. Rep. No. 108-2, at 13 (2003).
13John Carr, Theme Paper on Child Pornography for the 2nd World Congress on Commercial Sexual
Exploitation of Children, NCH Children's Charities, Children & Technology Unit (Yokohama, 2001).
(http://www.ecpat.net/eng/Ecpat_inter/projects/monitoring/wc2/yokohama_theme_child_pornography.
pdf)
Page 4 GAO-03-1115T
According to experts, pornographers have traditionally exploited--and
sometimes pioneered--emerging communication technologies--from the
dial-in bulletin board systems of the 1970s to the World Wide Web--to
access, trade, and distribute pornography, including child pornography.14
Today, child pornography is available through virtually every Internet
technology (see table 1).
Table 1: Internet Technologies Providing Access to Child Pornography
Technology Characteristics
World Wide Web Web sites provide on-line access to text and multimedia materials
identified and accessed through the uniform resource locator
(URL).
Usenet A distributed electronic bulletin system, Usenet offers over 80,000
newsgroups, with many newsgroups dedicated to sharing of digital
images.
Peer-to-peer filesharing
programs
Internet applications operating over peer-to-peer networks enable
direct communication between users. Used largely for sharing of
digital music, images, and video, peer-to-peer applications include
BearShare, Gnutella, LimeWire, and KaZaA. KaZaA is the most
popular, with over 3 million KaZaA users sharing files at any time.
E-mail E-mail allows the transmission of messages over a network or the
Internet. Users can send E-mail to a single recipient or broadcast it
to multiple users. E-mail supports the delivery of attached files,
including image files.
Instant messaging Instant messaging is not a dial-up system like the telephone; it
requires that both parties be on line at the same time. AOL's Instant
Messenger and Microsoft's MSN Messenger and Internet Relay
Chat are the major instant messaging services. Users may
exchange files, including image files.
Chat and Internet
Relay Chat
Chat technologies allow computer conferencing using the keyboard
over the Internet between two or more people.
Source: GAO.
14 Frederick E. Allen, "When Sex Drives Technological Innovation and Why It Has to," American
Heritage Magazine, vol. 51, no. 5 (September 2000), p. 19.
(http://www.plannedparenthood.org/education/updatearch.html)
Allen notes that pornographers have driven the development of some of the Internet technologies,
including the development of systems used to verify on-line financial transactions and that of digital
watermarking technology to prevent the unauthorized use of on-line images.
Page 5 GAO-03-1115T
Among the principal channels for the distribution of child pornography are
commercial Web sites, Usenet newsgroups, and peer-to-peer networks.15
Web sites. According to recent estimates, there are about 400,000
commercial pornography Web sites worldwide,16 with some of the sites
selling pornographic images of children. The child pornography trade on
the Internet is not only profitable, it has a worldwide reach: recently a
child pornography ring was uncovered that included a Texas-based firm
providing credit card billing and password access services for one Russian
and two Indonesian child pornography Web sites. According to the U.S.
Postal Inspection Service, the ring grossed as much as $1.4 million in just
1 month selling child pornography to paying customers.
Usenet. Usenet newsgroups also provide access to pornography, with
several of the image-oriented newsgroups being focused on child erotica
and child pornography. These newsgroups are frequently used by
commercial pornographers who post "free" images to advertise adult and
child pornography available for a fee from their Web sites.
Peer-to-peer networks. Although peer-to-peer file-sharing programs are
largely known for the extensive sharing of copyrighted digital music,17 they
are emerging as a conduit for the sharing of pornographic images and
videos, including child pornography. In a recent study by congressional
staff,18 a single search for the term "porn" using a file-sharing program
yielded over 25,000 files. In another study, focused on the availability of
pornographic video files on peer-to-peer sharing networks, a sample of 507
pornographic video files retrieved with a file-sharing program included
about 3.7 percent child pornography videos.19
15 According to Department of Justice officials, other forums and technologies are used to disseminate
pornography on the Internet. These include Web portal communities such as Yahoo! Groups and MSN
Groups, as well as file servers operating on Internet Relay Chat channels.
16 Dick Thornburgh and Herbert S. Lin, editors, Youth, Pornography, and The Internet, National
Academy Press (Washington, D.C.: 2002). (http://www.nap.edu/html/youth_internet/)
17 According to the Yankee Group, a technology research and consulting firm, Internet users aged 14
and older downloaded 5.16 billion audio files in the United States via unlicensed file-sharing services in
2001.
18 Minority Staff, Children's Access to Pornography through Internet File-Sharing Programs, Special
Investigations Division, Committee on Government Reform, U.S. House of Representatives (July 27,
2001). (http://www.house.gov/reform/min/pdfs/pdf_inves/pdf_pornog_rep.pdf)
19 Michael D. Mehta, Don Best, and Nancy Poon, "Peer-to-Peer Sharing on the Internet: An Analysis of
How Gnutella Networks Are Used to Distribute Pornographic Material," Canadian Journal of Law and
Technology, vol. 1, no. 1 (January 2002).
(http://cjlt.dal.ca/vol1_no1/articles/01_01_MeBePo_gnutella.pdf)
Page 6 GAO-03-1115T
Several Agencies Have Law Enforcement Responsibilities Regarding Child Pornography
on Peer-to-Peer Networks
Table 2 shows the key national organizations and agencies that are
currently involved in efforts to combat child pornography on peer-to-peer
networks.
Table 2: Organizations and Agencies Involved with Peer-to-Peer Child Pornography Efforts
Agency Unit Focus
Nonprofit
National Center for Missing
and Exploited Children
Exploited Child Unit Works with the Customs Service, Postal Service, and the FBI to
analyze and investigate child pornography leads.
Federal entities
Department of Justice Federal Bureau of
Investigation a
Proactively investigates crimes against children. Operates a national
"Innocent Images Initiative" to combat Internet-related sexual
exploitation of children.
Criminal Division, Child
Exploitation and Obscenity
Section
Is a specialized group of attorneys who, among other things, prosecute
those who possess, manufacture, or distribute child pornography. Its
High Tech Investigative Unit actively conducts on-line investigations to
identify distributors of obscenity and child pornography.
Department of Homeland
Security
U.S. Customs Service
CyberSmuggling Center a, b
Conducts international child pornography investigations as part of its
mission to investigate international criminal activity conducted on or
facilitated by the Internet.
Department of the Treasury U.S. Secret Service a Provides forensic and technical assistance in matters involving missing
and sexually exploited children.
Source: GAO.
a Agency has staff assigned to NCMEC.
b At the time of our review, the Customs Service was under the Department of the Treasury. Under the
Homeland Security Act of 2002, it became part of the new Department of Homeland Security on
March 1, 2003.
The National Center for Missing and Exploited Children (NCMEC), a
federally funded nonprofit organization, serves as a national resource
center for information related to crimes against children. Its mission is to
find missing children and prevent child victimization. The center's
Exploited Child Unit operates the CyberTipline, which receives child
pornography tips provided by the public; its CyberTipline II also receives
tips from Internet service providers. The Exploited Child Unit investigates
and processes tips to determine if the images in question constitute a
violation of child pornography laws. The CyberTipline provides
investigative leads to the Federal Bureau of Investigation (FBI), U.S.
Customs, the Postal Inspection Service, and state and local law
enforcement agencies. The FBI and the U.S. Customs also investigate
leads from Internet service providers via the Exploited Child Unit's
Page 7 GAO-03-1115T
CyberTipline II. The FBI, Customs Service, Postal Inspection Service, and
Secret Service have staff assigned directly to NCMEC as analysts.20
Two organizations in the Department of Justice have responsibilities
regarding child pornography: the FBI and the Justice Criminal Division's
Child Exploitation and Obscenity Section (CEOS).21
? The FBI investigates various crimes against children, including federal
child pornography crimes involving interstate or foreign commerce. It
deals with violations of child pornography laws related to the production
of child pornography; selling or buying children for use in child
pornography; and the transportation, shipment, or distribution of child
pornography by any means, including by computer.
? CEOS prosecutes child sex offenses and trafficking in women and children
for sexual exploitation. Its mission includes prosecution of individuals
who possess, manufacture, produce, or distribute child pornography; use
the Internet to lure children to engage in prohibited sexual conduct; or
traffic in women and children interstate or internationally to engage in
sexually explicit conduct.
Two other organizations have responsibilities regarding child
pornography: the Customs Service (now part of the Department of
Homeland Security) and the Secret Service in the Department of the
Treasury.
? The Customs Service targets illegal importation and trafficking in child
pornography and is the country's front line of defense in combating child
pornography distributed through various channels, including the Internet.
Customs is involved in cases with international links, focusing on
pornography that enters the United States from foreign countries. The
Customs CyberSmuggling Center has the lead in the investigation of
international and domestic criminal activities conducted on or facilitated
by the Internet, including the sharing and distribution of child
pornography on peer-to-peer networks. Customs maintains a reporting
link with NCMEC, and it acts on tips received via the CyberTipline from
callers reporting instances of child pornography on Web sites, Usenet
newsgroups, chat rooms, or the computers of users of peer-to-peer
20 According to the Secret Service, its staff assigned to NCMEC also includes an agent.
21 Two additional Justice agencies are involved in combating child pornography: the U.S. Attorneys
Offices and the Office of Juvenile Justice and Delinquency Prevention. The 94 U.S. Attorneys Offices
can prosecute federal child exploitation-related cases; the Office of Juvenile Justice and Delinquency
Prevention funds the Internet Crimes Against Children Task Force Program, which encourages
multijurisdictional and multiagency responses to crimes against children involving the Internet.
Page 8 GAO-03-1115T
networks. The center also investigates leads from Internet service
providers via the Exploited Child Unit's CyberTipline II.
? The U.S. Secret Service does not investigate child pornography cases on
peer-to-peer networks; however, it does provide forensic and technical
support to NCMEC, as well as to state and local agencies involved in cases
of missing and exploited children.
Peer-to-Peer Applications Provide Easy Access to Child Pornography
Child pornography is easily shared and accessed through peer-to-peer filesharing
programs. Our analysis of 1,286 titles and file names identified
through KaZaA searches on 12 keywords22 showed that 543 (about 42
percent) of the images had titles and file names associated with child
pornography images.23 Of the remaining files, 34 percent were classified as
adult pornography, and 24 percent as nonpornographic (see fig. 1). No
files were downloaded for this analysis.
Figure 1: Classification of 1,286 Titles and File Names of Images Identified in KaZaA
Search
22 The 12 keywords were provided by the Cybersmuggling Center as examples known to be associated
with child pornography on the Internet.
23 We categorized a file as child pornography if one keyword indicating a minor and one word with a
sexual connotation occurred in either the title or file name. Files with sexual connotation in title or
name but without age indicators were classified as adult pornography.
Page 9 GAO-03-1115T
The ease of access to child pornography files was further documented by
retrieval and analysis of image files, performed on our behalf by the
Customs CyberSmuggling Center. Using 3 of the 12 keywords that we used
to document the availability of child pornography files, a CyberSmuggling
Center analyst used KaZaA to search, identify, and download 305 files,
including files containing multiple images and duplicates. The analyst was
able to download 341 images from the 305 files identified through the
KaZaA search.
The CyberSmuggling Center analysis of the 341 downloaded images
showed that 149 (about 44 percent) of the downloaded images contained
child pornography (see fig. 2). The center classified the remaining images
as child erotica (13 percent), adult pornography (29 percent), or
nonpornographic (14 percent).
Figure 2: Classification of 341 Images Downloaded through KaZaA
Note: GAO analysis of data provided by the Customs CyberSmuggling Center.
These results are consistent with the observations of NCMEC, which has
stated that peer-to-peer technology is increasingly popular for the
dissemination of child pornography. However, it is not the most prominent
source for child pornography. As shown in table 3, since 1998, most of the
child pornography referred by the public to the CyberTipline was found on
Internet Web sites. Since 1998, the center has received over 76,000 reports
of child pornography, of which 77 percent concerned Web sites, and only
1 percent concerned peer-to-peer networks. Web site referrals have grown
from about 1,400 in 1998 to over 26,000 in 2002--or about a nineteenfold
increase. NCMEC did not track peer-to-peer referrals until 2001. In 2002,
Page 10 GAO-03-1115T
peer-to-peer referrals increased more than fourfold, from 156 to 757,
reflecting the increased popularity of file-sharing programs.
Table 3: NCMEC CyberTipline Referrals to Law Enforcement Agencies, Fiscal Years
1998-2002
Number of tips
Technology 1998 1999 2000 2001 2002
Web sites 1,393 3,830 10,629 18,052 26,759
E-mail 117 165 120 1,128 6,245
Peer-to-peer -- -- -- 156 757
Usenet newsgroups & bulletin
boards
531 987 731 990 993
Unknown 90 258 260 430 612
Chat rooms 155 256 176 125 234
Instant Messaging 27 47 50 80 53
File Transfer Protocol 25 26 58 64 23
Total 2,338 5,569 12,024 21,025 35,676
Source: Exploited Child Unit, National Center for Missing and Exploited Children.
Juvenile Users of Peer-to-Peer Applications May Be Inadvertently
Exposed to Pornography
Juvenile users of peer-to-peer networks face a significant risk of
inadvertent exposure to pornography when searching and downloading
images. In a search using innocuous keywords likely to be used by
juveniles searching peer-to-peer networks (such as names of popular
singers, actors, and cartoon characters), almost half the images
downloaded were classified as adult or cartoon pornography. Juvenile
users may also be inadvertently exposed to child pornography through
such searches, but the risk of such exposure is smaller than that of
exposure to pornography in general.
To document the risk of inadvertent exposure of juvenile users to
pornography, the Customs CyberSmuggling Center performed KaZaA
searches using innocuous keywords likely to be used by juveniles. The
center image searches used three keywords representing the names of a
popular female singer, child actors, and a cartoon character. A center
analyst performed the search, retrieval, and analysis of the images. These
searches produced 157 files, some of which were duplicates. From these
157 files, the analyst was able to download 177 images..
Figure 3 shows our analysis of the CyberSmuggling Center's classification
of the 177 downloaded images. We determined that 61 images contained
Page 11 GAO-03-1115T
adult pornography (34 percent), 24 images consisted of cartoon
pornography (14 percent), 13 images contained child erotica (7 percent),
and 2 images (1 percent) contained child pornography. The remaining 77
images were classified as nonpornographic.
Figure 3: Classification of 177 Images of a Popular Singer, Child Actors, and a
Cartoon Character Downloaded through KaZaA
Federal Law Enforcement Agencies Are Beginning to Focus Resources
on Child Pornography on Peer-to-Peer Networks
Because law enforcement agencies do not track the resources dedicated to
specific technologies used to access and download child pornography on
the Internet, we were unable to quantify the resources devoted to
investigations concerning peer-to-peer networks. These agencies
(including the FBI, CEOS, and Customs) do devote significant resources to
combating child exploitation and child pornography in general. Law
enforcement officials told us, however, that as tips concerning child
pornography on the peer-to-peer networks increase, they are beginning to
focus more law enforcement resources on this issue. Table 4 shows the
levels of funding related to child pornography issues that the primary
organizations reported for fiscal year 2002, as well as a description of their
efforts regarding peer-to-peer networks in particular.
Page 12 GAO-03-1115T
Table 4: Resources Related to Combating Child Pornography on Peer-to-Peer Networks in 2002
Organization Resources a Efforts regarding peer-to-peer networks
National Center for
Missing and
Exploited Children
$12 million to act as national resource center and
clearinghouse for missing and exploited children
$10 million for law enforcement training
$3.3 million for the Exploited Child Unit and the
CyberTipline
$916,000 allocated to combat child pornography
NCMEC referred 913 tips concerning peer-to-peer
networks to law enforcement agencies.
Federal Bureau of
Investigation
$38.2 million and 228 agents and support personnel
for Innocent Images Unit
According to FBI officials, they have efforts under way
to work with some of the peer-to-peer companies to
solicit their cooperation in dealing with the issue of
child pornography.
Justice Criminal
Division, Child
Exploitation and
Obscenity Section
$4.38 million and 28 personnel allocated to
combating child exploitation and obscenity offenses
The High Tech Investigative Unit deals with
investigating any Internet medium that distributes
child pornography, including peer-to-peer networks.
U.S. Customs
Service
CyberSmuggling
Center
$15.6 million (over 144,000 hours) allocated to
combating child exploitation and obscenity offenses b
The center is beginning to actively monitor peer-topeer
networks for child pornography, devoting one
half-time investigator to this effort. As of December
16, 2002, the center had sent 21 peer-to-peer
investigative leads to field offices for follow-up.
Source: GAO and agencies mentioned.
a Dollar amounts are approximate.
b Customs was unable to separate the staff hours devoted or funds obligated to combating child
pornography from those dedicated to combating child exploitation in general.
An important new resource to facilitate the identification of the victims of
child pornographers is the National Child Victim Identification Program,
run by the CyberSmuggling Center. This resource is a consolidated
information system containing seized images that is designed to allow law
enforcement officials to quickly identify and combat the current abuse of
children associated with the production of child pornography. The
system's database is being populated with all known and unique child
pornographic images obtained from national and international law
enforcement sources and from CyberTipline reports filed with NCMEC. It
will initially hold over 100,000 images collected by federal law
enforcement agencies from various sources, including old child
pornography magazines.24 According to Customs officials, this information
will help, among other things, to determine whether actual children were
used to produce child pornography images by matching them with images
of children from magazines published before modern imaging technology
24 According to federal law enforcement agencies, most of the child pornography published before 1970
has been digitized and made widely available on the Internet.
Page 13 GAO-03-1115T
was invented. Such evidence can be used to counter the assertion that
only virtual children appear in certain images.
The system, which became operational in January 2003,25 is housed at the
Customs CyberSmuggling Center and can be accessed remotely in "read
only" format by the FBI, CEOS, the U.S. Postal Inspection Service, and
NCMEC.
In summary, Mr. Chairman, our work shows that child pornography as
well as adult pornography is widely available and accessible on peer-topeer
networks. Even more disturbing, we found that peer-to-peer searches
using seemingly innocent terms that clearly would be of interest to
children produced a high proportion of pornographic material, including
child pornography. The increase in reports of child pornography on peerto-
peer networks suggests that this problem is increasing. As a result, it
will be important for law enforcement agencies to follow through on their
plans to devote more resources to this technology and continue their
efforts to develop effective strategies for addressing this problem.
Mr. Chairman, this concludes my statement. I would be pleased to answer
any questions that you or other Members of the Committee may have at
this time.
Contact and Acknowledgements
If you should have any questions about this testimony, please contact me
at (202) 512-6240 or by E-mail at koontzl@gao.gov. Key contributors to this
testimony were Barbara S. Collier, Mirko Dolak, James M. Lager, Neelaxi
V. Lakhmani, James R. Sweetman, Jr., and Jessie Thomas.
25 One million dollars has already been spent on the system, with an additional $5 million needed for
additional hardware, the expansion of the image database, and access for all involved agencies. The
10-year lifecycle cost of the system is estimated to be $23 million.
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Attachment: How File Sharing Works on Peer-to-Peer Networks
Peer-to-peer file-sharing programs represent a major change in the way
Internet users find and exchange information. Under the traditional
Internet client/server model, access to information and services is
accomplished by interaction between clients--users who request
services--and servers--providers of services, usually Web sites or portals.
Unlike this traditional model, the peer-to-peer model enables consenting
users--or peers--to directly interact and share information with each
other, without the intervention of a server. A common characteristic of
peer-to-peer programs is that they build virtual networks with their own
mechanisms for routing message traffic.26
The ability of peer-to-peer networks to provide services and connect users
directly has resulted in a large number27 of powerful applications built
around this model.28 These range from the SETI@home network (where
users share the computing power of their computers to search for
extraterrestrial life) to the popular KaZaA file-sharing program (used to
share music and other files).
As shown in figure 4,29 there are two main models of peer-to-peer
networks: (1) the centralized model, in which a central server or broker
directs traffic between individual registered users, and (2) the
decentralized model, based on the Gnutella30 network, in which individuals
find each other and interact directly.
26 Matei Ripenau, Ian Foster, and Adriana Iamnitchi, "Mapping the Gnutella Network: Properties of
Large Scale Peer-to-Peer Systems and Implication for System Design," IEEE Internet Computing, vol.
6, no. 1 (January-February 2002). (people.cs.uchicago.edu/~matei/PAPERS/ic.pdf)
27 Zeropaid.com, a file-sharing portal, lists 88 different peer-to-peer file-sharing programs available for
download. (http://www.zeropaid.com/php/filesharing.php)
28 Geoffrey Fox and Shrideep Pallickara, "Peer-to-Peer Interactions in Web Brokering Systems,"
Ubiquity, vol. 3, no. 15 (May 28-June 3, 2002) (published by Association of Computer Machinery).
(http://www.acm.org/ubiquity/views/g_fox_2.html)
29Illustration adapted by Lt. Col. Mark Bontrager from original by Bob Knighten, "Peer-to-Peer
Computing," briefing to Peer-to-Peer Working Groups (August 24, 2000), in Mark D. Bontrager, Peering
into the Future: Peer-to-Peer Technology as a Model for Distributed Joint Battlespace Intelligence
Dissemination and Operational Tasking, Thesis, School of Advanced Airpower Studies, Air University,
Maxwell Air Force Base, Alabama (June 2001).
30 According to LimeWire LLC, the developer of a popular file-sharing program, Gnutella was originally
designed by Nullsoft, a subsidiary of America Online. The development of the Gnutella protocol was
halted by AOL management shortly after the protocol was made available to the public. Using
downloads, programmers reverse-engineered the software and created their own Gnutella software
packages. (http://www.limewire.com/index.jsp/p2p)
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Figure 4: Peer-to-Peer Models
As shown in figure 4, in the centralized model, a central server/broker
maintains directories of shared files stored on the computers of registered
users. When Bob submits a request for a particular file, the server/broker
creates a list of files matching the search request by checking it against its
database of files belonging to users currently connected to the network.
The broker then displays that list to Bob, who can then select the desired
file from the list and open a direct link with Alice's computer, which
currently has the file. The download of the actual file takes place directly
from Alice to Bob.
This broker model was used by Napster, the original peer-to-peer network,
facilitating mass sharing of material by combining the file names held by
thousands of users into a searchable directory that enabled users to
connect with each other and download MP3 encoded music files. Because
much of this material was copyrighted, Napster as the broker of these
exchanges was vulnerable to legal challenges,31 which eventually led to its
demise in September 2002.
In contrast to Napster, most current-generation peer-to-peer networks are
decentralized. Because they do not depend on the server/broker that was
the central feature of the Napster service, these networks are less
vulnerable to litigation from copyright owners, as pointed out by Gartner.32
In the decentralized model, no brokers keep track of users and their files.
To share files using the decentralized model, Ted starts with a networked
computer equipped with a Gnutella file-sharing program such KaZaA or
31 A&M Records v. Napster, 114 F.Supp.2d 896 (N.D. Cal. 2000).
32 Lydia Leong, "RIAA vs.Verizon, Implications for ISPs," Gartner (Oct. 24, 2002).
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BearShare. Ted connects to Carol, Carol to Bob, Bob to Alice, and so on.
Once Ted's computer has announced that it is "alive" to the various
members of the peer network, it can search the contents of the shared
directories of the peer network members. The search request is sent to all
members of the network, starting with Carol; members will in turn send
the request to the computers to which they are connected, and so forth. If
one of the computers in the peer network (say, for example, Alice's) has a
file that matches the request, it transmits the file information (name, size,
type, etc.) back through all the computers in the pathway towards Ted,
where a list of files matching the search request appears on Ted's
computer through the file-sharing program. Ted can then open a
connection with Alice and download the file directly from Alice's
computer.33
The file-sharing networks that result from the use of peer-to-peer
technology are both extensive and complex. Figure 5 shows a map or
topology of a Gnutella network whose connections were mapped by a
network visualization tool.34 The map, created in December 2000, shows
1,026 nodes (computers connected to more than one computer) and 3,752
edges (computers on the edge of the network connected to a single
computer). This map is a snapshot showing a network in existence at a
given moment; these networks change constantly as users join and depart
them.
33 LimeWire, Modern Peer-to-Peer File Sharing over the Internet.
(http://www.limewire.com/index.jsp/p2p)
34 Mihajlo A. Jovanovic, Fred S. Annexstein, and Kenneth A. Berman, Scalability Issues in Large Peerto-
Peer Networks: A Case Study of Gnutella,
University of Cincinnati Technical Report (2001).
(http://www.ececs.uc.edu/~mjovanov/Research/paper.html)
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Figure 5: Topology of a Gnutella Network
One of the key features of many peer-to-peer technologies is their use of a
virtual name space (VNS). A VNS dynamically associates user-created
names with the Internet address of whatever Internet-connected computer
users happen to be using when they log on.35 The VNS facilitates point-topoint
interaction between individuals, because it removes the need for
users and their computers to know the addresses and locations of other
users; the VNS can, to certain extent, preserve users' anonymity and
provide information on whether a user is or is not connected to the
Internet at a given moment. Peer-to-peer users thus may appear to be
35 S. Hayward and R. Batchelder, "Peer-to-Peer: Something Old, Something New," Gartner (Apr. 10,
2001).
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anonymous; they are not, however. Law enforcement agents may identify
users' Internet addresses during the file-sharing process and obtain, under
a court order, their identities from their Internet service providers.
(310381)