Reliable re-encryption in unreliable clouds

Abstract-A key approach to secure cloud computing is for the data owner to store encrypted data in the cloud, and issue decryption keys to authorized users. Then, when a user is revoked, the data owner will issue re-encryption commands to the cloud to re-encrypt the data, to prevent the revoked user from decrypting the data, and to generate new decryption keys to valid users, so that they can continue to access the data. However, since a cloud computing environment is comprised of many cloud servers, such commands may not be received and executed by all of the cloud servers due to unreliable network communications. In this paper, we solve this problem by proposing a timebased re-encryption scheme, which enables the cloud servers to automatically re-encrypt data based on their internal clocks. Our solution is built on top of a new encryption scheme, attributebased encryption, to allow fine-grain access control, and does not require perfect clock synchronization for correctness

Implementing RAAC Model for Cloud Storage

Data access control is a challenging issue in public cloud storage systems. Cipher text-Policy Attribute-Based Encryption (CP-ABE) has been adopted as a promising technique to provide flexible, fine-grained and secure data access control for cloud storage with honest-but curious cloud servers. However, in the existing CP-ABE schemes, the single attribute authority must execute the time-consuming user legitimacy verification and secret key distribution, and hence it results in a single-point performance bottleneck when a CP-ABE scheme is adopted in a large-scale cloud storage system. Users may be stuck in the waiting queue for a long period to obtain their secret keys, thereby resulting in low-efficiency of the system. Although multi authority access control schemes have been proposed, these schemes still cannot overcome the drawbacks of single-point bottleneck and low efficiency, due to the fact that each of the authorities still independently manages a disjoint attribute set. In this paper we propose a system that improves the approach of CP-ABE from text based asymmetric to Image based symmetric approach for faster encryption as well as access to data. We also propose a multiple access policy generation for single user where we will be able to implement one to many and many to many methodology

Re-Encryption Scheme for Providing Data Security in Clouds

Cloud computing is the trendy topic all over the world. With increase in popularity of cloud computing, more and more enterprises will outsource their sensitive data for sharing in a cloud. Cloud computing allows the users to share the data among the members of cloud. One of the issue in cloud computing is data security. Here the problem is whenever a user is revoked from cloud the data owners will send re-encryption command to cloud in order to re-encrypt the data so that the data is prevented from revoked users. In this paper, we propose a time-based re-encryption scheme using blowfish algorithm. This scheme allows the cloud to automatically re-encrypt the data based on the internal clock, users can access data within given time period, after time period get over user cannot access data, this scheme also prevents the revoked users from decrypting the data using their old decryption keys

Designing Security Model for Un-Reliable Cloud IAAS Storage

With the internet getting so popular data sharing and security of personal data has gain much more importance than before. Cloud provides and efficient way to outsource the data either online or offline but data security becomes one of the major issues in unreliable cloud environment. The proposed system addresses the security issues in cloud environment and also provides a way to provide better security and load balancing in cloud environment. The proposed system uses cryptographic symmetric algorithm AES with key size of 256 for data encryption and Ultra Zip compression which provides a compression ratio up to 50% depending on the file type. After encryption and compression the data is splitted into multiple parts and each part is stored in separate data server. The proposed work can be used in many different application like social networking sites and file hosting websites

Load Balancing By Cloud Computing

With the internet getting so popular data sharing and security of personal data has gain much more importance than before. Cloud provides and efficient way to outsource the data either online or offline but data security becomes one of the major issues in unreliable multi-cloud environment. This paper addresses the issues in multi-cloud environment and also provides a way to provide better security in multi-cloud environment. Further it discusses the different encryption algorithms that can be used to maintain a design framework for cloud environment

Novel Proposed Work for Empirical Word Searching in Cloud Environment

People's lives have become much more convenient as a result of the development of cloud storage. The third-party server has received a lot of data from many people and businesses for storage. Therefore, it is necessary to ensure that the user's data is protected from prying eyes. In the cloud environment, searchable encryption technology is used to protect user information when retrieving data. The versatility of the scheme is, however, constrained by the fact that the majority of them only offer single-keyword searches and do not permit file changes.A novel empirical multi-keyword search in the cloud environment technique is offered as a solution to these issues. Additionally, it prevents the involvement of a third party in the transaction between data holder and user and guarantees integrity. Our system achieves authenticity at the data storage stage by numbering the files, verifying that the user receives a complete ciphertext. Our technique outperforms previous analogous schemes in terms of security and performance and is resistant to inside keyword guessing attacks.The server cannot detect if the same set of keywords is being looked for by several queries because our system generates randomized search queries. Both the number of keywords in a search query and the number of keywords in an encrypted document can be hidden. Our searchable encryption method is effective and protected from the adaptive chosen keywords threat at the same time

Algorithm-Based Secure and Fault Tolerant Outsourcing of Matrix Computations

page number : 7 , Extended abstractWe study interactive algorithmic schemes for outsourcing matrix computations on untrusted global computing infrastructures such as clouds or volunteer peer-to-peer platforms. In these schemes the client outsources part of the computation with guaranties on both the inputs' secrecy and output's integrity. For the sake of efficiency, thanks to interaction, the number of operations performed by the client is almost linear in the input/output size, while the number of outsourced operations is of the order of matrix multiplication. Our scheme is based on efficient linear codes (especially evaluation/interpolation version of Reed-Solomon codes). Confidentiality is ensured by encoding the inputs using a secret generator matrix, while fault tolerance is ensured together by using fast probabilistic verification and high correction capability of the code. The scheme can tolerate multiple malicious errors and hence provides an efficient solution beyond resilience against soft errors. These schemes also allow to securely compute multiplication of a secret matrix with a known public matrix. Under reasonable hypotheses, we further prove the non-existence of such unconditionally secure schemes for general matrices