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The extensive growth of the Internet of Things (IoT) devices leads to the evolution of the broad range of smart applications in numerous fields such as smart home, wearable, education, agriculture, health care, transportation and many more. But security for IoT devices is still a challenging issue as many attacks are possible in the environment. Therefore strong security requirements are an important concern to safeguard the IoT smart devices. The sensor network has to select an efficient encryption algorithm to provide secure communication between sensor nodes. The basic requirement for encrypted communication is key establishment and distribution. The currently available key management process involves large computational overhead, energy consumption, and delay. This makes the network inefficient since sensor nodes have limited bandwidth capacity. The main aim of this paper is to establish a strong key management mechanism to overcome the issues in the current cluster based key management technologies. The work proposed a secure hash key-based key management scheme for the cluster based network environment. The proposed scheme considers the two-level verification process, a one-hop way for the nodes within the cluster and a multi-hop way for the nodes outside the transmission range. The work done is examined through simulation by varying the number of malicious nodes in the environment. The result shows that the rate of packet loss has been reduced when compared with a one-hop way of key management solution. The proposed work also enhances the performance of the network by lowering the energy, computational overheads, and delay.

Attribute-based encryption (ABE) provides a promising solution for enabling scalable access control over encrypted data stored in the untrusted servers (e.g., cloud) due to its ability to perform data encryption and decryption defined over descriptive attributes . In order to bind different components which correspond to different attributes in a user’s attribute-based decryption key together, key randomization technique has been applied in most existing ABE schemes. This randomization method , however, also empowers a user the capability of regenerating a newly randomized decryption key over a subset of the attributes associated with the original decryption key. Because key randomization breaks the linkage between this newly generated key and the original key, a malicious user could leak the new decryption key to others without taking any responsibility for the key abuse. To solve this problem, we think of key regeneration-free ABE to disallow a user from randomizing his/her decryption key in any manner, i.e., a user can only delegate his/her decryption key in exactly the same form without any modification so that any abused or pirated key can be traced back to its original owner. Motivated by strongly unforgeable signature, we first define a security notion called strong key unforgeability, and show that ABE schemes equipped with the strong key unforgeability are immune to key regeneration. We then provide a generic transformation to convert ciphertext-policy ABE (CP-ABE) schemes of certain type to key regeneration-free CP-ABE schemes, and show how the transformation works by presenting two concrete constructions.

This paper proposes a solution for low-cost consumer IoT devices to employ end-to-end security without requiring additional hardware. Manufacturers of consumer IoT devices often sacrifice security in favour of features, user-friendliness, time to market or cost, in order to stay ahead of their competitors. However, this is unwise, as demonstrated by recent hacks on consumer IoT devices. Low-cost embedded devices struggle to create suitable entropy for key generation; on the other hand, smartphones are both abundant and have multiple sources of entropy for strong key generation. The proposed architecture takes advantage of these properties and offloads key generation and transfer to the user's smartphone, removing the need for constrained IoT devices to perform public key infrastructure and generate symmetric keys. The authors implemented the design on a \$1 general-purpose microcontroller and then analysed the performance. The design allows all communication to and from the device to be encrypted while being simple to setup, low-cost and responsive without any additional manufacturing cost. The architecture presents a general solution, which could be implemented on any microcontroller. Since the architecture does not require any additional hardware, it can be retroactively applied to deployed devices through a firmware update.

As content is transmitted in content-driven manner in the content-centric network (CCN), it does not require any host address; therefore, it is infeasible to establish a traditional secure channel between hosts. Securing the content transmission in the CCN is a challenging problem. We solve this problem with the content-based encryption, where the encryption key is associated with the content itself, and the private decryption keys are distributed to the authorized consumers. To deal with the security requirements for content-based encryption, we define a security model that captures the key existential unforgeability and semantic security. We then propose a content-based encryption scheme with short ciphertexts, which is proven to be strong key existentially unforgeable and semantically secure in the standard model. We apply the scheme to construct a secure content transmission protocol in the CCN, which captures the security properties of content confidentiality, integrity, resistance to replay attacks and resistance to key forgery attacks. The performance analysis shows that our protocol is efficient for large content transmission.

To achieve large-scale access control over the shared data, attribute-based encryption(ABE) is a good choice. However, in the existing ABE schemes, a data user which possessing a decryption-key can regenerate a new key since key randomization technique is introduced, which will incur key abuse without any responsibility. In addition, to decrypt the ciphertext, computational complexity of a user is linear to the size of attribute set, it is a formidable challenge for the resource-constrained users. To overcome the problem above, we proposed a lightweight data sharing scheme with Resisting Key Abuse in MEC base on CP-ABE. By using transforming key technique and unforgeability of signature, the proposed scheme can not only resist decryption-key regeneration but also offload decryption computation to MEC server in order to reduce the computation complexity of data user. For a data user, it only takes two exponential operations to decrypt the ciphertext. Security proofs show that our proposed scheme can provide data confidentiality and strong key unforgeability. Compared to several schemes, the proposed scheme is show to have more advantages in terms of computational cost and communication overhead by experiment simulation.

In the present era, the progression of the Internet has given a huge impetus to the sharing of multimedia over various communication channels. But the data once distributed over the communication network is prone to several security risks. To handle these security risks, various encryption algorithms have been proposed to date. In this chapter, a new color image encryption algorithm is presented using DNA sequence substitution and chaos. The work suggested in this chapter is aimed at strengthening the encryption to improve the security of the system. A DNA sequence obtained from an RGB image is encrypted using a random DNA sequence. This encryption is performed using DNA substitution. Further, this encrypted sequence is doubly secured by performing the XOR operation of this sequence with a sequence generated using chaos. The result of this conversion is an encrypted RGB image. Thus, the encrypted image is doubly secured using the proposed algorithm. The evaluation of the algorithm presented in this chapter shows strong key sensitivity along with large key space and can be seen from the experimental results. The results obtained for the proposed method stand testimony that the proposed technique shows high resistance to statistical attacks and thus can prove to be a good candidate for image encryption.

In recent years, chaotic cryptography has greatly promoted the development of image encryption technology, but some chaotic-based digital image encryption systems have some flaws. In order to enhance the security and reliability of digital images in network transmission, this paper presents a new two-dimensional chaotic map (2D-CCLS), which is derived from Logistic and Sine map, and then applied in a chaotic image encryption algorithm to scramble, rotate and diffuse the pixels of the image. Theoretical analysis and simulation experiment results show that the algorithm has good performance such as large key space, strong anti-noise attack capability, strong key sensitivity and high security.

To ensure the safety and reliability of medical image during information transmission, a medical image encryption algorithm based on Hermite chaotic neural network is proposed. Firstly, the medical image encryption algorithm uses chaotic sequences generated by the logistic map. Secondly, this chaotic sequence is used to train a Hermite chaotic neural network. Finally, the medical image is encrypted by two key streams generated by the trained Hermite chaotic neural network. Experimental results show that the encryption algorithm is very effective. The security analysis shows that the encryption algorithm can effectively resist statistical analysis, has strong key sensitivity, large keyspace, and greatly improves the security of medical images.

This work presents a new method of encrypting and decrypting speech based on a chaotic key generator. The proposed scheme takes advantage of the best features of chaotic systems. In the proposed method, the input speech signal is converted into an image which is ciphered by an encryption function using a chaotic key matrix generated from a fractional-order chaotic map. Based on a deadbeat observer, the exact synchronization of system used is established, and the decryption is performed. Different analysis are applied for analyzing the effectiveness of the encryption system. The obtained results confirm that the proposed system offers a higher level of security against various attacks and holds a strong key generation mechanism for satisfactory speech communication.

This paper presents a medical image encryption algorithm using edge maps derived from a source image. The algorithm is composed by three parts: bit-plane decomposition, generator of random sequence, and permutation. It offers users the following flexibilities: (1) any type of images can be used as the source image; (2) different edge maps can be generated by various edge detectors and thresholds; (3) selection of appropriate bit-plane decomposition method is flexible; (4) many permutation methods can be cascaded with the proposed algorithm. A significantly large key space and strong key sensitive are possessed by the proposed algorithm to protect different types of medical images. Furthermore, it has a wider applicability than other methods for fuzzy edge maps. Experiments and security analysis further demonstrate that it has a strong resistance against various security attacks and outperforms other state-of-the-art methods. HighlightsA lossless edge maps based image cryptosystem for medical image is proposed.Many kinds of edge maps with various edge detectors can be applied as the keys.The algorithm costs little time with a machine-friendly binary system.The scheme shows a higher security level with other state-of-the-art methods.

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

IoT Consist of interrelated devices such as digital devices, mechanical devices, computer system, sensors, etc. for transceiving the information over the network. The scalability is essential to enhance the energy utilization and the performance of the environment, while mobility enhances the coverage of the system. Key management is vital for encrypted information transmitted over the network. Although many key management techniques are available, still it is a challenging issue concerning energy and computational cost, so robust key management technique is required that guarantees the required security requirements. In this paper, we proposed a cognitive key management technique (CKMT). The CKMT mechanism is helpful for key management and maintenance in a cluster-based mobile environment that reduces the rekeying process which is required for the mobile node when it enters the new location area, thereby reducing the computational overhead and enhances the scalability to large size network which makes our scheme more robust because strong key management technique is important while providing security services. Initially, we form a cluster, then Cluster-Head (CH) will be elected, it’s a coordinator node that acts as a key manager. We also made an assumption that the sensors and Cluster-Heads are mobile, they can be able to shift from one position to another. This CH oversees and keeps up the private keys of sensors. When CH changes its location, it will hand over its responsibilities to the other CH in the network for uninterrupted communication. Our scheme uses local keys and foreign keys for each node and pairwise key is used only for the common nodes among the cluster so our scheme reduces the computational cost in the network under mobility condition. The results show that our proposed algorithm lowers the overhead in terms of computational costs, energy consumption, and delay.

This paper proposes an image encryption algorithm based on the combination of low-dimensional chaos and highdimensional chaos. Some key parameters are given by the encryption operator and the rest are obtained from the original image. These two parts constitute the complete key system of the encryption algorithm. The chaotic sequences generated by Logistic map and improved Logistic map are used to scramble the positions of the original image pixels. Two chaotic sequences generated by Lorenz system are used to diffuse the scrambled image. Simulation experiment shows that this algorithm has great encryption effect, large key space and strong key sensitivity and can effectively resist various attacks. Thus, it has high security and practicability

Cryptography can be considered as toolbox, where potential attackers have access to different computing resources and techniques to try and calculate key values. In a modern cryptography the strength of the cryptographic algorithm is nothing but the key size. So, our objective is to generate strong key value having minimum length of bits which will be useful in lightweight cryptography. Using Elliptic Curve Cryptography (ECC) with algebraic graph we are finding secret key value. ECC is itself a strong algorithm which generates pair of public and private We are generating secret key value with the help of above pair of key. Secret key parameters not shared in network so it will defense against man-in-middle attack. In this paper we are performing encryption and decryption process with mid-point of graph. This algorithm may be applicable for Smart card, Sensors and wireless network security.

A wireless sensor network (WSN) is a group of resource-constrained, inexpensive, tiny, and homogeneous or heterogeneous sensor nodes. The inherent nature of WSNs such that it makes them deployable in a variety of circumstances, which increases the interest towards them but at the same time poses tremendous challenges such as resource-constrained nodes, unattended operations, unknown topology and wireless communication links. Security in WSNs can be achieved with the help of various cryptographic operations. The strength of cryptographic system depends on the secrecy of the key it uses. So, a solid strong key management frame work is the prerequisite for the cryptographic primitive upon which other security primitives are built.To improve the energy efficiency and increase the resilience more effectively, an Energy Efficient Hierarchical Key management Protocol (EEHKMP) for hierarchical homogeneous WSN is proposed. In this protocol, a Differentiated random KPD (DKPD) process is employed for randomly deployed distributed WSN. Its main objective is to distribute different number of keys which are chosen randomly to different sensors in order to enhance the resilience of certain links such that the nodes can route through those links with higher resilience. This DKPD process divides the sensor nodes into different classes and pre-distributes the keys according to each class. Nodes with maximum residual energy and minimum distance are elected as cluster heads (CHs). The CH sets up the intra-cluster and inter-cluster routes with nodes having more shared keys. CH generates multiple random key shares to generate pair-wise key and transmits each key share to source and destination on each hop route, which is selected based on the cost function. Key shares are hop-by-hop encrypted / decrypted by a combination of all shared pre-distributed keys on that hop. Finally, a key update mechanism is presented to update the keys.

© 2013 IEEE. Image encryption is an efficient and vital way to protect classified and secret images. With the advancement of the processing power of the computer, AES, DES, or chaotic series type just alike image encryption schemes are not as secure as before. Therefore, in this paper, we present a new hybrid image encryption method for protecting secret and imperative images by employing logistic sine system (LSS) together with two-dimensional cellular automata and FSM-based DNA rule generator. The secure hash (SHA-256) algorithm is used to generate a secret key and to compute initial values for the LSS. In our proposed method, there are three stages and each stage has its own rule. After the scrambling process, the first stage is the Feistel structure-based bit inversion (FSBI) to change the pixels' value. The second stage is 2D-CA with Moore neighborhood structure-based local rules. The third is DNA conversion based on finite-state machine (FSM-DNA) rule generator. The proposed encryption scheme is robust against the well-known attacks, such as statistical attacks, brute force attacks, differential attacks, and pixel correlation attacks, and also possesses strong key sensitivity. The results show that our three-layer hybrid image encryption technique is robust against many well-known attacks and can be applied directly to all types of classified gray-scale images to make them more secure from such cryptography attacks.

Security and privacy of patients’ information remains a major issue of concern among health practitioners. Therefore, measures must be put in place to ensure that unauthorized individual do not have access to this information. However, the adoption of digital alternative of retrieving and documenting medical information has further opened it up to more attacks. This article presents a modified blowfish algorithm for securing textual and graphical medical information. The F-function used in generating round sub-keys was strengthened so as to produce a strong key that could resist differential attacks. Number of Pixel Change Rate (NPCR) and Unified Average Changing Intensity (UACI) of 98.85% and 33.65% revealed that the modified algorithm is sensitive to changes in its key and also resistive to differential attacks. Furthermore, the modified algorithm demonstrated a better encryption and decryption time than the existing blowfish algorithm.

Access control is an indispensable security component of cloud computing, and hierarchical access control is of particular interest since in practice one is entitled to different access privileges. This paper presents a hierarchical key assignment scheme based on linear-geometry as the solution of flexible and fine-grained hierarchical access control in cloud computing. In our scheme, the encryption key of each class in the hierarchy is associated with a private vector and a public vector, and the inner product of the private vector of an ancestor class and the public vector of its descendant class can be used to derive the encryption key of that descendant class. The proposed scheme belongs to direct access schemes on hierarchical access control, namely each class at a higher level in the hierarchy can directly derive the encryption key of its descendant class without the need of iterative computation. In addition to this basic hierarchical key derivation, we also give a dynamic key management mechanism to efficiently address potential changes in the hierarchy. Our scheme only needs light computations over finite field and provides strong key indistinguishability under the assumption of pseudorandom functions. Furthermore, the simulation shows that our scheme has an optimized trade-off between computation consumption and storage space.

Cryptography is not only a science of applying complex mathematics and logic to design strong methods to hide data called as encryption, but also to retrieve the original data back, called decryption. The purpose of cryptography is to transmit a message between a sender and receiver such that an eavesdropper is unable to comprehend it. To accomplish this, not only we need a strong algorithm, but a strong key and a strong concept for encryption and decryption process. We have introduced a concept of DNA Deep Learning Cryptography which is defined as a technique of concealing data in terms of DNA sequence and deep learning. In the cryptographic technique, each alphabet of a letter is converted into a different combination of the four bases, namely; Adenine (A), Cytosine (C), Guanine (G) and Thymine (T), which make up the human deoxyribonucleic acid (DNA). Actual implementations with the DNA don't exceed laboratory level and are expensive. To bring DNA computing on a digital level, easy and effective algorithms are proposed in this paper. In proposed work we have introduced firstly, a method and its implementation for key generation based on the theory of natural selection using Genetic Algorithm with Needleman-Wunsch (NW) algorithm and Secondly, a method for implementation of encryption and decryption based on DNA computing using biological operations Transcription, Translation, DNA Sequencing and Deep Learning.

Cryptography is one of the important and useful technique in which usually a particular file is converted into unreadable format by using public key and private key system called as public key cryptosystem. Then as per the user requirement that file is send to another user for secure data or file transmission between original sender and receiver. In this transmission file of unreadable format is send, after receiving this file receiver used the similar algorithm technique and private key for getting the original file data. In this procedure various algorithms are used as a processing function and depending on that algorithm, used the private key. The power or strength of any algorithm is depending on the secret key used in sender client and receiver side client. For this type of secure transmission we traditionally used RSA algorithm which is more secure for use so most of the system used the same type of algorithm for secure way of communication. Even most of the financial transaction is done by the use of this algorithm as it used the strong key while encryption and decryption. But In today‟s new digital world there is a numerous growth in the use of the Internet service. Behind every software generator there is lots of hacker present. So, very little amount of time will be enough to explore the security. Hence we require more strong and complex algorithms, which provide the security the Internet work of transmitting and receiving. So this proposed system enhanced the security of existing RSA algorithm by using elliptical curve cryptography (ECC) algorithm. This system secures the important data of the administrator and safely sends to the registered user by text encryption and image encryption. Also proposed system provide good authentication for the user.

This letter presents a new color image encryption scheme based on the coupled chaos maps. First, the algorithm uses the coupled logistic map to generate random strong key stream, and then designed a kind of initial simple diffusion-joint scrambling-combined diffusion method from the point of the relationships of components R, G, B. The simulation results indicate that this algorithm has stronger security compared with the independent encryption of each color component.

The cloud offers increased efficiencies and cost savings, and the US Federal Government has taken notice. A massive migration to commercial cloud services is underway, and it's no mean feat. It necessitates the creation and implementation of a migration strategy that moves selected new and legacy functions to cloud technology without disruption - and with maximum security.In the US, FedRAMP was created to make the cost-saving cloud migration for federal agencies both safe and hopefully stress-free. But IT admins must make a commitment to strong key management and effective monitoring of their encrypted networks in order to build on FedRAMP's foundation, says Matthew McKenna of SSH Communication Security.

A hierarchical key assignment scheme distribute some private information and encryption keys to a set of classes in a partially ordered hierarchy, so that the private information of higher classes can be employed to derive the keys of classes lower down in the hierarchy. A hierarchical key assignment scheme for dynamic structures allows to make dynamic updates to the hierarchy, such as addition, deletion and modification of classes and relations among them, as well as the revocation of users. In this work we analyze security notions for hierarchical key assignment schemes supporting dynamic structures. In particular, we first propose the notion of key recovery for those schemes. Furthermore, we extend to such schemes the strong key indistinguishability and strong key recovery security definitions proposed by Freire et al. for hierarchical key assignment schemes. Finally, we investigate the relations occurring between all the state-of-the-art security notions for hierarchical key assignment schemes supporting dynamic structures, showing implications and separations which hold between such notions. In detail, we prove that also in the case of dynamic structures, security with respect to strong key indistinguishability is equivalent to the one with respect to key indistinguishability.

A hierarchical key assignment scheme is a method to assign some private information and encryption keys to a set of classes in a partially ordered hierarchy, in such a way that the private information of a higher class can be used to derive the keys of all classes lower down in the hierarchy. In this paper we analyze the security of hierarchical key assignment schemes according to different notions: security with respect to key indistinguishability and against key recovery , as well as the two recently proposed notions of security with respect to strong key indistinguishability and against strong key recovery . We first explore the relations between all security notions and, in particular, we prove that security with respect to strong key indistinguishability is not stronger than the one with respect to key indistinguishability. Afterwards, we propose a general construction yielding a hierarchical key assignment scheme offering security against strong key recovery, given any hierarchical key assignment scheme which guarantees security against key recovery.

The access control problem in a hierarchy can be solved by using a hierarchical key assignment scheme , where each class is assigned an encryption key and some private information. A formal security analysis for hierarchical key assignment schemes has been traditionally considered in two different settings, i.e., the unconditionally secure and the computationally secure setting, and with respect to two different notions: security against key recovery (KR-security) and security with respect to key indistinguishability (KI-security), with the latter notion being cryptographically stronger. Recently, Freire, Paterson and Poettering proposed strong key indistinguishability (SKI-security) as a new security notion in the computationally secure setting, arguing that SKI-security is strictly stronger than KI-security in such a setting. In this paper we consider the unconditionally secure setting for hierarchical key assignment schemes. In such a setting the security of the schemes is not based on specific unproven computational assumptions, i.e., it relies on the theoretical impossibility of breaking them, despite the computational power of an adversary coalition. We prove that, in this setting, SKI-security is not stronger than KI-security, i.e., the two notions are fully equivalent from an information-theoretic point of view.

Data security has become an important issue in recent times. Confidential data needs to be protected from unauthorized users. Various image encryption techniques have been proposed for the secure transmission of images to protect the authenticity, integrity and confidentiality of images. Fractal images can be used as a strong key for the encryption due to the random and chaotic nature of fractals. The infinite boundaries of fractals provide highly complex structure that leads to confusion and it becomes a tedious task for an unauthenticated user to crack the exact secret fractal key. In this paper, a review of various techniques used for image encryption using fractal geometry has been illustrated. All these techniques have their own advantages and disadvantages in terms of execution time, key generation time and Peak Signal to Noise Ratio.

In this paper, Adomian decomposition method (ADM) with high accuracy and fast convergence is introduced to solve the fractional-order piecewise-linear (PWL) hyperchaotic system. Based on the obtained hyperchaotic sequences, a novel color image encryption algorithm is proposed by employing a hybrid model of bidirectional circular permutation and DNA masking. In this scheme, the pixel positions of image are scrambled by circular permutation, and the pixel values are substituted by DNA sequence operations. In the DNA sequence operations, addition and substraction operations are performed according to traditional addition and subtraction in the binary, and two rounds of addition rules are used to encrypt the pixel values. The simulation results and security analysis show that the hyperchaotic map is suitable for image encryption, and the proposed encryption algorithm has good encryption effect and strong key sensitivity. It can resist brute-force attack, statistical attack, differential attack, known-plaintext, and chosen-plaintext attacks.

The paper introduces a new secret data communication system that employs the usage of two state-of-the art cryptographic algorithms (RSA with asymmetric keys and AES with symmetric key) together with steganography. The joining of these three techniques builds a robust steganography-based communication system capable of withstanding multiple types of attacks, detection and reverse engineering. Our system was designed in a way that offers a solution to the major flaws presented in other steganographic communication systems [2][4][5][6]. The secret data is encrypted using AES with a strong key prior to being embedded using a steganographic algorithm [1]. The key used for the data encryption uses a combination between a random generated sequence and a hash of the cover image's color information that remains untouched throughout the entire embedding process. The secret data and the key used for encryption both pass multiple levels of security checks that assure the integrity, authenticity and security, making this a reliable communication channel for sensitive data. While all encryption stages assure that the secret data becomes obsolete without the proper decryption perquisites (keys), the steganographic algorithm introduces an additional level of security: stealth.