Reliable access control is a major challenge of cloud storage services. This paper presents a cloud-based file-sharing architecture with ciphertext-policy attribute-based Encryption (CP-ABE) access control mechanism. In CP-ABE, the data owner can specify the ciphertext access structure, and if the user key satisfies this access structure, the user can decrypt the ciphertext. The trusted authority embeds the private key of each attribute in a so-called attribute access polynomial and stores its coefficients publicly on the cloud. By means of the access polynomial, each authorized user will be able to retrieve the private key of the attribute by using her/his owned pre-shard key. In contrast, the data owner encrypts the file with a randomly selected key, namely the cipher key. The data owner encrypts the cipher key by CP-ABE scheme with the desired policies. Further, the data owner can create a different polynomial called query access polynomial for multi-keyword searching. Finally, the data owner places the encrypted file along the encrypted cipher key and query access polynomial in the cloud. The proposed scheme supports fast attribute revocation using updating the corresponding access polynomial and re-encrypting the affected cipher keys by the cloud server. Moreover, most of the calculations at the Decryption and searching phases are outsourced to the cloud server, thereby allowing the lightweight nodes with limited resources to act as data users. Our analysis shows that the proposed scheme is both secure and efficient.

This paper mainly focused on implementation of AES Encryption and Decryption standard AES-128. All the transformations of both Encryption and Decryption are simulated using an iterative design approach in order to minimize the hardware consumption. This method can make it a very low-complex architecture, especially in saving the hardware resource in implementing the AES InverseSub Bytes module and Inverse Mix columns module. As the S -box is implemented by look-up-table in this design, the chip area and power can still be optimized. The new Mix Column transformation improves the performance of the inverse cipher and also reduces the complexity of the system that supports the inverse cipher. As a result this transformation has relatively low relevant diffusion power. This allows for scaling of the architecture towards vulnerable portable and cost-sensitive communications devices in consumer and military applications.

One of the most important technologies that has affected our lives today is cyberspace. On the other hand, one of the most important problems of social networks is the disclosure of users' information, i.e. the violation of their privacy. Therefore, protecting the privacy of users is very important, so the use of Encryption methods is an important tool in ensuring the privacy and security of shared data users. The proposed framework of this paper is based on AES and RSA algorithms. This framework is designed to be decentralized and takes advantage of the AES and RSA algorithms to provide a framework that prevents unauthorized entities from accessing users' data and messages. Any safe method must be designed in such a way that there is no escape route for attackers and unauthorized entities. Therefore, our focus is on two important parts of secure methods, namely key management and privacy, which the results of this article show, the security assessment proved that our proposed framework is designed to be completely safe and correct, and increased security and efficiency.

With the development of the internet and social networks, the multimedia data, particularly digital images, has been of increasing interest to scientists. Due to their advantages including high speed, high security, and complexity, chaotic functions have been broadly employed in image Encryption. The present paper proposed a modified logistic map function which resulted in higher scattering in the obtained results. Confusion and diffusion functions, as the two main actions in cryptography, are not necessarily performed in order, i. e. each of these two functions can be applied on the image in either order, provided that the sum of total functions does not exceed 10. So, to calculate the sum of functions, confusion has the factor of 1 and diffusion has the factor of 2. To simulate this method, a binary stack was used. Application of binary stack and pseudo-random numbers obtained from the modified chaotic function increased the complexity of the proposed Encryption algorithm. The security key length, entropy value, NPCR and UACI values, and correlation coefficient represented in the analytical results revealed the capability and validity of the proposed method. Analyzing the obtained results and comparing the algorithm to other investigated methods clearly verified high efficiency of the proposed method.

Abstract This paper proposes a new plaintext-related mechanism based on plaintext Encryption.  For simplicity, PCODE was proposed as the image Encryption code. The original picture was encoded to get the proposed Encryption and plaintext Encryption with a chaotic sequence to control the PCODE rules. Another chaotic sequence was encoded into a PCODE sequence for the PCODE XOR operation. The remaining two chaotic sequences were then processed with the proposed scheme to get two key streams for the permutation phase. The cipher image was obtained after the conventional permutation and PCODE XOR operations. The use of the proposed plaintext Encryption leads to the correlation between the keystreams used in the displacement phase and both the secret key and the plaintext image. This correlation increases the sensitivity and security of the Encryption system with respect to the plaintext. The experimental findings from simulation show that the proposed Encryption system shows significant efficiency and security.

In this research paper, we will present how to hide confidential information in a color image randomly using a mathematical equation; by apply this equation to the number of image bytes after converting the image into a digital image, the number of randomly selected bytes depends on the length of the secret message. After specifying the bytes, we include the secret message in those selected bytes utilizing least significant bit (LSB) of steganography, and return the new bytes in the same place in the original image by using the same mathematical equation, after the hiding process using steganography, and then we encrypt the image and send it to the recipient. Several statistical measures applied to the original image, compared with the image after embedding, and after the image encrypted. The results obtained are very good. The statistical measures were used the histogram, mean square error (MSE) and the peak signal to noise ratio (PSNR).The system is designed to perform these processes, which consists of two stages, hiding stage and extract stage. The first stage contains from four steps, the first step of this stage reading the image and converting it to a digital image and make an index on each byte of the image bytes and the application of the mathematical equation to select the bytes by randomly, second step is the process of hiding the secret message in selected bytes and return those bytes to the original locations, third step is the calculation of the statistical measures to determine the rate of confusion after the inclusion of the confidential message, fourth step to encrypt the image of the message carrier and measure the rate of confusion after the Encryption and compare with the original image. The extraction process consists of three steps, the first step is to use the private key to decrypt, and the second step is to apply the same mathematical equation to extract the embedded bytes of the confidential message, third step use the same method of hiding the information and extracting the confidential message.