Attribute Based Encryption with Privacy Preserving In Clouds

Presented By:

Shrihari C S1CG11IS080

IntroductionExisting SystemSecure cloud storage modelProposed workSecure Hash AlgorithmPaillier AlgorithmConclusion

OVERVIEW

INTRODUCTIONA new decentralized access control schema.

Distributed access control so that only users with valid attributes can access them.

Support the creation, modification and reading the data stored in the cloud

EXISTING SYSTEMThe existing access control in cloud are

centralized in nature.

This scheme uses a symmetric key approach.

This approach does not support the authentication.

SECURE CLOUD STORAGE MODEL

PROPOSED WORK A. Creation of KDC

Create KDC

KDC Password

KDC Password

Add User

B. KDC AuthenticationKDC User

User Registration process

Data Stored in Database

C. Trustee and User Accessibility

Database

Request Token

User id

Trustee Verifying

Provide Token

D. Creation of access policy

Access policies

KDC

Cloud

Token

Creation of access policy

C

C

KDC

User Token

Public keyPrivate key

File Download

G. File Accessing

File Recovery Technique

Recovery File

Corrupted File

F. File Restoration

F. Secure Hash Algorithm

H. Paillier Algorithm

Key generationStep 1: Choose two large prime numbers p and q randomly and independently of each other such that  gcd (pq, (p-1)(q-1))=1. This property is assured if both primes are of equal length.

Step 2: Compute n=pq and λ=lcm(p-1,q-1).

Step 3: Select random integer g where gZ*n2.

Step 4: Ensure n divides the order of g by checking the existence of the following modular multiplicative inverse μ= (L(gλ mod n2))-1mod n. where function L is defined as L(u)= (u-1)/n.

Encryption

• Let m be a message to be encrypted where m Zn.• Select random r where r Z*n. • Compute cipher text as: c= ek (x; r ) = gm.rn mod n2

Decryption

• Cipher text: cZ*n2.• Compute message: m=dk(y)= (L(yλ mod n2 ))/((L(gλ

mod n2 )) mod n.

Contd …

CONCLUSION

• A decentralized access control technique with anonymous authentication.

• Provides user revocation.

• The cloud does not know the identity of the user who stores information, but only verifies the user’s credentials.

• One limitation is that the cloud knows the access policy for each record stored in the cloud.

Future WorkIn future, using SQL queries for hide the

attributes and access policy of a user.

Files stored in cloud can be corrupted. So for this issue using the file recovery technique to recover the corrupted file successfully and to hide the access policy and the user attributes

THANK YOU