Elliptic curve analogue ElGamal encryption scheme requires encoding of the plain message onto elliptic curve coordinate using Koblitz encoding technique before encryption operation. The paper ...proposes a medical image encryption scheme using improved ElGamal encryption technique. A new finding has been made in the proposed method where separate calculations for encoding plain message to elliptic curve coordinate is removed. The algorithm in the improved version of ElGamal encryption scheme is designed to encrypt medical image where data expansion issue is resolved and execution speed is enhanced. The strength of the proposed method is insured through various statistical and security analyses and comparison with other existing encryption schemes.
Color image can provide more information than gray image, so it is used more widely in the field of the communication. In recent years, how to safely encrypt images has received increasing attention. ...Numerous previous image encryption algorithms are based on the symmetric encryption algorithm, but each pair of users communicating with symmetric encryption algorithm can only use the key that others do not know, so when the sender communicates with a receiver multiple times or sends the message to multiple receivers, the key number will grow at a geometric rate, and key management will become a burden on the users. In this paper, we propose an asymmetric image encryption algorithm for the advantages that the key groups and the number of keys in secret information transmission among multiple people are very small, and key transmission mode is relatively simple and secure. In our algorithm, first, the plain image is compressed and then the color image is encrypted by using the improved 4D cat map followed by asymmetric encryption which is based on elliptic curve ElGamal encryption, and finally, the encrypted image is globally diffused. The performance analysis is performed on key spaces, key sensitivity, the capability of resisting statistical attacks, differential attacks, known plaintext attacks and chosen plaintext/ciphertext attacks and quality evaluation metrics of decrypted image. Simulation results show that the proposed algorithm has better security comparing with other algorithms.
Despite the importance of cyber-security for networked control systems, no suitable cryptosystem exists for networked control systems that guarantees stability and has low computational complexity. ...This study proposes a novel dynamic ElGamal cryptosystem for encrypted control systems. The proposed cryptosystem is a multiplicative homomorphic cryptosystem, and it updates key pairs and ciphertexts by simple updating rules with modulo operations at every sampling period. Furthermore, the authors modify the proposed cryptosystem by using a dynamic encoder and decoder so that the asymptotic stability of the encrypted control systems is guaranteed. Numerical simulations demonstrate that the encrypted controller with the proposed cryptosystem achieves asymptotic stability while randomly updating key pairs and ciphertexts. The feasibility of the proposed encrypted control system is evaluated through regulation control with a positioning table testbed. The processing time of the proposed encrypted control system is on the order of milliseconds, indicating that the system achieves real-time control.
Reputation-based authentication is a mechanism used to establish trust and ensure the reliability of vehicle communication in vehicular ad hoc networks (VANETs). However, existing schemes ignore the ...importance of privacy protection and face issues such as malicious vehicles spreading false or duplicate messages. To address these issues, this paper proposes a secure and anonymous reputation-based authentication scheme based on the ElGamal cryptosystem for the vehicular communication system, which promotes cooperative behavior and encourages vehicles' positive contribution to the network. In particular, we design an efficient duplicate detection mechanism based on the technique of Bloom filter to aid in identifying and isolating malicious vehicles. Security analysis is conducted to demonstrate the robust security of the proposed scheme. The results of performance evaluation highlight the superiority of the proposed scheme in addressing the identified shortcomings while maintaining reasonable computation and communication costs.
With the rise in medical imaging tools and telemedicine technology, the distance barriers in providing health care have been reduced by communicating patients data over the internet. To provide ...patients with privacy, the data are encrypted while transmitting over the insecure network. The paper proposes an encryption scheme for multiple medical images using a new finding in elliptic curve analogue ElGamal cryptosystem and Mersenne Twister pseudo-random number generator. The new finding quickens the encryption time as well as solve the problem of data expansion associated with ElGamal cryptosystem. Results from simulation, security and statistical analyses show that the proposed encryption algorithm can be used for multiple medical images encryption.
An efficient ElGamal cryptosystem scheme Hussein, Haval I.; Abduallah, Wafaa M.
International journal of computers & applications,
11/26/2021, Letnik:
43, Številka:
10
Journal Article
Recenzirano
ElGamal Cryptosystem (EC) is a non-deterministic scheme which produces different outputs for the same input, making the cryptosystem more secure. On the other hand, the efficiency of its cryptosystem ...is low as it produces a 2:1 expansion in size from plaintext to ciphertext, resulting in a delay in execution time. Therefore, this paper presents a Modified ElGamal Cryptosystem (MEC) to increase the efficiency by speeding up the execution time and reducing the expansion rate in the file size after the encryption process. A comparison between the proposed MEC and the traditional EC is carried out using the same programming environment, and the implementation is tested using text data of different sizes. The results show that the performance of the proposed MEC is better than the traditional EC in terms of execution time and expansion rate. Whereas, the security of the proposed MEC is analogous to the traditional EC, which is based on the difficulty of solving the discrete logarithm problem.
This article is devoted to the novel situation, where a large distributed cloud database is a union of several separate databases belonging to individual database owners who are not allowed to ...transfer their data for storage in locations different from their already chosen separate cloud service providers. For example, a very large number of medical records may be stored in a distributed cloud database, which is a union of several separate databases from different hospitals, or even from different countries. The owners of the databases may need to provide answers to certain common aggregated queries using all information available without sharing or transferring all data. It is necessary to minimize the communication costs, improve efficiency, and comply with the legal requirements protecting the privacy of confidential data. In this situation, it is impossible to aggregate the whole database in one location, but effective methods for answers to the aggregated queries with privacy protection are required.
To solve this important problem, the present article proposes a Multistage Separate Query Processing (MSQP) protocol employing homomorphic encryption with split keys. We show that our protocol can answer a large class of natural queries of practical significance. The running time of the MSQP protocol isO(d+md), whered is the number of database owners andm is the total number of records in the whole database. In practice,d is small,m can be very large, and so the running time isO(m). This means that the protocol is very efficient for large databases. It dramatically reduces the communication costs of computation and completely eliminates the need for exchange of confidential data.
We define a new generalized additive homomorphic property and introduce a Multipart ElGamal Cryptosystem (MEC) with split keys, which enjoys this property. MEC is a novel modification of the ElGamal cryptosystem with split keys. This paper presents the results of extensive experiments evaluating the effectiveness of the MSQP protocol employing MEC and comparing it with MSQP employing the ElGamal cryptosystem, for a collection of publicly available medical datasets. The experiments evaluating our protocol on 11 real-life databases and a synthetic database demonstrate that the MSQP protocol employing MEC is more efficient than other options and can be recommended for practical implementations.
•We consider a situation when it is impossible to aggregate data from separate databases.•We introduce a Multistage Separate Query Processing (MSQP) protocol.•We use 11 real-life databases to investigate the MSQP protocol.•The experimental results show that the MSQP protocol is highly efficient.
This paper focuses on the design of a privacy-preserving distributed Kalman filtering algorithm for a class of linear time-varying systems in signal-to-interference-plus-noise ratio (SINR)-based ...sensor networks, where packet dropouts may occur in information transmission between neighboring sensor nodes. Considering the potential occurrence of eavesdropping attacks during information transmission, which is common due to the inherent vulnerability of SINR-based sensor networks, a new class of distributed secure Kalman filtering algorithm is developed. The presented algorithm incorporates a modified ElGamal cryptosystem and adaptive fusion weights to significantly enhance security, resist privacy leakage, and bolster robustness against packet dropping. Then, a detailed performance analysis for the presented distributed secure Kalman filtering algorithm is conducted, where the security and unbiasedness of the designed algorithm are discussed. Sufficient conditions for the stability of the estimation error are further established to ensure that the estimation error is ultimately bounded in the almost sure sense. Finally, numerical examples are given to illustrate the effectiveness of the proposed algorithm.
Life in modern society becomes easier due to the rapid growth of different technologies like real-time analytic, ubiquitous wireless communication, commodity sensors, machine learning and embedded ...systems. Nowadays, there seems to be a need to merge these technologies in the form of Internet of Things (IoT) so that smart systems can be achieved. On the other hand, cloud computing is a pillar in IoT by which end users get connected through the cloud servers for getting different services. However, to recognise the legitimacy of communicators during communication sessions through insecure channels like the Internet, serious issues in cloud-based IoT applications need to be addressed. Thus, authentication procedure is highly desirable to remove the unapproved access in IoT applications. This study presents an ElGamal cryptosystem and biometric information along with a user's password-based authentication scheme for cloud-based IoT applications refereed as SAS-Cloud. Security of the proposed scheme has been analysed by well popular random oracle model and it is found that SAS-Cloud has the ability to defend all the possible attacks. Furthermore, the performance of SAS-Cloud has been evaluated and it was found that SAS-Cloud has better efficiency than other existing competing ElGamal cryptosystem-based authentication schemes.
•We proposed an attack algorithm for an ElGamal-based homomorphic encryption scheme constructed by Bae et al. 11.•The proposed attack is thorough and efficient.•The proposed attack algorithm can be ...considered when designing ElGamal-based encryption schemes.
Based on the ElGamal cryptosystem, Bae et al. (J. Netw. Comput. Appl., vol. 59, pp. 333–344, 2016) proposed a new homomorphic encryption algorithm to reduce the network traffic and data processing time brought by their data communication and aggregation scheme. However, there is no security analysis of this encryption algorithm in their scheme. In this paper, we analyze the security of their proposed encryption algorithm and prove that it is not secure.
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