164 research outputs found
Privacy protection for telecare medicine information systems using a chaotic map-based three-factor authenticated key agreement scheme
Telecare Medicine Information Systems (TMIS) provides flexible and convenient e-health care. However the medical records transmitted in TMIS are exposed to unsecured public networks, so TMIS are more vulnerable to various types of security threats and attacks. To provide privacy protection for TMIS, a secure and efficient authenticated key agreement scheme is urgently needed to protect the sensitive medical data. Recently, Mishra et al. proposed a biometrics-based authenticated key agreement scheme for TMIS by using hash function and nonce, they claimed that their scheme could eliminate the security weaknesses of Yan et al.âs scheme and provide dynamic identity protection and user anonymity. In this paper, however, we demonstrate that Mishra et al.âs scheme suffers from replay attacks, man-in-the-middle attacks and fails to provide perfect forward secrecy. To overcome the weaknesses of Mishra et al.âs scheme, we then propose a three-factor authenticated key agreement scheme to enable the patient enjoy the remote healthcare services via TMIS with privacy protection. The chaotic map-based cryptography is employed in the proposed scheme to achieve a delicate balance of security and performance. Security analysis demonstrates that the proposed scheme resists various attacks and provides several attractive security properties. Performance evaluation shows that the proposed scheme increases efficiency in comparison with other related schemes
Dynamic Response Recovery Using Ambient Synchrophasor Data: A Synthetic Texas Interconnection Case Study
Wide-area dynamic studies are of paramount importance to ensure the stability and reliability of power grids. This paper puts forth a comprehensive framework for inferring the dynamic responses in the small-signal regime using ubiquitous fast-rate ambient data collected during normal grid operations. We have shown that the impulse response between any pair of locations can be recovered in a model-free fashion by cross-correlating angle and power flow data streams collected only at these two locations, going beyond previous work based on frequency data only. The result has been established via model-based analysis of linearized second-order swing dynamics under certain conditions. Numerical validations demonstrate its applicability to realistic power system models including nonlinear, higher-order dynamics. In particular, the case study using synthetic PMU data on a synthetic Texas Interconnection (TI) system strongly corroborates the benefit of using angle PMU data over frequency one for real-world power system dynamic modeling
Dynamic Response Recovery Using Ambient Synchrophasor Data: A Synthetic Texas Interconnection Case Study
Wide-area dynamic studies are of paramount importance to ensure the stability
and reliability of power grids. This paper puts forth a comprehensive framework
for inferring the dynamic responses in the small-signal regime using ubiquitous
fast-rate ambient data collected during normal grid operations. We have shown
that the impulse response between any pair of locations can be recovered in a
model-free fashion by cross-correlating angle and power flow data streams
collected only at these two locations, going beyond previous work based on
frequency data only. The result has been established via model-based analysis
of linearized second-order swing dynamics under certain conditions. Numerical
validations demonstrate its applicability to realistic power system models
including nonlinear, higher-order dynamics. In particular, the case study using
synthetic PMU data on a synthetic Texas Interconnection (TI) system strongly
corroborates the benefit of using angle PMU data over frequency data for
real-world power system dynamic modeling.Comment: arXiv admin note: text overlap with arXiv:2104.0561
A lightweight privacy preserving authenticated key agreement protocol for SIP-based VoIP
Session Initiation Protocol (SIP) is an essential part of most Voice over Internet Protocol (VoIP) architecture. Although SIP provides attractive features, it is exposed to various security threats, and so an efficient and secure authentication scheme is sought to enhance the security of SIP. Several attempts have been made to address the tradeoff problem between security and efficiency, but designing a successful authenticated key agreement protocol for SIP is still a challenging task from the viewpoint of both performance and security, because performance and security as two critical factors affecting SIP applications always seem contradictory.
In this study, we employ biometrics to design a lightweight privacy preserving authentication protocol for SIP based on symmetric encryption, achieving a delicate balance between performance and security. In addition, the proposed authentication protocol can fully protect the privacy of biometric characteristics and data identity, which has not been considered in previous work. The completeness of the proposed protocol is demonstrated by Gong, Needham, and Yahalom (GNY) logic. Performance analysis shows that our proposed protocol increases efficiency significantly in comparison with other related protocols
A Dynamic Response Recovery Framework Using Ambient Synchrophasor Data
Wide-area dynamic studies are of paramount importance to ensure the stability
and reliability of power grids. The rising deployment synchrophasor and other
sensing technologies has made data-driven modeling and analysis possible using
the synchronized fast-rate dynamic measurements. This paper presents a general
model-free framework of inferring the grid dynamic responses using the
ubiquitous ambient data collected during normal grid operations. Building upon
the second-order dynamic model, we have established the connection from the
cross-correlation of various types of angle, frequency, and line flow data at
any two locations, to their corresponding dynamic responses. The theoretical
results enabled a fully data-driven framework for estimating the latter using
real-time ambient data. Numerical results using the WSCC 9-bus system and a
synthetic 2000-bus Texas system have demonstrated the effectiveness of proposed
approaches for dynamic modeling of realistic power systems
Topology-aware Graph Neural Networks for Learning Feasible and Adaptive ac-OPF Solutions
Solving the optimal power flow (OPF) problem is a fundamental task to ensure
the system efficiency and reliability in real-time electricity grid operations.
We develop a new topology-informed graph neural network (GNN) approach for
predicting the optimal solutions of real-time ac-OPF problem. To incorporate
grid topology to the NN model, the proposed GNN-for-OPF framework innovatively
exploits the locality property of locational marginal prices and voltage
magnitude. Furthermore, we develop a physics-aware (ac-)flow feasibility
regularization approach for general OPF learning. The advantages of our
proposed designs include reduced model complexity, improved generalizability
and feasibility guarantees. By providing the analytical understanding on the
graph subspace stability under grid topology contingency, we show the proposed
GNN can quickly adapt to varying grid topology by an efficient re-training
strategy. Numerical tests on various test systems of different sizes have
validated the prediction accuracy, improved flow feasibility, and topology
adaptivity capability of our proposed GNN-based learning framework
Two-factor remote authentication protocol with user anonymity based on elliptic curve cryptography
In order to provide secure remote access control, a robust and efficient authentication protocol should realize mutual authentication and session key agreement between clients and the remote server over public channels. Recently, Chun-Ta Li proposed a password authentication and user anonymity protocol by using smart cards, and they claimed that their protocol has satisfied all criteria required by remote authentication. However, we have found that his protocol cannot provide mutual authentication between clients and the remote server. To realize ârealâ mutual authentication, we propose a two-factor remote authentication protocol based on elliptic curve cryptography in this paper, which not only satisfies the criteria but also bears low computational cost. Detailed analysis shows our proposed protocol is secure and more suitable for practical application
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