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A novel symmetric and asymmetric hybrid optical cryptosystem is proposed based on compressive sensing combined with computer generated holography. In this method there are six encryption keys, among which two decryption phase masks are different from the two random phase masks used in the encryption process. Therefore, the encryption system has the feature of both symmetric and asymmetric cryptography. On the other hand, because computer generated holography can flexibly digitalize the encrypted information and compressive sensing can significantly reduce data volume, what is more, the final encryption image is real function by phase truncation, the method favors the storage and transmission of the encryption data. The experimental results demonstrate that the proposed encryption scheme boosts the security and has high robustness against noise and occlusion attacks.

As there is rapid revolution in digital multimedia which is in compressed encrypted format, the ability for creating similar and unauthorized data, that can be easily copied, manipulated and distributed has been increased. Hence for copyright management protection, ownership identification, tamper detection and for other security issues watermarking has to be carried out for tamper proofing, quality assessment and copy control for those media content. Thus there is a need for an encryption scheme which could provide security as well as allow us to watermarking these compressed encrypted data. For encryption we propose a stream cipher called Modified Rivest Cipher 4 that overcome several weaknesses of the RC4. The embedding capacity, robustness, perceptual quality and security of the proposed algorithm, using the watermarking schemes: spread spectrum, scalar costa scheme quantization index modulation has been proposed and the comparison based on PSNR, MSE and BER values has been done between various encryption algorithms.

Public key encryption with equality test (PKE-ET) is a public key encryption with an extra functionality, so-called ‘equality test’. An authorized third party can verify the equivalence between two ciphertexts encrypted under different public keys, while the decryption keeps unavailable. However, the privacy of most existing PKE-ET schemes drop to one-way security owing to the ‘equality test’ functionality. In this work, we propose a novel architecture called filtered equality test (FET), which ‘filtered’ denotes only few receiver-selected messages can be equality tested. In such model, we propose an equality test scheme, PKE-FET, which is the first one to be proved (somewhat) semantic secure. The concrete PKE-FET scheme and its rigorous security proof in the standard model are proposed. Furthermore, FET is also applied to construct a searchable encryption named PE-MKS, which is inherently proved semantic secure (so called the indistinguishability against chosen keyword attacks) in the standard model.

The paper proposes a secure audio cryptosystem that realize integrity, authentication and confidentiality. The proposed audio cryptosystem achieves integrity by applying a message digest algorithm, authentication by employing LSB watermarking and confidentiality through encryption with Advanced Encryption Standard (AES) or RC6. The main concept of the proposed audio cryptosystem relays on XORing the plain-audio with one selected image from a private image database. Then, the mixed plain-audio blocks are LSB watermarked with the selected image hash value prior to ciphering. The proposed audio cryptosystem is prepared with the potential of increasing immunity against brute force attacks and providing integrity, authentication and confidentiality through the selected image hash value addition using LSB embedding as an extra key. Also, the extra XORing step removes residual intelligibility from the plain-audio blocks, fills the speechless intervals of audio conversation and helps in destroying format and pitch information. The proposed audio cryptosystem is compared with audio encryption using AES, and RC6 through encryption key performance indicators. The comparison outcomes ensured the superiority of the proposed audio cryptosystem. Security investigation of the proposed audio cryptosystem is studied from a precise cryptographic standpoint and tests ensured the superiority of the proposed audio cryptosystem from a cryptographic standpoint.

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.

Cryptographic architectures provide different security properties to sensitive usage models. However, unless reliability of architectures is guaranteed, such security properties can be undermined through natural or malicious faults. In this paper, two underlying block ciphers which can be used in authenticated encryption algorithms are considered, i.e., light encryption device and high security and lightweight block ciphers. The former is of the Advanced Encryption Standard type and has been considered area-efficient, while the latter constitutes a Feistel network structure and is suitable for low-complexity and low-power embedded security applications. In this paper, we propose efficient error detection architectures including variants of recomputing with encoded operands and signature-based schemes to detect both transient and permanent faults. Authenticated encryption is applied in cryptography to provide confidentiality, integrity, and authenticity simultaneously to the message sent in a communication channel. In this paper, we show that the proposed schemes are applicable to the case study of simple lightweight CFB for providing authenticated encryption with associated data. The error simulations are performed using Xilinx Integrated Synthesis Environment tool and the results are benchmarked for the Xilinx FPGA family Virtex-7 to assess the reliability capability and efficiency of the proposed architectures.

We propose a modified optical asymmetric cryptosystem based on coherent superposition and equal modulus decomposition (EMD). In the encryption process, the asymmetric cells of the previous cryptosystem is cascaded, while some small changes are made. In the first cell, only one mask, whose phase is not equal with the public key, is generated to be used as the input of the second cell. As a consequence, the modified cryptosystem decreases available constrain conditions for attackers, resulting in a high robustness of the cryptosystem against the attack based on iterative Fourier transform. Furthermore, the modified scheme maintains the good performance of our previous cryptosystem, especially the benefit of key management. Some numerical simulations are presented to verify the validity and the performance of the modified cryptosystem.

A robust encryption algorithm using DNA and chaotic logistic maps was recently proposed, which can resist exhaustive attack, statistical attack and differential attack. The security of this encryption algorithm depends on the initial conditions of 1D and 2D logistic chaotic maps, which include the front and latter pixel sum of plain image. However, this scheme is not secure enough because the front half and latter half pixel sum can be known to the attacker. According to this security weakness the encryption algorithm is completely cracked by a novel chosen-plaintext attack scheme. Experiments and analysis verify our approach.

Over the past two decades, chaos-based encryption appeared as an original application for nonlinear dynamics and deterministic chaos to encrypt and decrypt data. In this paper, an implementation of digital image encryption scheme based on the Lorenz chaotic system is proposed. While in the process of generating chaotic key stream, the hash value of the plain image is embedded in the proposed cryptosystem to dynamically alter the initial secret keys to increase the security level. The proposed digital image encryption algorithm is described in detail along with its security analysis and implementation. The experimental results show that the proposed digital image encryption algorithm is efficient and has high security features and is suitable for practical uses across insecure networks.

Over the past decade, big data analysis has seen an exponential growth and will certainly continue to witness spectacular developments due to the emergence of new interactive multimedia applications and highly integrated systems driven by the rapid growth in information services and microelectronic devices. Up to yet, large no. of the existing mobile systems is mainly targeted to voice communications with low transmission rates. Big-Data has always been a part of our lives knowingly or unknowingly. This is a review on accessible big-data systems that include a set of tools and technique to load, extract, and improve dissimilar data while leveraging the immensely parallel processing power to perform complex transformations and analysis. Big-Data” technology faces a list of technical challenges.

Recently, a feedback image encryption algorithm with compound chaotic stream cipher based on perturbation was proposed. This paper analyzes security of the algorithm and reports that there exist some security defects, i.e., encryption of a pixel is independent on the position scrambling and the encryption round is controlled by the users. Based on them, a chosen-ciphertext attack is proposed to obtain the equivalent version of the secret key of the algorithm with $$n\cdot \lceil \log _{256} MN +2 \rceil $$ chosen cipher-images, where $$M\times N$$ is the size of the corresponding plain-images and n is the round number of encryption.

Efficient searching on encrypted data outsourced to the cloud remains a research challenge. Identity-based encryption with equality test (IBEET) scheme has recently been identified as a viable solution, in which users can delegate a trapdoor to the server and the server then searches on user outsourced encrypted data to determine whether two different ciphertexts are encryptions of the same plaintext. Such schemes are, unfortunately, inefficient particularly for deployment on mobile devices (with limited power/battery life and computing capacity). In this paper, we propose an efficient IBEET scheme with bilinear pairing, which reduces the need for time-consuming HashToPoint function. We then prove the security of our scheme for one-way secure against chosen identity and chosen ciphertext attacks (OWIDCCA) in the random oracle model (ROM). The performance evaluation of our scheme demonstrates that in comparison to the scheme of Ma (2016), our scheme achieves a reduction of 36.7% and 39.24% in computation cost during the encryption phase and test phase, respectively, and that our scheme is suitable for (mobile) cloud deployment. We propose an identity-based encryption with equality test (IBEET) scheme using bilinear pairing for cloud storage.We show that our proposed concrete scheme is provably secure. It satisfies required security properties.Detailed performance analysis and experimental result are given.

More and more sensitive information is transmitted and stored in computer networks. Security has become a critical issue. As traditional cryptographic systems are now vulnerable to attacks, DNA based cryptography has been identified as a promising technology because of the vast parallelism and extraordinary information density. While a body of research has proposed the DNA based encryption algorithm, no research has provided solutions to distribute complex and long secure keys. This paper introduces a Hamming code and a block cipher mechanism to ensure secure transmission of a secure key. The research overcomes the limitation on the length of the secure key represented by DNA strands. Therefore it proves that real biological DNA strands are useful for encryption computing. To evaluate our method, we apply the block cipher mechanism to optimize a DNA-based implementation of a conventional symmetric encryption algorithm, described as “yet another encryption algorithm”. Moreover, a maximum length matching algorithm is developed to provide immunity against frequency attacks.

Multimedia is currently seen to dominate the internet network and the mobile network traffic; hence, it is seen as the largest Big data. Generally, the symmetric encryption algorithms are applied to the ‘big multimedia data’; however; these algorithms are thought as very slow. In our study, we developed and designed a resource-efficient encryption algorithm system which applies the multithreaded programming process for the encryption of the big multimedia data. This proposed system describes a multi-level encryption model which uses the Feistel Encryption Scheme, genetic algorithms and the Advanced Encryption Standard (AES). Our system has been assessed for actual medical-based big multimedia data and compared to the benchmarked encryption algorithms like the RC6, MARS, 3-DES, DES, and Blowfish with regards to the computational run time and its throughput for the encryption and decryption procedures. In addition, the multithreaded programming approach is adopted to implement the proposed encryption system in order to enhace the system effeciencey and porfermance. Furthermore, we also compared our system with its sequential version for showing its resource efficiency. Our results indicated that our system had the least run time and a higher throughput for the encryption and decryption processes in comparison to the already existing standard encryption algorithms. Also, our system could improve the computation run time by approximately 75% and its throughput was also increased by 4-times in comparison to its sequential version. For fulfilling the security objectives, our algorithm showed a better Avalanche Effect in comparison to the existing algorithms and therefore, could be included in any encryption/decryption process of a big plain multimedia data.

In recent years, researchers have been focused on the optical asymmetric cryptosystem (OACS). The encryption key and decryption key are independent, the fact of which overcomes the linearity defect of optical encryption system. So the OACS has attracted more and more researchers’ attention. We have deeply studied the existing OACS, and found that the cryptosystem is unable to realize communication in practice. In this paper, we demonstrate the shortcomings of the present OACS and propose a practical scheme. The analysis shows that this scheme meets the communication protocol of asymmetric cryptography (ACS).

Objectives: The principal objective of this paper is to develop an enhanced algorithm of cryptography through the hybridization of existing symmetric and asymmetric encryption. Methods/Analysis: The strength of several prevailing symmetric and asymmetric encryption were utilized in the proposed methodology. ElGamal’s key security based on difficulty of solving discrete logarithm, Chaos-based’s avalanche effect of using multiple keys, RSA’s security based on the difficulty of factorization of large numbers and AES’s S-Box mapping, which makes the encryption complex and unpredictable were adapted. Findings: The strength of security of the proposed hybrid algorithm is tested by the provided examples. It was found out that with the use of different keys in encryption, various ciphertexts were generated. The published public keys using such algorithm also make it infeasible to intrude because of the difficulty of solving discrete logarithm with large prime numbers. Furthermore, the value of the ciphertext of the proposed method is significantly different and, in some cases, larger than that of RSA’s. Applications: With this newly enhanced hybrid algorithm of data encryption, transferring and conveying of data will be much more secured.

Public key encryption with keyword search is a useful primitive that provides searchable ciphertexts for some predefined keywords. It allows a user to send a trapdoor to a storage server, which enables the latter to locate all encrypted data containing the keyword(s) encoded in the trapdoor. To remove the requirement of a secure channel between the server and the receiver in identity-based encryption with keyword search, Wu et al. proposed a designated server identity-based encryption scheme with keyword search. However, our cryptanalysis indicates that Wu et al.’s scheme fails in achieving the ciphertext indistinguishability. To overcome the security weakness in the scheme and offer the multiple-keyword search function, we put forward a designated server identity-based encryption scheme with conjunctive keyword search. In the random oracle model, we formally prove that the proposed scheme satisfies the ciphertext indistinguishability, the trapdoor indistinguishability and the off-line keyword-guessing attack security. Comparison analysis shows that it is efficient and practical.

Motivated by applications in large storage systems, we initiate the study of incremental deterministic public-key encryption. Deterministic public-key encryption, introduced by Bellare, Boldyreva, and O'Neill (CRYPTO '07), provides an alternative to randomized public-key encryption in various scenarios where the latter exhibits inherent drawbacks. A deterministic encryption algorithm, however, cannot satisfy any meaningful notion of security for low-entropy plaintexts distributions, but Bellare et al. demonstrated that a strong notion of security can in fact be realized for relatively high-entropy plaintext distributions. In order to achieve a meaningful level of security, a deterministic encryption algorithm should be typically used for encrypting rather long plaintexts for ensuring a sufficient amount of entropy. This requirement may be at odds with efficiency constraints, such as communication complexity and computation complexity in the presence of small updates. Thus, a highly desirable property of deterministic encryption algorithms is incrementality: Small changes in the plaintext translate into small changes in the corresponding ciphertext. We present a framework for modeling the incrementality of deterministic public-key encryption. Our framework extends the study of the incrementality of cryptography primitives initiated by Bellare, Goldreich and Goldwasser (CRYPTO '94). Within our framework, we propose two schemes, which we prove to enjoy an optimal tradeoff between their security and incrementality up to lower-order factors. Our first scheme is a generic method which can be based on any deterministic public-key encryption scheme, and, in particular, can be instantiated with any semantically secure (randomized) public-key encryption scheme in the random-oracle model. Our second scheme is based on the Decisional Diffie---Hellman assumption in the standard model. The approach underpinning our schemes is inspired by the fundamental "sample-then-extract" technique due to Nisan and Zuckerman (JCSS '96) and refined by Vadhan (J. Cryptology '04), and by the closely related notion of "locally computable extractors" due to Vadhan. Most notably, whereas Vadhan used such extractors to construct private-key encryption schemes in the bounded-storage model, we show that techniques along these lines can also be used to construct incremental public-key encryption schemes.

A symmetric key image cryptosystem based on the piecewise linear map is presented in this paper. In this cryptosystem, the encryption process and the decryption process are exactly same. They both include the same operations of plaintext-related scrambling once, diffusion twice and matrix rotating of 180 degrees four times. The length of secret key in the system is 64d where d is a positive integer. The proposed system can fight against the chosen/known plaintext attacks due to the using of plaintext-related scrambling. The simulate results and comparison analysis show that the proposed system has many merits such as high encryption/decryption speed, large key space, strong key sensitivity, strong plaintext sensitivity, strong cipher-text sensitivity, good statistical properties of cipher images, and large cipher-text information entropy. So the proposed system can be applied to actual communications.

Due to the availability and increased usage of multimedia applications, features such as compression and security has gained more importance. Here, we propose a key generation algorithm and a double image encryption scheme with combined compression and encryption. The keys for encryption are generated using a novel modified convolution and chaotic mapping technique. First, the four least significant bits of the two images were truncated and then combined after permutation using the proposed logistic mapping. Also, cellular automata based diffusion is performed on the resultant image to strengthen the security further. Here, both confusion and diffusion seem to be integrated thus improvising the encryption scheme. The performance results and the test of randomness of the key and the algorithm were found to be successful. Since two images are compressed and encrypted simultaneously, it is useful in real - time scenarios.

We present a non-embedding image cryptosystem to accomplish the meaningful encryption. Thanks to the non-embedding superiority, the encrypted images are robust to both human eyes and steganalysis methods.We incorporate coupled dictionary learning and compressive sensing techniques into an unified framework, and further apply it to accomplish the task of non-embedding image encryption.Our scheme can reconstruct an image of more information with the image of little information. In this paper, we propose a novel image cryptosystem, which enables to encrypt the secret images with a smaller-size cover image. Compared with the existing meaningful encryption methods, our cryptosystem has three advantages: (1) non-embedding encryption, i.e., there isnt any data embedding into the cover image during the encryption process. (2) Our cryptosystem can simultaneously encrypt multiple secret images with one cover image, which greatly improves the security of secret images. (3) Our cryptosystem can accomplish not only the meaningful encryption, but also the meaningless encryption. Thus, people dont switch encryption methods when meeting different encryption requirements. Our scheme leverages the popular coupled dictionary learning and compressive sensing techniques to accomplish the whole task. Specifically, we use the coupled dictionaries to build connection between the cover image and the secret image, and apply the compressive sensing to decrypt the secret image. To demonstrate the effectiveness of the proposed cryptosystem, a series of experiments are conducted. Experimental results on gray images and colorful RGB images verify its superiority.

Recently, a novel image fusion encryption algorithm based on DNA sequence operation and hyper-chaotic system were proposed. It was reported that the encryption algorithm can be broken by chosen-plaintext attack. This paper re-evaluates the security of the encryption algorithm, and finds that the encryption algorithm can be broken by known-plaintext attack as well. Besides, it also gives another method of chosen-plaintext attack which is more effective. The effectiveness of the proposed know-plaintext attack and chosen-plaintext attack is supported both by rigorous theoretical analysis and experimental results.

A joint image compression and encryption scheme based on JPEG is proposed.Encryption is mainly realized at JPEGs transformation stage.The scheme is format compliant to JPEG with tunable encryption parameters.Good encryption and compression performances can be achieved simultaneously. In this paper, we propose a novel joint image compression and encryption scheme based on JPEG standard. We realize image encryption at JPEGs transformation stage. Instead of only using 88 discrete cosine transform (DCT) for transformation, we generate new orthogonal transforms by embedding an extra rotation angle of to different stages butterflies in 88 DCTs flow-graph, and then apply them alternatively for transformation according to a predefined secret key. By carefully controlling the number of rotation angles embedded, the quality control of encrypted images can also be achieved. The encryption algorithm is further enhanced by performing block permutation before the entropy encoding stage. Extensive experiments have been conducted to show the good protection and compression performance of our encryption schemes. Finally, a detailed security analysis is provided to show the encryption schemes resistance to various cryptanalysis methods, such as brute-force attack, key sensitivity analysis, replacement attack and statistical attack.

Cloud computing is one of the great tasks in the business world nowadays, which provides shared processing resources. In cloud area network, security is the main challenge faced by cloud providers and their customers. The advantage of cloud computing includes reduced cost, re-provisioning of resources etc. The cloud network makes use of standard encryption method to secure documents while storing in online. In this paper, we have depicted two efficient encryption algorithms that meet security demand in cloud. Probabilistic encryption, one of these algorithms may be used to produce randomness of text encryption. With this algorithm, if the same message is encrypted twice it should yield different secret coded texts on both calculations. Another crucial algorithm is homomorphic encryption, is a cryptographic method to define the sample system and to provide a software implementation. In order to maintain quality of service (QoS) and improve customer satisfaction, we are going to propose an efficient algorithm which combines the characteristics of both probabilistic and homomorphic encryption techniques, to provide high level of security. Our proposed scheme will yield better encryption techniques reduce security attacks, increased throughput and improve the QoS.

We propose a novel color image encryption scheme based on DNA permutations. In the proposed scheme, the chaotic pseudo-random sequences for encryption depend on the plaintext image and secret keys. Besides, the proposed DNA permutation and addition/subtraction operations can break the bit planes of the plaintext image entirely. Therefore, the proposed scheme is sensitive to the plaintext image and can resist common attacks such as differential attack, brute-force attack, and statistical attack. Simulation results show the feasibility and effectiveness of the proposed scheme.

We give a new black-box transformation from any semantically secure encryption scheme into a non-malleable one which has a better rate than the best previous work of Coretti et al. (in: Kushilevitz and Malkin (eds) TCC 2016-A, Part I, Springer, Heidelberg, 2016). We achieve a better rate by departing from the "matrix encoding" methodology used by previous constructions, and working directly with a single codeword. We also use a Shamir secret-share packing technique to improve the rate of the underlying error-correcting code.

We show how to transform any semantically secure encryption scheme into a non-malleable one, with a black-box construction that achieves a quasi-linear blow-up in the size of the ciphertext. This improves upon the previous non-black-box construction of Pass, Shelat and Vaikuntanathan (Crypto '06). Our construction also extends readily to guarantee non-malleability under a bounded-CCA2 attack, thereby simultaneously improving on both results in the work of Cramer et al. (Asiacrypt '07). Our construction departs from the oft-used paradigm of re-encrypting the same message with different keys and then proving consistency of encryption. Instead, we encrypt an encoding of the message; the encoding is based on an error-correcting code with certain properties of reconstruction and secrecy from partial views, satisfied, e.g., by a Reed---Solomon code.

A novel image encryption scheme employing the memristive hyperchaotic system, cellular automata (CA) and DNA sequence operations is presented, which consists of diffusion process. SHA 256 hash function is used to give the secret key and compute the initial values of the chaotic system. Moreover, a dynamic DNA encoding scheme is introduced. Two DNA rule matrices for encoding the plain image and two-dimensional (2D) CA are generated from chaotic sequences, and they are controlled by the plain image, so that there are different DNA encoding rules for different original image. Besides, we manipulate block diffusion encryption method to the plain image in order to save time. The previous diffused block image and 2D CA are combined to affect the encryption effect of the current block image. Among them, 2D CA is updated by the local rule computed from the previous diffused sub image, and its initial configuration is determined by the chaotic sequences. Simulation results and security analyses both confirm that the proposed image encryption scheme not only demonstrates extraordinary encryption performance, but also resists various attacks. It can be applied in secure image and video communication fields. A novel chaos-based image encryption scheme is presented.The proposed encryption algorithm is sensitive to the plain image.This algorithm is highly secure enough to resist common attacks.

Ye and Zhou [Appl. Soft. Comput. 22 (2014) 351–357] proposed an efficient chaotic based image encryption scheme which only employs diffusion, while usually both confusion and diffusion are used for encryption structures. We present both chosen-plaintext and chosen-ciphertext attacks against the scheme for any number of its rounds r by exploiting r -round differentials with probability 1. The result shows that the encryption structure proposed by Ye and Zhou does not fulfill basic requirements of a secure image encryption scheme.

Recently, a number of chaos-based image encryption algorithms that use low-dimensional chaotic map and permutation-diffusion architecture have been proposed. However, low-dimensional chaotic map is less safe than high-dimensional chaotic system. And permutation process is independent of plaintext and diffusion process. Therefore, they cannot resist efficiently the chosen-plaintext attack and chosen-ciphertext attack. In this paper, we propose a hyper-chaos-based image encryption algorithm. The algorithm adopts a 5-D multi-wing hyper-chaotic system, and the key stream generated by hyper-chaotic system is related to the original image. Then, pixel-level permutation and bit-level permutation are employed to strengthen security of the cryptosystem. Finally, a diffusion operation is employed to change pixels. Theoretical analysis and numerical simulations demonstrate that the proposed algorithm is secure and reliable for image encryption.

Revocation and key evolving paradigms are central issues in cryptography, and in PKI in particular. A novel concern related to these areas was raised in the recent work of Sahai, Seyalioglu, and Waters (CRYPTO 2012) who noticed that revoking past keys should at times (e.g., the scenario of cloud storage) be accompanied by revocation of past ciphertexts (to prevent unread ciphertexts from being read by revoked users). They introduced revocable-storage attribute-based encryption (RS-ABE) as a good access control mechanism for cloud storage. RS-ABE protects against the revoked users not only the future data by supporting key-revocation but also the past data by supporting ciphertext-update, through which a ciphertext at time T can be updated to a new ciphertext at time T + 1 using only the public key. Motivated by this pioneering work, we ask whether it is possible to have a modular approach, which includes a primitive for time managed ciphertext update as a primitive. We call encryption which supports this primitive a "self-updatable encryption" (SUE). We then suggest a modular cryptosystems design methodology based on three sub-components: a primary encryption scheme, a key-revocation mechanism, and a time-evolution mechanism which controls the ciphertext self-updating via an SUE method, coordinated with the revocation (when needed). Our goal in this is to allow the self-updating ciphertext component to take part in the design of new and improved cryptosystems and protocols in a flexible fashion. Specifically, we achieve the following results:We first introduce a new cryptographic primitive called self-updatable encryption (SUE), realizing a time-evolution mechanism. In SUE, a ciphertext and a private key are associated with time. A user can decrypt a ciphertext if its time is earlier than that of his private key. Additionally, anyone (e.g., a cloud server) can update the ciphertext to a ciphertext with a newer time. We also construct an SUE scheme and prove its full security under static assumptions. Following our modular approach, we present a new RS-ABE scheme with shorter ciphertexts than that of Sahai et al. and prove its security. The length efficiency is mainly due to our SUE scheme and the underlying modularity. We apply our approach to predicate encryption (PE) supporting attribute-hiding property, and obtain a revocable-storage PE (RS-PE) scheme that is selectively-secure. We further demonstrate that SUE is of independent interest, by showing it can be used for timed-release encryption (and its applications), and for augmenting key-insulated encryption with forward-secure storage. A new cryptographic primitive called self-updatable encryption is introduced to realize a time-evolution mechanism.A revocable-storage attribute-based encryption scheme with shorter ciphertexts was proposed by following our modular approach.A revocable-storage predicate encryption scheme that additionally supports attribute-hiding property is presented.

We propose two Key-Policy Attribute-Based Encryption (KP-ABE) schemes for Linear Secret-Sharing Scheme (LSSS)-realizable Monotone Access Structure (MAS). We show that the first construction is secure against Chosen Plaintext Attacks (CPAs) while the second scheme is secure against Chosen Ciphertext Attacks (CCAs), without introducing any random oracle heuristic. Both the schemes enjoy constant-size ciphertext, constant number of pairing operations, and constant computation cost during encryption and decryption. We further propose two non-monotone access structure variants, one is CPA secure and another is CCA secure, preserving the same functionality as that of MAS primitives. We thereafter present a large attribute universe KP-ABE for MAS, still utilizing low computation cost together with constant number of pairing operations and public parameters. Unlike the existing approaches, this does not impose a bound on the size of attribute sets used in encryption, however, the security is in random oracle model. Our final result is a dual-policy ABE supporting LSSS-realizable MAS with significantly low communication and computation cost. Furthermore, we extend our KP-ABE to efficient key-policy attribute-based broadcast encryption. While the secret key in all our constructions has quadratic-size in the number of attributes, the number of pairing evaluations is constant. The CPA and CCA security against selective-adversary of proposed schemes are achieved under the decisional Bilinear DiffieHellman Exponent assumption over prime order groups.

Wearable devices can be potentially captured or accessed in an unauthorized manner because of their physical nature. In such cases, they are in white-box attack contexts, where the adversary may have total visibility on the implementation of the built-in cryptosystem, with full control over its execution platform. Dealing with white-box attacks on wearable devices is undoubtedly a challenge. To serve as a countermeasure against threats in such contexts, we propose a lightweight encryption scheme to protect the confidentiality of data against white-box attacks. We constructed the scheme’s encryption and decryption algorithms on a substitution-permutation network that consisted of random secret components. Moreover, the encryption algorithm uses random padding that does not need to be correctly decrypted as part of the input. This feature enables non-bijective linear transformations to be used in each encryption round to achieve strong security. The required storage for static data is relatively small and the algorithms perform well on various devices, which indicates that the proposed scheme satisfies the requirements of wearable computing in terms of limited memory and low computational power.

In this study, an encryption algorithm that uses chaos based S-BOX is developed for secure and speed image encryption. First of all, a new chaotic system is developed for creating S-Box and image encryption algorithm. Chaos based random number generator is designed with the help of the new chaotic system. Then, NIST tests are run on generated random numbers to verify randomness. A new S-Box design algorithm is developed to create the chaos based S-Box to be utilized in encryption algorithm and performance tests are made. As the next step, the new developed S-Box based image encryption algorithm is introduced in detail. Finally, image encryption application is carried out. To show the quality and strong of the encryption process, security analysis are performed. Proposed algorithm is compared with the AES and chaos algorithms. According to tests results, the proposed image encryption algorithm is secure and speed for image encryption application. (C) 2016 Elsevier Ltd. All rights reserved.

In order to construct efficient public-key encryption scheme that is secure against adaptive chosen-ciphertext attacks (CCA), an efficient signature scheme and an identity-based encryption (IBE) scheme from the learning with errors over rings are presented firstly in this paper, whose security are reducible to the hardness of the shortest vector problem in the worst case on ideal lattices. Secondly, a CCA-secure public key cryptosystem is constructed on the basis of the IBE and signature proposed above. The efficiency analysis indicates the proposed signature and encryption schemes are much more efficient than correlative cryptosystems. The security analysis shows that the IBE scheme is secure against chosen-plaintext attacks, and the public-key encryption scheme is CCA-secure in the random oracle model.

The principle of compressed sensing (CS) can be applied to a cryptosystem in which the sensing matrix is employed for the secret key. In this letter, we study the security of a CS-based cryptosystem that encrypts a plaintext with a secret circulant matrix and transmits the ciphertext over a wireless channel. The relative entropy is considered as a security measure for the indistinguishability of the CS-based cryptosystem. By developing an upper bound on the entropy, the security analysis reveals that the presence of wireless channels and additive noise contributes to reducing the relative entropy of the cryptosystem. Consequently, the CS-based cryptosystem with circulant matrices can guarantee wireless security in terms of the indistinguishability, as long as the channel gains and the plaintext-to-noise power ratio of an adversary are kept to be low for a long keystream and a short ciphertext.

Nowadays, multimedia is considered to be the biggest big data as it dominates the traffic in the Internet and mobile phones. Currently symmetric encryption algorithms are used in IoT but when considering multimedia big data in IoT, symmetric encryption algorithms incur more computational cost. In this paper, we have designed and developed a resource-efficient encryption system for encrypting multimedia big data in IoT. The proposed system takes the advantages of the Feistel Encryption Scheme, an Advanced Encryption Standard (AES), and genetic algorithms. To satisfy high throughput, the GPU has also been used in the proposed system. This system is evaluated on real IoT medical multimedia data to benchmark the encryption algorithms such as MARS, RC6, 3-DES, DES, and Blowfish in terms of computational running time and throughput for both encryption and decryption processes as well as the avalanche effect. The results show that the proposed system has the lowest running time and highest throughput for both encryption and decryption processes and highest avalanche effect with compared to the existing encryption algorithms. To satisfy the security objective, the developed algorithm has better Avalanche Effect with compared to any of the other existing algorithms and hence can be incorporated in the process of encryption/decryption of any plain multimedia big data. Also, it has shown that the classical and modern ciphers have very less Avalanche Effect and hence cannot be used for encryption of confidential multimedia messages or confidential big data. The developed encryption algorithm has higher Avalanche Effect and for instance, AES in the proposed system has an Avalanche Effect of %52.50. Therefore, such system is able to secure the multimedia big data against real-time attacks.

This paper introduces a secure speech communication approach, which is based on encryption and authentication. This system is based on Advanced Encryption Standard (AES) for encryption and private image database for enhancement of encryption and for authentication. The idea of this cryptosystem is based on XOR of one image from image database with the clear speech before encryption and embedding the index number of this image in the database as a least significant bit watermark into speech. A comparison study is held between the AES block cipher algorithm and the proposed algorithm. This proposed cryptosystem used to enhance the security of AES algorithm and increase its immunity to brute force attacks. It used also to provide authentication and enhance security by addition of extra key which don't need to be exchanged between parts depending on the embedded image. The extra proposed step remove residual intelligibility from clear speech and fill the silent periods within speech conversation and help in destroy format and pitch information. Security analyses are presented for the proposed cryptosystem from a strict cryptographic viewpoint. Experimental results verify and prove that the proposed cryptosystem is highly secure from the cryptographic viewpoint.

Most current symmetric cryptographic algorithms (symmetric ciphers and hash functions) are considered to be relatively secure against attacks by quantum computers. Here we propose an adaptive color double-image encryption scheme based on autonomous ODE chaotic system and SHA-512. The double-image is diffused firstly by chaotic sequences with bitwise exclusive or operation, and an algorithm is designed to transform two 512-bit hash values into two S-Boxes, to substitute for the pixels of diffused double-image respectively. In each encryption process, the initial values of chaotic system are from random signal, they are true random numbers. Simulation results demonstrate that the scheme is suitable and effective for color double-image encryption.

The majority of encryption schemes based on double random phase encoding usually encrypt one or more plaintext images into a complex-valued ciphertext, which may cause inconvenience of the management, storage and transmission of the encrypted information. This paper aims to develop a real-valued image cryptosystem based on chaotic map and mixture amplitude-phase retrieval in gyrator domain. It can realize encryption for double grayscale images. Firstly, the double plaintext images are perturbed by chaotic maps and then combined into a single-channel architecture through complex representation. Subsequently, an iterative amplitude and phase retrieval process is performed in gyrator domain to determine the real-valued ciphertext and double phase masks. Experimental results have demonstrated the feasibility and security of the proposed scheme. Moreover, the proposed encryption scheme shows better robustness against Gaussian noise and data loss attacks compared with one random phase modulation based scheme.