File-Sharing Programs: Users of Peer-to-Peer Networks Can Readily Access Child Pornography
Published: 2003-09-09T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: 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, chatrooms, 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 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. 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.
section_title: What GAO Found
paragraphs: 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 non-pornographic. In another search using three keywords, a Customs analyst downloaded 341 images, of which 149 (about 44 percent) contained child pornography. 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 peer-to-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.

section_title: Letter
paragraphs: Thank you for inviting us to discuss our work on the availability of child  pornography on peer-to-peer networks.
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.
subsections: section_title: Background
paragraphs: Child pornography is prohibited by federal statutes, which provide for civil  and criminal penalties for its production, advertising, possession, receipt,  distribution, and sale. Defined by statute as the visual depiction of a  minor—a person under 18 years of age—engaged in sexually explicit  conduct, child pornography is unprotected by the First Amendment, as it  is intrinsically related to the sexual abuse of children.
In the Child Pornography Prevention Act of 1996, 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 pornography 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, which attempts to address the constitutional  issues raised in The Free Speech Coalition decision.
subsections: section_title: The Internet Has Emerged as the Principal Tool for Exchanging Child Pornography
paragraphs: Historically, pornography, including child pornography, tended to be found  mainly in photographs, magazines, and videos. 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.
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.  Today, child pornography is available through virtually every Internet  technology (see table 1).
Among the principal channels for the distribution of child pornography are  commercial Web sites, Usenet newsgroups, and peer-to-peer networks.
Web sites. According to recent estimates, there are about 400,000  commercial pornography Web sites worldwide, 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, they  are emerging as a conduit for the sharing of pornographic images and  videos, including child pornography. In a recent study by congressional  staff, 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.
section_title: Several Agencies Have Law Enforcement Responsibilities Regarding Child Pornography on Peer- to-Peer Networks
paragraphs: Table 2 shows the key national organizations and agencies that are  currently involved in efforts to combat child pornography on peer-to-peer  networks.
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 CyberTipline  II. The FBI, Customs Service, Postal Inspection Service, and Secret Service  have staff assigned directly to NCMEC as analysts.
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).
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  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.
section_title: Peer-to-Peer Applications Provide Easy Access to Child Pornography
paragraphs: Child pornography is easily shared and accessed through peer-to-peer file- sharing programs. Our analysis of 1,286 titles and file names identified  through KaZaA searches on 12 keywords showed that 543 (about 42  percent) of the images had titles and file names associated with child  pornography images. 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.
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).
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,  peer-to-peer referrals increased more than fourfold, from 156 to 757,  reflecting the increased popularity of file-sharing programs.
section_title: Juvenile Users of Peer- to-Peer Applications May Be Inadvertently Exposed to Pornography
paragraphs: 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  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.
section_title: Federal Law Enforcement Agencies Are Beginning to Focus Resources on Child Pornography on Peer- to-Peer Networks
paragraphs: 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.
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. 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 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, 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-to-peer  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 peer-to-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.
section_title: Contact and Acknowledgments
paragraphs: 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.
section_title: How File Sharing Works on Peer-to-Peer Networks
paragraphs: 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.
The ability of peer-to-peer networks to provide services and connect users  directly has resulted in a large number of powerful applications built  around this model. 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, 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 Gnutella network, in which individuals find each other and  interact directly.
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, 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.
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  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.
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. 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.
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. The VNS facilitates point-to- point 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 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.
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