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Broadcast encryption is a novel concept for sending a special message to a subset of users. In broadcast encryption schemes, the distribution center broadcasts the message in encrypted form and expect that only the intended users be able to decrypt the message. This concept has several applications such as pay-per-service TVs. In this paper, we investigate one of the most recent broadcast encryption schemes and show that the introduced scheme does not provide the main requirement of broadcast encryption schemes. For this purpose, we demonstrate that all of the users, including authorized and unauthorized users, can decrypt the broadcasted encrypted message. © 2016 IEEE  

Security in mobile handsets of telecommunication standards such as GSM, Project 25 and TETRA is very important, especially when governments and military forces use handsets and telecommunication devices. Although telecommunication could be quite secure by using encryption, coding, tunneling and exclusive channel, attackers create new ways to bypass them without the knowledge of the legitimate user. In this paper we introduce a new, simple and economical circuit to warn the user in cases where the message is not encrypted because of manipulation by attackers or accidental damage. This circuit not only consumes very low power but also is created to sustain telecommunication devices in aspect... 

Since their introduction, Cognitive Radio Networks (CRN), as a new solution to the problem of spectrum scarcity, have received great attention from the research society. An important field in database-driven CRN studies is pivoted on their security issues. A critical issue in this context is user’s location privacy, which is potentially under serious threat. The query process by secondary users (SU) from the database is one of the points where the problem rises. In this paper, we propose a Privacy-Preserving Query Process (PPQP), accordingly. This method lets SUs deal in the process of spectrum query without sacrificing their location information. Analytical assessment of PPQP’s privacy... 

Popularity of data outsourcing and its consequent access control issues such as dynamism and efficiency is the main motivation of this paper. Existing solutions suffer from the potential unlimited number of user keys, inefficient update of policies, and disclosure of data owner’s access control policies. Using Chinese remainder theorem and proxy re-encryption together, in this paper, we propose an efficient access control enforcement mechanism based on selective encryption that addresses all the shortages. The overall architecture, required algorithms, and access control policy update are discussed. The mechanism is evaluated through simulation and, the given results are satisfactory  

This letter presents an efficient polar code-based physical layer encryption (PLE) scheme with a short key length in comparison to the conventional symmetric key cryptosystems. By using the properties of polar codes, we consider several efficient techniques to reduce the key length and the computational overhead of the presented PLE scheme. Moreover, the results of the security analyses show that the proposed scheme has a high level of security against conventional attacks on the PLE schemes. In fact, reducing the key length and the computational overhead of the presented PLE scheme has no effect on its security level, which makes it suitable for secure mobile communication devices with... 

Abstract In this paper, a word based chaotic image encryption scheme for gray images is proposed that can be used in both synchronous and self-synchronous modes. The encryption scheme operates in a finite field where we have also analyzed its performance according to numerical precision used in implementation. We show that the scheme not only passes a variety of security tests, but also it is verified that the proposed scheme operates faster than other existing schemes of the same type even when using lightweight short key sizes  

Temporary keyword search on confidential data in a cloud environment is the main focus of this research. The cloud providers are not fully trusted. So, it is necessary to outsource data in the encrypted form. In the attribute-based keyword search (ABKS) schemes, the authorized users can generate some search tokens and send them to the cloud for running the search operation. These search tokens can be used to extract all the ciphertexts which are produced at any time and contain the corresponding keyword. Since this may lead to some information leakage, it is more secure to propose a scheme in which the search tokens can only extract the ciphertexts generated in a specified time interval. To... 

It is quite common nowadays for clients to outsource their personal data to a cloud service provider. However, it causes some new challenges in the area of data confidentiality and access control. Attribute-based encryption is a promising solution for providing confidentiality and fine-grained access control in a cloud-based cryptographic system. Moreover, in some cases, to preserve the privacy of clients and data, applying hidden access structures is required. Also, a data owner should be able to update his defined access structure at any time when he is online or not. As in several real-world application scenarios like e-health systems, the anonymity of recipients, and the possibility of... 

With the development of cloud computing, many enterprises have been interested in outsourcing their data to cloud servers to decrease IT costs and rise capabilities of provided services. To afford confidentiality and fine-grained data access control, attribute-based encryption (ABE) was proposed and used in several cloud storage systems. However, scalability and flexibility in key delegation and user revocation mechanisms are primary issues in ABE systems. In this paper, we introduce the concept of a fully distributed revocable ciphertext-policy hierarchical ABE (FDR-CP-HABE) and design the first FDR-CP-HABE scheme. Our scheme offers a high level of flexibility and scalability in the key... 

Temporary keyword search on confidential data in a cloud environment is the main focus of this research. The cloud providers are not fully trusted. So, it is necessary to outsource data in the encrypted form. In the attribute-based keyword search (ABKS) schemes, the authorized users can generate some search tokens and send them to the cloud for running the search operation. These search tokens can be used to extract all the ciphertexts which are produced at any time and contain the corresponding keyword. Since this may lead to some information leakage, it is more secure to propose a scheme in which the search tokens can only extract the ciphertexts generated in a specified time interval. To... 

Advance Encryption Standard (AES), has received significant interest over the past decade due to its performance and security level. In this paper, we propose a compact 8-bit AES crypto-processor for area constrained and low power applications where both encryption and decryption is needed. The cycle count of the design is the least among previously reported 8-bit AES architectures and the throughput is 203 Mbps. The AES core consumes 5.6k gates in 0.18 μm standard-cell CMOS technology. The power consumption of the core is 49 μW/MHz at 128 MHz which is the minimum power reported thus far  

We introduce a new secret-key cryptosystem based on 1-level QC-LDPC integer lattices. These lattices are practically implementable in high dimensions due to their low-complexity encoding and decoding algorithms. We exploit their efficient encoding and decoding algorithms to make a significant reduction in the complexity of lattice-based cryptosystems. Furthermore, the sparseness of the corresponding parity check matrix of 1-level QC-LDPC lattices and their good error performance, make them efficient choices in real world applications. In this paper, we propose a Rao-Nam like encryption scheme using 1-level QC-LDPC lattices. Some chosen-plaintext attacks and recent results on the Rao-Nam... 

One of the organizations’ main concerns is to protect sensitive data in database systems, especially the ones outsourced to untrusted service providers. An effective solution for this issue is to employ database encryption methods. Among different encryption approaches, Bucket-based method has the advantage of balancing security and performance of database operations. However, generating false-positive results in executing queries is the main drawback of this method. On the other hand, multi-join queries are one of the most critical operations executed on these stored sensitive data. Hence, acceptable processing and response time in executing multi-join queries is required. In this paper, we... 

In recent years, mobile social networks have largely been developed and gained considerable popularity. An approach to protecting privacy on mobile social networks is the use of encryption and access control. Good alternatives for use on mobile social networks are the Public Broadcast Encryption approach for appropriate concordance and consistency with the structure of social networks as well as the Attribute-Based Encryption owing to its capability and proper implementation of the access control policy. Accordingly, in this paper, a framework was presented based on the Public Broadcast Encryption and Attribute-Based Encryption. Using proxies, we outsourced some of these operations in the...