IMPROVE AES ALGORITHM TO MAINTAIN DATA INTEGRITY USING THIRD PARTY AUDITING IN CLOUD COMPUTING

Abstract

Cloud computing is a new concept of Data processing .In cloud computing client are allowed to use variety of
IT services to large poll of computer resources , using the internet as a computation bus. In cloud computing all resources
are available in 24*7 hours, used on demand and paid according to use resource. It is a distributed computing, parallel
computing and grid computing development. Cloud storage is one of the service provided by Cloud computing in which
data is maintained, managed, backed up remotely and made available to users over a network (typically the Internet). The
user is concerned about the integrity of data stored in the cloud as the user’s data can be attacked or modified by outside
attacker. Therefore, a new concept called data auditing is introduced which check the integrity of data with the help of an
entity called Third Party Auditor (TPA). The purpose of this work is to develop an auditing scheme which is secure,
efficient to use and possess the capabilities such as privacy preserving, public auditing, maintaining the data integrity
along with confidentiality. Thus the new auditing scheme has been developed by considering all these requirements. It
consist of three entities: data owner, TPA and cloud server. The data owner performs various operations such as splitting
the file to blocks, encrypting them, generating a hash value for each, concatenating it and generating a signature on it.
The TPA performs the main role of data integrity check. It performs activities like generating hash value for encrypted
blocks received from cloud server, concatenating them and generates signature on it. It later compares both the signatures
to verify whether the data stored on cloud is tampered or not. It verifies the integrity of data on demand of the users. The
cloud server is used only to save the encrypted blocks of data. This proposed auditing scheme make use of AES-200bit
algorithm for encryption, Markel Hashing Tree and SHA-512 for integrity check and RSA signature for digital signature
calculation.