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diff --git a/doc/rfc/rfc2057.txt b/doc/rfc/rfc2057.txt new file mode 100644 index 0000000..4973629 --- /dev/null +++ b/doc/rfc/rfc2057.txt @@ -0,0 +1,1123 @@ + + + + + + +Network Working Group S. Bradner +Request for Comments: 2057 Harvard University +Category: Informational November 1996 + + + Source Directed Access Control on the Internet + +Status of this Memo + + This memo provides information for the Internet community. This memo + does not specify an Internet standard of any kind. Distribution of + this memo is unlimited. + +1. Abstract + + This memo was developed from a deposition that I submitted as part of + a challenge to the Communications Decency Act of 1996, part of the + Telecommunications Reform Act of 1996. The Telecommunications Reform + Act is a U.S. federal law substantially changing the regulatory + structure in the United States in the telecommunications arena. The + Communications Decency Act (CDA) part of this law has as its aim the + desire to protect minors from some of the material carried over + telecommunications networks. In particular the law requires that the + sender of potentially offensive material take "effective action" to + ensure that it is not presented to minors. A number of people have + requested that I publish the deposition as an informational RFC since + some of the information in it may be useful where descriptions of the + way the Internet and its applications work could help clear up + confusion in the technical feasibility of proposed content control + regulations. + +2. Control and oversight over the Internet + + No organization or entity operates or controls the Internet. The + Internet consists of tens of thousands of local networks linking + millions of computers, owned by governments, public institutions, + non-profit organizations, and private companies around the world. + These local networks are linked together by thousands of Internet + service providers which interconnect at dozens of points throughout + the world. None of these entities, however, controls the Internet; + each entity only controls its own computers and computer networks, + and the links allowed into those computers and computer networks. + + Although no organizations control the Internet, a limited number of + organizations are responsible for the development of communications + and operational standards and protocols used on the Internet. These + standards and protocols are what allow the millions of different (and + sometimes incompatible) computers worldwide to communicate with each + + + +Bradner Informational [Page 1] + +RFC 2057 Source Directed Access Control November 1996 + + + other. These standards and protocols are not imposed on any computer + or computer network, but any computer or computer network must follow + at least some of the standards and protocols to be able to + communicate with other computers over the Internet. + + The most significant of the organizations involved in defining these + standards include the Internet Society (ISOC), the Internet + Architecture Board (IAB), Internet Engineering Steering Group (IESG), + and the Internet Engineering Task Force (IETF). The following + summary outlines the relationship of these four organizations: + + The Internet Society (ISOC) is a professional society that is + concerned with the growth and evolution of the worldwide Internet, + with the way in which the Internet is and can be used, and with the + social, political, and technical issues which arise as a result. The + ISOC Trustees are responsible for approving appointments to the IAB + from among the nominees submitted by the IETF nominating committee + and ratifying the IETF Standards Process. + + The Internet Architecture Board (IAB) is a technical advisory group + of the ISOC. It is chartered to provide oversight of the + architecture of the Internet and its protocols, and to serve, in the + context of the Internet standards process, as a body to which the + decisions of the IESG may be appealed. The IAB is responsible for + approving appointments to the IESG from among the nominees submitted + by the IETF nominations committee and advising the IESG on the + approval of Working Group charters. + + The Internet Engineering Steering Group (IESG) is responsible for + technical management of IETF activities and the Internet standards + process. As a part of the ISOC, it administers the process according + to the rules and procedures which have been ratified by the ISOC + Trustees. The IESG is directly responsible for the actions + associated with entry into and movement along the Internet "standards + track," including final approval of specifications as Internet + Standards. + + The Internet Engineering Task Force (IETF) is a self-organized group + of people who make technical and other contributions to the + engineering and evolution of the Internet and its technologies. It + is the principal body engaged in the development of new Internet + standard specifications. The IETF is divided into eight functional + areas. They are: Applications, Internet, IP: Next Generation, + Network Management, Operational Requirements, Routing, Security, + Transport and User Services. Each area has one or two area + directors. These area directors, along with the IETF/IESG Chair, + form the IESG. + + + + +Bradner Informational [Page 2] + +RFC 2057 Source Directed Access Control November 1996 + + + In addition to these organizations, there are a variety of other + formal and informal groups that develop standards and agreements + about specialized or emerging areas of the Internet. For example, + the World Wide Web Consortium has developed agreements and standards + for the Web. + + None of these organizations controls, governs, runs, or pays for the + Internet. None of these organizations controls the substantive + content available on the Internet. None of these organizations has + the power or authority to require content providers to alter, screen, + or restrict access to content on the Internet other than content that + they themselves create. + + Beyond the standards setting process, the only Internet functions + that are centralized are the allocation of numeric addresses to + networks and the registration of "domain names." Three entities + around the world share responsibility for ensuring that each network + and computer on the Internet has a unique 32-bit numeric "IP" address + (such as 123.32.22.132), and for ensuring that all "domain names" + (such as "harvard.edu") are unique. InterNIC allocates IP addresses + for the Americas, and has counterparts in Europe and Asia. InterNIC + allocates large blocks of IP addresses to major Internet providers, + who in turn allocate smaller blocks to smaller Internet providers + (who in turn allocate even smaller blocks to other providers or end + users). InterNIC does not, however, reliably receive information on + who receives each numeric IP address, and thus cannot provide any + central database of computer addresses. In addition, a growing + number of computers access the Internet indirectly through address + translating devices such as application "firewalls". With these + devices the IP address used by a computer on the "inside" of the + firewall is translated to another IP address for transmission over + the Internet. The IP address used over the Internet can be + dynamically assigned from a pool of available IP addresses at the + time that a communication is initiated. In this case the IP + addresses used inside the firewall is not required to be globally + unique and the IP addresses used over the Internet do not uniquely + identify a specific computer. Neither the InterNIC nor its + counterparts in Europe and Asia control the substantive content + available on the Internet, nor do they have the power or authority to + require content providers to alter, screen, or restrict access to + content on the Internet. + + + + + + + + + + +Bradner Informational [Page 3] + +RFC 2057 Source Directed Access Control November 1996 + + +3. Characteristics of Internet communications + + There are a wide variety of methods of communications over the + Internet, including electronic mail, mail exploders such as listserv, + USENET newsgroups, Internet Relay Chat, gopher, FTP, and the World + Wide Web. With each of these forms of communication, the speaker has + little or no way to control or verify who receives the communication. + + As detailed below, for each of these methods of communications, it is + either impossible or very difficult for the speaker to restrict + access to his or her communications "by requiring use of a verified + credit card, debit account, adult access code, or adult personal + identification number." Similarly, for each of these methods of + communication, there are no feasible actions that I know of that the + speaker can take that would be reasonably effective to "restrict or + prevent access by minors" to the speaker's communications. + + With each of these methods of communications, it is either + technologically impossible or practically infeasible for the speaker + to ensure that the speech is not "available" to a minor. For most of + these methods--mail exploders such as listserv, USENET newsgroups, + Internet Relay Chat, gopher, FTP, and the World Wide Web--there are + technological obstacles to a speaker knowing about or preventing + access by minors to a communication. Yet even for the basic point- + to-point communication of electronic mail, there are practical and + informational obstacles to a speaker ensuring that minors do not have + access to a communication that might be considered "indecent" or + "patently offensive" in some communities. + +3.1 Point-to-Point Communications + +3.1.1 Electronic Mail. + + Of all of the primary methods of communication on the Internet, there + is the highest likelihood that the sender of electronic mail will + personally know the intended recipient (and know the intended + recipient's true e-mail address), and thus the sender (i.e., the + speaker or content provider) may be able to transmit potentially + "indecent" or "patently offensive" content with relatively little + concern that the speech might be "available" to minors. + + There is significantly greater risk for the e-mail speaker who does + not know the intended recipient. As a hypothetical example, if an + AIDS information organization receives from an unknown individual a + request for information via electronic mail, the organization has no + practical or effective way to verify the identity or age of the e- + mail requester. + + + + +Bradner Informational [Page 4] + +RFC 2057 Source Directed Access Control November 1996 + + + An electronic mail address provides no authoritative information + about the addressee. Addresses are often chosen by the addressees + themselves, and may or may not be based on the addressees' real + names. For millions of people with e-mail addresses, no additional + information is available over the Internet. Where information is + available (via, for example, inquiry tools such as "finger"), it is + usually provided by the addressee, and thus may not be accurate + (especially in a case of a minor seeking to obtain information the + government has restricted to adults). + + There exists no universal or even extensive "white pages" listing of + e-mail addresses and corresponding names or telephone numbers. Given + the rapidly expanding and global nature of the Internet, any attempt + as such a listing likely will be incomplete (and likely will not + contain information about the age of the e-mail addressee). Nor is + there any systematic, practical, and efficient method to obtain the + identity of an e-mail address holder from the organization or + institution operating the addressee's computer system. + + Moreover, it is relatively simple for someone to create an e-mail + "alias" to send and receive mail under a different name. Thus, a + given e-mail address may not even be the true e-mail address of the + recipient. On some systems, for example, an individual seeking to + protect his or her anonymity could easily create a temporary e-mail + address for the sole purpose of requesting information from an AIDS + information resource. In addition, there exist "anonymous remailers" + which replace the original e-mail address on messages with a randomly + chosen new one. The remailer keeps a record of the relationship + between the original and the replacement name so that return mail + will get forwarded to the right person. These remailers are used + frequently for discussion or support groups on sensitive or + controversial topics such as AIDS. + + Thus, there is no reasonably effective method by which one can obtain + information from existing online information sources about an e-mail + address sufficient to ensure that a given address is used by an adult + and not a minor. + + Absent the ability to comply with the Communications Decency Act + based on information from existing online information sources, an e- + mail speaker's only recourse is to interrogate the intended e-mail + recipient in an attempt to verify that the intended recipient is an + adult. Such verification inherently and unavoidably imposes the + burden of an entirely separate exchange of communications prior to + sending the e-mail itself, and is likely to be unreliable if the + recipient intends to deceive the speaker. + + + + + +Bradner Informational [Page 5] + +RFC 2057 Source Directed Access Control November 1996 + + + This separate preliminary communication is required because with + electronic mail, there is a complete electronic and temporal + "disconnect" between the sender and recipient. Electronic mail can + be routed through numerous computers between the sender and the + recipient, and the recipient may not "log in" to retrieve mail until + days or even weeks after the sender sent the mail. Thus, at no point + in time is there any direct or even indirect electronic linkage + between sender and recipient that would allow the sender to + interrogate the recipient prior to sending an e-mail. Thus, + unavoidably, the Communications Decency Act requires that the sender + incur the administrative (and in some cases financial) cost of an + entirely separate exchange of communications between sender and + recipient prior to the sender having sufficient information to ensure + that the recipient is an adult. Even if the sender were to + establish that an e-mail addressee is not a minor, the sender could + not be sure that the addressee was not sharing their computer account + with someone else, as is frequently done, who is a minor. + + If an e-mail is part of a commercial transaction of sufficient value + to justify the time and expense of obtaining payment via credit card + from the e-mail addressee, an e-mail sender may be able to utilize + the credit card or debit account options set out in the + Communications Decency Act. At this time, however, one cannot verify + a credit or debit transaction over the Internet, and thus an e-mail + speaker would have to incur the expense of verifying the transaction + via telephone or separate computer connection to the correct banking + entity. Because of current concerns about data security on the + Internet, such an e-mail credit card transaction would likely also + require that the intended e-mail recipient transmit the credit card + information to the e-mail sender via telephone or the postal service. + + Similarly, utilizing the "adult access code" or "adult personal + identification number" options set out in the statute would at this + time require the creation and maintenance of a database of adult + codes. While such a database would not be an insurmountable + technological problem, it would require a significant amount of human + clerical time to create and maintain the information. As with the + credit or debit transactions, an adult code database would also + likely require that information be transmitted by telephone or postal + mail. + + Moreover, such an adult access code would likely be very ineffective + at screening access by minors. For the adult access code concept to + work at all, any such code would have to be transmitted over the + Internet, and thus would be vulnerable to interception and + disclosure. Any sort of "information based" code--that is, a code + that consists of letters and numbers transmitted in a message--could + be duplicated and circulated to other users on the Internet. It is + + + +Bradner Informational [Page 6] + +RFC 2057 Source Directed Access Control November 1996 + + + highly likely that valid adult access codes would themselves become + widely distributed on the Internet, allowing industrious minors to + obtain a valid code and thus obtain access the material sought to be + protected. + + A somewhat more effective alternative to this type of "information + based" access code would be to link such a code to the unique 32-bit + numeric "IP" addresses of networks and computers on the Internet. + Under this approach, "adult" information would only be transmitted to + the particular computer with the "approved" IP address. For tens of + millions of Internet users, however, IP addresses for a given access + session are dynamically assigned at the time of the access, and those + users will almost certainly utilize different IP addresses in + succeeding sessions. For example, users of the major online services + such as America Online (AOL) are only allocated a temporary IP + address at the time they link to the service, and the AOL user will + not retain that IP address in later sessions. Also, as discussed + above, the use of "firewalls" can dynamically alter the apparent IP + address of computers accessing the Internet. Thus, any sort of IP + address-based screening system would exclude tens of millions of + potential recipients, and thus would not be a viable screening + option. + + At bottom, short of incurring the time and expense of obtaining and + charging the e-mail recipient's credit card, there are no reasonably + effective methods by which an e-mail sender can verify the identity + or age of an intended e-mail recipient even in a one-to-one + communication to a degree of confidence sufficient to ensure + compliance with the Communications Decency Act (and avoid the Act's + criminal sanction). + +3.2 Point-to-Multipoint Communications + + The difficulties described above for point-to-point communications + are magnified many times over for point-to-multipoint communications. + In addition, for almost all major types of point-to-multipoint + communications on the Internet, there is a technological obstacle + that makes it impossible or virtually impossible for the speaker to + control who receives his or her speech. For these types of + communications over the Internet, reasonably effective compliance + with the Communications Decency Act is impossible. + +3.2.1 Mail Exploders + + Essentially an extension of electronic mail allowing someone to + communicate with many people by sending a single e-mail, "mail + exploders" are an important means by which the Internet user can + exchange ideas and information on particular topics with others + + + +Bradner Informational [Page 7] + +RFC 2057 Source Directed Access Control November 1996 + + + interested in the topic. "Mail exploders" is a generic term covering + programs such as "listserv" and "Majordomo." These programs typically + receive electronic mail messages from individual users, and + automatically retransmit the message to all other users who have + asked to receive postings on the particular list. In addition to + listserv and Majordomo, many e-mail retrieval programs contain the + option to receive messages and automatically forward the messages to + other recipients on a local mailing list. + + Mail exploder programs are relatively simple to establish. The + leading programs such as listserv and Majordomo are available for + free, and once set up can generally run unattended. There is no + practical way to measure how many mailing lists have been established + worldwide, but there are certainly tens of thousands of such mailing + lists on a wide range of topics. + + With the leading mail exploder programs, users typically can add or + remove their names from the mailing list automatically, with no + direct human involvement. To subscribe to a mailing list, a user + transmits an e-mail to the automated list program. For example, to + subscribe to the "Cyber-Rights" mailing list (relating to censorship + and other legal issues on the Internet) one sends e-mail addressed to + "listserv@cpsr.org" and includes as the first line of the body of the + message the words "subscribe cyber-rights name" (inserting a person's + name in the appropriate place). In this example, the listserv + program operated on the cpsr.org computer would automatically add the + new subscriber's e-mail address to the mailing list. The name + inserted is under the control of the person subscribing, and thus may + not be the actual name of the subscriber. + + A speaker can post to a mailing list by transmitting an e-mail + message to a particular address for the mailing list. For example, + to post a message to the "Cyber-Rights" mailing list, one sends the + message in an e-mail addressed to "cyber-rights@cpsr.org". Some + mailing lists are "moderated," and messages are forwarded to a human + moderator who, in turn, forwards messages that moderator approves of + to the whole list. Many mailing lists, however, are unmoderated and + postings directed to the appropriate mail exploder programs are + automatically distributed to all users on the mailing list. Because + of the time required to review proposed postings and the large number + of people posting messages, most mailing lists are not moderated. + + + + + + + + + + +Bradner Informational [Page 8] + +RFC 2057 Source Directed Access Control November 1996 + + + An individual speaker posting to a mail exploder mailing list cannot + control who has subscribed to the particular list. In many cases, + the poster cannot even find out the e-mail address of who has + subscribed to the list. A speaker posting a message to a list thus + has no way to screen or control who receives the message. Even if + the mailing list is "moderated," an individual posting to the list + still cannot control who receives the posting. + + Moreover, the difficulty in knowing (and the impossibility of + controlling) who will receive a posting to a mailing list is + compounded by the fact that it is possible that mail exploder lists + can themselves be entered as a subscriber to a mailing list. Thus, + one of the "subscribers" to a mailing list may in fact be another + mail exploder program that re-explodes any messages transmitted using + the first mailing list. Thus, a message sent to the first mailing + list may end up being distributed to many entirely separate mailing + lists as well. + + Based on the current operations and standards of the Internet, it + would be impossible for someone posting to a listserv to screen + recipients to ensure the recipients were over 17 years of age. Short + of not speaking at all, I know of no actions available to a speaker + today that would be reasonably effective at preventing minors from + having access to messages posted to mail exploder programs. + Requiring such screening for any messages that might be "indecent" or + "patently offensive" to a minor would have the effect of banning such + messages from this type of mailing list program. + + Even if one could obtain a listing of the e-mail addresses that have + subscribed to a mailing list, one would then be faced with the same + obstacles described above that face a point-to-point e-mail sender. + Instead of obtaining a credit card or adult access code from a single + intended recipient, however, a posted to a mailing list may have to + obtain such codes from a thousand potential recipients, including new + mailing list subscribers who may have only subscribed moments before + the poster wants to post a message. As noted above, complying with + the Communications Decency Act for a single e-mail would be very + difficult. Complying with the Act for a single mailing list posting + with any reasonable level of effectiveness is impossible. + +3.2.2 USENET Newsgroups. + + One of the most popular forms of communication on the Internet is the + USENET newsgroup. USENET newsgroups are similar in objective to mail + exploder mailing lists--to be able to communicate easily with others + who share an interest in a particular topic--but messages are + conveyed across the Internet in a very different manner. + + + + +Bradner Informational [Page 9] + +RFC 2057 Source Directed Access Control November 1996 + + + USENET newsgroups are distributed message databases that allow + discussions and exchanges on particular topics. USENET newsgroups + are disseminated using ad hoc, peer-to-peer connections between + 200,000 or more computers (called USENET "servers") around the world. + There are newsgroups on more than twenty thousand different subjects. + Collectively, almost 100,000 new messages (or "articles") are posted + to newsgroups each day. Some newsgroups are "moderated" but most + are open access. + + For unmoderated newsgroups, when an individual user with access to a + USENET server posts a message to a newsgroup, the message is + automatically forwarded to adjacent USENET servers that furnish + access to the newsgroup, and it is then propagated to the servers + adjacent to those servers, etc. The messages are temporarily stored + on each receiving server, where they are available for review and + response by individual users. The messages are automatically and + periodically purged from each system after a configurable amount of + time to make room for new messages. Responses to messages--like the + original messages--are automatically distributed to all other + computers receiving the newsgroup. The dissemination of messages to + USENET servers around the world is an automated process that does not + require direct human intervention or review. + + An individual who posts a message to a newsgroup has no ability to + monitor or control who reads the posted message. When an individual + posts a message, she transmits it to a particular newsgroup located + on her local USENET server. The local service then automatically + routes the message to other servers (or in some cases to a + moderator), which in turn allow the users of those servers to read + the message. The poster has no control over the handling of her + message by the USENET servers worldwide that receive newsgroups. + Each individual server is configured by its local manager to + determine which newsgroups it will accept. There is no mechanism to + permit distribution based on characteristics of the individual + messages within a newsgroup. + + The impossibility of the speaker controlling the message distribution + is made even more clear by the fact that new computers and computer + networks can join the USENET news distribution system at any time. + To obtain newsgroups, the operator of a new computer or computer + network need only reach agreement with a neighboring computer that + already receives the newsgroups. Speakers around the world do not + learn that the new computer had joined the distribution system. + Thus, just as a speaker cannot know or control who receives a + message, the speaker does not even know how many or which computers + might receive a given newsgroup. + + + + + +Bradner Informational [Page 10] + +RFC 2057 Source Directed Access Control November 1996 + + + For moderated newsgroups, all messages to the newsgroup are forwarded + to an individual who can screen them for relevance to the topics + under discussion. The screening process, however, does not increase + the ability of the original speaker to control who receives a given + message. A newsgroup moderator has as little control as the original + speaker over who receives a message posted to the newsgroup. + + Based on the current operations and standards of the Internet, it + would be impossible for someone posting to a USENET newsgroup to + screen recipients to ensure that the recipients were over 17 years of + age. Short of not speaking at all, I know of no actions available to + a speaker today that would be reasonably effective at preventing + minors from having access to USENET newsgroup messages. Requiring + such screening for any messages that might be "indecent" or "patently + offensive" to a minor would have the effect of banning such messages + from USENET newsgroups. + + A speaker also has no means by which he or she could require + listeners to provide a credit card, debit account, adult access code, + or adult personal identification number. Each individual USENET + server controls access to the newsgroups on that server, and a + speaker has no ability to force a server operator to take any + particular action. The message is out of the speaker's hands from + the moment the message is posted. + + Moreover, even if one hypothesized a system under which a newsgroup + server would withhold access to a message until the speaker received + a credit card, debit account, adult access code, or adult personal + identification number from the listener, there would be no feasible + way for the speaker to receive such a number. Because a listener may + retrieve a message from a newsgroup days after the speaker posted the + message, such a hypothetical system would require the speaker either + to remain at his or her computer 24 hours a day for as many as ten + days after posting the message, or to finance, develop, and maintain + an automated system to receive and validate access numbers. All of + this effort would be required for the speaker to post even a single + potentially "patently offensive" message to a single newsgroup. + + Moreover, even if such a hypothetical system did exist and a speaker + were willing to remain available 24 hours a day (or operate a costly + automated system) in order to receive access numbers, not all + computers that receive USENET newsgroups could reasonably transmit + such access numbers. Some computers that receive newsgroups do so + only by a once-a-day telephone connection to another newsgroup + server. Some of these computers do not have any other type of + Internet connection, and indeed some computers that receive USENET + newsgroups do not even utilize the TCP/IP communications protocol + that is required for direct or real time communications on the + + + +Bradner Informational [Page 11] + +RFC 2057 Source Directed Access Control November 1996 + + + Internet. These computers would have no means by which a prospective + listener's access code could be communicated back to a speaker. + + It is my opinion that if this hypothetical access system ever were + created, it would be so burdensome as to effectively ban from USENET + newsgroups messages that might be "indecent" or "patently offensive." + Moreover, the communications standards and protocols that would allow + such a hypothetical access system have not as of today been + developed, and no Internet standards setting body of which I am aware + is currently developing such standards and protocols. Specifically, + such a hypothetical access system is not part of the "next + generation" Internet Protocol that I helped to develop. + +3.2.3 Internet Relay Chat. + + Another method of communication on the Internet is called "Internet + Relay Chat" (or IRC). IRC allows for real time communication between + two or more Internet users. IRC is analogous to a telephone party + line, using a computer and keyboard rather than a telephone. With + IRC, however, at anyone time there are thousands of different party + lines available, in which collectively tens of thousands of users are + engaging in discussions, debates, and conversations on a huge range + of subjects. Moreover, an individual can create a new party line to + discuss a different topic at any time. While many discussions on IRC + are little more than social conversations between the participants, + there are often conversations on important issues and topics. + Although I have not personally operated an IRC server in my career, I + am familiar enough with the operations of IRC servers to be able to + identify the obstacles that a speaker would encounter attempting to + identify other participants and to verify that those participants + were not minors. + + There exists a network of dozens of IRC servers across the world. To + speak through IRC, a speaker connects to one of these servers and + selects the topic the speaker wishes to "join." Within a particular + topic (once a speaker joins a topic), all speakers on that topic can + see and read everything that everyone else transmits. As a practical + matter, there is no way for each person who joins a discussion to + interrogate all other participants (sometimes dozens of participants) + as to their identity and age. Because people join or drop out of + discussions on a rolling basis, the discussion line would be + overwhelmed with messages attempting to verify the identity of the + participants. + + Also as a practical matter, there is no way that an individual + speaker or an individual IRC server operator could enforce an "adults + only" rule for a selection of the discussion topics. Dozens of IRC + servers are interconnected globally so that people across the world + + + +Bradner Informational [Page 12] + +RFC 2057 Source Directed Access Control November 1996 + + + can talk to each other. Thus, a speaker connected to an IRC server + in the United States can speak directly to a listener in Asia or + Europe. There is no practical way that a speaker in the United + States can be reasonably certain that a given IRC discussion is in + fact "adults only." + + Nor can a speaker, prior to or at the time of joining an IRC + discussion, ascertain with any confidence the identity of the other + participants in the discussion. Individual participants in an IRC + conversation are able to participate anonymously by using a + pseudonym. A new speaking joining the conversation can see a list of + pseudonyms of other participants, but has no possibly way of + determining the real identify (or even the real e-mail address) of + the individuals behind each pseudonym. + + Based on the current operations and standards of the Internet, it + would be impossible for someone participating in a IRC discussion to + screen recipients with a level of certainty needed to ensure the + recipients were over 17 years of age. Short of not speaking at all, + I know of no actions available to a speaker today that would be + reasonably effective at preventing minors from having access to + speech in an IRC discussion. Requiring such screening of recipients + by the speakers for any IRC discussions that might be "indecent" or + "patently offensive" to a minor would have the effect of banning such + discussions. + +4.0 Information Retrival Systems + + With FTP (or File Transfer Protocol), gopher, and the World Wide Web, + the Internet is a vast resource for information made available to + users around the world. All three methods (FTP, gopher, and the Web) + are specifically geared toward allowing thousands or millions of + users worldwide to access content on the Internet, and none are + specifically designed to limit access based on criteria such as the + age of the Internet user. Currently much of this information is + offered for free access. + +4.1 Anonymous FTP + + "Anonymous FTP" is a basic method by which a content provider can + make content available to users on the Internet. FTP is a protocol + that allows the efficient and error free transfer of files from one + computer to another. To make content available via FTP, a content + provider establishes an "Anonymous FTP server" capable of receiving + FTP requests from remote users. This approach is called "anonymous" + because when a remote user connects to an FTP server, the remote user + enters the word "anonymous" in response to the server's request for a + user name. By convention, the remote user is requested to enter his + + + +Bradner Informational [Page 13] + +RFC 2057 Source Directed Access Control November 1996 + + + or her e-mail address when prompted for a "password." The user is + then given access to a restricted portion of the server disk and to + the files in that area. Even though the user may have entered their + e-mail address in response to the password prompt, there is no + effective validation or screening is possible using the FTP server + software that is currently available. Using currently available FTP + software, a content provider has no way to screen access by + "anonymous" users that may be minors. Even if a content provider + could determine the age of a particular remote user, the currently + available FTP software cannot be set to limit the user's access to + non-"adult" file areas. + + FTP server software can allow non-"anonymous" users to access the FTP + server, and in that mode can require the users to have individual + passwords that are verified against a pre-existing list of passwords. + There are two major problems, however, that prevent this type of + non-"anonymous" FTP access from being used to allow broad access to + information over the Internet (as anonymous FTP can allow). First, + with current server software each non-"anonymous" FTP user must be + given an account on the server computer, creating a significant + administrative burden and resource drain. If more than a limited + number of users want access to the FTP system, the requirement of + separate accounts would quickly overwhelm the capacity of the server + to manage the accounts--the FTP server software was not designed to + manage thousands or millions of different user/password combinations. + Second, under existing FTP server software, each of these named users + would have complete access to the server file system, not a + restricted area like the anonymous FTP function supports. This would + create a significant security problem. For these two reasons, as a + practical matter FTP cannot be used to give broad access to content + except via the anonymous FTP option (which, as noted above, does not + allow for screening or blocking of minors). + + As discussed below with regard to the World Wide Web, even if someone + re-designed the currently available FTP server software to allow the + screening of minors, the administrative burden of such screening + would in many cases overwhelm the resources of the content provider. + + + + + + + + + + + + + + +Bradner Informational [Page 14] + +RFC 2057 Source Directed Access Control November 1996 + + + Based on the current operations and standards of the Internet, it is + not possible or practically feasible for someone operating an + anonymous FTP file server to screen recipients with a level of + certainty needed to ensure the recipients were over 17 years of age. + Short of not operating an anonymous FTP server at all, I know of no + actions available to a content provider today that would be + reasonably effective at preventing minors from having access to + "adult" files on the FTP server. Requiring such screening by + anonymous FTP server operators to prevent minors from accessing FTP + files that might be "indecent" or "patently offensive" to a minor + would have the effect of banning such anonymous FTP access. + +4.2 Gopher. + + The gopher program is similar to FTP in that it allows for basic + transfer of files from one computer to another, but it is also a + precursor to the World Wide Web in that it allows a user to + seamlessly jump from one gopher file server to another in order to + locate the desired information. The development of gopher and the + linking of gopher servers around the worlds dramatically improved the + ability of Internet users to locate information across the Internet. + + Although in many ways an improvement over FTP, gopher is simpler than + FTP in that users need not enter any username or password to gain + access to files stored on the gopher server. Under currently + available gopher server software, a content provider has no built-in + ability to screen users. Thus a content provider could not prevent + minors from retrieving "adult" files. + + As discussed below with regard to the World Wide Web, even if the + gopher server software allowed the screening of minors, the + administrative burden of such screening would in many cases overwhelm + the resources of the content provider. + + Based on the current operations and standards of the Internet, it is + not possible for someone operating a gopher file server to screen + recipients with a level of certainty needed to ensure the recipients + were over 17 years of age. Short of not operating a gopher server at + all, I know of no actions available to a content provider today that + would be reasonably effective at preventing minors from having access + to "adult" files on a gopher server. Requiring such screening of + users by gopher server operators to prevent minors from accessing + files that might be "indecent" or "patently offensive" to a minor + would have the effect of banning gopher servers wherever there is any + such material. + + + + + + +Bradner Informational [Page 15] + +RFC 2057 Source Directed Access Control November 1996 + + +4.3 World Wide Web (WWW). + + Fast becoming the most well known method of communicating on the + Internet, the "World Wide Web" offers users the easy ability to + locate and view a vast array of content on the Internet. The Web + uses a "hypertext" formatting language called hypertext markup + language (HTML), and Web "browsers" can display HTML documents + containing text, images, and sound. Any HTML document can include + links to other types of information or resources anywhere in the + world, so that while viewing an HTML document that, for example, + describes resources available on the Internet, an individual can + "click" using a computer mouse on the description of the resource and + be immediately connected to the resource itself. Such "hyperlinks" + allow information to be accessed and organized in very flexible ways, + and allow individuals to locate and efficiently view related + information even if the information is stored on numerous computers + all around the world. + + Unlike with USENET newsgroups, mail exploders, FTP, and gopher, an + operator of a World Wide Web server does have some ability to + interrogate a user of a Web site on the server, and thus has some + ability to screen out users. An HTML document can include a fill-in- + the-blank "form" to request information from a visitor to a Web site, + and this information can be transmitted back to the Web server. The + information received can then be processed by a computer program + (usually a "Common Gateway Interface," or "CGI," script), and based + on the results of that computer program the Web server could grant or + deny access to a particular Web page. Thus, it is possible for some + (but not all, as discussed below) World Wide Web sites to be designed + to "screen" visitors to ensure that they are adults. + + The primary barrier to such screening is the administrative burden of + creating and maintaining the screening system. For an individual Web + site to create a software system capable of screening thousands of + visitors a day, determining (to the extent possible) whether a + visitor is an adult or a minor, and maintaining a database to allow + subsequent access to the Web site would require a significant on- + going effort. Moreover, as discussed above with regard to electronic + mail, the task of actually establishing a Web visitor's identity or + "verifying" a credit card would require a significant investment of + administrative and clerical time. As there is no effective method to + establish identity over the Internet, nor is there currently a method + to verify credit card numbers over the Internet (and given the + current cost of credit card verifications done by other means), this + type of identification process is only practical for a commercial + entity that is charging for access to the Web information. + + + + + +Bradner Informational [Page 16] + +RFC 2057 Source Directed Access Control November 1996 + + + Beyond the major administrative burden that would be required for a + Web site host to comply with the Communications Decency Act, there + are two additional problems presented by the Act. First, many Web + publishers cannot utilize computer programs such as CGI scripts to + process input from a Web visitor. For example, I have been informed + that the major online services such as America Online and Compuserve + do not allow their customers to run CGI scripts or other processes + that could be a significant drain on the online services' computers + as well as a potential security risk. Thus, for this category of Web + publisher, the Communications Decency Act works as a ban on any + arguably "indecent" or "patently offensive" speech. It is impossible + for this category of Web publisher to control access to their Web + sites. + + Moreover, even for Web publishers who can use CGI scripts to screen + access, the existence of Web page caching on the Internet can make + such screening ineffective. "Caching" refers to a method to speed up + access to Internet resources. Caching is often used at one or both + ends of, for example, a transatlantic or transpacific cable that + carries Internet communications. An example of caching might occur + when a Internet user in Europe requests access to a World Wide Web + page located in the United States. The request travels by + transatlantic cable to the United States, and the Web page is + transmitted back across the ocean to Europe (and ultimately to the + user who requested access). But, the operator of the transatlantic + cable will place the Web page in a storage "cache" located on the + European side of the cable. Then, if a second Internet user in + Europe requests the same Web page, the operator of the transatlantic + cable will intercept the request and provide the page from its + "cache" (thereby reducing traffic on the transatlantic cable). This + type of caching typically occurs without the awareness of the + requesting user. Moreover, in this scenario, the original content + provider is not even aware that the second user requested the Web + page--and the original content provider has no opportunity to screen + the access by the second user. Nevertheless, the original content + provider risks prosecution if the content is "adult" content and the + second requester is a minor. The use of caching web servers is + rapidly increasing within the United States (mostly to help moderate + the all too rapid growth in Internet traffic), and thus can affect + entirely domestic communications. For example, a growing number of + universities use caching web servers to reduce the usage of the link + to their Internet service provider. In light of this type of + caching, efforts to screen access to Web pages can only at best be + partially effective. + + + + + + + +Bradner Informational [Page 17] + +RFC 2057 Source Directed Access Control November 1996 + + + In light of the existence of Web page caching on the Internet, it + would be extremely difficult if not impossible to for someone + operating a World Wide Web server to ensure that no minors received + "adult" content. + + Moreover, for those Web page publishers who lack access to CGI + scripts, there is no possible way for them to screen recipients to + ensure that all recipients are over 17 years of age. For these + content providers, short of not supporting World Wide Web access to + their materials, I know of no actions available to them that would be + reasonably effective at preventing minors from having access to + "adult" files on a World Wide Web server. Requiring such screening + by these Web publishers to prevent minors from accessing files that + might be "indecent" or "patently offensive" to a minor would have the + effect of banning their speech on the World Wide Web. + + The Web page caching described above contributes to the difficulty of + determining with specificity the number of visitors to a particular + Web site. Some Web servers can count how many different Web clients, + some of which could be caching Web servers, requested access to a Web + site. Some Web servers can also count how many "hits"--or separate + file accesses--were made on a particular Web site (a single access to + a Web page that contains a images or graphic icons would likely be + registered as more than one "hit"). With caching, the actual number + of users that retrieved information that originated on a particular + Web server is likely to be greater than the number of "hits" recorded + for the server. + +5.0 Client-end Blocking + + As detailed above, for many important methods of communication on the + Internet, the senders--the content providers--have no ability to + ensure that their messages are only available to adults. It is also + not possible for a Internet service provider or large institutional + provider of access to the Internet (such as a university) to screen + out all or even most content that could be deemed "indecent" or + "patently offensive" (to the extent those terms can be understood at + all). A large institution could at least theoretically screen a + portion of the communications over the Internet, scanning for example + for "indecent" words, but not pictures. Such a screening program + capable of screening a high volume of Internet traffic at the point + of its entry into the institution would require an investment of + computing resources of as much as one million dollars per major + Internet information conduit. In addition it would be quit difficult + to configure such a system to only control the content for those + users that are under-age recipients, since in many cases the + information would be going to a server within the university where + many users, under-age and not, would have access to it. + + + +Bradner Informational [Page 18] + +RFC 2057 Source Directed Access Control November 1996 + + + Based on my experience and knowledge of the Internet, I believe that + the most effective way to monitor, screen, or control the full range + of information transmitted over the Internet to block undesired + content is at the client end--that is, by using software installed in + the individual user's computer. Such software could block certain + forms of incoming transmissions by using content descriptive tags in + the messages, or could use content ratings developed by third parties + to select what can and cannot be retrieved for display on a user's + computer. + +6.0 Tagging Material + + I am informed that the government in this action may advocate the use + of special tags or flags in electronic mail messages, USENET + newsgroup postings, and World Wide Web HTML documents to indicate + "adult" material. To my knowledge, no Internet access software or + World Wide Web browsers are currently configurable to block material + with such tags. Thus, the headers and flags the government may + advocate is currently an ineffective means to ensure the blocking of + access by minors to "adult" material. Even in a predictable future + where there are defined standards for such tags and there are + readably available browsers that are configurable to make use of + those tags, a content provider--e.g., a listserv or Newsgroup poster + or a Web page author--will have little power to ensure that the + client software used to receive the postings was in all cases + properly configured to recognize these tags and to block access to + the posting when required. Thus I feel that the tagging that may be + proposed by the government would in fact not be "effective" in + ensuring that the poster's speech would not be "available to a person + under 18 years of age," as the Communications Decency Act requires. + Although I strongly support both voluntary self-rating and third- + party rating (as described in the preceding paragraph), I do not feel + that the use of tags of this type would satisfy the speaker's + obligation to take effective actions to ensure that "patently + offensive" material would not be "available" to minors. Furthermore, + since it is impossible to embed such flags or headers in many of the + documents currently made available by anonymous FTP, gopher and the + World Wide Web without rendering the files useless (executable + programs for example), any government proposal to require the use of + tags to indicate "adult" material would not allow the continued use + of those methods of communication for speech that might be deemed + "indecent" or "patently offensive." + + With the exception of electronic mail and e-mail exploders all of the + methods of Internet communications discussed above require an + affirmative action by the listener before the communication takes + place. A listener must take specific action to receive + communications from USENET newsgroups, Internet Relay Chat, gopher, + + + +Bradner Informational [Page 19] + +RFC 2057 Source Directed Access Control November 1996 + + + FTP, and the World Wide Web. In general this is also true for e-mail + exploders except in the case where a third party subscribes the user + to the exploder list. These communications over the Internet do not + "invade" a person's home or appear on a person's computer screen + unbidden. Instead, a person must almost always take specific + affirmative steps to receive information over the Internet. + +7.0 Acknowledgment + + I owe a great deal of thanks to John Morris of Jenner and Block, one + of the law firms involved in the CDA challenge. Without his + extensive help this document would not exist, or if it did, it would + be even more scattered. + +8.0 Security Considerations + + To be actually able to do the type of content access control that the + CDA envisions would require a secure Internet infrastructure along + with secure ways to determine the minor status of potential + reciepiants around the world. Developing such a system is outside of + the scope of this document. + +9.0 Author's Address + + Scott Bradner + Harvard University + 1350 Mass Ave. + Cambridge MA 02138 USA + + Phone: +1 617 495 3864 + EMail: sob@harvard.edu + + + + + + + + + + + + + + + + + + + + +Bradner Informational [Page 20] + |