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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.

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.

In this work, we investigate how to protect public key encryption from both key-leakage attacks and tampering attacks. First, we formalize the notions of chosen ciphertext (CCA) security against key-leakage and tampering attacks. To this goal, we then introduce the concept of key-homomorphic hash proof systems and present a generic construction of public key encryption based on this new primitive. Our construction, compared with previous works, realizes leakage-resilience and tampering-resilience simultaneously but completely independently, so it can tolerate a larger amount of bounded-memory leakage and be instantiated with more flexibility. Moreover, it allows for an unbounded number of affine-tampering queries, even after the challenge phase. With slight adaptations, our construction also achieves CCA security against subexponentially hard auxiliary-input leakage attacks and a polynomial of affine-tampering attacks. Thus, to the best of our knowledge, we get the first public key encryption scheme secure against both auxiliary-input leakage attacks and tampering attacks.

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.

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.

At FOCS2011 Brakerski and Vaikuntanathan proposed a single-server LWE-based private information retrieval (abbreviated as PIR) protocol with a security reduction to hard standard lattice problems and nearly optimal communication complexity. However, Brakerski just described a generic PIR protocol that utilized a somewhat homomorphic encryption and an arbitrary symmetric encryption as building blocks, he did not instantiate the generic construction. In this work, we first modify Brakerski's construction without the evaluating key and construct a new PIR model. Moreover, we instantiate our new model via matrix FHE first proposed by Ryo et al. at PKC2015 and vector symmetric encryption scheme proposed in this work as building block. Then we optimize the Response operations and several other aspects of the scheme.

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.

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.

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%.

Confidentiality is among the most important obstacles for widespread adoption of cloud services. In fact, researchers have invented a new promising form of encryption, homomorphic encryption, that can be considered as an effective way to overcome these obstacles. Since cloud computing environment is more threatened by attacks and since cloud consumers often use resource-constrained devices to access to cloud computing services, the homomorphic encryption schemes must be promoted, in terms of security level and running time, to work efficiently. At EMENA-TSSL’16, we boosted the standard RSA encryption scheme at security level, Cloud-RSA. In this paper, we propose a new fast variant of the Cloud-RSA scheme to speed up its algorithms. The proposed variant uses a modulus of the form N = prqs for r, s ≥ 2 and employs Hensel lifting and Chinese remaindering to decrypt. Simulation results show that the proposed variant gives a large speed up over the Cloud-RSA scheme while preserving a prescribed security level.

Public key encryption with equality test (PKEET), which was first introduced by Yang et al. (CT-RSA, 2010), has various applications including facilitating keyword search on encrypted data and partitioning encrypted data on the cloud. It can be also applied to manage personal health records on the internet. For these reasons, there have been improvements on earlier PKEET schemes in terms of performance and functionality. We present a semi-generic method for PKEET constructions, assuming only the existence of IND-CCA2 secure traditional public key encryption (PKE) schemes, the hardness of Computational Diffie-Hellman (CDH) problems, and random oracles. Our approach has several advantages; it enables us to understand requirements for the equality test functionality more clearly. Furthermore, our approach is quite general, in that if we change the underlying PKE scheme with the identity-based encryption (IBE) scheme (and we assume the hardness of Bilinear Diffie-Hellman problems instead of CDH), then we obtain the first IBE scheme with equality test (IBEET) satisfying analogous security arguments to those of PKEET. Although an IBEET construction was recently proposed, but we note that it satisfies only weak security requirements. MOE (Min. of Education, S’pore) Accepted version

Traditional cipher systems are not appropriate for video encryption due to the high computation overhead. Video encryption must take account of the trade-off of both data security and real-time performance. In this paper, an efficient chaos pseudo-random number generator is designed to generate key stream for encrypting video syntax elements of H.264/AVC. In view of the efficiency and security, the intra-prediction mode (IPM), signs of trailing ones (T1s), signs of non-zero (NZ) coefficients, signs of motion vector difference (MVD) are chosen for selective encryption. The proposed scheme provides sufficient protection for the video commercial value. Experimental results demonstrate that the course of encryption will not affect the coding efficiency of H.264/AVC by keeping exactly the same bitrate and negligible time overhead. Security analysis shows that the proposed scheme has the ability to resist malicious attacks.

Cloud security is a huge concern when users and enterprises consider to deploy cloud computing services. This article mainly presented an important aspect of cloud security which is called searchable encryption. Searchable encryption is a scheme that enable users to?secure search on encrypted data stored in cloud. To guarantee privacy of users' data, users encrypt their data files before uploading, then when they need to fetch some files, they can use searchable encryption to execute keyword search on encrypted data. Searchable encryption can be classified by three models, each is corresponding with different application scenario. Two of them are suitable with cloud architecture. They are called searchable public key encryption and searchable symmetric encryption respectively. Searchable public key encryption is mainly for data sharing scenario. A user wants to share some data files with other users privately. He can encrypt these files with receivers' public key. And receivers can securely search on it with their private keys. Searchable symmetric encryption can enable users securely using their online storage. They can upload data files which are encrypted with their secret keys. And then they can securely search on these encrypted data with the secret key no matter when and where they are. Comprehensive survey on searchable encryption for cloud security.A new classification of searchable encryption applicable to cloud security.Open and future research directions and questions.

Predicate encryption is a cryptographic primitive that provides fine-grained control over access to encrypted data. It is often used for encrypted data search in a cloud storage environment. In this paper, we propose an enabled/disabled predicate encryption scheme, which is the first work that provides timed-release services and data self-destruction (they correspond to the terms "enabled" and "disabled," respectively). Owing to these properties, the sender can set the readable/unreadable time of the files to be sent to the receiver. The receiver can read the sent file only after the readable time. After the unreadable time, the structure of the file will be destroyed and the file will become unreadable. Furthermore, for practical usage purposes, the extended scheme, which is based on the proposed scheme, provides not only timed-release services and data self-destruction but also long message encryption and undecryptable search. In the extended scheme, the length of encrypted messages does not depend on the order of the group. Moreover, the cloud server can obtain only the matched ciphertexts after the search. We model timed-release and data self-destruction functionalities for predicate encryption in clouds.A sender can set the readable/unreadable time of the files to be sent to the receiver.It also supports long message encryption and undecryptable search.The cloud server can obtain only the matched ciphertexts after the search.

Along with the popularization and rapid development of cloud-computing, more and more individuals and enterprises choose to store their data in cloud servers. However, in order to protect data privacy and deter illegal accesses, the data owner has to encrypt his data before outsourcing it to the cloud server. In this situation, searchable encryption, especially searchable symmetric encryption (SSE) has become one of the most important techniques in cloud-computing area. In the last few years, researchers have presented many secure and efficient SSE schemes. Like traditional encryption, the security of all existing SSE schemes are based on the assumption that the data owner holds a secret key that is unknown to the adversary. Unfortunately, in practice, attackers are often able to obtain some or even all of the data owner's secret keys by a great variety of inexpensive and fast side channel attacks. Facing such attacks, all existing SSE schemes are no longer secure. In this paper, we investigate how to construct secure SSE schemes with the presence of memory attack. We firstly propose the formal definition of memory leakage-resilient searchable symmetric encryption (MLR-SSE, for short). Based on that, we present one adaptive MLR-SSE scheme and one efficient non-adaptive dynamic MLR-SSE scheme based on physical unclonable functions (PUFs), and formally prove their security in terms of our security definitions. Two symmetric searchable encryption protocols against memory leakage are proposed.The mechanism mainly relies on the character of physical unclonable functions.The attacker considered here is a non-volatile memory attacker.

Chaotic encryption algorithm is implemented in 32 bit microcontroller to protect text.Security analysis shows the effectiveness of the encryption for real-time applications.Performance and resources analysis justify the implementation of the system.The implementation has high potential to be used in embedded systems in military, telemedicine, etc. Currently, several embedded applications in military, industry, banking transference, e-commerce, biometric systems and others use insecure communication channels such as Internet to transmit or store confidential information. Therefore, the integrity and security of information are an important issue in continuous research. In last years, chaotic systems have been proposed in cryptography due they have several properties related with cryptography properties such as extreme sensibility on initial conditions with confusion and ergodicity with diffusion. In this paper, we present a 32-bit microcontroller implementation of an improved text encryption algorithm (based on Murillo-Escobar's algorithm 13) for real-time embedded systems and we present a complete security analysis such as key size analysis, key sensitivity, plain text sensitivity, floating frequency, histograms, N-grams, autocorrelation, information entropy, robustness against classic attacks, randomness analysis, and security characteristics. In addition, the digital implementation and performance are analyzed such as programming details, memory required, frequency system, implementation costs and encryption time. In contrast with recent approaches presented in literature, we present a complete security analysis in both statistical and implementation level, to justify the proposed scheme in a real application. Based in the results, the proposed embedded text encryption system is secure, effective and at low cost, and it could be implemented in real-time cryptosystem based on microcontroller.

Encryption schemes are generally considered to be secure in an ideal environment, where the adversary cannot obtain the secret internal state of schemes. However, in the realistic environment, the adversary can gain partial information about decryption private key through various types of side channel attacks. In order to capture these attacks, it is crucial to design encryption schemes which are resilient to leakage. In this article, we first formalize a continuous leakage-resilient security model of certificate-based encryption. In the model, the adversary continuously obtains partial information about the secret states through the continuous leakage attacks. Furthermore, we construct a continuous leakage-resilient certificate-based encryption (CLR-CBE) scheme which is resilient to continuous leakage, and it is secure against adaptive chosen ciphertext attacks under the bilinear Diffie-Hellman inversion (BDHI) hardness assumption. Lastly, we show the bound on leakage and make comparison between proposed and existing schemes in terms of security properties and efficiency.

Despite the great efforts to secure wireless sensor network (WSN), the dynamic nature and the limited resources of sensor nodes make searching for a secure and optimal network structure an open challenge. In this paper, we propose a novel encryption schema based on Elliptic Curve Cryptography (ECC) and homomorphic encryption to secure data transmission in WSN. The proposed encryption schema is built upon GASONeC algorithm (Elhoseny et al., 2014) that uses genetic algorithm to build the optimum network structure in the form of clusters. ECC is used to exchange public and private keys due to its ability to provide high security with small key size. The proposed encryption key is 176-bit and is produced by combining the ECC key, node identification number, and distance to its cluster head (CH). To reduce energy consumption of CH, homomorphic encryption is used to allow CH to aggregate the encrypted data without having to decrypt them. We demonstrated that the proposed method is capable to work with different sensing environments that need to capture text data as well as images. Compared with the state-of-the-art methods, our experimental results demonstrated that our proposed method greatly improve the network performance in terms of lifetime, communication overhead, memory requirements, and energy consumption.

Certificate-based encryption (CBE) is an important class of public key encryption but the existing schemes are secure only under the premise that the decryption key (or private key) and master secret key are absolutely secret. In fact, a lot of side channel attacks and cold boot attacks can leak secret information of a cryptographic system. In this case, the security of the cryptographic system is destroyed, so a new model called leakage-resilient (LR) cryptography is introduced to solve this problem. While some traditional public key encryption and identity-based encryption with resilient-leakage schemes have been constructed, as far as we know, there is no leakage-resilient scheme in certificate-based cryptosystems. This paper puts forward the first certificate-based encryption scheme which can resist not only the decryption key leakage but also the master secret key leakage. Based on composite order bilinear group assumption, the security of the scheme is proved by using dual system encryption. The relative leakage rate of key is close to 1/3. We put forward the formal definition and security model of LR-CBE.We present first certificate-based encryption scheme with leakage resilience.The security of the scheme is reduced to composite order bilinear group assumption.The relative leakage rate of key is close to 1/3.

Dynamic threshold public-key encryption, proposed by Delerablee and Pointcheval (CRYPTO 2008), is an extension of ordinary threshold encryption which enables decryption servers to join the system even after the setup phase, and to choose the authorized set and the threshold of decryption dynamically. Delerablee and Pointcheval proposed the first dynamic threshold public-key encryption scheme, which they proved secure under a non-standard q-type assumption. However, decryption consistency, which is an important security property that guarantees uniqueness of decryption, even when a sender and decryption servers behave maliciously, is only shown to hold in the random oracle model. In this paper, we propose three threshold public-key encryption schemes. The first and second schemes are both dynamic schemes. The former achieves a relatively weaker variant of decryption consistency, while the latter achieves a strong variant thereof. The former is a generic construction from public-key encryption with non-interactive opening (PKENO), while the latter is a specific construction from a standard number-theoretic assumption. These are the first constructions of dynamic public-key encryption, which achieve decryption consistency without relying on the random oracle model. Furthermore, both schemes can be realized based on standard assumptions. The third construction is a generic construction from PKENO achieving the strong variant of decryption consistency. This construction affirmatively answers the question indirectly posed by Galindo et al. (AFRICACRYPT 2010) of whether a generic construction achieving strong decryption consistency is possible.

In order to limit the damage of key exposure for identity-based encryption, we propose a new paradigm called intrusion-resilient identity-based encryption (IRIBE) in this paper. Compared with key-insulated identity-based encryption and forward-secure identity-based encryption, IRIBE can achieve a stronger level of security. In our proposed scheme, the ciphertexts in any other time periods are secure even after arbitrarily many compromises of the base and the user, as long as compromises do not happen simultaneously. Furthermore, the intruder cannot decrypt the ciphertexts pertaining to previous time periods, even if it compromises the base and the user simultaneously. Therefore, our IRIBE scheme can greatly enhance the security of identity-based encryption. We also formalize the definition and the security notions of this paradigm. The proposed scheme is proven secure in the standard model.

This paper describes an approach and implementation issues of client-side data encryption for thin client-web browser. Since the service provider may be a competitor of the service user, sensitive parts of data are encrypted and decrypted by the client. Cipher key generation and distribution issues are discussed: although the cipher key is kept in private, the paper shows the way for the key validation by the server side to maintain data consistency.

With the growth in technology, there is always a need of good encryption method which may provide better security and authenticity with lesser computational complexities. Although there are a lot of symmetric key algorithms which are already been proposed, yet we are going to propose a content based symmetric key algorithm. This algorithm has two rounds and each round uses the ASCII code of characters, round two serves as the heart of this algorithm as XOR operation is performed here. It uses only two operation addition and XOR for encryption process and to generate two sub key, it uses two operation addition and subtraction. The goal of the algorithm is to reduce the correlation between plain text and cipher.

Attribute Based Encryption (ABE) is a type of public encryption in decryptor can only decrypt the ciphertext if its attributes of secret key matches the attributes of ciphertext but functionality comes at higher cost. The main idea of this paper is to provide multi authority in attribute based encryption which also allows fast decryption. Multi authority concept allows any polynomial number of independent authorities to monitor attributes, distribute secret keys and decrypt the message. In this paper, a secure multi authority attribute based encryption with fast decryption scheme is design.

It is the first time to integrate identity-based encryption into public key encryption with equality test.It extends identity-based encryption with keyword search to yield a general function: equality test.It is proven to be one-way chosen-ciphertext security against a chosen identity attack as a desirable security.Unlike PEKS or IBEKS, it can be used alone since it contains decryption algorithm besides encryption algorithm. We firstly combine the concepts of public key encryption with equality test (PKEET) and identity-based encryption (IBE) to obtain identity-based encryption with equality test (IBEET). Inheriting the advantage of IBE, IBEET can simplify the certificate management of PKEET with all messages encrypted with the receiver's public identity. In the IBEET scheme, the receiver computes a trapdoor using the secret value for the identity and then sends it to a cloud server for equality test on its ciphertexts with others' ciphertexts. Using this primitive someone with the trapdoor for its identity can delegate out the capability of equality test on its ciphertexts without requiring a central authority to act as a delegator. So it is very suitable for the client with minimal computation resource, e.g, mobile phone. Furthermore, compared with PKEET, it has security improvement since not anyone can perform the test. Therefore, IBEET may have interesting applications in cloud computing, e.g., partition of encrypted emails. We define one-way chosen-ciphertext security against a chosen identity attack (OW-ID-CCA) and propose a construction in bilinear pairing. Finally, extensive security analysis and comparison with related works show that the proposed scheme is proven secure and useful.

In this fast world of networking, secure image transmission of data whether the image having some information or some text, is one of the area focus for security. Here we had tried to implement the proposed technique fuzzy logic based image encryption for confidential data transfer using (2, 2) secret sharing scheme. Using fuzzy logic makes encryption and decryption complex. The (2, 2) secret sharing scheme provides secured and confidential authentication. For image encryption AES algorithm is used for encryption and decryption. The implementation of encryption algorithms can be very complex when we are focusing on rule based share generation.

There are important concerns when trusting sensitive information to the cloud. Health and financial records, for instance, suffer strict legal restrictions to data escrow. Organizations holding such information need to assure end-users and authorities that a third party will never access restricted data. Client-side encryption is a common solution in literature. Most works fail, however, to reason the impact of security solutions on performance and usability. Homomorphic and order preserving encryption systems can mitigate such negative impacts, as they allow the computation of regular searches over encrypted records on the cloud, while preserving information confidentiality and the privacy if end-users.

Every Organization uses data encryption for securing their communication. It provides data integrity, confidentiality and authentication. The primary goal of this paper is to combine the reversible data hiding and encryption to get maximum security. There are some areas like military, medical, forensic, bank, etc. which cannot compromise with any security issue. In the above areas both data and image are highly confidential, so no permanent distortion is acceptable. The paper proposes the algorithm reversible data hiding with a novel lightweight software oriented symmetric stream cipher namely A-S algorithm. The reversible data hiding algorithm used here produces maximum data capacity and contrast improved cover image. When applying the A-S encryption algorithm on the reversible data hiding process results a very good amount of security level. This new combined algorithm tested with two different datasets and the result shows a maximum data capacity and enhanced contrast of the cover image. The paper also measures another important metric of performance which results an extra ordinary result.

Disk encryption is frequently used to secure confidential data on mobile devices. However, the high energy cost of disk encryption poses a heavy burden on those devices with limited battery capacity especially when a large amount of data needs to be protected by disk encryption. To address the challenge, we develop a new kernel-level disk encryption software, Populus. Almost 98% of Populus's encryption/decryption computation is not related with the input plaintext/ciphertext, so we accomplish the computation in advance during initialization when a consistent power supply is available. We conduct cryptanalysis on Populus and finally conclude that state-of-the-art cryptanalysis techniques fail to break Populus in reasonable computational complexity. We also conduct energy consumption experiments on Populus and dm-crypt, a famous disk encryption software for Android and Linux mobile devices. The experimental results demonstrate that Populus consumes 50%-70% less energy than dm-crypt.

A chaotic-cipher-based packet body encryption algorithm for JPEG2000 images is proposed in this paper. In order to produce a compliant codestream, a 2-byte block encryption procedure including bit-wise exclusive OR and cyclic rotation operations is investigated. Moreover, a repeatedly encryption process is adopted to eliminate the undesirable marker codes during encryption. The repeatedly encryption process only introduces a negligible computational overhead. Both simulations and analysis show that the proposed algorithm is of high security and simplicity. Therefore, these good properties make the algorithm efficient to process and useful for image applications.

Data security has a major role in the development of communication system, where more randomization in the secret keys increases the security as well as the complexity of the cryptography algorithms. In the recent years network security has become an important concern. Cryptography plays a vital role in the information security system against various attacks. Efficient and newer versions of cryptography techniques can help to reduce this security threat. The Advanced Encryption Standard is a strong symmetric key cryptographic algorithm which uses a number of table look ups to increase its performance. The Cache Timing Attack correlates the timing details for encryption under a known key with an unknown key to infer the unknown key. This paper proposes an extension of a public-key cryptosystem to support a private key cryptosystem which is a combination of Advanced Encryption Standard and ECC. The past results have been computed on the basis of AES key length as 128 bit and no. of iterations as 10.To increase competency and to minimize drawbacks this paper proposes a hybrid encryption scheme. The parameters to be studied will primarily focus on the key length, no. of iterations and the type of side channel attack to be implemented. The key length for this work has been increased to 192 bit and the no. of iterations taken will be 12.

Networked control systems with encrypted sensors measurements is considered. Semi-homomorphic encryption is used so that the controller can perform the required computation on the encrypted data. Specifically, in this paper, the Paillier encryption technique is utilized that allows summation of decrypted data to be performed by multiplication of the encrypted data. Conditions on the parameters of the encryption technique are provided that guarantee the stability of the closed-loop system and ensure certain bounds on the closed-loop performance.

Proxy Re-Encryption (PRE) is a useful cryptographic primitive that allows a data owner to delegate the access rights of the encrypted data stored on a cloud storage system to others without leaking the information of the data to the honest-but-curious cloud server. It provides effectiveness for data sharing as the data owner even using limited resource devices (e.g. mobile devices) can offload most of the computational operations to the cloud. Since its introduction many variants of PRE have been proposed. A Ciphertext-Policy Attribute-Based Proxy Re-Encryption (CP-ABPRE), which is regarded as a general notion for PRE, employs the PRE technology in the attribute-based encryption cryptographic setting such that the proxy is allowed to convert an encryption under an access policy to another encryption under a new access policy. CP-ABPRE is applicable to many network applications, such as network data sharing. The existing CP-ABPRE systems, however, leave how to achieve adaptive CCA security as an interesting open problem. This paper, for the first time, proposes a new CP-ABPRE to tackle the problem by integrating the dual system encryption technology with selective proof technique. Although the new scheme supporting any monotonic access structures is built in the composite order bilinear group, it is proven adaptively CCA secure in the standard model without jeopardizing the expressiveness of access policy. We further make an improvement for the scheme to achieve more efficiency in the re-encryption key generation and re-encryption phases. This paper proposes a new Ciphertext-Policy Attribute-Based Proxy Re-Encryption scheme.The scheme is proved adaptively chosen ciphertext secure by leveraging dual system encryption technology and selective proof technique.The paper also proposes an improvement for re-encryption key generation and re-encryption phases so as to reduce computational and communication cost.

Data confidentiality in the Cloud Computing is a very challenging task. Encryption is one of the most secure methods ensuring this task, and searchable encryption techniques are used to search on encrypted data without the need for decryption. But, despite this secure measure some leaks may appear when searching over data. In this article, we propose to improve confidentiality of outsourced data. We are particularly interested in reinforcing the access control on the search result, when the search is performed over encrypted data. The property behind this aspect of security is known as ACAS (Access Control Aware Search) principle. We present a hybridization of Searchable Encryption and Attribute Based Encryption techniques in order to satisfy the ACAS property. The proposed model supports a personalized and secure multi-user access to outsourced data, presenting high search performance. It deals with multi-keywords searches and is designed to speed up the search time by taking advantage of High Performance Computing, which is widely used in Cloud Computing. Two Attribute Based Encryption techniques are considered on the side of the Cloud and some conducted experiments show the efficiency of the proposed method.

An authenticated encryption scheme is a message transmission scheme, which can send a message in a secure and authentic way, and allows the specified recipient to simultaneously recover and verify the validity of a message. In the large message transmission, traditional authenticated encryption schemes have the disadvantages that communication overheads and the computation costs are too high. In this work, we propose a secure authentication encryption scheme and show that the scheme is secure in the random oracle model. In comparison with Lv et al.'s scheme and Li et al.'s scheme, our proposed scheme is the most efficient one in terms of computation complexity and communication cost. Finally, we extend our proposed scheme to adapt to the authenticated encryption for a large message, which is secure against the message block being reordered, replicated or partially deleted during transmission.

Recently, in Information Sciences, Zhang et?al. (2014) claimed that they proposed the first anonymous spatial encryption under affine space delegation functionality with full security, which solves the open problems of full security proposed in Boneh and Hamburg (2008) and anonymity left in Boneh and Hamburg (2008) and Moriyama and Doi (2011). In this paper, we show their construction cannot achieve recipient anonymity as the ciphertext terms leak information about the encryption vector. Hence realizing anonymous spatial encryption with full security is still an open problem. We propose a new fully secure anonymous spatial encryption under an affine space delegation mechanism that addresses the open problem positively. Our construction utilizes composite order bilinear groups where the group order is a product of four primes and achieves the same efficiency as that of the Zhang et?al. (2014) construction. Under some well-established cryptographic assumptions, the proposed construction is proven to be fully semantically secure with anonymity in the standard model within the dual encryption system framework.

Proposal of a new multivariate encryption scheme.Improvement of the SimpleMatrix scheme of PQCrypto 2013.Faster decryption.Probability of decryption failures is reduced. Multivariate cryptography is one of the main candidates to guarantee the security of communication in the presence of quantum computers. While there exist a large number of secure and efficient multivariate signature schemes, the number of practical multivariate encryption schemes is somewhat limited. In this paper we present our results on creating a new multivariate encryption scheme, which is an extension of the original SimpleMatrix encryption scheme of PQCrypto 2013. Our scheme allows fast en- and decryption and resists all known attacks against multivariate cryptosystems. Furthermore, we present a new idea to solve the decryption failure problem of the original SimpleMatrix encryption scheme.

Privacy protection has become a major issue in modern societies. Many efforts have been provided in the last years to catch properly the requirements that cryptographic primitives and low-level protocols should meet in order to be useful for building privacy-preserving applications. In particular, anonymity is an important property to achieve, and the notion of key privacy in public-key encryption, which guarantees that an adversary is unable to tell with which public key a certain ciphertext has been produced, plays a key-role in the design of anonymous protocols.Secret sets and anonymous broadcast encryption are two examples of useful anonymous protocols. A secret set is a representation of a subset of users of a given universe satisfying some basic membership privacy properties, and anonymous broadcast encryption is a mechanism to encrypt a broadcast message that only authorized users, whose identities are kept secret, can decrypt.In this paper we show that, even if apparently the key privacy property of an encryption scheme seems to be unrelated to the security of the encrypted content, and it looks like just an additional property the encryption scheme can enjoy, for a robust encryption scheme key privacy under chosen ciphertext attack implies non-malleability and, hence, security under chosen ciphertext attacks. This result helps to simplify the set of requirements that public key encryption schemes need to satisfy when stating and proving theorems regarding anonymous protocols in which the encryption schemes are used.Then, we provide a formal model for both secret sets and anonymous broadcast encryption and we prove that they are equivalent with respect to non-adaptive adversaries: the former can be used to design the latter and vice versa.Finally, we revisit some previous constructions for secret sets, and we analyze the security properties they enjoy within our adversarial model.

Cloud computing is emerging paradigm provides various IT related services. The security and privacy are two major factors that inhibits the growth of cloud computing. Security factors are reasons behind lesser number of real times and business related cloud applications compared to consumer related cloud application. Firstly, the pros and cons of different Attribute Based encryption methods are analysed. Secondly, a new encryption method based on Attribute Based Encryption (ABE) using hash functions, digital signature and asymmetric encryptions scheme has been proposed. Our proposed algorithm is simplified yet efficient algorithm that can implemented for cloud critical application.

The enlarged size of the internet and vast communication across it and also medical needs digital images require of security plays vital role. So different techniques are used to protect confidential image data from unauthorized access. In this paper, we propose a New encryption technique Using elliptic curve cryptography with a magic matrix operations for securing images that transmits over a public unsecured channel. There are two most important groups of image encryption algorithms: some are non chaos-based selective methods and chaos- based selective methods. The majority of these algorithms is planned for a specific image format, compressed or uncompressed.

This paper presents a simple Encryption/Decryption technique which enables all kinds of file for encryption and decryption. The method of encryption is not only simple, but also secured enough for transmission. The technique uses simple key generation using an arbitrary matrix. The final encryption is performed through a set of operations using the generated key and original data block and vice-versa in decryption. The generation of keys along with encryption and decryption is performed by the algorithm by putting in the data block and arbitrary matrix. The encryption process can be done by modifying the arbitrary matrix and multiple key can be generated for a single data block.

In current Internet, data owners can provide integrity and authentication when data is generated. However confidentiality is usually implemented by symmetric keys between two corresponding programs in an end-to-end manner. A symmetric key for confidentiality is not suitable for Internet of Things (IoT) environment where there are one producer of data and multiple consumers of data. Further the consumers differ in their qualification about what part of the data is allowed to access under which context. In the paper we describe our work in progress of confidentiality scheme in which the producer encrypts data along with context. We improve Key Policy Attribute Based Encryption (KP-ABE) and Ciphertext Policy Attribute Based Encryption (CP-ABE) to allow consumers to decrypt data as their contexts dictate. We describe briefly our scheme to implement the idea.

Anonymous encryption provides the decrypter’s identity privacy preservation as well as plaintext confidentiality. Spatial encryption, which is a kind of functional encryption, provides a generalized framework for special property encryption schemes such as broadcast encryption, predicate encryption, forward secure encryption, (hierarchical) identity-based encryption, delegatable attribute-based encryption etc. In this paper, we propose an anonymous spatial encryption scheme that deploys an affine subspace delegation mechanism. Our proposed scheme captures the message confidentiality , recipient anonymity , adaptive security , partial-order delegation and short ciphertext , simultaneously. To the best of our knowledge, the proposed scheme is the first anonymous spatial encryption that provides the anonymity property in adaptive security model, whose construction is based on a dual system encryption mechanism in bilinear composite-order groups. We also give a conversion construction to move into a prime-order setting with canceling property , whose security is based on the Decision Linear Problem. Finally, we provide a transformation methodology to obtain a CCA-secure scheme that combines a one-time signature, delegation functionality and the CPA-secure scheme.

A novel way to provide fast authenticated and randomized encryption is proposed using reversible cellular automata for the first time. A block-based cryptosystem is presented and shown to provide security against both active and passive attackers by the way of a strong authentication mechanism. The proposed system is much faster than existing authenticated encryption standards since only one pass per block is performed to ensure both encryption and integrity. Experimental results show robustness of the cryptosystem against several cryptanalysis techniques, when a formal proof of strict integrity preserving is included. Obtained results demonstrate superiority of the approach in both security and rapidity aspects.

Ciphertext-Policy Attribute-Based Encryption (CP-ABE) allows to encrypt data under an access policy, specified as a logical combination of attributes. Such ciphertexts can be decrypted by anyone with a set of attributes that satisfy the access policy. We propose a Ciphertext-Policy Attribute-Based Encryption, which is based on a recent secret sharing method called Linear Integer Secret Sharing Scheme (LISS). In this scheme, the encryptor can specify the access policy in terms of LISS matrix M, over the attributes in the system. The scheme is selectively secure under Decisional Bilinear Diffie-Hellman (DBDH) assumption.

Searching on remote encrypted data (commonly known as searchable encryption) has become an important issue in secure data outsourcing, since it allows users to outsource encrypted data to an untrusted third party while maintains the capability of keyword search on the data. Searchable encryption can be achieved using the classical method called oblivious RAM, but the resultant schemes are too inefficient to be applied in the real-world scenarios (e.g., cloud computing). Recently, a number of efficient searchable encryption schemes have been proposed under weaker security guarantees. Such schemes, however, still leak statistical information about the users' search pattern. In this paper, we first present two concrete attack methods to show that the search pattern leakage will result in such a situation: an adversary who has some auxiliary knowledge can uncover the underlying keywords of user queries. To address this issue, we then develop a grouping-based construction (GBC) to transform an existing searchable encryption scheme to a new scheme hiding the search pattern. Finally, experiments based on the real-world dataset demonstrate the effectiveness of our attack methods and the feasibility of our construction.

Users are inclined to share sensitive data in a remote server if no strong security mechanism is in place. Searchable encryption satisfies the need of users to execute a search encrypted data. Previous searchable encryption methods such as "public key encryption with keyword search (PEKS)" restricted the data access to certain users, because only the assigned users were able to search the encrypted data. In this paper we will discuss the relation between Attribute Based Encryption (ABE) and searchable encryption and define a weak anonymity of the ABE scheme, named "attribute privacy". With this weak anonymity, we propose a general transformation from ABE to Attribute Based Encryption with Keyword Search (ABEKS) and a concrete attribute private key-policy ABE (KP-ABE) scheme. We present an ABEKS scheme based on this KP-ABE scheme and permit multi-users to execute a flexible search on the remote encrypted data. We have proposed a KP-ABE scheme with "attribute privacy" features.We have introduced a general transformation from the KP-ABE scheme to the ABEKS scheme.We have designed a secure ABEKS scheme by the transformation.We have provided the proof of security and consistency of the ABEKS scheme.

In recent years, security of multimedia systems such as image and video has become one of the main needs in computer and communication networks. To encrypt multimedia content, lightweight and fast algorithms are usually used in frequency transform domain and in a partial encryption form, having time efficiency, high execution speed and correspondence with compression structures. In this article, a lightweight and fast algorithm is proposed and two designs in partial encryption scheme of DCT transform coefficients are introduced based on three fundamental principles and confrontation the partial encryption attacks (cryptographic attack, replacement attack and statistical model based attack). Moreover, the proposed algorithm is compared with A5/1 and W7 stream ciphers. The results of analyses and simulations by MATLAB software show that the proposed encryption algorithm and two introduced designs are applicable for real-time security applications of multimedia which require high-speed computations and sufficient security levels.