Cloud Security Framework Using Enhanced Certificate less Elliptic Curve Cryptography and Attribute Based Access Control

Abstract

Data security is one of the major challenges in storing sensitive information over the cloud. The attacks on cloud are increasing at a higher rate in this advanced technology era. The existing cloud storage security services mostly uses symmetric key encryption schemes that requires the exchange of secret keys which may be vulnerable to third party attacks. Public Key Cryptosystems (PKC) with certified keys for cloud storage possess the risk of certification authority getting compromised and also demands the public key of the data user to be known in prior to data owner for encrypting the data. Certificateless encryption combined with proper authorization and authentication methods are considered more efficient in sharing encrypted data to multiple users. Ciphertext Policy Attribute Based Encryption (CPABE) allows access to encrypted data based on attributes of users by employing complex access control over encrypted data. Pairing operations involved in Attribute Based Encryption (ABE) incurs high computational cost. newlineThis work focuses on developing a pairing free cryptographic algorithm as an alternative to ABE for secure cloud storage. The proposed cloud storage security framework comprises of data owner who has to encrypt the plain text and build the access control policy, attribute authority which is a trusted agent of data owner that stores attribute-based access control policy for key generation and to limit the access to legitimate users, cloud storage for storing encrypted data and the data users. The major focus is to develop enhanced encoding scheme in Elliptic Curve Cryptography (ECC) and enhanced access control mechanism built on Reduced Ordered Binary Decision Diagram (ROBDD) supported by cryptographically secure pseudorandom secrets for key generation. The proposed mapping scheme in ECC included conversions of plain text along with scalar multiplication over defined generator point G of chosen elliptic curve. newlineThe enhanced mapping scheme is secure under the discrete logarithm hard