14,868 research outputs found
Accountability of Perfect Concurrent Signature
Concurrent signature provided a novel idea for fair exchange protocol without trusted third party. Perfect Concurrent Signature is proposed to strengthen theambiguity of the concurrent signature. Wang et al, pointed out there exist an attack against the fairness of Perfect Concurrent Signature and proposed the improved perfect
concurrent signature. This paper find that in proposed (perfect) concurrent signature protocol, no matter two party or multi-party, the signer could bind multiple messages with one keystone set but let the other signers know only one of the messages. This is a
new unfair case in the application of concurrent signature. Based on this observation, we propose that accountability should be one of the security properties of (perfect) concurrent signature and we give the definition of accountability of concurrent signature. To illustrate this idea, we give an attack scene against the accountability of
improved perfect concurrent signature proposed by Wang et al, and propose an update
version of perfect concurrent signature to avoid such attack
Flowers Hospital: Nearing Perfection on Core Measures
Describes elements of a strategy for achieving high process-of-care performance by continuously monitoring patients in four clinical areas and ensuring they receive the right care -- including concurrent reviews and quality improvement teams
Introducing Accountability to Anonymity Networks
Many anonymous communication (AC) networks rely on routing traffic through
proxy nodes to obfuscate the originator of the traffic. Without an
accountability mechanism, exit proxy nodes risk sanctions by law enforcement if
users commit illegal actions through the AC network. We present BackRef, a
generic mechanism for AC networks that provides practical repudiation for the
proxy nodes by tracing back the selected outbound traffic to the predecessor
node (but not in the forward direction) through a cryptographically verifiable
chain. It also provides an option for full (or partial) traceability back to
the entry node or even to the corresponding user when all intermediate nodes
are cooperating. Moreover, to maintain a good balance between anonymity and
accountability, the protocol incorporates whitelist directories at exit proxy
nodes. BackRef offers improved deployability over the related work, and
introduces a novel concept of pseudonymous signatures that may be of
independent interest.
We exemplify the utility of BackRef by integrating it into the onion routing
(OR) protocol, and examine its deployability by considering several
system-level aspects. We also present the security definitions for the BackRef
system (namely, anonymity, backward traceability, no forward traceability, and
no false accusation) and conduct a formal security analysis of the OR protocol
with BackRef using ProVerif, an automated cryptographic protocol verifier,
establishing the aforementioned security properties against a strong
adversarial model
Security of 5G-V2X: Technologies, Standardization and Research Directions
Cellular-Vehicle to Everything (C-V2X) aims at resolving issues pertaining to
the traditional usability of Vehicle to Infrastructure (V2I) and Vehicle to
Vehicle (V2V) networking. Specifically, C-V2X lowers the number of entities
involved in vehicular communications and allows the inclusion of
cellular-security solutions to be applied to V2X. For this, the evolvement of
LTE-V2X is revolutionary, but it fails to handle the demands of high
throughput, ultra-high reliability, and ultra-low latency alongside its
security mechanisms. To counter this, 5G-V2X is considered as an integral
solution, which not only resolves the issues related to LTE-V2X but also
provides a function-based network setup. Several reports have been given for
the security of 5G, but none of them primarily focuses on the security of
5G-V2X. This article provides a detailed overview of 5G-V2X with a
security-based comparison to LTE-V2X. A novel Security Reflex Function
(SRF)-based architecture is proposed and several research challenges are
presented related to the security of 5G-V2X. Furthermore, the article lays out
requirements of Ultra-Dense and Ultra-Secure (UD-US) transmissions necessary
for 5G-V2X.Comment: 9 pages, 6 figures, Preprin
Blacklistable Anonymous Credentials: Blocking Misbehaving Users without TTPs (Extended Version)
Several credential systems have been proposed in which users can authenticate to services anonymously. Since anonymity can give users the license to misbehave, some variants allow the selective deanonymization (or linking) of misbehaving users upon a complaint to a trusted third party (TTP). The ability of the TTP to revoke a user\u27s privacy at any time, however, is too strong a punishment for misbehavior. To limit the scope of deanonymization, systems such as ``e-cash\u27\u27 have been proposed in which users are deanonymized under only certain types of well-defined misbehavior such as ``double spending.\u27\u27 While useful in some applications, it is not possible to generalize such techniques to more subjective definitions of misbehavior. We present the first anonymous credential system in which services can ``blacklist\u27\u27 misbehaving users without contacting a TTP. Since blacklisted users remain anonymous, misbehaviors can be judged subjectively without users fearing arbitrary deanonymization by a TTP
Accountability and Reconfiguration: Self-Healing Lattice Agreement
An accountable distributed system provides means to detect deviations of system components from their expected behavior. It is natural to complement fault detection with a reconfiguration mechanism, so that the system could heal itself, by replacing malfunctioning parts with new ones. In this paper, we describe a framework that can be used to implement a large class of accountable and reconfigurable replicated services. We build atop the fundamental lattice agreement abstraction lying at the core of storage systems and cryptocurrencies.
Our asynchronous implementation of accountable lattice agreement ensures that every violation of consistency is followed by an undeniable evidence of misbehavior of a faulty replica. The system can then be seamlessly reconfigured by evicting faulty replicas, adding new ones and merging inconsistent states. We believe that this paper opens a direction towards asynchronous "self-healing" systems that combine accountability and reconfiguration
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