By,

S.Kayalvizhi Sharmila

PRIVACY-PRESERVING PUBLIC AUDITING FOR

DATA STORAGESECURITY IN CLOUD

COMPUTING

ABSTRACT

Cloud Computing, enabling convenient network access to a shared pool of configurable computing resources

Enabling public auditability, so that users can resort to an external audit party to check the integrity of outsourced data when needed.

TPA audit the cloud data storage without demanding the local copy of data, and introduce no additional on-line burden to the cloud user.

OUR CONTRIBUTION

The scheme supports an external auditor to audit user’s outsourced data in the cloud without learning knowledge on the data content.

Achieves batch auditing where multiple delegated auditing tasks from different users can be performed simultaneously by the TPA.

To prove the security and justify the performance of proposed schemes through concrete experiments and comparisons with the state-of-the-art.

THIRD PARTY AUDITOR (TPA)

Third Party Auditor (TPA) TPA helps the user to audit the data To allow TPA securely: 1) TPA should audit the data from the cloud, not ask

for a copy 2) TPA should not create new vulnerability to user

data privacy This paper presents a privacy-preserving public

auditing system for cloud data storage

Cloud network

Data use

r

user

user

External Audit party

ARCHITECTURE

DESIGN GOALS

I. Public auditabilityII. Storage correctnessIII. Privacy-preservingIV. Batch auditingV. Lightweight

THE EXISTING SYSTEM

THE PROPOSED SCHEME

We utilize the public key based homomorphic authenticator and uniquely integrate it with random mask technique.

TPA can perform multiple auditing tasks simultaneously.

Four algorithmsKeyGen, SigGen, GenProof, VerifyProof.

FIG: PROPOSED SYSTEM

PRIVACY-PRESERVING PUBLIC AUDITING MODULE:

Homomorphic authenticators are unforgeable verification metadata.

Block 1 Block 2 Block k…

Verification Metadata

Verification Metadata

Verification Metadata

Aggregate Verification Metadata

A linear combination of data blocks can be verified by looking only at the aggregated authenticator

Homomorphic authenticator

11

Setup

Audit

user KeyGen

Public & Secretparameters

SigGen File F

Verification Metadata

TPA

TPA issues an audit message or a challenge to CSP

GenProof

VerifyProof

CSP

TPA

File F

Response message

Verification Metadata

Phases

MORE EXTENSIONS

Batch auditing There are K users having K files on the same cloud They have the same TPA Then, the TPA can combine their queries and save in

computation time The comparison function that compares the aggregate

authenticators has a property that allows checking multiple messages in one equation

Instead of 2K operation, K+1 are possible

Data dynamics The data on the cloud may change according to applications This is achieved by using the data structure Merkle Hash

Tree (MHT) With MHT, data changes in a certain way; new data is added

in some places There is more overhead involved ; user sends the tree root

to TPA

CONCLUSION

Utilizing the homomorphic authenticator and random mask technique to guarantee that TPA would not learn any knowledge about the data content

Considering TPA may concurrently handle multiple audit sessions from different users for their outsourced data files

Thank You