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Network Working Group IAB Request for Comments: 2804 IESG Category: Informational May 2000

                     IETF Policy on Wiretapping

Status of this Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

 The Internet Engineering Task Force (IETF) has been asked to take a
 position on the inclusion into IETF standards-track documents of
 functionality designed to facilitate wiretapping.

 This memo explains what the IETF thinks the question means, why its
 answer is "no", and what that answer means.

1. Summary position

 The IETF has decided not to consider requirements for wiretapping as
 part of the process for creating and maintaining IETF standards.

 It takes this position for the following basic reasons:

1. The IETF, an international standards body, believes itself to be

the wrong forum for designing protocol or equipment features that

   address needs arising from the laws of individual countries,
   because these laws vary widely across the areas that IETF standards
   are deployed in.  Bodies whose scope of authority correspond to a
   single regime of jurisdiction are more appropriate for this task.

1. The IETF sets standards for communications that pass across

networks that may be owned, operated and maintained by people from

   numerous jurisdictions with numerous requirements for privacy.  In
   light of these potentially divergent requirements, the IETF
   believes that the operation of the Internet and the needs of its
   users are best served by making sure the security properties of

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   connections across the Internet are as well known as possible.  At
   the present stage of our ignorance this means making them as free
   from security loopholes as possible.

1. The IETF believes that in the case of traffic that is today going

across the Internet without being protected by the end systems (by

   encryption or other means), the use of existing network features,
   if deployed intelligently, provides extensive opportunities for
   wiretapping, and should be sufficient under presently seen
   requirements for many cases. The IETF does not see an engineering
   solution that allows such wiretapping when the end systems take
   adequate measures to protect their communications.

1. The IETF believes that adding a requirement for wiretapping will

make affected protocol designs considerably more complex.

   Experience has shown that complexity almost inevitably jeopardizes
   the security of communications even when it is not being tapped by
   any legal means; there are also obvious risks raised by having to
   protect the access to the wiretap. This is in conflict with the
   goal of freedom from security loopholes.

1. The IETF restates its strongly held belief, stated at greater

length in [RFC 1984], that both commercial development of the

   Internet and adequate privacy for its users against illegal
   intrusion requires the wide availability of strong cryptographic
   technology.

1. On the other hand, the IETF believes that mechanisms designed to

facilitate or enable wiretapping, or methods of using other

   facilities for such purposes, should be openly described, so as to
   ensure the maximum review of the mechanisms and ensure that they
   adhere as closely as possible to their design constraints. The IETF
   believes that the publication of such mechanisms, and the
   publication of known weaknesses in such mechanisms, is a Good
   Thing.

2. The Raven process

 The issue of the IETF doing work on legal intercept technologies came
 up as a byproduct of the extensive work that the IETF is now doing in
 the area if IP-based telephony.

 In the telephony world, there has been a tradition of cooperation
 (often mandated by law) between law enforcement agencies and
 telephone equipment operators on wiretapping, leading to companies
 that build telephone equipment adding wiretapping features to their
 telephony-related equipment, and an emerging consensus in the

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 industry of how to build and manage such features. Some traditional
 telephony standards organizations have supported this by adding
 intercept features to their telephony-related standards.

 Since the future of the telephone seems to be intertwined with the
 Internet it is inevitable that the primary Internet standards
 organization would be faced with the issue sooner or later.

 In this case, some of the participants of one of the IETF working
 groups working on a new standard for communication between components
 of a distributed phone switch brought up the issue. Since adding
 features of this type would be something the IETF had never done
 before, the IETF management decided to have a public discussion
 before deciding if the working group should go ahead. A new mailing
 list was created (the Raven mailing list, see
 http://www.ietf.org/mailman/listinfo/raven) for this discussion.
 Close to 500 people subscribed to the list and about 10% of those
 sent at least one message to the list. The discussion on this list
 was a precursor to a discussion held during the IETF plenary in
 Washington, D.C.

 Twenty-nine people spoke during the plenary session. Opinions ranged
 from libertarian: 'governments have no right to wiretap' - to
 pragmatic: 'it will be done somewhere, best have it done where the
 technology was developed'. At the end of the discussion there was a
 show of hands to indicate opinions: should the IETF add special
 features, not do this or abstain. Very few people spoke out strongly
 in support for adding the intercept features, while many spoke out
 against it, but a sizable portion of the audience refused to state an
 opinion (raised their hands when asked for "abstain" in the show of
 hands).

 This is the background on the basis of which the Internet Engineering
 Steering Group (IESG) and the Internet Architecture Board (IAB) was
 asked to formulate a policy.

3. A definition of wiretapping

 The various legal statutes defining wiretapping do not give adequate
 definitions to distinguish between wiretapping and various other
 activities at the technical level. For the purposes of this memo, the
 following definition of wiretapping is used:

 Wiretapping is what occurs when information passed across the
 Internet from one party to one or more other parties is delivered to
 a third party:

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 1. Without the sending party knowing about the third party

 2. Without any of the recipient parties knowing about the delivery to
    the third party

 3. When the normal expectation of the sender is that the transmitted
    information will only be seen by the recipient parties or parties
    obliged to keep the information in confidence

 4. When the third party acts deliberately to target the transmission
    of the first party, either because he is of interest, or because
    the second party's reception is of interest.

 The term "party", as used here, can refer to one person, a group of
 persons, or equipment acting on behalf of persons; the term "party"
 is used for brevity.

 Of course, many wiretaps will be bidirectional, monitoring traffic
 sent by two or more parties to each other.

 Thus, for instance, monitoring public newsgroups is not wiretapping
 (condition 3 violated), random monitoring of a large population is
 not wiretapping (condition 4 violated), a recipient passing on
 private email is not wiretapping (condition 2 violated).

 An Internet equivalent of call tracing by means of accounting logs
 (sometimes called "pen registers") that is a feature of the telephone
 network is also wiretapping by this definition, since the normal
 expectation of the sender is that the company doing the accounting
 will keep this information in confidence.

 Wiretapping may logically be thought of as 3 distinct steps:

1. Capture - getting information off the wire that contains the

information wanted.

1. Filtering - selecting the information wanted from information

gathered by accident.

1. Delivery - transmitting the information wanted to the ones who want

it.

 The term applies to the whole process; for instance, random
 monitoring followed by filtering to extract information about a
 smaller group of parties would be wiretapping by this definition.

 In all these stages, the possibility of using or abusing mechanisms
 defined for this purpose for other purposes exists.

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 This definition deliberately does not include considerations of:

1. Whether the wiretap is legal or not, since that is a legal, not a

technical matter.

1. Whether the wiretap occurs in real time, or can be performed after

the fact by looking at information recorded for other purposes

   (such as the accounting example given above).

1. What the medium targeted by the wiretap is - whether it is email,

IP telephony, Web browsing or EDI transfers.

 These questions are believed to be irrelevant to the policy outlined
 in this memo.

 Wiretapping is also sometimes called "interception", but that term is
 also used in a sense that is considerably wider than the monitoring
 of data crossing networks, and is therefore not used here.

4. Why the IETF does not take a moral position

 Much of the debate about wiretapping has centered around the question
 of whether wiretapping is morally evil, no matter who does it,
 necessary in any civilized society, or an effective tool for catching
 criminals that has been abused in the past and will be abused again.

 The IETF has decided not to take a position in this matter, since:

1. There is no clear consensus around a single position in the IETF.

1. There is no means of detecting the morality of an act "on the

wire". Since the IETF deals with protocol standardization, not

   protocol deployment, it is not in a position to dictate that its
   product is only used in moral or legal ways.

 However, a few observations can be made:

1. Experience shows that tools which are effective for a purpose tend

to be used for that purpose.

1. Experience shows that tools designed for one purpose that are

effective for another tend to be used for that other purpose too,

   no matter what its designers intended.

1. Experience shows that if a vulnerability exists in a security

system, it is likely that someone will take advantage of it sooner

   or later.

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1. Experience shows that human factors, not technology per se, is the

biggest single source of such vulnerabilities.

 What this boils down to is that if effective tools for wiretapping
 exist, it is likely that they will be used as designed, for purposes
 legal in their jurisdiction, and also in ways they were not intended
 for, in ways that are not legal in that jurisdiction. When weighing
 the development or deployment of such tools, this should be borne in
 mind.

5. Utility considerations

 When designing any communications function, it is a relevant question
 to ask if such functions efficiently perform the task they are
 designed for, or whether the work spent in developing them is not, in
 fact, worth the benefit gained.

 Given that there are no specific proposals being developed in the
 IETF, the IETF cannot weigh proposals for wiretapping directly in
 this manner.

 However, as above, a few general observations can be made:

1. Wiretapping by copying the bytes passed between two users of the

Internet with known, static points of attachment is not hard.

   Standard functions designed for diagnostic purposes can accomplish
   this.

1. Correlating users' identities with their points of attachment to

the Internet can be significantly harder, but not impossible, if

   the user uses standard means of identification. However, this means
   linking into multiple Internet subsystems used for address
   assignment, name resolution and so on; this is not trivial.

1. An adversary has several simple countermeasures available to defeat

wiretapping attempts, even without resorting to encryption. This

   includes Internet cafes and anonymous dialups, anonymous remailers,
   multi-hop login sessions and use of obscure communications media;
   these are well known tools in the cracker community.

1. Of course, communications where the content is protected by strong

encryption can be easily recorded, but the content is still not

   available to the wiretapper, defeating all information gathering
   apart from traffic analysis.  Since Internet data is already in
   digital form, encrypting it is very simple for the end-user.

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 These things taken together mean that while wiretapping is an
 efficient tool for use in situations where the target of a wiretap is
 either ignorant or believes himself innocent of wrongdoing,
 Internet-based wiretapping is a less useful tool than might be
 imagined against an alerted and technically competent adversary.

6. Security Considerations

 Wiretapping, by definition (see above), releases information that the
 information sender did not expect to be released.

 This means that a system that allows wiretapping has to contain a
 function that can be exercised without alerting the information
 sender to the fact that his desires for privacy are not being met.

 This, in turn, means that one has to design the system in such a way
 that it cannot guarantee any level of privacy; at the maximum, it can
 only guarantee it as long as the function for wiretapping is not
 exercised.

 For instance, encrypted telephone conferences have to be designed in
 such a way that the participants cannot know to whom any shared
 keying material is being revealed.

 This means:

1. The system is less secure than it could be had this function not

been present.

1. The system is more complex than it could be had this function not

been present.

1. Being more complex, the risk of unintended security flaws in the

system is larger.

 Wiretapping, even when it is not being exercised, therefore lowers
 the security of the system.

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7. Acknowledgements

 This memo is endorsed by the IAB and the IESG.

 Their membership is:

 IAB:

 Harald Alvestrand
 Randall Atkinson
 Rob Austein
 Brian Carpenter
 Steve Bellovin
 Jon Crowcroft
 Steve Deering
 Ned Freed
 Tony Hain
 Tim Howes
 Geoff Huston
 John Klensin

 IESG:

 Fred Baker
 Keith Moore
 Patrik Falstrom
 Erik Nordmark
 Thomas Narten
 Randy Bush
 Bert Wijnen
 Rob Coltun
 Dave Oran
 Jeff Schiller
 Marcus Leech
 Scott Bradner
 Vern Paxson
 April Marine

 The number of contributors to the discussion are too numerous to
 list.

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8. Author's Address

 This memo is authored by the IAB and the IESG.

 The chairs are:

 Fred Baker, IETF Chair
 519 Lado Drive
 Santa Barbara California 93111

 Phone: +1-408-526-4257
 EMail: fred@cisco.com

 Brian E. Carpenter, IAB Chair
 IBM
 c/o iCAIR
 Suite 150
 1890 Maple Avenue
 Evanston IL 60201
 USA

 EMail: brian@icair.org

9. References

 [RFC 1984]  IAB and IESG, "IAB and IESG Statement on Cryptographic
             Technology and the Internet", RFC 1984, August 1996.

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9. Full Copyright Statement

 Copyright (C) The Internet Society (2000).  All Rights Reserved.

 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.

 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.

 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

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