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[liberationtech] "Accountability"

Richard Brooks rrb at
Thu Sep 18 11:21:10 PDT 2014

On 09/18/2014 02:15 PM, Richard Brooks wrote:
> In a serious publication (Communications of the ACM), researchers
> from ETH in Zurich explain that cybersecurity becomes
> easier, if only we make everyone "accountable" by making
> the infrastructure indelibly track every packet:
> What a brilliant idea. While we are at it, we could install
> videocameras in every home that tell participants they are
> being watched. Bentham's Panopticon personified.
> -Richard

Excuse me. Full text follows.

Accountability in Future Internet Architectures
By Stefan Bechtold, Adrian Perrig
Communications of the ACM, Vol. 57 No. 9, Pages 21-23

Accountability in Future Internet Architectures, illustration
When the Internet architecture was designed some 40 years ago, its
architects focused on the challenges of the time. These included the
creation of a distributed communication network that is robust against
packet loss and other network failures; support across multiple types of
networks and communication services; and the management of Internet
resources in a cost-effective and distributed way. As history has shown,
the Internet's architects succeeded on many dimensions. The phenomenal
success of the Internet has often been attributed to its basic
architectural principles.

As the uses of the Internet have expanded beyond the original creators'
wildest dreams, its protocols have been stretched to accommodate new
usage models, such as mobile, video, real-time, and security-sensitive
applications. A string of extensions has resulted in an infrastructure
that has increasingly become ossified due to the numerous constraints
each extension introduces, in turn complicating further extensions.
These challenges have prompted researchers to rethink architectural
principles, thereby engaging in visionary thinking about what a future
Internet architecture, which should last for many decades, should look like.
One important dimension of clean-slate Internet architecture proposals
is to rethink the role of accountability. The general idea is that
accountability for one's actions would enable identification of the
offender, making it possible to either defend oneself against
misbehavior or deter it altogether. It is therefore natural to consider
accountability as a way of addressing network attacks, ranging from
route hijacking, to various kinds of network denial-of-service attacks
and remote exploitation of host vulnerabilities. Increased
accountability could not only address some of the technical shortcomings
of the current Internet architecture. It could also enable various
partly legal solutions to problems which, to date, have not been solved
by purely technical means.

In recent years, security incidents have repeatedly stressed the need
for accountability mechanisms. We highlight the use of accountability to
address the hijacking of Internet traffic routing by altering or
deleting authorized Border Gateway Protocol (BGP) routes. In 2008,
YouTube became globally unreachable after a Pakistani Internet service
provider (ISP) altered a route in an attempt to block YouTube access in
Pakistan. In 2013, the network intelligence firm Renesys documented that
traffic routes from Mexico to Washington, D.C., and from Denver to
Denver had been rerouted via Belarus and Iceland. In March 2014,
Google's Public Domain Name System (DNS) server, which handles
approximately 150 billion queries a day, had its IP address hijacked for
22 minutes. During this time, millions of Internet users were redirected
to British Telecom's Latin America division in Venezuela and Brazil.
Such rerouting, whether deliberate or not, abuses the implicit trust
enshrined in the BGP routing protocol. Traffic rerouting is often
difficult to detect for both Internet users and network operators. It
can be used for a wide range of attacks. Despite the introduction of
BGPSEC (a security protocol that promises to stop hijacking attacks),
accountability—which makes it possible for an attacker to be identified,
sued, and prosecuted—may prove a better solution to the hijacking problem.

Another example where accountability matters is the network neutrality
debate. Insufficient accountability mechanisms in today's Internet
prevent consumers from finding out why their access to particular
services has been blocked or slowed down. Is today's access to Hulu slow
due to technical problems at Hulu's servers, due to delays somewhere in
the network, or due to bandwidth limitations between your ISP and your
home network? It is difficult to determine. More generally, if a
technical architecture does not provide means for users to monitor
whether service providers keep their promises with regard to service
quality and features, service providers may have insufficient incentives
to actually keep their promises.

An architecture that leaves loopholes in legal and technical
accountability has it costs. As the Internet traffic hijacking example
shows, it may encourage unlawful online activities, with all the
negative effects this entails for society. As the network neutrality
example demonstrates, it may deter business partners from entering into
contractual agreements, as their terms may be unenforceable.

Currently, manifold attempts are being made to deal with accountability
loopholes. On the legal front, legislators and government agencies are
designing rules to provide network providers and users with the right
incentives despite limited accountability. In the ongoing battle over
network neutrality regulations, for example, the U.S. Federal
Communications Commission (FCC) has proposed rules that will force ISPs
to disclose their network management practices.a In June 2014, the FCC
announced it would investigate the impact peering agreements between
ISPs such as Comcast and Verizon and content providers such as Netflix
have on broadband consumption and Internet congestion.

Security incidents have repeatedly stressed the need for accountability

On the technical front, any technology aimed at increasing
accountability should provide irrefutable proof that parties have
performed certain actions: in particular, of who is being held
accountable for what action to whom. End users, hosts, ISPs (or their
routers and network equipment), service operators, or content providers
could all potentially be held accountable or be enabled to verify the
accountability. Consider a system that would hold an ISP's routers
accountable for delayed packet forwarding. It would have to ensure the
routers cannot hide the fact they delayed forwarding a packet. Such
accountability for delays could serve as a technical measure to validate
the network neutrality of an ISP.

Researchers have proposed numerous technical solutions for various types
of accountability. Bender et al. propose to hold the source accountable
for packets created, and enable each router to verify.2 Such packet
origin accountability is a popular property, which subsequent
researchers have pursued with varying assumptions and approaches for
cryptographic key setup.1,3,7 Li et al. propose a general key setup
mechanism between sources and network routers to enable packet origin,
router forwarding, and routing message accountability.6 Naous et al.
propose a system for packet origin and strong router forwarding
accountability.9 Zhou et al.11 propose a strong notion of making the
network accountable for any state it may have ("secure network
provenance"). The same authors have extended their work to also provide
time-aware provenance.12

Implementing only legal or technical measures to increase accountability
on the Internet has limitations. We believe it is a fruitful exercise to
combine technical and legal aspects for two reasons. First, this
challenges perceptions lawyers have about technology and vice versa. As
the Internet traffic hijacking and the network neutrality examples
demonstrate, it is often difficult to identify what caused network
errors. From a legal perspective, lacking identifiability makes it
impossible to hold someone accountable for the error. This, in turn,
reduces everyone's incentive to prevent network errors, as the risk of
being held liable is low. All too often, the legal debate simply assumes
such accountability loopholes are a given fact on the Internet. The
debate has not considered how liability regimes and the types of
contracts and services offered on the Internet would change if a future
Internet architecture were to provide enhanced accountability
mechanisms. The current lack of accountability, for example, prevents
service level agreements that span beyond a single autonomous system.
Accountability for network operations could enable an ISP to provide
inter-ISP service-level agreements, as the ISP could restrict his
liability to internal errors, thereby excluding external errors that can
be attributed to the appropriate responsible party. Increasing
accountability could thus make liability risks manageable and contractable.

Second, by combining technical and legal aspects of accountability in
network design, we can focus on trade-offs in network design decisions
that might otherwise pass unnoticed. An important issue is the trade-off
between accountability and privacy. Usually they are in conflict, as
accountability requires sacrificing privacy.5 However, in some cases,
both can be achieved. For example, Mallios et al. have proposed a system
where privacy is achieved as long as a user does not misbehave, whereas
misbehavior will render the user accountable.8,b Another important
trade-off exists between accountability and personal freedom. Lessig
argues that e-commerce will require accountability at the cost of
personal freedom.5 There might be other issues here. If everyone's
actions on the Internet were traceable, how could political activists
communicate under oppressive political systems? How could highly
privacy-sensitive citizens communicate? Technical solutions such as
anonymous communication systems implemented as an overlay network on the
Internet can achieve anonymous communication despite a traceable or
accountable underlying network architecture. The important research
question is how the two properties can be meaningfully combined. The
answer may be something similar to the privacy example described
previously: As long as users communicate within some defined traffic
pattern, their communications remain anonymous. If they deviate from the
pattern, their (potential mis-) behavior can be traced back. It is also
worth noting that increased accountability can be advantageous to
political activists. In societies where governments control Internet
traffic within the country and across borders, increased accountability
can impede unobtrusive censorship, as the increase in transparency makes
it more difficult for the government to hide its censoring activities.

Many design decisions have implications for social interactions that lie
in the realm of the law.

We cannot offer any easy ways to deal with such trade-offs. We can,
however, observe that many important problems in today's Internet are
due to a lack of accountability and transparency. The response—to
increase accountability—is not a mere technical enterprise. Many design
decisions have implications for social interactions that lie in the
realm of the law. Because law and technology are sometimes
interchangeable and sometimes lead to difficult trade-offs, legal
considerations should be taken into account not only after a novel
Internet architecture has been implemented, but as an integral part of
the design process of the architecture itself.4,10 Such an approach
could do more than enhance the value of the architecture itself.
Increased accountability may also produce novel services that we cannot
envision at present, precisely because of accountability loopholes that
affect the current Internet.

As the interaction between network usage and the law increases, the
network's technical architecture must cope with trade-offs and policy
values that have long been familiar within the legal system. It is one
of the challenges of future Internet architecture design to develop
holistic approaches that will integrate technical and legal aspects and
enable researchers and developers to be versatile in both fields.

Back to Top

1. Andersen, D.G. et al. Accountable Internet Protocol (AIP). In
Proceedings of ACM SIGCOMM, 2008.

2. Bender, A. et al. Accountability as a service. In Proceedings of

3. Andersen, D., Parno, B., and Perrig, A. SNAPP: Stateless
network-authenticated path pinning. In Proceedings of AsiaCCS, March 2008.

4. Flanagan, M., Howe, D.C., and Nissenbaum, H. Embodying Values in
Technology: Theory and Practice. Cambridge University Press, Cambridge,
2008, 322–353.

5. Lessig, L. Code and Other Laws of Cyberspace. Basic Books, NY, 1999.

6. Li, A., Liu, X., and Yang, X. Bootstrapping accountability in the
Internet we have. In Proceedings of USENIX NSDI, 2011.

7. Liu, X. et al. Passport: Secure and adoptable source authentication.
In Proceedings of USENIX NSDI, 2008.

8. Mallios, Y. et al. Persona: Network layer anonymity and
accountability for next generation Internet. In IFIP TC 11 International
Information Security Conference, May 2009.

9. Naous, J. et al. Verifying and enforcing network paths with ICING. In
Proceedings of ACM CoNEXT, 2011.

10. Nissenbaum, H. How computer systems embody values. IEEE Computer 34,
3 (2001), 118–120.

11. Zhou, W. et al. Secure network provenance. In Proceedings of the ACM
Symposium on Operating Systems Principles (SOSP), October 2011.

12. Zhou, W. et al. Distributed time-aware provenance. In Proceedings of
the International Conference on Very Large Databases (VLDB), August 2013.

Back to Top

Stefan Bechtold (sbechtold at is Professor of Intellectual
Property at ETH Zurich and a Communications Viewpoints section board member.

Adrian Perrig (adrian.perrig at is Professor of Computer
Science at ETH Zurich.

Back to Top

a. This aspect of the proposed Open Internet Rules has not been affected
by the January 2014 decision of the U.S. Court of Appeals for the
District of Columbia, which struck down antiblocking and
anti-discrimination obligations.

b. This works like the detection of double spending in digital cash: a
payment is untraceable as long as the user spends the coin only once,
but the identity is revealed if the coin is spent twice.

The authors would like to thank Srdjan Capkun, Susanne Hambrusch, John
L. King, and Timothy Roscoe for helpful feedback.

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