In this paper, we leverage multi-cloud storage systems to provide data confidentiality against an adversary which has access to the encryption key, and can compromise a large fraction of the storage servers. For this purpose, we first introduce a novel security definition that captures data confidentiality in the new adversarial model. | ISSN: 2249-5789 P Subhadra Devi et al, International Journal of Computer Science & Communication Networks,Vol 8(4),25-31 Secure Cloud Data Storage with Efficient Key Exposure P. Subhadra Devi M. Tech, Department of CSE, Shri Vishnu Engineering College for Women (A), Vishnupur, Bhimavaram, West Godavari District, Andhra Pradesh. Dr. P. Kiran Sree . Professor Department of CSE Shri Vishnu Engineering College for Women (A), Vishnupur, Bhimavaram, West Abstract— The world just witnessed the surge of a new adversarial model. We then propose Bastion, a new and powerful attacker, which was able to coerce primitive that is secure according to our definition operators and acquire the necessary keys to break the and, therefore, guarantees data confidentiality even privacy of users. Once the encryption key is exposed, when the encryption key is exposed, as long as the the data adversary cannot compromise all storage servers. We confidentiality is to limit the adversary’s access to the analyze the security of Bastion, and we evaluate its ciphertext. This may be achieved, for example, using performance multi-cloud storage systems. These systems spread implementation. data only viable across measure multiple to servers preserve in different administrative domains, to cater for availability and fault tolerance. If the adversary can only compromise a subset of these domains, multi-cloud storage systems may prevent the adversary from accessing Godavari District, Andhra Pradesh. by means of a prototype Keywords— Key exposure, cryptography, Security, Data confidentiality. 1 Introduction the entire ciphertext. However, if data is encrypted The world became aware of a massive surveillance using existing encryption schemes, spreading the program which mined data from operators and ISPs, ciphertext on multiple servers does not entirely solve and performed illegal taps on digital communication the problem since an adversary which has .
