500 research outputs found
Interest-Based Access Control for Content Centric Networks (extended version)
Content-Centric Networking (CCN) is an emerging network architecture designed
to overcome limitations of the current IP-based Internet. One of the
fundamental tenets of CCN is that data, or content, is a named and addressable
entity in the network. Consumers request content by issuing interest messages
with the desired content name. These interests are forwarded by routers to
producers, and the resulting content object is returned and optionally cached
at each router along the path. In-network caching makes it difficult to enforce
access control policies on sensitive content outside of the producer since
routers only use interest information for forwarding decisions. To that end, we
propose an Interest-Based Access Control (IBAC) scheme that enables access
control enforcement using only information contained in interest messages,
i.e., by making sensitive content names unpredictable to unauthorized parties.
Our IBAC scheme supports both hash- and encryption-based name obfuscation. We
address the problem of interest replay attacks by formulating a mutual trust
framework between producers and consumers that enables routers to perform
authorization checks when satisfying interests from their cache. We assess the
computational, storage, and bandwidth overhead of each IBAC variant. Our design
is flexible and allows producers to arbitrarily specify and enforce any type of
access control on content, without having to deal with the problems of content
encryption and key distribution. This is the first comprehensive design for CCN
access control using only information contained in interest messages.Comment: 11 pages, 2 figure
Timed Analysis of Security Protocols
We propose a method for engineering security protocols that are aware of
timing aspects. We study a simplified version of the well-known Needham
Schroeder protocol and the complete Yahalom protocol, where timing information
allows the study of different attack scenarios. We model check the protocols
using UPPAAL. Further, a taxonomy is obtained by studying and categorising
protocols from the well known Clark Jacob library and the Security Protocol
Open Repository (SPORE) library. Finally, we present some new challenges and
threats that arise when considering time in the analysis, by providing a novel
protocol that uses time challenges and exposing a timing attack over an
implementation of an existing security protocol
FAIR: Forwarding Accountability for Internet Reputability
This paper presents FAIR, a forwarding accountability mechanism that
incentivizes ISPs to apply stricter security policies to their customers. The
Autonomous System (AS) of the receiver specifies a traffic profile that the
sender AS must adhere to. Transit ASes on the path mark packets. In case of
traffic profile violations, the marked packets are used as a proof of
misbehavior.
FAIR introduces low bandwidth overhead and requires no per-packet and no
per-flow state for forwarding. We describe integration with IP and demonstrate
a software switch running on commodity hardware that can switch packets at a
line rate of 120 Gbps, and can forward 140M minimum-sized packets per second,
limited by the hardware I/O subsystem.
Moreover, this paper proposes a "suspicious bit" for packet headers - an
application that builds on top of FAIR's proofs of misbehavior and flags
packets to warn other entities in the network.Comment: 16 pages, 12 figure
Execution Models for Choreographies and Cryptoprotocols
A choreography describes a transaction in which several principals interact.
Since choreographies frequently describe business processes affecting
substantial assets, we need a security infrastructure in order to implement
them safely. As part of a line of work devoted to generating cryptoprotocols
from choreographies, we focus here on the execution models suited to the two
levels.
We give a strand-style semantics for choreographies, and propose a special
execution model in which choreography-level messages are faithfully delivered
exactly once. We adapt this model to handle multiparty protocols in which some
participants may be compromised.
At level of cryptoprotocols, we use the standard Dolev-Yao execution model,
with one alteration. Since many implementations use a "nonce cache" to discard
multiply delivered messages, we provide a semantics for at-most-once delivery
Specifying authentication using signal events in CSP
The formal analysis of cryptographic protocols has developed into a comprehensive body of knowledge, building on a wide variety of formalisms and treating a diverse range of security properties, foremost of which is authentication. The formal specification of authentication has long been a subject of examination. In this paper, we discuss the use of correspondence to formally specify authentication and focus on Schneider's use of signal events in the process algebra Communicating Sequential Processes (CSP) to specify authentication. The purpose of this effort is to strengthen this formalism further. We develop a formal structure for these events and use them to specify a general authentication property. We then develop specifications for recentness and injectivity as sub-properties, and use them to refine authentication further. Finally, we use signal events to specify a range of authentication definitions and protocol examples to clarify their use and make explicit related theoretical issues. our work is motivated by the desire to effectively analyse and express security properties in formal terms, so as to make them precise and clear. (C) 2008 Elsevier Ltd. All rights reserved
A formal specification and verification framework for timed security protocols
Nowadays, protocols often use time to provide better security. For instance, critical credentials are often associated with expiry dates in system designs. However, using time correctly in protocol design is challenging, due to the lack of time related formal specification and verification techniques. Thus, we propose a comprehensive analysis framework to formally specify as well as automatically verify timed security protocols. A parameterized method is introduced in our framework to handle timing parameters whose values cannot be decided in the protocol design stage. In this work, we first propose timed applied π-calculus as a formal language for specifying timed security protocols. It supports modeling of continuous time as well as application of cryptographic functions. Then, we define its formal semantics based on timed logic rules, which facilitates efficient verification against various authentication and secrecy properties. Given a parameterized security protocol, our method either produces a constraint on the timing parameters which guarantees the security property satisfied by the protocol, or reports an attack that works for any parameter value. The correctness of our verification algorithm has been formally proved. We evaluate our framework with multiple timed and untimed security protocols and successfully find a previously unknown timing attack in Kerberos V
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