Abstract
In this paper we propose N-Cloud scheme which improves performance, availability, and confidentiality in cloud storage. N-Cloud provides availability by dividing/splitting a file into many chunks, and replicating in a non-overlapping manner these chunks into many cloud storages, based on security and reliability consideration. In this scheme, the chunks of a file can be encrypted concurrently while the encrypted chunks can be uploaded to geographical separated cloud storages in parallel. Same benefit can be achieved for the downloading and decrypting process. It greatly speeds up the processing and transfer. N-Cloud provides confidentiality by dividing/splitting a file into many chunks, encrypting all chunks, and distributing these chunks to many clouds. N-Cloud ensures that no one cloud has the whole file; the scheme will not be compromised unless an attacker breaks into all cloud storage. A preliminary results show significant performance improvement over existing schemes.