draft-arkko-iab-data-minimization-principle-04.txt | draft-arkko-iab-data-minimization-principle.txt | |||
---|---|---|---|---|
Network Working Group J. Arkko | Network Working Group J. Arkko | |||
Internet-Draft Ericsson | Internet-Draft Ericsson | |||
Intended status: Informational March 14, 2023 | Intended status: Informational March 2023 | |||
Expires: September 15, 2023 | Expires: September 2, 2023 | |||
Data minimization among protocol participants | Emphasizing data minimization among protocol participants | |||
draft-arkko-iab-data-minimization-principle-04 | draft-arkko-iab-data-minimization-principle | |||
Abstract | Abstract | |||
Communications security has been at the center of many security | Data minimization is an important privacy technique, as it can reduce | |||
improvements in the Internet. The goal has been to ensure that | the amount information exposed about a user. This document | |||
communications are protected against outside observers and attackers. | emphasizes the need for data minimization among primary protocol | |||
Privacy has also been a key focus area, and understanding the privacy | participants, such as between clients and servers. Avoiding data | |||
implications of new Internet technology is an important factor when | leakage to outside parties is of course very important as well, but | |||
IETF works on such technologies. One key aspect of privacy is | both need to be considered in minimization. | |||
minimization of data disclosed to other parties. | ||||
This document highlights the need for a particular focus with respect | ||||
to data minimization. Avoiding data leakage to outside parties is of | ||||
course important, but it can also be necessary to limit it among the | ||||
primary protocol participants. | ||||
This is because is necessary to protect against endpoints that are | This is because is necessary to protect against endpoints that are | |||
compromised, malicious, or whose interests simply do not align with | compromised, malicious, or whose interests simply do not align with | |||
the interests of users. It is important to consider the role of a | the interests of users. It is important to consider the role of a | |||
participant and limit any data provided to it according to that role. | participant and limit any data provided to it according to that role. | |||
Status of This Memo | Status of This Memo | |||
This Internet-Draft is submitted in full conformance with the | This Internet-Draft is submitted in full conformance with the | |||
provisions of BCP 78 and BCP 79. | provisions of BCP 78 and BCP 79. | |||
skipping to change at page 1, line 46 | skipping to change at page 1, line 40 | |||
Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
This Internet-Draft will expire on September 15, 2023. | This Internet-Draft will expire on September 2, 2023. | |||
Copyright Notice | Copyright Notice | |||
Copyright (c) 2023 IETF Trust and the persons identified as the | Copyright (c) 2023 IETF Trust and the persons identified as the | |||
document authors. All rights reserved. | document authors. All rights reserved. | |||
This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
(http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
publication of this document. Please review these documents | publication of this document. Please review these documents | |||
carefully, as they describe your rights and restrictions with respect | carefully, as they describe your rights and restrictions with respect | |||
to this document. Code Components extracted from this document must | to this document. Code Components extracted from this document must | |||
include Simplified BSD License text as described in Section 4.e of | include Simplified BSD License text as described in Section 4.e of | |||
the Trust Legal Provisions and are provided without warranty as | the Trust Legal Provisions and are provided without warranty as | |||
described in the Simplified BSD License. | described in the Simplified BSD License. | |||
Table of Contents | Table of Contents | |||
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 | 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 | |||
2. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3 | 2. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
2.1. Types of information . . . . . . . . . . . . . . . . . . 4 | 3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
2.2. Dealing with compromise . . . . . . . . . . . . . . . . . 4 | 3.1. Types of Protocol Exchanges . . . . . . . . . . . . . . . 3 | |||
2.3. Related work . . . . . . . . . . . . . . . . . . . . . . 5 | 3.2. Types of information . . . . . . . . . . . . . . . . . . 4 | |||
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 | 3.3. Different Ways of Avoiding Information Sharing . . . . . 4 | |||
4. Informative References . . . . . . . . . . . . . . . . . . . 8 | 3.4. Role of Trust . . . . . . . . . . . . . . . . . . . . . . 5 | |||
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 12 | 3.5. Evolvability and Fingerprinting . . . . . . . . . . . . . 5 | |||
3.6. Related work . . . . . . . . . . . . . . . . . . . . . . 5 | ||||
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 | ||||
5. Informative References . . . . . . . . . . . . . . . . . . . 7 | ||||
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11 | ||||
1. Introduction | 1. Introduction | |||
Communications security has been at the center of many security | Privacy been at the center of many activities in the IETF. Privacy | |||
improvements on the Internet. The goal has been to ensure that | and its impact on protocol development activities at IETF is | |||
communications are protected against outside observers and attackers. | discussed in [RFC6973], covering a number of topics, from | |||
understanding privacy threats to threat mitigation, including data | ||||
This has been exemplified in many aspects of IETF efforts, in the | minimization. | |||
threat models [RFC3552], concerns about surveillance [RFC7258], IAB | ||||
statements [Confidentiality], and the introduction of encryption in | ||||
many protocols [RFC9000], [RFC7858], [RFC8484]. This has been very | ||||
successful. Advances in protecting most of our communications with | ||||
strong cryptographic has resulted in much improved security. Work on | ||||
these advances continues to be a key part of IETF's security effort. | ||||
Privacy has also been at the center of many activities in the IETF. | ||||
Improvements in communications security obviously have improved | ||||
privacy as well, but the concept is broader. Privacy and its impact | ||||
on protocol development activities at IETF is discussed in [RFC6973], | ||||
covering a number of topics, from understanding privacy threats to | ||||
threat mitigation, including data minimization. | ||||
One key aspect of privacy is minimization of data disclosed to other | This document emphasizes the need for data minimization among primary | |||
parties. | protocol participants, such as between clients and servers. Avoiding | |||
data leakage to outside parties such as observers or attackers is of | ||||
course very important as well, but minimization needs to consider | ||||
both. | ||||
This document highlights the need for a particular focus with respect | As RFC 6973 states: | |||
to data minimization. Avoiding data leakage to outside parties is of | ||||
course important, but it can also be necessary to limit it among the | ||||
primary protocol participants (and not just observers/attackers). As | ||||
RFC 6973 states: | ||||
"Limiting the data collected by protocol elements to | "Limiting the data collected by protocol elements to | |||
only what is necessary (collection limitation) is | only what is necessary (collection limitation) is | |||
the most straightforward way to help reduce privacy | the most straightforward way to help reduce privacy | |||
risks associated with the use of the protocol." | risks associated with the use of the protocol." | |||
This document offers some further discussion and motivation for this. | This document offers some further discussion, recommendations, and | |||
This document suggests that limiting the sharing of data to the | clarifications for this. This document suggests that limiting the | |||
protocol participants is a key technique in limiting the data | sharing of data to the protocol participants is a key technique in | |||
collection mentioned above. This document also suggests that what | limiting the data collection mentioned above. It is important that | |||
information is given to any other participant should depend on the | minimization happens prior to disclosing information to another | |||
role of that participant. | party, rather than relying on the good will of the other party to | |||
avoid storing the information. | ||||
The reason why this is important is that it is possible that | This is because is necessary to protect against endpoints that are | |||
endpoints are compromised, malicious, or have interests that do not | compromised, malicious, or whose interests simply do not align with | |||
align with the interests of users. Even closed, managed networks may | the interests of users. It is important to consider the role of a | |||
have compromised nodes, justifying careful consideration of what | participant and limit any data provided to it according to that role. | |||
information is provided to different nodes in the network. And in | ||||
all networks, increased use of communication security means | Even closed, managed networks may have compromised nodes, justifying | |||
adversaries may resort to new avenues of attack. New adversaries and | careful consideration of what information is provided to different | |||
risks have also arisen, e.g., due to increasing amount of information | nodes in the network. And in all networks, increased use of | |||
stored in various Internet services. And in situations where | communication security means adversaries may resort to new avenues of | |||
interests do not align across the protocol participants, limiting | attack. New adversaries and risks have also arisen, e.g., due to | |||
data collection by a protocol participant itself - who is interested | increasing amount of information stored in various Internet services. | |||
in data collection - may not be sufficient. | And in situations where interests do not align across the protocol | |||
participants, limiting data collection by a protocol participant | ||||
itself - who is interested in data collection - may not be | ||||
sufficient. | ||||
Careful control of information is also useful for technology | Careful control of information is also useful for technology | |||
evolution. For instance, allowing a party to unnecessarily collect | evolution. For instance, allowing a party to unnecessarily collect | |||
or receive information may lead to a similar effect as described in | or receive information may lead to a similar effect as described in | |||
[RFC8546] for protocols: regardless of initial expectations, over | [RFC8546] for protocols: regardless of initial expectations, over | |||
time unnecessary information will get used, leading to, for instance, | time unnecessary information will get used, leading to, for instance, | |||
ossification. Systems end up depend on having access to exactly the | ossification. Systems end up depend on having access to exactly the | |||
same information as they had access to previously. This makes it | same information as they had access to previously. This makes it | |||
hard to change what information is provided or how it is provided. | hard to change what information is provided or how it is provided. | |||
skipping to change at page 4, line 14 | skipping to change at page 3, line 45 | |||
"Every program and every user of the system should operate | "Every program and every user of the system should operate | |||
using the least set of privileges necessary to complete the | using the least set of privileges necessary to complete the | |||
job." | job." | |||
In this context, it is recommended that the protocol participants | In this context, it is recommended that the protocol participants | |||
minimize the information they share. I.e., they should provide only | minimize the information they share. I.e., they should provide only | |||
the information to each other that is necessary for the function that | the information to each other that is necessary for the function that | |||
is expected to be performed by the other party. | is expected to be performed by the other party. | |||
3. Discussion | ||||
3.1. Types of Protocol Exchanges | ||||
Information sharing may relate to different types of protocol | Information sharing may relate to different types of protocol | |||
exchanges, e.g., interaction of an endpoint with the network or with | exchanges, e.g., interaction of an endpoint with outsiders, the | |||
intermediaries. Other documents address aspects related to networks | network, or intermediaries. | |||
([RFC8546], [RFC8558], [I-D.iab-path-signals-collaboration]). | ||||
Thomson [I-D.thomson-tmi] discusses the role intermediaries. | Other documents address aspects related to networks ([RFC8546], | |||
Communications security largely addresses observers and outsider | [RFC8558], [I-D.iab-path-signals-collaboration]). Thomson | |||
adversaries, and [RFC6973] discusses associated traffic analysis | [I-D.thomson-tmi] discusses the role intermediaries. Communications | |||
threats. The focus in this document is on the primary protocol | security largely addresses observers and outsider adversaries, see | |||
participants, such as a server in a client-server architecture or a | for instance [Confidentiality], [RFC7858], [RFC8446], [RFC8484], | |||
service enables some kind of interaction among groups of users. | [RFC9000]. And [RFC6973] discusses associated traffic analysis | |||
threats. | ||||
The focus in this document is on the primary protocol participants, | ||||
such as a server in a client-server architecture or a service enables | ||||
some kind of interaction among groups of users. | ||||
As with communication security, we try to avoid providing too much | As with communication security, we try to avoid providing too much | |||
information as it may be misused or leak through attacks. The same | information as it may be misused or leak through attacks. The same | |||
principle applies not just to routers and potential attackers on | principle applies not just to routers and potential attackers on | |||
path, but also many other services in the Internet, including servers | path, but also many other services in the Internet, including servers | |||
that provide some function. | that provide some function. | |||
Of course, participants may provide more information to each after | 3.2. Types of information | |||
careful consideration, e.g., information provided in exchange of some | ||||
benefit, or to parties that are trusted by the participant. | ||||
2.1. Types of information | ||||
The use of identifiers has been extensively discussed in [RFC6973], | The use of identifiers has been extensively discussed in [RFC6973], | |||
Note that indirectly inferred information can also end up being | Note that indirectly inferred information can also end up being | |||
shared, such as message arrival times or patterns in the traffic flow | shared, such as message arrival times or patterns in the traffic flow | |||
([RFC6973]). Information may also be obtained from fingerprinting | ([RFC6973]). Information may also be obtained from fingerprinting | |||
the protocol participants, in an effort to identify unique endpoints | the protocol participants, in an effort to identify unique endpoints | |||
or users ([RFC6973]). Information may also be combined from multiple | or users. Information may also be combined from multiple sources, | |||
sources, e.g., websites and social media systems collaborating to | e.g., websites and social media systems collaborating to identify | |||
identify visiting users [WP2021]. | visiting users [WP2021]. | |||
2.2. Dealing with compromise | 3.3. Different Ways of Avoiding Information Sharing | |||
Even with careful exposure of information, compromises may occur. It | The most straightforward approach is of course to avoid sending a | |||
is important to build defenses to protect information, even when some | particular piece of information at all. | |||
component in a system becomes compromised. This may involve designs | ||||
where no single party has all information such as with Oblivious DNS | Or the information needs to be encrypted to very specific recipients, | |||
even if the encrypted message is shared with a broader set of | ||||
protocol participants. For instance, a client can encrypt a message | ||||
only to the actual final recipient, even if the server holds the | ||||
message before it is delivered. | ||||
Architectural note: A transport connection between | ||||
two components of a system is not an end-to-end | ||||
connection even if it encompasses all the protocol | ||||
layers up to the application layer. It is not | ||||
end-to-end, if the information or control function | ||||
it carries extends beyond those components. Just | ||||
because an e-mail server can read the contents of | ||||
an e-mail message do not make it a legitimate | ||||
recipient of the e-mail. | ||||
This document recommends that information should not be disclosed, | ||||
stored, or routed in cleartext through services that do not need to | ||||
have that information for the function they perform. | ||||
Where the above methods are not possible due to the information being | ||||
necessary for a function that the user wishes to be performed, there | ||||
are still methods to set limits on the information sharing. | ||||
Kuehlewind et al discuss the concept of Privacy Partititioning | ||||
[I-D.iab-privacy-partitioning]. This may involve designs where no | ||||
single party has all information such as with Oblivious DNS | ||||
[I-D.annee-dprive-oblivious-dns], [I-D.pauly-dprive-oblivious-doh] or | [I-D.annee-dprive-oblivious-dns], [I-D.pauly-dprive-oblivious-doh] or | |||
HTTP [I-D.ietf-ohai-ohttp], cryptographic designs where a service | HTTP [I-D.ietf-ohai-ohttp], cryptographic designs where a service | |||
such as with the recent IETF PPM effort [I-D.ietf-ppm-dap], service | such as with the recent IETF PPM effort [I-D.ietf-ppm-dap], and so | |||
side encryption of data at rest, confidential computing, and other | on. | |||
mechanisms. | ||||
Protocols can ensure that forward secrecy is provided, so that the | ||||
damage resulting from a compromise of keying material has limited | ||||
impact. | ||||
On the client side, the client may trust that another party handles | 3.4. Role of Trust | |||
information appropriately, but take steps to ensure or verify that | ||||
this is the case. For instance, as discussed above, the client can | ||||
encrypt a message only to the actual final recipient, even if the | ||||
server holds the message before it is delivered. | ||||
A corollary of the recommendation is that information should not be | Of course, participants may provide more information to each other | |||
disclosed, stored, or routed in cleartext through services that do | after careful consideration, e.g., information provided in exchange | |||
not need to have that information for the function they perform. | of some benefit, or to parties that are trusted by the participant. | |||
For instance, a transport connection between two components of a | 3.5. Evolvability and Fingerprinting | |||
system is not an end-to-end connection even if it encompasses all the | ||||
protocol layers up to the application layer. It is not end-to-end, | ||||
if the information or control function it carries extends beyond | ||||
those components. For instance, just because an e-mail server can | ||||
read the contents of an e-mail message do not make it a legitimate | ||||
recipient of the e-mail. | ||||
The general topic of ensuring that protocol mechanisms stays | The general topic of ensuring that protocol mechanisms stays | |||
evolvable and workable is covered in [I-D.iab-use-it-or-lose-it]. | evolvable and workable is covered in [I-D.iab-use-it-or-lose-it]. | |||
But the associated methods for reducing fingerprinting possibilities | But the associated methods for reducing fingerprinting possibilities | |||
probably deserve further study [Fingerprinting] [AmIUnique]. | probably deserve further study [Fingerprinting] [AmIUnique]. | |||
[I-D.wood-pearg-website-fingerprinting] discusses one aspect of this. | [I-D.wood-pearg-website-fingerprinting] discusses one aspect of this. | |||
2.3. Related work | 3.6. Related work | |||
Cooper et al. [RFC6973] discuss the general concept of privacy, | Cooper et al. [RFC6973] discuss the general concept of privacy, | |||
including data minimization. Section 6.1 in RFC 6973 is about data | including data minimization. Among other things, it provides the | |||
minimization, and there they provide the general statement quoted in | general statement quoted in Section 1. It also provides guidelines | |||
Section 1. That is exactly about what the present document is also | to authors of specifications, a number of questions that protocol | |||
about. Section 7 in RFC 6973 is about guidelines to authors of | designers can use to further analyze the impact of their design. For | |||
specifications. And Section 7.1 in turn asks the a number of | data minimization the questions relate to identifiers, data, | |||
questions that protocol designers can use to further analyse the | observers, and fingerprinting. This includes, for instance, asking | |||
impact of their design. For data minimization the questions relate | what information is exposed to which protocol entities, and if there | |||
to identifiers, data, observers, and fingerprinting. This includes, | are ways to limit such exposure: | |||
for instance, asking what information is exposed to which protocol | ||||
entities, and if there are ways to limit such exposure. For the | ||||
present document this is the particularly important question in RFC | ||||
6973: | ||||
Observers. Which information discussed in (a) and (b) | ||||
is exposed to each other protocol entity (i.e., recipients, | ||||
intermediaries, and enablers)? Are there ways for protocol | ||||
implementers to choose to limit the information shared with | ||||
each entity? Are there operational controls available to | ||||
limit the information shared with each entity? | ||||
These questions are in line with avoiding sharing information to a | ||||
protocol participant unless it is needed for its role. Therefore, | ||||
this too is exactly what the present document is about. It is clear | ||||
from both the text and interviewing the authors of RFC 6973 that they | ||||
believed in the importance of limiting data disclosure across all | ||||
possible parties, from outsiders to the primary protocol | ||||
participants, just as the author of the current document does. | ||||
However, if there's something to be wished, RFC 6973 could perhaps | ||||
been more explicit: | ||||
o It should be stated that information should not even be shared | ||||
with a participant if it is not necessary for the expected role of | ||||
that participant. Yet, RFC 6973 says "Limiting the data collected | ||||
by protocol elements to only what is necessary (collection | ||||
limitation)". But when there are potentially conflicting | ||||
interests among the protocol participants, expecting a participant | ||||
to limit its data collection itself seems insufficient. What we | ||||
need to do is to not even give that that participant the | ||||
information. Interviewing the authors of the RFC, this what the | ||||
intent of the text was, but the text isn't explicit about it. | ||||
o Similarly, the Section 7.1 guidance is merely questions, not | ||||
recommendations about limiting to the necessary information. | ||||
o The examples in Section 6 are largely related to cases where some | Observers. Which information discussed in (a) and (b) | |||
information is relayed to some parties but not others. For | is exposed to each other protocol entity (i.e., recipients, | |||
instance, the anonymity and identity confidentiality examples are | intermediaries, and enablers)? Are there ways for protocol | |||
about withholding identity from some parties such as the other | implementers to choose to limit the information shared with | |||
endpoint of a call or outsiders observing an authentication | each entity? Are there operational controls available to | |||
exchange. But they still disclose an identity to a party running | limit the information shared with each entity? | |||
a service. This is of course necessary in many situations, but it | ||||
would be useful to provide examples where information is withheld | ||||
entirely. | ||||
These are of course nuances that may change in a future revision of | This is very much in line with this document, although today it would | |||
RFC 6973. | be desirable to have recommendation as well as questions. For | |||
instance, recommending against sharing information with a participant | ||||
if it is not necessary for the expected role of that participant. | ||||
And, as discussed earlier, it is important to distinguish between the | ||||
choices of a sender not sharing information and a receiver choosing | ||||
to not collect information. Trusting an entity to not collect is not | ||||
sufficient. | ||||
In the years after publishing [RFC6973] there has also been a number | There has also been a number of documents that address data | |||
of documents on specific issues, such as one DNS Query Name | minimization for specific situations, such as one DNS Query Name | |||
Minimization [RFC7816], general DNS privacy advice including data | Minimization [RFC7816], general DNS privacy advice including data | |||
minimization [RFC9076], advice for DHCP clients for minimizing | minimization [RFC9076], advice for DHCP clients for minimizing | |||
information in requests they send to DHCP servers [RFC7844] (along | information in requests they send to DHCP servers [RFC7844] (along | |||
with general privacy considerations of DHCP [RFC7819] [RFC7824]). | with general privacy considerations of DHCP [RFC7819] [RFC7824]). | |||
These are on the topic of limiting information sent by one primary | These are on the topic of limiting information sent by one primary | |||
protocol particiant (client) to another (server). | protocol particiant (client) to another (server). | |||
Hardie [RFC8558] discusses path signals, i.e., messages to or from | Hardie [RFC8558] and Arkko et al. | |||
on-path elements to endpoints. In the past, path signals were often | [I-D.iab-path-signals-collaboration] discuss path signals, i.e., | |||
implicit, e.g., network nodes interpreting in a particular way | messages to or from on-path elements to endpoints. In the past, path | |||
transport protocol headers originally intended for end-to-end | signals were often implicit, e.g., network nodes interpreting in a | |||
consumption. The document recommends a principle that implicit | particular way transport protocol headers originally intended for | |||
signals should be avoided and that explicit signals be used instead, | end-to-end consumption. Implicit signals should be avoided and that | |||
and only when the signal's originator intends that it be used by the | explicit signals be used instead. | |||
network elements on the path. | ||||
Arkko, Kuhlewind, Pauly, and Hardie | ||||
[I-D.iab-path-signals-collaboration] discuss the same topic, and | ||||
extend the RFC 8558 principles with recommendations to ensure minimum | ||||
set of parties, minimum information, and consent. | ||||
Kuehlewind, Pauly, and Wood [I-D.iab-privacy-partitioning] discuss | Kuehlewind, Pauly, and Wood [I-D.iab-privacy-partitioning] discuss | |||
the concept of privacy partitioning: how information can be split and | the concept of privacy partitioning: how information can be split and | |||
carefully shared in ways where no individual party beyond the client | carefully shared in ways where no individual party beyond the client | |||
requesting a service has full picture of who is asking and what is | requesting a service has full picture of who is asking and what is | |||
being asked. This is of course a highly relevant technique, and | being asked. | |||
should be a part of the data minimization toolkit. | ||||
Thomson [I-D.thomson-tmi] discusses the role intermediaries in the | Thomson [I-D.thomson-tmi] discusses the role intermediaries in the | |||
Internet architecture, at different layers of the stack. For | Internet architecture, at different layers of the stack. For | |||
instance, a router is an intermediary, some parts of DNS | instance, a router is an intermediary, some parts of DNS | |||
infrastructure can be intermediaries, messaging gateways are | infrastructure can be intermediaries, messaging gateways are | |||
intermediaries. Thomson discusses when intermediaries are or are not | intermediaries. Thomson discusses when intermediaries are or are not | |||
an appropriate tool, and presents a number of principles relating to | an appropriate tool and presents a number of principles relating to | |||
the use of intermediaries, e.g., deliberate selection of protocol | the use of intermediaries. | |||
participants or limiting the capabilities or information exposure | ||||
related to the intermediaries. | ||||
Trammel and Kuehlewind [RFC8546] discuss the concept of a "wire | Trammel and Kuehlewind [RFC8546] discuss the concept of a "wire | |||
image" of a protocol. This is an abstraction of the information | image" of a protocol, and how network elements may start to rely on | |||
available to an on-path non-participant in a networking protocol. It | information in the image, even if it was not originally intended for | |||
relates to the topic of non-participants interpreting information | them. The issues are largely the same even for participants. | |||
that is available to them in the "wire image" (or associated timing | ||||
and other indirect information). The issues are largely the same | ||||
even for participants. Even proper protocol participants may start | ||||
to use information available to them, regardless of whether it was | ||||
intended to that participant or simply relayed through them. | ||||
3. Acknowledgements | 4. Acknowledgements | |||
The author would like to thank the participants of various IAB | The author would like to thank the participants of various IAB | |||
workshops and programs, and IETF discussion list contributors for | workshops and programs, and IETF discussion list contributors for | |||
interesting discussions in this area. The author would in particular | interesting discussions in this area. The author would in particular | |||
like to acknowledge the significant contributions of Martin Thomson, | like to acknowledge the significant contributions of Martin Thomson, | |||
Nick Doty, Alissa Cooper, Stephen Farrell, Mark McFadden, John | Nick Doty, Alissa Cooper, Stephen Farrell, Mark McFadden, John | |||
Mattsson, Chris Wood, Dominique Lazanski, Eric Rescorla, Russ | Mattsson, Chris Wood, Dominique Lazanski, Eric Rescorla, Russ | |||
Housley, Robin Wilton, Mirja Kuehlewind, Tommy Pauly, Jaime Jimenez | Housley, Robin Wilton, Mirja Kuehlewind, Tommy Pauly, Jaime Jimenez | |||
and Christian Huitema. | and Christian Huitema. | |||
This work has been influenced by [RFC6973], [RFC8980], | This work has been influenced by [RFC6973], [RFC8980], | |||
[I-D.farrell-etm] [I-D.arkko-arch-internet-threat-model-guidance], | [I-D.farrell-etm] [I-D.arkko-arch-internet-threat-model-guidance], | |||
[I-D.lazanski-smart-users-internet], | [I-D.lazanski-smart-users-internet], | |||
4. Informative References | 5. Informative References | |||
[AmIUnique] | [AmIUnique] | |||
INRIA, ., "Am I Unique?", https://amiunique.org , 2020. | INRIA, ., "Am I Unique?", https://amiunique.org , 2020. | |||
[Confidentiality] | [Confidentiality] | |||
The Internet Architecture Board, ., "IAB Statement on | The Internet Architecture Board, ., "IAB Statement on | |||
Internet Confidentiality", https://www.iab.org/2014/11/14/ | Internet Confidentiality", https://www.iab.org/2014/11/14/ | |||
iab-statement-on-internet-confidentiality/ , November | iab-statement-on-internet-confidentiality/ , November | |||
2014. | 2014. | |||
skipping to change at page 9, line 35 | skipping to change at page 8, line 42 | |||
[I-D.iab-use-it-or-lose-it] | [I-D.iab-use-it-or-lose-it] | |||
Thomson, M. and T. Pauly, "Long-Term Viability of Protocol | Thomson, M. and T. Pauly, "Long-Term Viability of Protocol | |||
Extension Mechanisms", draft-iab-use-it-or-lose-it-04 | Extension Mechanisms", draft-iab-use-it-or-lose-it-04 | |||
(work in progress), October 2021, | (work in progress), October 2021, | |||
<https://datatracker.ietf.org/doc/html/draft-iab-use-it- | <https://datatracker.ietf.org/doc/html/draft-iab-use-it- | |||
or-lose-it-04>. | or-lose-it-04>. | |||
[I-D.ietf-ohai-ohttp] | [I-D.ietf-ohai-ohttp] | |||
Thomson, M. and C. Wood, "Oblivious HTTP", draft-ietf- | Thomson, M. and C. Wood, "Oblivious HTTP", draft-ietf- | |||
ohai-ohttp-07 (work in progress), March 2023, | ohai-ohttp-08 (work in progress), March 2023, | |||
<https://datatracker.ietf.org/doc/html/draft-ietf-ohai- | <https://datatracker.ietf.org/doc/html/draft-ietf-ohai- | |||
ohttp-07>. | ohttp-08>. | |||
[I-D.ietf-ppm-dap] | [I-D.ietf-ppm-dap] | |||
Geoghegan, T., Patton, C., Rescorla, E., and C. Wood, | , , , and , "Distributed Aggregation Protocol for Privacy | |||
"Distributed Aggregation Protocol for Privacy Preserving | Preserving Measurement", draft-ietf-ppm-dap-05 (work in | |||
Measurement", draft-ietf-ppm-dap-04 (work in progress), | progress), July 2023, | |||
March 2023, <https://datatracker.ietf.org/doc/html/draft- | <https://datatracker.ietf.org/api/v1/doc/document/draft- | |||
ietf-ppm-dap-04>. | ietf-ppm-dap/>. | |||
[I-D.lazanski-smart-users-internet] | [I-D.lazanski-smart-users-internet] | |||
Lazanski, D., "An Internet for Users Again", draft- | Lazanski, D., "An Internet for Users Again", draft- | |||
lazanski-smart-users-internet-00 (work in progress), July | lazanski-smart-users-internet-00 (work in progress), July | |||
2019, <https://datatracker.ietf.org/doc/html/draft- | 2019, <https://datatracker.ietf.org/doc/html/draft- | |||
lazanski-smart-users-internet-00>. | lazanski-smart-users-internet-00>. | |||
[I-D.pauly-dprive-oblivious-doh] | [I-D.pauly-dprive-oblivious-doh] | |||
Kinnear, E., McManus, P., Pauly, T., Verma, T., and C. | Kinnear, E., McManus, P., Pauly, T., Verma, T., and C. | |||
Wood, "Oblivious DNS over HTTPS", draft-pauly-dprive- | Wood, "Oblivious DNS over HTTPS", draft-pauly-dprive- | |||
skipping to change at page 10, line 30 | skipping to change at page 9, line 36 | |||
Goldberg, I., Wang, T., and C. Wood, "Network-Based | Goldberg, I., Wang, T., and C. Wood, "Network-Based | |||
Website Fingerprinting", draft-wood-pearg-website- | Website Fingerprinting", draft-wood-pearg-website- | |||
fingerprinting-00 (work in progress), November 2019, | fingerprinting-00 (work in progress), November 2019, | |||
<https://datatracker.ietf.org/doc/html/draft-wood-pearg- | <https://datatracker.ietf.org/doc/html/draft-wood-pearg- | |||
website-fingerprinting-00>. | website-fingerprinting-00>. | |||
[PoLP] Saltzer, J. and M. Schroader, "The Protection of | [PoLP] Saltzer, J. and M. Schroader, "The Protection of | |||
Information in Computer Systems", Fourth ACM Symposium on | Information in Computer Systems", Fourth ACM Symposium on | |||
Operating System Principles , October 1975. | Operating System Principles , October 1975. | |||
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC | ||||
Text on Security Considerations", BCP 72, RFC 3552, | ||||
DOI 10.17487/RFC3552, July 2003, <https://www.rfc- | ||||
editor.org/info/rfc3552>. | ||||
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., | [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., | |||
Morris, J., Hansen, M., and R. Smith, "Privacy | Morris, J., Hansen, M., and R. Smith, "Privacy | |||
Considerations for Internet Protocols", RFC 6973, | Considerations for Internet Protocols", RFC 6973, | |||
DOI 10.17487/RFC6973, July 2013, <https://www.rfc- | DOI 10.17487/RFC6973, July 2013, <https://www.rfc- | |||
editor.org/info/rfc6973>. | editor.org/info/rfc6973>. | |||
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an | ||||
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May | ||||
2014, <https://www.rfc-editor.org/info/rfc7258>. | ||||
[RFC7816] Bortzmeyer, S., "DNS Query Name Minimisation to Improve | [RFC7816] Bortzmeyer, S., "DNS Query Name Minimisation to Improve | |||
Privacy", RFC 7816, DOI 10.17487/RFC7816, March 2016, | Privacy", RFC 7816, DOI 10.17487/RFC7816, March 2016, | |||
<https://www.rfc-editor.org/info/rfc7816>. | <https://www.rfc-editor.org/info/rfc7816>. | |||
[RFC7819] Jiang, S., Krishnan, S., and T. Mrugalski, "Privacy | [RFC7819] Jiang, S., Krishnan, S., and T. Mrugalski, "Privacy | |||
Considerations for DHCP", RFC 7819, DOI 10.17487/RFC7819, | Considerations for DHCP", RFC 7819, DOI 10.17487/RFC7819, | |||
April 2016, <https://www.rfc-editor.org/info/rfc7819>. | April 2016, <https://www.rfc-editor.org/info/rfc7819>. | |||
[RFC7824] Krishnan, S., Mrugalski, T., and S. Jiang, "Privacy | [RFC7824] Krishnan, S., Mrugalski, T., and S. Jiang, "Privacy | |||
Considerations for DHCPv6", RFC 7824, | Considerations for DHCPv6", RFC 7824, | |||
skipping to change at page 11, line 20 | skipping to change at page 10, line 20 | |||
[RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity | [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity | |||
Profiles for DHCP Clients", RFC 7844, | Profiles for DHCP Clients", RFC 7844, | |||
DOI 10.17487/RFC7844, May 2016, <https://www.rfc- | DOI 10.17487/RFC7844, May 2016, <https://www.rfc- | |||
editor.org/info/rfc7844>. | editor.org/info/rfc7844>. | |||
[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., | [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., | |||
and P. Hoffman, "Specification for DNS over Transport | and P. Hoffman, "Specification for DNS over Transport | |||
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May | Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May | |||
2016, <https://www.rfc-editor.org/info/rfc7858>. | 2016, <https://www.rfc-editor.org/info/rfc7858>. | |||
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol | ||||
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, | ||||
<https://www.rfc-editor.org/info/rfc8446>. | ||||
[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS | [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS | |||
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, | (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, | |||
<https://www.rfc-editor.org/info/rfc8484>. | <https://www.rfc-editor.org/info/rfc8484>. | |||
[RFC8546] Trammell, B. and M. Kuehlewind, "The Wire Image of a | [RFC8546] Trammell, B. and M. Kuehlewind, "The Wire Image of a | |||
Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April | Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April | |||
2019, <https://www.rfc-editor.org/info/rfc8546>. | 2019, <https://www.rfc-editor.org/info/rfc8546>. | |||
[RFC8558] Hardie, T., Ed., "Transport Protocol Path Signals", | [RFC8558] Hardie, T., Ed., "Transport Protocol Path Signals", | |||
RFC 8558, DOI 10.17487/RFC8558, April 2019, | RFC 8558, DOI 10.17487/RFC8558, April 2019, | |||
End of changes. 38 change blocks. | ||||
213 lines changed or deleted | 164 lines changed or added | |||
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