In Otherwise data owner need to update the key.

In the proposed system,
uses a concept called revocable-storage identity-based encryption (RS-IBE) for
building a cost-effective data sharing system which can provide the data
confidentiality and  forward/backward
security of cipher text by introducing the functionalities of user revocation
and cipher text update simultaneously. The data provider decides the user group
who can access the data before uploading them in the cloud storage. The
encrypted data can be decrypted by only those users who is non revoked
(authorization not expired).This system uses KUNodes algorithm to restrict
revoked user at a time period from decrypting the cipher text. Inputs to the
KUNodes algorithm is the revocation list and the time period. It outputs the
smallest subset Y of nodes of BT such that Y contains an ancestor for each node
that is not revoked before the time period t.

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1. Data owner upload the
file in cloud with validity time              

2. Data user access the
data.

2.1. If the user tries
to access the data within a specified time only he is able to access the data

2.2. Otherwise data
owner need to update the key.   

3. Data owner update the
key used by the user.           

4. Then he will update
the cipher text. This will provide both forward and backward security to the
data stored in a cloud

The LCD TFT display is
interfaced through GPIO pins and Bluetooth dongle is interfaced through USB
port of raspberry pi.

 

 

 

 

V.IMPLEMENTATION

For developing
secure data sharing in cloud using RSIB encryption,we use NetBeans as the
environment. We use Java as the language for developing our software. For
storing the details we use Microsoft SQL Server. It is
also a Microsoft product which acts as database. Implementation of RS-IBE
system consist of 4 modules namely data provider module, user group, key
provider and storage server. User module is for user. It contains user
registration, login, upload file, download file. It also contains AES
encryption. The user (data provider) can register by entering user name,
email-id, password, confirm password, mobile number. User (data provider) can
login by entering the user name and password which was already registered.
After login user can view a form which have the following tabs-action, start,
stop, restart, upload, add user. By clicking the upload button, upload text and
upload multimedia options. For uploading a multimedia click on the browse tab select
the file from directory, enter the file name and click the upload button. After
successfully uploading the file, the file get encrypted and store in storage
media(cloud). When clicking add user tab, data provider can add user group
whose which the data provider had wish to see the uploaded data. The user can
change password by filling the change password form which contains current
password, new password, confirm password. The uploaded file by the client is
encrypted and decrypted using AES algorithm,user revocation is performed by
using KU Nodes algorithm.

KUNode algorithm

1 KUNodes(BT, RL,
t) 1: X,Y???

2: for all
(?i,ti)?RL do

3: if ti?t then

4: Add Path(?i)
to X

5: end if

 6: end for

7: for all ??X do

8: if ?l?/X then

 9: Add ?l to Y

10: end if

11: if ?r?/X then

12: Add ?r to Y

13: end if

14: end for

15: if Y=? then

16: Add the root
node ? to Y

17: end if

18: returnY