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The study of sending and receiving secret messages is called cryptography. Generally, senders and receivers are unaware about the process of encryption and decryption. Hence, encryption plays an important role in data communication and data security. The meaning of encryption is not only to keep data confidential from unwanted access but also ensuring the data integrity through available way. As the capacity of breaking the security is increasing rapidly, so, the process that hides information is one of the most concerned topics. Advanced Encryption Standard is a popular, widely used and efficient encryption algorithm, which has been used since it was invented. This paper focuses on the AES key generation process and Substitution box. It modifies the conventional key generation technique and builds the dynamic 3-Dimensional S-box of Advance Encryption Standard. The proposed approach suggests 3-Dimensioanl Key Generation Matrix and S-box. As per shown this novel technique increases the amount of time it needs during encryption and decryption. The experimental result shows that it also enhances the strength of AES algorithm. The proposed approach illustrates the theoretical analysis and corresponding experimented results., 7 pages, 14 figures, 4 tables. Published in IJCSA in 2017

International audience; Functional encryption lies at the frontiers of the current research in cryptography; some variants have been shown sufficiently powerful to yield indistinguishability obfuscation (IO), while other variants have been constructed from standard assumptions such as LWE. Indeed, most variants have been classified as belonging to either the former or the latter category. However, one mystery that has remained is the case of secret-key functional encryption with an unbounded number of keys and ciphertexts. On the one hand, this primitive is not known to imply anything outside of minicrypt, the land of secret-key cryptography, but, on the other hand, we do no know how to construct it without the heavy hammers in obfustopia. In this work, we show that (subexponentially secure) secret-key functional encryption is powerful enough to construct indistinguishability obfuscation if we additionally assume the existence of (subexponentially secure) plain public-key encryption. In other words, secret-key functional encryption provides a bridge from cryptomania to obfustopia. On the technical side, our result relies on two main components. As our first contribution, we show how to use secret-key functional encryption to get “exponentially efficient indistinguishability obfuscation” (XIO), a notion recently introduced by Lin et al. (PKC’16) as a relaxation of IO. Lin et al. show how to use XIO and the LWE assumption to build IO. As our second contribution, we improve on this result by replacing its reliance on the LWE assumption with any plain public-key encryption scheme. Lastly, we ask whether secret-key functional encryption can be used to construct public-key encryption itself and therefore take us all the way from minicrypt to obfustopia. A result of Asharov and Segev (FOCS’15) shows that this is not the case under black-box constructions, even for exponentially secure functional encryption. We show, through a non-black-box construction, that subexponentially secure-key functional encryption indeed leads to public-key encryption. The resulting public-key encryption scheme, however, is at most quasi-polynomially secure, which is insufficient to take us to obfustopia.

Image encryption is rapidly increased recently by the increasing use of the internet and communication media. Sharing important images over unsecured channels is liable for attacking and stealing. Encryption techniques are the suitable methods to protect images from attacks. Hill cipher algorithm is one of the symmetric techniques, it has a simple structure and fast computations, but weak security because sender and receiver need to use and share the same private key within a non-secure channels. A new image encryption technique that combines Elliptic Curve Cryptosystem with Hill Cipher (ECCHC) has been proposed in this paper to convert Hill cipher from symmetric technique to asymmetric one and increase its security and efficiency and resist the hackers. Self-invertible key matrix is used to generate encryption and decryption secret key. So, no need to find the inverse key matrix in the decryption process. A secret key matrix with dimensions 4 × 4 will be used as an example in this study. Entropy, Peak Signal to Noise Ratio (PSNR), and Unified Average Changing Intensity (UACI) will be used to assess the grayscale image encryption efficiency and compare the encrypted image with the original image to evaluate the performance of the proposed encryption technique. Keywords: Elliptic Curve Cryptography, Hill cipher, Self-invertible, Entropy, Peak Signal to Noise Ratio, Unified Average Changing Intensity

Database encryption is essential for cloud database systems. For a large database, decryption could take a lot of computational time. Therefore, verifying an encryption that contains a correct plaintext without decryption becomes significant for a large database system. Plaintext-checkable encryption (PCE) is a potential tool for such database systems, which is first proposed by Canard et al. in CT-RSA 2012. Although the generic PCE in the random oracle model has been studied intensively, the generic PCE in the standard model and its efficient implementation are still challenging problems. This paper presents the first generic PCE in the standard model using smooth projective hash function (SPHF) and prove its s-priv1-cca security, which is independent of current unlink security. Based on the instantiated SPHF from DDH assumption, we obtain the most efficient PCE in the standard model, without any pairing operation. Finally, we improve two existing generic constructions in the random oracle model so that they are secure under chosen ciphertext attack.

Identity-based broadcast encryption (IBBE) is an important type of broadcast encryption. In the paper, we put forward the formal definition and security model of IBBE with leakage-resilience. Furthermore, we propose an IBBE scheme with continuous leakage-resilience. The presented scheme is resilient to private key leakage. By refreshing the private key, our scheme can resist continuous private key leakage. Based on dual system encryption technique, we prove the security of the proposed scheme under subgroup decisional assumptions. We give the specific performance analysis of leakage-resilience. The relative leakage ratio can amount to 1/3.

This paper presents the weaknesses in the cryptosystem proposed by W. Zhang and his colleagues. The proposed method to restore the permutation rule is based on the chosen-ciphertext attack. The method is successful in restoration of the permutation rule in the case of multiple encryption rounds without any knowledge about the cryptosystem. In order to improve the security of W. Zhang's cryptosystem, the proposed modifications are made to the equations to resist against the chosen-ciphertext attack. The specific examples will demonstrate the cryptanalysis and the security improvement.

Lightweight devices, such as a smartcard associated with a top-box decoder in pay-TV or a SIM card coupled with a powerful (but not totally trusted) smartphone, play an important role in modern applications. The essential requirements for a cryptographic scheme to be truly implemented in lightweight devices are that it should have compact secret key size and support fast decryption. Attribute-based broadcast encryption (ABBE) combines the functionalities of both broadcast encryption and attribute-based encryption in an efficient way, ABBE is therefore a promising cryptographic scheme to be used in practical applications such as mobile pay-TV, satellite transmission, or Internet of Things. Designing an ABBE scheme which can be truly implemented in lightweight devices is still an open question. In this study, the authors solve it by proposing an efficient constant-size private key ciphertext-policy ABBE scheme for disjunctive normal form supporting fast decryption and achieving standard security levels of an ABBE scheme. They concretely show that the authors’ scheme can be truly implemented in a prototype for a smartphone-based cloud storage use case. In particular, they show how to alleviate some parts of their scheme so as to obtain a very practical system, and they give some concrete benchmarks.

Usage of EC operations as initial random generator and encrypting through AES to generate new pseudo random to mask whole image pixels.Simulations and analysis results show that cooperation of AES and EC random numbers makes great results in randomness and image encryption field.Comparable security and speed with other trend schemes like chaos based encryptions. Elliptic Curve Cryptography (ECC) has proven to be an effective cryptography. ECC has its own advantages such as efficient key size compared to other Public Key Infrastructures. This paper exploits the Elliptic curve random generator defined by National Institute of Standards and Technology (NIST) to generate a sequence of arbitrary numbers based on curves. The random generation phase is based on public shared key and a changing point G, which is a generator of a curve to obtain random sequences. Then, Advanced Encryption System is applied to these sequences acquiring arbitrary keys for encrypting image. Using AES alongside well distributed randoms provides a prominent encryption technique. Our experiments show that the proposed method fulfills the basics of cryptography including simpleness and correctness. Moreover, the results of the evaluation prove the effectiveness and security of the proposed method.

To protect receiver privacy, researchers constructed anonymous multireceiver encryption by implanting anonymity in multireceiver encryption. It allows a sender to produce the identical ciphertext for multiple designated receivers. Every designated receiver can decrypt the ciphertext, but does not know who the other designated receivers are. Recently, several anonymous multireceiver identity (ID)-based encryption (AMIBE) schemes were proposed without the utilization of certificates. However, these AMIBE schemes are not efficient because their decryption cost of each receiver grows linearly with the number of the designated receivers. Moreover, all the ID-based cryptographic schemes suffer from the key escrow problem, which has been resolved by using certificateless public key settings. Very recently, Islam et al. proposed an anonymous multireceiver certificateless encryption (AMCLE) scheme. However, the encryption cost of a sender is quadric with the number of designated receivers, whereas the decryption cost of each receiver is linear with the number. In this paper, we propose an efficient AMCLE scheme with constant decryption cost, namely, the required decryption cost of each receiver is independent of the number of receivers. When compared with previously proposed AMIBE and AMCLE schemes, our scheme solves the key escrow problem and improves the efficiency of encryption/decryption significantly as well.

Networked control systems with encrypted sensors measurements is considered. Semi-homomorphic encryption, specifically the Paillier encryption, is used so that the controller can perform the required computation on the encrypted data. Conditions on the parameters of the encryption technique are provided that guarantee the stability and the performance of the closed-loop system. The results are subsequently extended Laplacian based distributed systems, such as formation-seeking algorithms. It is shown that the problem of figuring out the state measurements of the neighbouring agents of a compromised agent upon using the proposed algorithm is numerically intractable.

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.

Cryptographyis the process of data hiding from unauthorised users. Historically, the term “Cryptography” has been associated with the problem of designing and analyzing encryptionschemes (i.e., scheme that provide secret communication over insecure communication media). With the growth of internet secure data transmission is more and more essential and important. Sometime single encryption technique is not sufficient to protect the valuable data. We developed a new algorithm which can change the encryptiontechnique with change of plane textpattern to enhance the confusion and as well as diffusion.

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.

Hierarchical identity-based encryption is an important extension from IBE and has found many applications in the network world. Private key revocation is a crucial requirement for any public key system. In this paper, we propose a novel revocation method for the hierarchical identity-based encryption. Existing revocable hierarchical identity-based encryption schemes have several disadvantages: the key update size increases logarithmically with the number of users in the system, the public information of key update received by each user is different and always related to the level of the identity hierarchy and the security proof of the revocable scheme is very complex. In our scheme, cryptographic accumulators are used to compress hierarchical levels and revoked users’ information into constant values. So we achieve almost constant size of private key update which is irrelevant with the user number in the system. Because of the compression of hierarchical information we can use simple dual system encryption techniques to prove our scheme to be fully secure under several common assumptions without resorting to complex nested dual system encryption techniques.

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 modern day technology, the Information Society is at risk. Passwords are a multi-user computer systems usual first line of defence against intrusion. A password may be textual with any combination of alphanumeric characters or biometric or 3-D. But no authentication protocol is fully secured against todays hackers as all of them are Static in type. Dynamic authentication protocol is still a theoretical concept. In this paper, we are focusing on a concept of authentication technique which is actually dynamic in genre, i.e. the password here will change in t time (where t is as small as possible). This technique comprises of both hardware and software part. In this paper, we have covered the idea of generating an efficient algorithm that can work as the final in the Dynamic Password Authentication system. We have used standard deviation within statistics to generalize the possible password which is further secured by Feistel Block Cipher and Advanced Encryption Standard technique (AES), leading and following the said mathematics respectively. In order to allow the system to create variable password in the least time interval possible, we must make sure our process is not much complex.

Newly applies transparent and reduced encryption to scalable video.Introduces two ways to lower encryption latency in the context of scalable video.Maintains decoder compatibility and adds no bitrate overhead after encryption.Analyses overall distortion from transparent encryption, with clear base layer.Application is protection of rapidly available streaming of short-lived material. Selective encryption masks all of the content without completely hiding it, as full encryption would do at a cost in encryption delay and increased bandwidth. Many commercial applications of video encryption do not even require selective encryption, because greater utility can be gained from transparent encryption, i.e. allowing prospective viewers to glimpse a reduced quality version of the content as a taster. Our lightweight selective encryption scheme when applied to scalable video coding is well suited to transparent encryption. The paper illustrates the gains in reducing delay and increased distortion arising from a transparent encryption that leaves reduced quality base layer in the clear. Reduced encryption of B-frames is a further step beyond transparent encryption in which the computational overhead reduction is traded against content security and limited distortion. This spectrum of video encryption possibilities is analyzed in this paper, though all of the schemes maintain decoder compatibility and add no bitrate overhead as a result of jointly encoding and encrypting the input video by virtue of carefully selecting the entropy coding parameters that are encrypted. The schemes are suitable both for H.264 and HEVC codecs, though demonstrated in the paper for H.264. Selected Content Adaptive Binary Arithmetic Coding (CABAC) parameters are encrypted by a lightweight Exclusive OR technique, which is chosen for practicality.

The secure storage of the sensitive data in mobile devices is an urgent issue. Most of the existed encryption algorithms are location independent, which means the encrypted data can be decrypted anywhere. In this work, we propose a novel location-based encryption model using a fuzzy vault scheme. First, we may choose a proper encryption algorithm, a symmetric algorithm or an asymmetric encryption algorithm, to encrypt the sensitive data in mobile devices. Then, the crucial issue comes to securely storing the secret key in the encryption algorithm, and it will be solved in the secret key protection phase by applying a fuzzy vault scheme using a location-based digital fingerprint, which represents the valid user in the valid location region. We bind the digital fingerprint and the secret key together to construct a fuzzy vault for storing the both securely. We simulate our model on an Android device and make some performance and security analysis on it. The main contribution of our model is applying a fuzzy vault scheme which uses the location information captured by the user’s mobile devices to securely protect the secret key used in the cryptosystem for encrypting the users sensitive data on the user’s mobile devices.

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.

Data and network security is one among the foremost necessary factors in today’s business world. In recent, businesses and firms like financial institutions, law firms, schools, health sectors, telecommunications, mining and a number of government agencies want a strategic security technique of managing its data. Organizations managing bigger monetary information, bio-data and alternative relevant info are losing its valuable information or data at rest, in usage or in motion to unauthorized parties or competitors as a result of activities of hackers. Organizations are losing millions of dollars as a result of unprotected data that gets into the hands of malicious persons. Data protection in an organization has become vital in today’s business. In order to possess secure information, this information should be protected in order that although malicious persons get access to the info, it becomes wealthless and useless to them. Advanced Encryption Standard (AES), could be a scientific discipline rule that may be used for secured data and communication in an organization, it uses same key that's isobilateral key for transmission additionally as reception. The AES rule is capable of using cryptographic keys of 128, 192, and 256 bits, this paper implement AES block cipher of 256-bits and 256-bit key size, developed with C# as a front-end client machine and MS SQL used for the database as a back-end machine.

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.

With increasing dependence on communications over internet and networks, secure data transmission is coming under threat. One of the best solutions to ensure secure data transmissions is encryption. Multiple forms of data, such as text, audio, image, and video can be digitally transmitted, nowadays images being the most popular and old encryption techniques such as: AES,DES,RSA etc., show low security level when used for image encryption. This problem was resolved by using of chaos encryption which is an acceptable form of encryption for image data. The sensitivity to initial conditions and control parameters make chaos encryption suitable for image applications. This study discusses various chaos encryption techniques.

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.

Encryption has become a necessity of life, especially in the field of exchanging and transmitting data through transmission media, such as internet, wireless networks, mobile networks, bluetooth, and infrared. The deoxyribonucleic acid (DNA) cryptography is a very promising approach which is shown to be efficient in computation, storage, and transmission. In this paper, we introduce a new technique for encryption called DNA-DES that is more robust than traditional data encryption standard (DES). The proposed technique integrates concepts derived from DNA, ribonucleic acid, and nucleic acids to increase the key space and number of available permutations of traditional DES. The theoretical and experimental analysis show that the proposed DNA-DES method is efficient in computation, storage, and transmission. The security analysis proves that DNA-DES has high confidential strength against brute-force and cryptanalysis attacks.

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 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.

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.

The challenge to which the encryption of multimedia data needs to respond is ensuring the security of data intensive video stream in an efficient way. Unlike full data encryption, selective encryption manages to achieve this by encrypting only a part of the data stream, while providing a satisfactory level of video security. This optimizes the processing time and the size of encrypted data. Regardless of the encryption technique, there is a lack of cryptographic synchronization when providing random access to the selected part of the encrypted multimedia stream. In this paper we propose a novel and efficient method of cryptographic synchronization as an extension to the H.265/HEVC crypto encoder in order to support random access in selectively encrypted video stream.

In 2009, Gentry first introduced an ideal lattices fully homomorphic encryption (FHE) scheme. Later, based on the approximate greatest common divisor problem, learning with errors problem or learning with errors over rings problem, FHE has developed rapidly, along with the low efficiency and computational security. Combined with quantum mechanics, Liang proposed a symmetric quantum somewhat homomorphic encryption (QSHE) scheme based on quantum one-time pad, which is unconditional security. And it was converted to a quantum fully homomorphic encryption scheme, whose evaluation algorithm is based on the secret key. Compared with Liang’s QSHE scheme, we propose a more efficient QSHE scheme for classical input states with perfect security, which is used to encrypt the classical message, and the secret key is not required in the evaluation algorithm. Furthermore, an efficient symmetric searchable encryption (SSE) scheme is constructed based on our QSHE scheme. SSE is important in the cloud storage, which allows users to offload search queries to the untrusted cloud. Then the cloud is responsible for returning encrypted files that match search queries (also encrypted), which protects users’ privacy.

Attributed-based encryption (ABE) is a promising cryptographic access control mechanism with a rich expressiveness of ABE policies. Due to the high complexities of encryption and decryption, users are burdened with large computation cost. Fortunately, outsourcing technologies can be used to reduce the computation overhead for the ABE schemes. In the recent decade, the achievements of the outsourced ciphertext-policy ABE (CP-ABE) schemes are inspiring. But, the outsourcing encryption algorithms for CP-ABE schemes are not addressed properly since the encryption exponents are dynamic. In this paper, we present an efficient outsourced CP-ABE scheme with checkability, where the number of the exponential operations in the encryption can be reduced to a constant by introducing a blinding algorithm. Meanwhile, the ciphertext size is not increased. Furthermore, to guarantee the correctness of our scheme, we provide the verification mechanism based on a collision-resistance hash function, which allows the users to efficiently check the validity of messages and outsourced computation results. Besides, the proposed scheme is secure against replayable chosen ciphertext attacks based on Green’s outsourcing security model. Intensive experiments are carried out to illustrate the efficiency of the proposed scheme.

In modern communication systems, one of the most challenging tasks involves the implementation of adequate methods for successful and secure transfer of confidential digital information over an unsecured communication channel. Many encryption algorithms have been developed for protection of confidential information. However, over time, flaws have been discovered even with the most sophisticated encryption algorithms. Each encryption algorithm can be decrypted within sufficient time and with sufficient resources. The possibility of decryption has increased with the development of computer technology since available computer speeds enable the decryption process based on the exhaustive data search. This has led to the development of steganography, a science which attempts to hide the very existence of confidential information. However, the stenography also has its disadvantages, listed in the paper. Hence, a new method which combines the favourable properties of cryptography based on substitution encryption and stenography is analysed in the paper. The ability of hiding the existence of confidential information comes from steganography and its encryption using a coding table makes its content undecipherable. This synergy greatly improves protection of confidential information.

Fog computing is a paradigm that extends cloud computing to the edge of the network. It can provide computation and storage services to end devices in Internet of Things (IoT). Attribute-based cryptography is a well-known technology to guarantee data confidentiality and fine-grained data access control. However, its computational cost in encryption and decryption phase is linear with the complexity of policy. In this paper, we propose a secure and fine-grained data access control scheme with ciphertext update and computation outsourcing in fog computing for IoT. The sensitive data of data owner are first encrypted using attribute-based encryption with multiple policies and then outsourced to cloud storage. Hence, the user whose attributes satisfy the access policy can decrypt the ciphertext. Based on the attribute-based signature technique, authorized user whose attributes integrated in the signature satisfy the update policy can renew the ciphertext. Specifically, most of the encryption, decryption, and signing computations are outsourced from end devices to fog nodes, and thus, the computations for data owners to encrypt, end users to decrypt, re-encrypt, and sign are irrelevant to the number of attributes in the policies. The security analysis shows that the proposed scheme is secure against known attacks, and the experimental results show that the fog nodes perform most of the computation operations of encryption, decryption, and signing, and hence, the time of encryption for data owner, decryption, re-encryption, and signing for users is small and constant.

Cyber Security has become rising issue in recent years where encryption is one of solution and has an important role in data protection. Encryption algorithms that widely used in information security are asymmetric and symmetric. Advanced Encryption Standard (AES) is one of symmetric encryption that most used often and the most secure encryption today. However, AES encryption has slow computation. Our experiment show that both of algorithms combination needs 3.045 milliseconds for 1024 bytes of data and increase 3-4 milliseconds for 2048 bytes of data and so on. This paper proposes a novelty method to improve AES algorithm with Shift Row and S.Box modification for Mix Column transformation. The result show that our optimization has reduced 3 milliseconds and continue to increase as the number of bytes increases. Percentage average of the optimization is 86.143%.

The paradigm of forward security provides a promising approach to deal with the key exposure problem as it can effectively minimize the damage caused by the key exposure. In this paper, we develop a new forward-secure identity-based encryption scheme without random oracles. We formally prove that the proposed scheme is secure against adaptive chosen-ciphertext attacks in the standard model. In the proposed scheme, the running time of the private key extraction and decryption algorithms and the sizes of the user's initial private key and the ciphertext are independent on the total number of time periods, and any other performance parameter has at most log-squared complexity in terms of the total number of time periods. Compared with the previous forward-secure identity-based encryption schemes, the proposed scheme enjoys obvious advantage in the overall performance. To the best of our knowledge, it is the first forward-secure identity-based encryption scheme that achieves direct chosen-ciphertext security in the standard model.

Code-based cryptography is one of the few mathematical techniques that enables the construction of public-key cryptosystems that are secure against an adversary equipped with a quantum computer. The McEliece public-key encryption scheme and its variants are candidates for a postquantum public-key encryption standard.

Community detection is an important aspect of social network analysis, but social factors such as user intimacy, influence, and user interaction behavior are often overlooked as important factors. Most of the existing methods are single classification algorithms; multi-classification algorithms that can discover overlapping communities are still incomplete. In former works, we calculated intimacy based on the relationship between users, and divided them into their social communities based on intimacy. However, a malicious user can obtain the other user relationships, thus to infer other users interests, and even pretend to be the another user to cheat others. Therefore the information users concerned about needs to be transferred in the manner of privacy protection. In this paper, we propose an efficient privacy preserving algorithm to preserve the privacy of information in social networks. First, during expansion of communities on the base of mining seed, in order to prevent others from malicious users, we verify their identities after they send a request. We make use of the recognition and nontampering of the block chain to store the user's public key and bind to the block address, which is used for authentication. At the same time, in order to prevent the honest but curious users from illegal access to other users' information, we do not send plaintext directly after the authentication, but hash the attributes by mixed hash encryption to make sure that users can only calculate the matching degree rather than know specific information of other users. Analysis shows that our protocol would serve well against different types of attacks.

For users in possession of password-protected encrypted data in persistent storage (i.e., “data at rest”), an obvious problem is that the password may be extracted by an adversary through dictionary attacks, or by coercing the user. Traditional full disk encryption (FDE) or plausibly deniable encryption cannot adequately address such situations. Therefore, making data verifiably inaccessible in a stealthy and quick fashion may be the preferred choice, specifically for users, such as government/corporate agents, journalists, and human rights activists with highly confidential secrets, when caught and interrogated in a hostile territory. Using secure storage on a trusted platform module (TPM) and modern CPU’s trusted execution mode (e.g., Intel TXT), we design Gracewipe to enable secure and verifiable deletion of encryption keys through a special deletion password. When coerced, a user can fake compliance and enter the deletion password; and then, the user can prove to the adversary that Gracewipe has been executed and the real key is no longer available (through a TPM quote), hoping for a favorable situation (e.g., end of torture). To unlock the target encryption key, the adversary can only guess passwords through the valid Gracewipe environment with a high-risk of triggering deletion of the real key. Based on our two primary Gracewipe prototypes (i.e., software-based FDE with TrueCrypt and hardware-based FDE with self-encrypting drive), we also design and implement an extended family of unlocking schemes for triggering deletion, to achieve better plausibility, security and usability. We incur between 2–2.5 seconds delay during boot, and no performance penalty at run-time.

The notion of selective opening attacks (SOAs) was first introduced by Dwork et al. at FOCS'99. Informally, an encryption scheme is SOA secure if an adversary is given a vector of ciphertexts and can adaptively corrupt some fraction of them by obtaining not only their messages but also their randomness, the uncorrupted ciphertexts retain secure. Provably achieving security against SOA has been proven extremely challenging. In this paper, we propose a security model to capture simulation-based selective opening chosen-plaintext attacks (SIM-SO-CPA) for certificateless encryption. We provide a concrete construction and prove its security in our simulation-based selective opening chosen-plaintext attack security model, based on the real or random and computational Diffie–Hellman assumptions. Compared with previous SOA-secure public key encryption and identity-based encryption, our certificateless encryption scheme is more simple and efficient. Copyright © 2017 John Wiley & Sons, Ltd.