Internet Draft
internet-draft IAB and IESG
draft-iab-raven-01.txt
Target Category: Informational February 2000
Expires: August 2000
IETF Policy on Wiretapping
Status of this Memo
The following text is food for the I-D machinery.
The file name of this memo is draft-iab-raven-01.txt
This document is an internet-draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet-
Drafts as reference material or to cite them other than as "work
in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of internet-draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
The intended place to discuss this memo is the RAVEN mailing list
.
Abstract
The 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.
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
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:
- 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.
- 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
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.
- 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.
- 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.
- 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.
- 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.
draft-iab-raven-00.txt [Page 2]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
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 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.
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 IESG and the 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:
draft-iab-raven-00.txt [Page 3]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
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:
- Capture - getting information off the wire that contains the
information wanted
- Filtering - selecting the information wanted from information
gathered by accident
- 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.
This definition deliberately does not include considerations of:
- Whether the wiretap is legal or not, since that is a legal, not a
technical matter
- 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)
draft-iab-raven-00.txt [Page 4]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
- 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:
- There is no clear consensus around a single position in the IETF
- 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:
- Experience shows that tools which are effective for a purpose tend to
be used for that purpose.
- 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.
- Experience shows that if a vulnerability exists in a security system,
it is likely that someone will take advantage of it sooner or later.
- 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.
draft-iab-raven-00.txt [Page 5]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
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:
- 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.
- 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.
- 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.
- 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.
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:
draft-iab-raven-00.txt [Page 6]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
- The system is less secure than it could be had this function not been
present.
- The system is more complex than it could be had this function not
been present.
- 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.
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.
8. Author's Address
This memo is authored by the IAB and the IESG.
draft-iab-raven-00.txt [Page 7]
IETF position on wiretapping IAB and IESG
draft-iab-raven-01.txt Expires August 2000
The chairs are:
Fred Baker, IETF Chair
519 Lado Drive
Santa Barbara California 93111
Phone: +1-408-526-4257
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 Statement on Cryptographic Technology and the
Internet. IAB & IESG. August 1996.
10. Changelog - to be deleted by RFC Editor
Changes from version -00 to version -01:
Language changes for clarity
Some clarifications in the "definition of wiretapping" section
No changes in position.
draft-iab-raven-00.txt [Page 8]