44,867 research outputs found
Quantum cryptography with finite resources: unconditional security bound for discrete-variable protocols with one-way post-processing
We derive a bound for the security of QKD with finite resources under one-way
post-processing, based on a definition of security that is composable and has
an operational meaning. While our proof relies on the assumption of collective
attacks, unconditional security follows immediately for standard protocols like
Bennett-Brassard 1984 and six-states. For single-qubit implementations of such
protocols, we find that the secret key rate becomes positive when at least
N\sim 10^5 signals are exchanged and processed. For any other discrete-variable
protocol, unconditional security can be obtained using the exponential de
Finetti theorem, but the additional overhead leads to very pessimistic
estimates
Sequential Circuit Design for Embedded Cryptographic Applications Resilient to Adversarial Faults
In the relatively young field of fault-tolerant cryptography, the main research effort has focused exclusively on the protection of the data path of cryptographic circuits. To date, however, we have not found any work that aims at protecting the control logic of these circuits against fault attacks, which thus remains the proverbial Achilles’ heel. Motivated by a hypothetical yet realistic fault analysis attack that, in principle, could be mounted against any modular exponentiation engine, even one with appropriate data path protection, we set out to close this remaining gap. In this paper, we present guidelines for the design of multifault-resilient sequential control logic based on standard Error-Detecting Codes (EDCs) with large minimum distance. We introduce a metric that measures the effectiveness of the error detection technique in terms of the effort the attacker has to make in relation to the area overhead spent in
implementing the EDC. Our comparison shows that the proposed EDC-based technique provides superior performance when compared against regular N-modular redundancy techniques. Furthermore, our technique scales well and does not affect the critical path delay
A Game of One/Two Strategic Friendly Jammers Versus a Malicious Strategic Node
We present a game-theoretic analysis of the interaction between a malicious node, attempting to perform unauthorized radio transmission, and friendly jammers trying to disrupt the malicious communications. We investigate the strategic behavior of the jammers against a rational malicious node and highlight counterintuitive results for this conflict. We also analyze the impact of multiple friendly jammers sharing the same goal but acting without coordination; we find out that this scenario offers a better payoff for the jammers, which has some strong implications on how to implement friendly jamming
Secure Cloud Storage with Client-Side Encryption Using a Trusted Execution Environment
With the evolution of computer systems, the amount of sensitive data to be
stored as well as the number of threats on these data grow up, making the data
confidentiality increasingly important to computer users. Currently, with
devices always connected to the Internet, the use of cloud data storage
services has become practical and common, allowing quick access to such data
wherever the user is. Such practicality brings with it a concern, precisely the
confidentiality of the data which is delivered to third parties for storage. In
the home environment, disk encryption tools have gained special attention from
users, being used on personal computers and also having native options in some
smartphone operating systems. The present work uses the data sealing, feature
provided by the Intel Software Guard Extensions (Intel SGX) technology, for
file encryption. A virtual file system is created in which applications can
store their data, keeping the security guarantees provided by the Intel SGX
technology, before send the data to a storage provider. This way, even if the
storage provider is compromised, the data are safe. To validate the proposal,
the Cryptomator software, which is a free client-side encryption tool for cloud
files, was integrated with an Intel SGX application (enclave) for data sealing.
The results demonstrate that the solution is feasible, in terms of performance
and security, and can be expanded and refined for practical use and integration
with cloud synchronization services
SecMon: End-to-End Quality and Security Monitoring System
The Voice over Internet Protocol (VoIP) is becoming a more available and
popular way of communicating for Internet users. This also applies to
Peer-to-Peer (P2P) systems and merging these two have already proven to be
successful (e.g. Skype). Even the existing standards of VoIP provide an
assurance of security and Quality of Service (QoS), however, these features are
usually optional and supported by limited number of implementations. As a
result, the lack of mandatory and widely applicable QoS and security guaranties
makes the contemporary VoIP systems vulnerable to attacks and network
disturbances. In this paper we are facing these issues and propose the SecMon
system, which simultaneously provides a lightweight security mechanism and
improves quality parameters of the call. SecMon is intended specially for VoIP
service over P2P networks and its main advantage is that it provides
authentication, data integrity services, adaptive QoS and (D)DoS attack
detection. Moreover, the SecMon approach represents a low-bandwidth consumption
solution that is transparent to the users and possesses a self-organizing
capability. The above-mentioned features are accomplished mainly by utilizing
two information hiding techniques: digital audio watermarking and network
steganography. These techniques are used to create covert channels that serve
as transport channels for lightweight QoS measurement's results. Furthermore,
these metrics are aggregated in a reputation system that enables best route
path selection in the P2P network. The reputation system helps also to mitigate
(D)DoS attacks, maximize performance and increase transmission efficiency in
the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On
Computer Science - Research And Applications, Poland, Kazimierz Dolny
31.01-2.02 2008; 14 pages, 5 figure
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