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Managing large personal image databases requires efficient privacy preserving indexing methods to allow for their outsourcing to possibly curious cloud servers. To construct a secure inverted index in this paper, first, visual words are extracted from stored images based on the Speeded-Up and Robust Features (SURF). Next, Order Preserving Encryption (OPE) is used to encipher the frequencies of occurrence of the extracted visual words. Another scale and rotation invariant feature, which is the local HSV histogram, is included for comparison. From the obtained results, it is apparent that SURF achieves more precise results. Aggregation of both features is considered to further improve the accuracy. The effects of the weighting scheme of the visual words and their number on the performance are investigated. Weighted term frequency inverse document frequency (tf-idf) together with the Jaccard similarity measure yield the best performance. OPE encryption is shown to have minor impact on the retrieval accuracy. To reduce encryption time, a lookup table is constructed. The inverted index reduces the search time significantly compared to a sequential search scheme as apparent from the results. A comparative study with recent related schemes demonstrates the competitiveness of the implemented system in terms of computational efficiency and accuracy.

Two new encryption algorithms for secure video transmission are proposed in this paper. The two algorithms employ different types of chaotic maps to generate the keystream for encrypting the video frames. Both algorithms involve a substitution step and a permutation step to achieve confusion and diffusion requirements. For efficient transmission, the video file is compressed before being encrypted. In the basic implementation of both algorithms, MPEG-2 standard is used for compression. However, the algorithms are shown to be compliant with other compression techniques. In the permutation step, the effect of the block size used in the shuffling process is examined. Smaller blocks result in increasing the processing time, while reducing both the correlation between adjacent pixels and the peak-signal-to noise ratio of an encrypted frame. The use of a Feistel structure is investigated to enhance security and its negative impact on the encryption time is demonstrated. The experimental results of the two proposed schemes confirm that they represent different tradeoffs between security and computational efficiency. Both schemes are sensitive to slight variations in the encryption key as apparent from the obtained differential measures. The conducted comparative study shows the competitiveness of the proposed schemes to existing schemes in literature.

Quantum cryptography utilizes the quantum properties of photons to construct an unbreakable crypto-algorithm in real-time. In this paper, based on quantum and classical computation principles, a new quantum encryption algorithm using the symmetric key is presented. It is a block-cipher algorithm which means that each message contains blocks in which 4 bits for each. Firstly, keyed rotations and permutation of the message bits are used. Secondly, the encrypted message is converted to qubits then several dynamic quantum gates are applied to them key dependently to make the ciphertext state reach the state of non-orthogonality. In consequence of the principles of quantum mechanics, the eaves cannot distinguish the non-orthogonal states of the encrypted message. The proposed algorithm is proofed to increase the message space, the various algorithm analysis proofed that our proposed algorithm has an improved strength against various attacks, including the brute force attack.

Quantum cryptography appropriates the features of photons to create a secured algorithm in real-time. In this study, a new algorithm is illustrated using the symmetric key based on the basics of quantum and classical computation. In this algorithm, the message contains blocks, the space of each block is 16 bits. First, the classical encryption process depends on the key that makes rotation and permutation in the bits of block message. Second, the bits of encrypted block messages are converted to qubits. Third, Pauli gates are used, and applies the output of the second stage to them depends on a key to achieving the non-orthogonality of ciphertext states. Because of the basis of quantum computing, the eavesdroppers cannot detect the encrypted message states that changed to non-orthogonal states. The proposed algorithm is proven to increase the message space, the various algorithm analysis proofed that our proposed algorithm has an improved strength against various attacks, including the brute force attack.

A huge amount of personal multimedia data is generated daily and stored on cloud servers. This data needs to be secure from curious servers, while also being searchable by them. The visual features used in a content-based image retrieval (CBIR) system are encrypted to ensure privacy of the cloud users. This paper aims to investigate several features for use in building a privacy-preserving CBIR system. These features range from simple and fast statistical bit plane distribution features to the more sophisticated local features such as Speeded-Up and Robust Features (SURF). Moreover, both series and parallel aggregation approaches of combining several features are studied to improve retrieval efficiency. Feature vectors are encrypted using distance-preserving techniques. The accuracy of the retrieval system is examined under different combinations of encrypted visual features. The results are insightful offering interesting trade-offs between security, computational efficiency and accuracy.

Cognitive radio networks serve different secondary user applications which have distinct delay requirements. In order to better support the delay-sensitive applications, we consider secondary user traffic to be classified into M prioritized classes based on delay requirements. The priority of a secondary user increases within the same class after each interruption to reduce the cumulative handoff delay. A mixed preemptive/non-preemptive resume priority M/G/1 queueing model is assumed to analyze multiple spectrum handoffs. Closed form expressions are derived for both the extended data delivery time and dropping probability for each secondary user class. The analysis assumes a general target channel sequence, where a secondary user can select either to stay at his current channel or change it after each interruption. This general target channel sequence is optimized using a genetic algorithm in order to minimize the average extended data delivery time of all secondary user classes. Numerical results show that the proposed interruption-based priority mechanism outperforms the existing priority mechanisms in terms of average handoff delay and extended data delivery time in case of changing the target channel while preserves the extended data delivery time in case of always stay. Moreover, the optimized general target channel sequence gives better performance compared to the target channel sequences mentioned in the IEEE 802.22 wireless regional area networks standard for different network cases.

Electronic commerce, as exemplified by the popularity of the Internet, is becoming more important along with fast progress in communications and information technology. The SET (Secure Electronic Transaction) protocol is a scheme designed to ensure that merchants and cardholders can conduct business over a public network. Although the SET protocol has some disadvantages, but still it is the most commonly used protocol in the Internet shopping. Signcryption is a cryptographic primitive which simultaneously provides both confidentiality and authenticity in a single logical step. Signcryption based on elliptic curves provides the same level of security using smaller keys compared to schemes based on the discrete logarithm problem over finite fields. This paper examines the benefits of using signcryption rather than signaturethen-encryption in the SET protocol. Using identity-based signcryption in the SET protocol reduces the number of encryption and decryption operations. Moreover, signcryption is less time consuming than signature-then-encryption.

This paper blends the ideas from recent researches into a simple, yet efficient image encryption scheme for colored images. It is based on the finite field cosine transform (FFCT) and symmetric-key cryptography. The FFCT is used to scramble the image yielding an image with a uniform histogram. The FFCT has been chosen as it works with integers modulo p and hence avoids numerical inaccuracies inherent to other transforms. Fractals are used as a source of randomness to generate a one-time-pad keystream to be employed in enciphering step. The fractal images are scanned in zigzag manner to ensure decorrelation of adjacent pixels values in order to guarantee a strong key. The performance of the proposed algorithm is evaluated using standard statistical analysis techniques. Moreover, sensitivity analysis techniques such as resistance to differential attacks measures, mean square error, and one bit change in system key have been investigated. Furthermore, security of the proposed scheme against classical cryptographic attacks has been analyzed. The obtained results show great potential of the proposed scheme and competitiveness with other schemes in literature. Additionally, the algorithm lends itself to parallel processing adding to its computational efficiency.

Cognitive radio (CR) is a technology that aims to enhance the use of the underutilized spectrum. Spectrum handoff plays this role by allowing the unlicensed secondary users (SUs) to use the licensed frequency bands of the primary users (PUs). Moreover, it helps the SU to vacate the channel at the presence of the PU and find a suitable channel for the interrupted SU to continue his unfinished transmission. In this paper, an analytical model for the general case of non-identical channels in CR networks is introduced for both fixed and probabilistic sequence approaches for target channel selection. Moreover, a new balancing model is suggested to generate the probabilistic sequence. Both the fixed and probabilistic sequence approaches are optimized using the meta-heuristic methods of particle swarm and genetic algorithm in the seek of finding an optimal approach to minimize the extended data delivery time of the SUs. The results are based on the pre-emptive resume priority M/M/1 queueing network model and are shown for different network cases. Based on the optimization results, a fast hybrid approach is proposed and found to achieve near optimal solution.

This paper presents a new approach for secure hiding of textual data in a colored digital image. Use of images as a cover media in steganography is based on the deficiencies in the human visual system (HVS). The proposed technique employs two independent chaotic sequences for specifying the locations where the message bits are embedded in the cover image using an adapted version of the least significant bit (LSB) method. Message bits are embedded using the 3-3-2 LSB insertion method for the chaotically selected pixels of the cover image. This technique provides sufficient security as the same sequence of numbers cannot be generated without knowing the exact key; that is; the initial conditions of the two chaotic maps used in the index selection process. Moreover, the preliminary results ensure that eavesdroppers will not have any suspicion that there is a message hidden within the sent image since the peak signal to noise ratio (PSNR) is high and the mean-squared-error (MSE) is low. Furthermore, the length of the secret message is another important component of the key, which standard steganography detection methods cannot estimate correctly. Finally, the proposed approach provides better PSNR values and MSE values compared to other existing techniques as apparent from our experimental results.

This paper investigates several alternative schemes for hiding a grayscale image in a colored cover image in the spatial domain. First, we consider the use of one-dimensional (Tent map) versus two-dimensional (Baker's map) chaotic maps for the selection of the set of pixels where the secret message bits are to be embedded. The red color channel of the cover image for the formerly selected pixels is affected by the embedding process since the eye is not very sensitive for slight variations in this color channel. Next, two LSB embedding schemes are examined; namely, embedding one bit per pixel and embedding two bits per pixel. The preliminary results ensure that, to eavesdroppers, there will be almost no suspicion regarding the existence of a secret message hidden within the sent image since the peak-signal-to-noise-ratio (PSNR) is high and the mean-squared-error (MSE) is low for the different alternatives investigated. However, there is a clear impact on the time required for the embedding process if two-dimensional maps and/or one bit per pixel LSB technique are used.

The use of capacitors in power systems has many well-known benefits that include improvement of the system power factor, improvement of the system voltage profile, increasing the maximum flow through cables and transformers and reduction of losses due to the compensation of the reactive component of power flow. By decreasing the flow through cables, the systems’ loads can be increased without adding any new cables or overloading the existing cables. These benefits depend greatly on how capacitors are placed in the system. In this paper, the problem of how to optimally determine the locations to install capacitors and the sizes of capacitors to be installed in the buses of radial distribution systems is addressed. The proposed methodology uses loss sensitivity factors to identify the buses requiring compensation and then a discrete particle swarm optimization algorithm (PSO) is used to determine the sizes of the capacitors to be installed. The proposed algorithm deals directly with discrete nature of the design variables. The results obtained are superior to those reported in Prakash and Sydulu (2007).

is an increased activity in research and development conducted to improve current payment systems in parallel with the progress of Internet. Signcryption combines the functionalities of encryption and digital signing in a single logical step. It is a cryptographic primitive that provides confidentiality, integrity, authentication and non-repudiation. Identity-based cryptography serves as an efficient alternative to the traditional certificate-based cryptosystems. This paper introduces an efficient electronic payment system based on signcryption without bilinear pairings. This e-cash system is more efficient than other schemes employing bilinear pairings and involves less computational cost. In the proposed protocol, the token is issued and authenticated by the bank to prevent double spending problem. The customer delegates his signing capability to the merchant. The bank verifies the identities of both the original signer (customer) and the proxy signer (merchant) and ensures the originality of the transaction. Unlike the existing e-payment systems, the problem of double spending of e-cash does not arise because each transaction is made uniquely identifiable. Hence, no separate protocol is needed to check double-spending. The performance and the security analysis of the proposed e-cash system are discussed revealing its strength from the viewpoint of security and efficiency with regard to computations required.

paper introduces a new authentication protocol using the tripartite signcryption scheme without bilinear pairings that provides confidentiality and authentication between three entities. Mobile communication seems very attractive to users as well as operators and service providers. However, despite of its numerous advantages, mobile communication has been facing many security problems. In this paper, it is demonstrated how the proposed tripartite signcryption scheme can be used to provide authentication and to guarantee secure communication. The use of the proposed tripartite signcryption scheme helps reduce the signaling overhead compared to the scheme in (1).

In this paper, a new image encryption scheme named (ArMTFr) is proposed. An image is encrypted using a combination of keyed permutations and substitution, where a fractal is XORed with the scrambled image. Fractal images are employed in order to improve the performance of the encryption scheme from the viewpoint of randomisation and to increase the encryption key space, thus boosting its security. The employed permutations are the Arnold map and Mersenne-Twister's permutation algorithm. Before the encryption process starts, histogram equalisation is used to enhance the contrast of the image by transforming the intensity values in it, so that the histogram of the output image approximately matches a uniform histogram. First, greyscale images are considered and then the basic algorithm is extended to handle coloured images. Three representations for coloured images are considered: RGB, YCbCr and HSI colour spaces. The security of the algorithm is enhanced in this case by applying RGB colour channels multiplexing. The experimental results show that the encrypted image has low correlation coefficients among adjacent pixels and a good histogram distribution, as well as resistance to various attacks.

key establishment protocol allows entities to establish a common secret key to ensure secure communications over an insecure public network. This paper proposes two new two- party key agreement protocols. Both protocols do not involve bilinear pairings. The first protocol is a certificate-based key agreement protocol that is more efficient than (1) due to its dependence on the elliptic curve discrete logarithm problem and the second is an extension to a certificateless key agreement protocol. Both protocols depend on the use of an authentication message to check that the shared session key is equal for both entities before using it. This authentication message prevents the key off-set attack that is valid for the Haiyan-Sun protocol (2). The security analysis of the second protocol is discussed. The proposed certificateless key agreement protocol is compared with other protocols in literature (2,3,4) and it requires minimal computational cost. Moreover, this protocol is implemented using the Mathematica (7) program.

Effective utilization plans for various resources at a container terminal are essential to reducing the turnaround time of cargo vessels. Among the scarcest resources are the berth and its associated cranes. Thus, two important optimization problems arise, which are the berth allocation and quay crane assignment problems. The berth allocation problem deals with the generation of a berth plan, which determines where and when a ship has to berth alongside the quay. The quay crane assignment problem addresses the problem of determining how many and which quay crane(s) will serve each vessel. In this paper, an integrated heuristics-based solution methodology is proposed that tackles both problems simultaneously. The preliminary experimental results show that the proposed approach yields high quality solutions to such an NP-hard problem in a reasonable computational time suggesting its suitability for practical use.

Achieving confidentiality and authentication in e-commerce transactions are among the primary security goals. In this paper, a new cryptographic scheme is proposed which guarantees the authenticity of the customer and ensures the confidentiality of the communications among the bank, the merchant and the customer. The proposed solution is the use of a tripartite signcryption scheme with low computational and communications overhead. A variant of the proposed scheme that enables a firewall to authenticate the origin of the ciphertext without disclosure of the contents of the original plaintext message is also presented. General Terms

Geographical routing protocols in highly-dynamic aeronautical ad-hoc networks are vulnerable to fake geo-location information as an attack that affects network performance. In this paper, a secure geographical routing protocol, called SAeroRP, for multi-hop routing in a highly dynamic aeronautical ad-hoc network is presented. SAeroRP uses the ground station as a trusted third party for authentication and key transport. SAeroRP requires that air-borne nodes be equipped with a second transceiver with a long range (150 Km) and wide downlink bandwidth for point-to-point communication with the ground station. Each packet used in the protocol is authenticated and encrypted to prevent fake geo-location information. NS3 simulation analysis shows that the packet delivery ratio for the aeronautical routing protocol AeroRP decreased to up to 50%, depending on attack type and number of attackers. On the contrary, the attack has minimal effect on SAeroRP and the packet delivery ratio is almost the same as that without attack.

The use of standardized containers in cargo transportation has gained undoubted worldwide importance during the last four decades. At a container terminal, containers are transferred between vessels and container yard blocks by different types of transporters. Improving transporter utilization can lead to improving terminal throughput and operational efficiency. This is why dual-cycle transfer mode is applied. In dual-cycle transfer mode, transporters operate in a pool serving several cranes in alternative modes of loading or discharging. Although empty travel distance can be reduced, it is difficult to apply dual-cycle transfer mode at manned container terminals. Grouping of transporters can combine ease of use and dual-cycle transfer mode, where transporters in the same group operate in a pool. In this paper, a Multi-Layer Genetic Algorithm (MLGA) is developed to first construct groups of transporters, and then schedule transporters in the same pool in a dual cycle mode of transfer. The decision aims to decrease the makespan of discharging and loading of containers.

Signcryption is a well-known cryptographic primitive that achieves various security goals including confidentiality of communications, source authentication, and integrity of message contents and ensuring non-repudiation. In e-cash systems, customers prefer to spend their e-coins anonymously. Blind signatures have been developed to meet this requirement. In the present paper, two new blind signcryption schemes are proposed in order to combine the functionalities of both primitives in a single logical step. The first one is tailored for traditional public key infrastructures; while the second one is an identity-based scheme. The proposed schemes have been designed with an eye on applications to e-cash systems and thus overcoming shortcomings in earlier attempts in blind signcryption. The two schemes are computationally efficient promoting their use in practical scenarios. The schemes involve three parties. In e-cash scenarios, these are the bank, the e-coin acquirer (customer) and the merchant which deposits the e-coin in his bank account.

Signcryption combines the functionalities of encryption and digital signing in a single logical step in order to obtain confidentiality, integrity, authentication and non-repudiation. It is more efficient than the sign-then-encrypt approach. Identity-based cryptography serves as an efficient alternative to the traditional certificate-based cryptosystems. The idea of identity-based cryptography is to enable a user to use any arbitrary string that uniquely identifies him as his public key. This paper proposes two new schemes. The first scheme involves a single recipient and the second is its extension in the multi-receiver setting. Both schemes outperform other schemes in literature as they do not involve any bilinear pairings in neither signcryption nor verification phases. Moreover, both satisfy various desirable security properties.

In this paper, a key distribution protocol based on the integration of both classical and quantum cryptography is developed. Quantum physics laws ensure detection of eavesdropping over optical channels, while classical cryptography provides convenient techniques that enable efficient user authentication and prevent denial of previous commitments. The proposed scheme is based on the RSA-TBOS signcryption scheme to achieve the combined functionality of a digital signature and encryption in an efficient manner. It therefore offers four security services: privacy, authenticity, data integrity and non-repudiation. The ciphertext is converted to binary bits and then to qubits. The protocol involves a small number of rounds and the number of keys stored at the user side is kept minimal promoting its use in large networks. A comparative study with other schemes in literature revealed that it represents a remarkably good trade-off between the storage as well as bandwidth requirements and the security services offered.

Signcryption is a public key cryptographic primitive that combines the functionalities of encryption and digital signatures in a single logical step at low computational and communications costs. This paper presents a new efficient multi-recipient identity-based signcryption scheme. The scheme provides public verifiability of ciphertext origin which is an essential requirement in firewall authentication protocols. The scheme offers considerable reductions in both the computational overhead and bandwidth requirements compared to other schemes in literature. The scheme is provably secure against chosen ciphertext attacks in the random oracle model under the assumption of the hardness of the decisional bilinear Diffie-Hellman problem. Moreover, the scheme is existentially unforgeable and thus supports some sort of non-repudiation. The performance enhancements offered by the proposed scheme promote its use in several applications such as authenticated mail transfers among large mailing groups as well as virtual conference scenarios.

In this paper, a new digital payment system based on an ID-based blind signature scheme is presented. Blind signatures represent one cryptographic primitive tailored for applications where anonymity of the participants is an important requirement for instance in electronic commerce, in particular for payment systems. Since anonymity could be in conflict with law enforcement, for instance in cases of black mailing or money laundering, it has been proposed in literature to design systems in which a trustee or a set of trustees can selectively revoke the anonymity of the participants involved in a suspicious transaction. The trustee in the proposed payment system is only invoked in case of disputes and does not get involved in neither opening accounts nor issuing digital coins.

Publishing digital content covered by intellectual property or copyright is faced by the challenge of countering illegal access to the digital good, while still enabling consumers to exercise their usage rights on purchased contents. Digital rights management (DRM) systems consist of architectures, protocols and technologies aimed at providing satisfactory solutions to the above problem. Trace and revoke schemes present one attractive cryptographic solution. This paper presents a scalable trace and revoke scheme that enables users verify their secret keys and thus protects them against corrupt ones due to malicious distributors or errors in communications. Moreover, the scheme is scalable supporting an unlimited number of revocations. Furthermore, the users secret keys are renewed which makes the task of external adversaries and traitors more difficult. In addition, broadcast messages are secure against chosen ciphertext attacks.

Anonymity of consumers is an essential functionality that should be supported in any digital rights management system. Privacy protection is an important aspect for wider acceptance of consumers of DRM systems. The concept of a blind signature is one possible cryptographic solution, yet it has not received much attention in the identity-based setting. In the identity-based setting, the public key of a user is derived from his identity, thus simplifying certificates management process compared to traditional public key cryptosystems. In this paper, a new blind identity-based signature scheme based on bilinear pairings on elliptic curves is presented. The use of bilinear pairings over elliptic curves enables utilizing smaller key sizes, while achieving the same level of security compared to other schemes not utilizing elliptic curves. The correctness of the proposed scheme is validated and the proof of the blindness property is provided. Performance and security related issues are addressed.

Achieving both message confidentiality and message origin authenticity at a reasonable computational cost, especially in case of using smart cards with limited processing capabilities, has always been considered a challenging problem. Signcryption is one attractive cryptographic solution. An even more challenging problem is that of achieving both goals in multi-cast operations necessary for secure group communications. This paper presents a new tree-based, multi-recipient identity-based signcryption scheme. Its basic idea is to split the group members into fixed subsets, which in turn are used to cover any arbitrary subset of users thereafter. This structure reduces both the computational overhead as well as the communications overhead required in the multi-recipient case. Performance of the proposed scheme is analyzed and possible applications are suggested.

We live in the digital information age. The growth of new technologies for communication infrastructure and the wide availability of digital storage devices resulted in most data being produced, distributed and ultimately consumed by end users in digital form. The intrinsic nature of digital data makes the task of manipulating, replicating and distributing digital copies extremely easy. Publishing content covered by intellectual property or copyright is then faced by the challenge of countering illegal access to the digital good, while still enabling consumers to exercise their usage rights on purchased contents. Digital rights management (DRM) systems consist of architectures, protocols and technologies aimed at providing satisfactory solutions to the above problem. Broadcast encryption is a cryptographic primitive that a DRM system designer should investigate carefully. This paper aims to guide DRM system designers through the realm of broadcast encryption mechanisms and hence choose a suitable one for the application in hand.

In this paper, a complete protocol is proposed to address the problem of user authentication in applications involving smart cards. The protocol employs Schnorr identification protocol to prove the matching of the private key on the smart card to the associated public key of the user. The proposed protocol does not involve the private key stored on card directly but rather the associated public key. To enhance the security of the proposed protocol, the private key stored on card is extracted from the iris of the user to whom the card is being issued.

In this paper, a new proxy signcryption scheme is proposed suitable for use by resource constrained devices such as pagers and mobile phones. The proposed scheme is based on delegating the signing rights of the original signer to one of his proxies using warrants. The use of warrants enables explicit specification of the signing rights of the proxy agent. The proxy agent and the original signer are assumed to be registered within the same traditional public key infrastructure. To offer a higher level of security, the proxy key is derived from the personal key of the proxy signer to prevent the proxy signer from denying a signature it created and protects it from framing attacks mounted by the original signer against it. We also consider a variant of our main scheme that works over elliptic curves since they have proven recently the possibility of reducing the key sizes.