A Secure Erasure Code-Based Cloud Storage System with Secure Data Forwarding

Abstract

Cloud system consisting of a collection of storage servers, provides long-term storage services. Storing data in a third party’s cloud system causes serious concern over data confidentiality. General encryption schemes protect data confidentiality. But also limit the functionality of the storage system because a few operations are supported over encrypted data. Constructing a secure storage system that supports multiple functions is challenging when the storage system is distributed and has no central authority. I propose a threshold proxy re-encryption scheme and integrate it with a decentralized erasure code such that a secure distributed storage system is formulated. The distributed storage system not only supports secure and robust data storage and retrieval, but also lets a user forward his data in the storage servers to another user without retrieving the data back. The main technical contribution is that the proxy re-encryption scheme supports encoding operations over encrypted messages as Ill as forwarding operations over encoded and encrypted messages. My method fully integrates encrypting, encoding, and forwarding. I analyze and suggest suitable parameters for the number of copies of a message dispatched to storage servers. The number of storage servers queried by a key server.

Existing System

In straightforward integration method Storing data in a TA’s cloud system causes serious concern on data confidentiality. To provide confidentiality for messages in storage servers, a user encrypt messages by a cryptographic method before applying an erasure code method and store messages. When use message, we retrieve the Code word symbols from storage servers, decode it. Then decrypt them by using cryptographic keys. General encryption schemes protect data confidentiality. Limit functionality of storage system, few operations are supported over encrypted data. A decentralized architecture for storage systems offers good scalability. Storage servers join or leave without control of a central authority.

Proposed System

I address the problem of forwarding data to another user by storage servers directly. I consider the system model that consists of distributed storage servers and key servers. Storing cryptographic keys in a single device is risky; User distributes cryptographic key to key servers. These key servers are highly protected by security mechanisms. The distributed systems require independent servers to perform all operations. A new threshold proxy re-encryption scheme integrates with a secure decentralized code to form a secure distributed storage system. The encoding operations encrypted messages and forwarding operations encrypted and encoded messages.

Architecture

System Flow Diagram