Ex-HABE with User Accountability for Secure Access Control in Cloud

Data outsourcing is becoming a useful and feasible paradigm with the rapid application of service-oriented technologies. Many researchers have tried combination of access control and cryptography to propose a model to protect sensitive information in this outsourcing scenario. However, these combinations in existing approaches have difficulty in key management and key distribution when fine-grained data access is required. Taking the complexity of fine-grained access control policy and the wide-reaching users of cloud in account, this issue would become extremely difficult to iron out. Various system models using attribute-based encryption (ABE) have been proposed however, most of them suffer from heavy overhead in implementing the access control policies. In this paper, a system is proposed with extended hierarchical attribute-based encryption (HABE) by using ciphertext-policy attribute-based encryption (ABE). It uses the hierarchical structure of users and bilinear mapping for generating the keys for various data handlers. Also the system focuses on user tracking by allocating an unique id to user. The system uses traitor tracing along with separation of duty made available by HABE and reduces the scope of key abuse. It is formally proved extended HABE with traitor tracing adds on to user accountability if user tracking for resource is maintained for hierarchical systems. DOI: 10.17762/ijritcc2321-8169.16042

Ciphertext Policy Attribute based Homomorphic Encryption (CP-ABHERLWE): a fine-grained access control on outsourced cloud data computation

Recently, homomorphic encryption is becoming one of the holy grail in modern cryptography research and serve as a promising tools to protect outsourced data solutions on cloud service providers. However, most of the existing homomorphic encryption schemes are designed to achieve Fully Homomorphic Encryption that aimed to support arbitrary computations for only single-data ownership scenario. To bridge these gaps, this paper proposed a non-circuit based Ciphertext Policy-Attribute Based Homomorphic Encryption (CP-ABHER-LWE) scheme to support outsourced cloud data computations with a fine-grained access control under the multi-user scenario. First, this paper incorporates Attribute Based Encryption (ABE) scheme into homomorphic encryption scheme in order to provide a fine grained access control on encrypted data computation and storage. Then, the proposed CP-ABHER-LWE scheme is further extended into non-circuit based approach in order to increase the practical efficiency between enterprise and cloud service providers. The result shows that the non-circuit based CP-ABHER-LWE scheme has greatly reduced the computation time and ciphertext size as compared to circuit based approach. Subsequently, the proposed CP-ABHER-LWE scheme was proven secure under a selective-set model with the hardness of Decision Ring-LWEd,q,ई problem

Directly revocable ciphertext-policy attribute-based encryption from lattices

Attribute-based encryption (ABE) is a promising type of cryptosystem achieving fine-grained access control on encrypted data. Revocable attribute-based encryption (RABE) is an extension of ABE that provides revocation mechanisms when user\u27s attributes change, key exposure, and so on. In this paper, we propose two directly revocable ciphertext-policy attribute-based encryption (DR-ABE) schemes from lattices, which support flexible threshold access policies on multi-valued attributes, achieving user-level and attribute-level user revocation, respectively. Specifically, the revocation list is defined and embedded into the ciphertext by the message sender to revoke a user in the user-level revocable scheme or revoke some attributes of a certain user in the attribute-level revocable scheme. We also discuss how to outsource decryption and reduce the workload for the end user. Our schemes are proved to be secure in the standard model, assuming the hardness of the learning with errors (LWE) problem

Robust Multiple Authority and ABE for Access Control in Cloud Computing

Data access control is a challenging issue in public cloud storage systems. Ciphertext-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

Fine-Grained Access Control Systems Suitable for Resource-Constrained Users in Cloud Computing

For the sake of practicability of cloud computing, fine-grained data access is frequently required in the sense that users with different attributes should be granted different levels of access privileges. However, most of existing access control solutions are not suitable for resource-constrained users because of large computation costs, which linearly increase with the complexity of access policies. In this paper, we present an access control system based on ciphertext-policy attribute-based encryption. The proposed access control system enjoys constant computation cost and is proven secure in the random oracle model under the decision Bilinear Diffie-Hellman Exponent assumption. Our access control system supports AND-gate access policies with multiple values and wildcards, and it can efficiently support direct user revocation. Performance comparisons indicate that the proposed solution is suitable for resource-constrained environment