13-06-2012, 05:04 PM
Cloud Storage
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Abstract
Cloud computing is a internet based computing which enables
sharing of services. Many users place their data in the cloud, so
correctness of data and security is a prime concern. This work
studies the problem of ensuring the integrity and security of data
storage in Cloud Computing. Security in cloud is achieved by
signing the data block before sending to the cloud. Signing is
performed using BLS algorithm which is more secure compared
to other algorithms. To ensure the correctness of data, we consider
the task of allowing a third party auditor (TPA), on behalf of
the cloud client, to verify the integrity of the data stored in the
cloud. By utilizing public key based homomorphic authenticator
with random masking privacy preserving public auditing can be
achieved. The technique of bilinear aggregate signature is used to
achieve batch auditing. Batch auditing reduces the computation
overhead. As the data in the cloud is used by many industries,
modification of data cannot be avoided. Unlike most prior works,
the new scheme further supports secure and efficient dynamic
operations on data blocks, including: data update, delete and
append. We explore the efficient technique for error correction
called reed Solomon technique which ensures the correctness
of data.
Key words
Third Party Auditor, Boneh–Lynn–Shacham, Bilinear aggregate
signature, Reed Solomon technique.
I. Introduction
Cloud computing is a general term for anything that involves
delivering hosted services over the internet. These services are
broadly divided into three categories: Infrastructure-as-a-Service
(IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service
(SaaS). A cloud service has three distinct characteristics that
differentiate it from traditional hosting. It is sold on demand,
typically by the minute or the hour; it is elastic - a user can have
as much or as little of a service as they want at any given time
and the service is fully managed by the cloud service provider
(the consumer needs nothing but a personal computer and
Internet access).The advantage of cloud is cost savings. The
prime disadvantage is security. Cloud computing is used by many
software industries nowadays. Since the security is not provided
in cloud, many companies adopt their unique security structure.
For eg) Amazon has its own security structure. Introducing a
new and uniform security structure for all types of cloud is the
problem we are going to tackle in this paper. Since the data placed
in the cloud is accessible to everyone, security is not guaranteed.
To ensure security, cryptographic techniques cannot be directly
adopted. Sometimes the cloud service provider may hide the data
corruptions to maintain the reputation. To avoid this problem,
we introduce an effective third party auditor to audit the user’s
outsourced data when needed. The security is achieved by signing
the data blocks. Signing is performed using BLS algorithm. We
utilized public key based homomorphic authenticator with random
masking to achieve privacy preserving auditing protocol.TPA
performs the auditing task for each user i.e. single auditing.
This increases the auditing time and computation overhead. The
technique of Bilinear Aggregate Signature is used to achieve batch
auditing i.e.) multiple auditing tasks simultaneously. Earlier works
performs auditing only for static data. We enhance the system
with dynamic operations on data blocks i.e.) data update, append
and delete. Reed Solomon technique is a best error correction
technique which ensures the correctness of the data stored in cloud.
Our contribution in this paper is summarized as follows:
• We provide a privacy preserving auditing protocol i.e.
our scheme supports an external auditor to audit the users
outsourced data without learning knowledge on the data
content.
• Our scheme supports dynamic operations on data blocks i.e.
data update, append and delete.
• We perform a technique called Reed Solomon technique
which is a best error correction method.
A. Characteristics
Cloud computing is cost-effective. Here, cost is greatly reduced
as initial expense and recurring expenses are much lower than
traditional computing. Maintenance cost is reduced as a third
party maintains everything from running the cloud to storing
data. Cloud is characterized by features such as platform, location
and device independency, which make it easily adoptable for all