compltedoc.docx

7/23/2019 compltedoc.docx

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CHAPTER 1

INTRODUCTION

1.1 OVERVIEW

A computer network is a collection of computersand other hardwarecomponents

interconnected by communication channels that allow sharing of resources and

information. Where at least one process in one device is able to send or receive data to and from

at least one process residing in a remote device, then the two devices are said to be in a network.

Simply, more than one computer interconnected through a communication medium for

information interchange is called a computer network.

1.2 CLOUD COMPUTING

Cloud computing is the use of computingresources i.e hardware and software that are

delivered as a service over a networktypically the Internet. Cloud computing entrusts remote

services with a user's data, software and computation. sing software as a service, users also rent

application software and databases. !he cloud providers manage the infrastructure and platforms

on which the applications run. "nd users access cloud#based applications through a web

browseror a light#weight desktop or mobile appwhile thebusiness softwareand user's data are

user's data are stored on servers at a remote location.

$ig.% Cloud Computing &verview

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1.3 SERVICE MODELS

$ig. Service (odel

1.4 ISSUES

)rivacy

Compliance

*egal

&pen source

&pen Standards Security

Sustainability

Abuse

I! governance

1.5 SECURITY

As cloud computing is achieving increased popularity, concerns are being voiced about

the security issues introduced through adoption of this new model. !he relative security of cloud

computing services is a contentious issue that may be delaying its adoption. )hysical control of

the )rivate Cloud e+uipment is more secure than having the e+uipment off site and under

someone elses control. Issues barring the adoption of cloud computing are due in large part to

the private and public sectors' unease surrounding the e-ternal management of security#based

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services. It is the very nature of cloud computing#based services, private or public, that promote

e-ternal management of provided services. !his delivers great incentive to cloud computing

service providers to prioritie building and maintaining strong management of secure services.

Securi! i""ue" #$%e &ee' c$e()ri*e+ i')

sensitive data access

data segregation

privacy

bug e-ploitation

recovery

accountability

malicious insiders

management console security

account control

multi#tenancy issues.

S),ui)'" ) %$ri)u" c,)u+ "ecuri! i""ue"

)ublic /ey Infrastructure 0)/I1

!o use multiple cloud providers

Standardiation of A)Is

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Improving virtual machine support and legal support.

CHAPTER 2

LITERATURE SURVEY

2.1 SECURITY ISSUES

2ata security and access control is one of the most challenging ongoing research work in

cloud computing, because of users outsourcing their sensitive data to cloud providers. "-isting

solutions that use pure cryptographic techni+ues to mitigate these security and access control

problems suffer from heavy computational overhead on the data owner as well as the cloud

service provider for key distribution and management. )roblems of access control in cloud

computing includes the mechanism to distribute decryption key, number of users may become

large and solution is not efficient345

In distributed systems users need to share sensitive ob6ects with others based on the

recipients ability to satisfy a policy. Attribute#7ased "ncryption 0A7"1 385 is paradigm where

such policies are specified and cryptographically enforced in the encryption algorithm itself. !he

drawbacks include the threshold lacks e-pressibility, fle-ibility .7oth cipher te-t and decryption

keys are associated with set of attributes.395

2.2 CIPHERTE-T POLICY AE

Cipher te-t#)olicy A7" 0C)#A7"1 3%:5 is a form of A7" where policies are associatedwith encrypted data and attributes are associated with keys. ser attributes are represented in

keys. !he advantage includes the user who can see the message content can decrypt in absence of

group keys, It save the cost to distribute group keys. !his scheme suffered with the ma6or

drawback of lacking in updating efficiency, if any changes made to the attribute the private key

associated with the attribute should also be changed .3%:5

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C)#AS7" a new form of C)#A7" which, unlike e-isting C)#A7" schemes that

represent user attributes as a monolithic set in keys, organies user attributes into a recursive set

based structure and allows users to impose dynamic constraints on how those attributes may be

combined to satisfy a policy. Specifically C)#AS7" allows user attributes to be organied into a

recursive family of sets and policies that can selectively restrict decrypting users to use

attributes from within a single set or allow them to combine attributes from multiple sets. !hus

by grouping user attributes into sets such that those belonging to a single set have no restrictions

on how they can be combined.

2.3 /EY POLICY ATTRIUTE ASED ENCRYPTION

/ey )olicy Attribute 7ased "ncryption 0/)#A7"1 3%95 Cipher te-t is associated with set

of attributes where the decryption key is associated with tree access structure. Interior nodes ofthe access tree are threshold gates and leaf nodes are associated with attributes. ser secret key is

defined to reflect the access structure so that the user is able to decrypt cipher te-t if and only if

the data attributes satisfy his access structure.

A /)#A7" scheme is composed of four algorithms

Seu0 !his algorithm takes as input a security parameter and the attribute universe

; of cardinality =. It defines a bilinear group ?% of prime order p with a generator

g ,a bilinear map e @ ?% ?% B ? which has the properties of bilinearity, computability, and

non#degeneracy .It returns the public key )/ as well as a system master key.

(/ as follows

)/ ; 0, !%, !, . . . , !=1

(/ ; 0y, t%, t, . . . ,t=1

While )/ is publicly known to all the parties in the system, (/ is kept as a secret by the

authority party.

E'cr!0i)' !his algorithm takes a message (, the public key )/, and a set of attributes I as

input. It outputs the cipher te-t

/e! Ge'er$i)' !his algorithm takes as input an access tree !, the master key (/, and the

public key )/. It outputs a user secret key S/ as follows. !hen it outputs S/ as follows.

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S/ "ii2L

where * denotes the set of attributes attached to the leaf nodes of ! and ski ; gpi0:1ti .

Decr!0i)' !his algorithm takes as input the cipher te-t " encrypted under the attribute set I,

the users secret key S/ for access tree !, and the public key )/. It first computes

e6Ei7 "i8 e6(7(80i698"for leaf nodes. !hen, it aggregates these pairing results in the bottom#up

manner using the polynomial interpolation techni+ue. $inally, it may recover the blind factor

Y " e6(7 (8!" and output the message ( if and only if I satisfies !.

!his is an enhanced /)#A7" scheme which supports user secret key accountability.35

2.4 :U;;Y IDENTITY ASED ENCRYPTION

$uy Identity 7ased "ncryption $rom *attices 3D5 ,In constructing a $uy Identity

7ased "ncryption 0$uy I7"1 scheme based on lattices. A fuy I7" scheme is e-actly like an

identity#based encryption scheme e-cept that cipher te-t encrypted under an identity id enccan be

decrypted using the secret key corresponding to any identity iddec that is Eclose enoughF to idenc.

"-amples arise when using one's biometric information as the identity, but also in general access

control systems that permit access as long as the user satisfies a certain number of conditions.

!he construction is secure in the selective security model under the learning with errors 0*W"1

secure under the worst#case hardness of Eshort vector problemsF on arbitrary lattices. "-tended

the construction to handle large universes ,and to resist chosen cipher te-t 0CCA1 attacks 3D5

2.5 IDENTITY ASED ENCRYPTION

Identity 7ased "ncryption 0I7"13%G5 is an important primitive ofI2#based cryptography.

As such it is a type ofpublic#key encryptionin which thepublic keyof a user is some uni+ue

information about the identity of the user 3%45. !his can use the te-t#value of the name or domain

name as a key or the physical I) address it translates to. !he first implementation of an email#

address based )/I was developed by Adi Shamirin %HD which allowed users to verify digital

signaturesusing only public information such as the user's identifier. Je was however only able

to give an instantiation ofidentity#based signatures. It includes the ma6or advantages of any

identity#based encryption scheme is that if there are only a finite number of users, after all users

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have been issued with keys the third party's secret can be destroyed 3%G5 .!his can take place

because this system assumes that, once issued, keys are always valid .

!he obtained drawback is if a )rivate /ey ?enerator 0)/?1 3%5 is compromised, all

messages protected over the entire lifetime of the public#private key pair used by that server are

also compromised. !his introduces a key#management problem where all users must have the

most recent public key for the server. 7ecause the )rivate /ey ?enerator 0)/?1 generates

private keys for users, it may decrypt andKor sign any message without authoriation. !his

implies that I7" systems cannot be used for non#repudiation I7" solutions may rely on

cryptographic techni+ues that are insecure against code breaking +uantum computerattacks .

2.< HIERARCHICAL IDENTITY ASED ENCRYPTION

Jierarchical Identity 7ased "ncryption 0JI7"1 3H5 system where the cipher te-t consists

of 6ust three group elements and decryption re+uires only two bilinear map computations,

regardless of the hierarchy depth. "ncryption is as e cient as in other JI7" systems. !heffi

scheme is selective#I2 secure in the standard model and fully secure in the random oracle model.

!his system has a number of applications, it gives very e cient forward secure public key andffi

identity based cryptosystems, it converts the ==* broadcast encryption 3H5 system into an

e cient public key broadcast system, and it provides an e cient mechanism for encrypting toffi ffi

the future. !he system also supports limited delegation where users can be given restricted

private keys that only allow delegation to bounded depth. !he JI7" system can be modiLed to

support sublinear sie private keys at the cost of some cipherte-t e-pansion.3H5

2.= HIERARCHICAL ATTRIUTE ASED ENCRYPTION

In Jierarchical Attribute 7ased "ncryption 395 to keep the shared data confidential

against untrusted cloud service providers , a natural way is to store only the encrypted data in a

cloud. !he key problems of this approach include establishing access control for the encrypted

data, and revoking the access rights from users when they are no longer authoried to access the

encrypted data. !his approach solves both problems.395 !he hierarchical attribute#based

encryption scheme is introduced by combining a hierarchical identity#based encryption system

and a cipherte-t#policy attribute#based encryption system, so as to provide not only fine#grained

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access control, but also full delegation and high performance.It provides the scalable revocation

scheme by applying pro-y re#encryption and lay re#encryption to the JA7" scheme, so as to

efficiently revoke access rights from users.395

$ine#grained access control systems 35 facilitate granting differential access rights to a

set of users and allow fle-ibility in specifying the access rights of individual users. Several

techni+ues are known for implementing fine grained access control.Common to the e-isting

techni+ues and the references therein is the fact that they employ a trusted server that stores the

data in clear. Access control relies on software checks to ensure that a user can access a piece of

data only if he is authoried to do so. !his situation is not particularly appealing from a security

standpoint. In the event of server compromise, for e-ample, as a result of a software vulnerability

e-ploit, the potential for information theft is immense. $urthermore, there is always a danger ofEinsider attacksM wherein a person having access to the server steals and leaks the information,

for e-ample, for economic gains. Some techni+ues create user hierarchies and re+uire the users

to share a common secret key if they are in a common set in the hierarchy. !he data is then

classified according to the hierarchy and encrypted under the public key of the set it is meant for.

Clearly, such methods have several limitations. If a third party must access the data for a set, a

user of that set either needs to act as an intermediary and decrypt all relevant entries for the party

or must give the party its private decryption key, and thus let it have access to all entries. In

many cases, by using the user hierarchies it is not even possible to realie an access control

e+uivalent to monotone access trees. Jere introduces new techni+ues to implement fine grained

access control. In this techni+ues, the data is stored on the server in an encrypted form while

different users are still allowed to decrypt different pieces of data security policy. !his

effectively eliminates the need to rely on the storage server for preventing unauthoried data

access.

Secret#sharing schemes0SSS1 35are used to divide a secret among a number of parties.

!he information given to a party is called the share for that party. "very SSS realies some

access structure that defines the sets of parties who should be able to reconstruct the secret by

using their shares.

(odification of N7AC such that it becomes rule#based, so they refer to it as Nule#7ased

N7AC or N7#N7AC. In this model, an enterprise defines the set of rules that are triggered to

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automatically assign users to roles. !hese rules take into account@ !he attributes of the client that

are e-pressed using attributes e-pressions as defined by the language provided by the model.

Any constraints on using roles. sers have many#to#many e-plicit relation with attribute values.

$urther, they have many#to#many implicit relation with attribute e-pressions. &ne user could

have one or more attribute e-pressions depending on the information he provides. Conversely,

two or more users may provide identical attribute e-pressions. A specific attribute e-pression

corresponds to one or more roles. An e-ample of a rule that yields multiple roles is when a client

is entitled to several mutually e-clusive roles.

2.> ILINEAR PAIRING

7ilinear )airing385 used in Cloud computing !he bilinear map was originally suggested

as a tool to attack elliptical curve encryption, by reducing the problem of discrete algebra onelliptical curve into the problem of discrete algebra on finite field, and thus reducing the

difficulty of it. Jowever, it began to be used recently not as an attacking tool, but as an

encryption tool for information protection.

2.? THE DECISIONAL ILINEAR DI::IE@HELLMAN 6DH8

ASSUMPTION3%5

*et a, b, c, z Opbe chosen at random andgbe a generator of ?%. !he decisional 72J

assumption 38, 95 is that no probabilistic polynomial#time algorithmB can distinguish the tuple

0A ;ga,B;gb,C;gc, e0g, g1abc1 from the tuple0A ;ga,B;gb,C;gc, e0g, g1z1 with more than a

negligible advantage. !he advantage ofB is

)r3B0A,B,C, e0g, g1abc1 ; :5 )r3B0A,B,C, e0g, g1z1 ; :

where the probability is taken over the random choice of the generatorg, the random choice of a,

b, c, z in Op, and the random bits consumed byB.

Access )olicy !ree, Piaoyan Jong et al 3%5 developed Situation Aware !rust 0SA!1 toprovide adaptive and proactive security in various Qehicular =etwork 0Q="!1 situations. SA! is

a trust built on C)A7" providing Edata#centric trustM. Attributes in SA! identify a group of

entities a type of events or the property of events. !his e-ample is a typical case in SA!. sers

who have attributes Company A, Washington St@ and %:# %%am in their private keys are satisfied

to decrypted the message. !hat means users that fulfill a set of descriptive attributes form a

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group. !he group boundary is not clearly defined, whoever satisfy the policy tree can 6oin in the

group. !his feature allows users in SA! set up trust proactively.

2.19 HAE MODEL

!he JA7" model 395 consists of a root master that corresponds to the third trusted

party ,multiple domain masters in which the top#level 2(s correspond to multiple enterprise

users, and numerous users that correspond to all personnel in an enterprise. !he N(, whose role

closely follows the root private key generator in a JI7" system, is responsible for the

generation and distribution of system parameters and domain keys. !he 2(, whose role

integrates both the properties of the domain )/? in a JI7" system and AA in a C)#A7"

system, is responsible for delegating keys to 2(s at the ne-t level and distributing keys to users.

Specifically, enable the leftmost 2( at the second level to administer all the users in a domain,6ust as the personnel office administers all personnel in an enterprise, and not to administer any

attribute. =otice that other 2(s administer an arbitrary number of dis6oint attributes, and have

full control over the structure and semantics of their attributes. In the JA7" model, we first

mark each 2( and attribute with a uni+ue identifier, but mark each user with both an I2 and a

set of descriptive attributes. we enable an entitys secret key to be e-tracted from the 2(

administering itself, and an entitys public key, which denotes its position in the JA7" model, to

be an I2 tuple consisting of the public key of the 2( administering itself and its I2, e.g., the

public key of 2(i with I2iis in the form of the public key of user U with I2uis in the form of

0)/i; I2u1, and the public key of attribute a with I2ais in the form of 0)/i; I2a1, where )/i%,

)/i, and )/iare assumed to be the public keys of the 2(s that administer 2( i, U, and a,

respectively.

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$ig.9 A three#level JA7" model

2elegation is handover of rights, &ne can delegate any key to a more restrictive policy.

Subsumes Jierarchical A7", cipher te-t policy#A7". "ncrypts data reflect decryption

policy.sers private key are descriptive attribute.3G5

Nevocation,35 by making slight alterations into JA7" scheme, and apply pro-y re#

encryption and lay re#encryption into scheme. (odifications in keys, We enable each attribute

a with I2 ato be bound to a version number, which increases by one whenever a user associated

with a is revoked. !herefore, an attribute public key is the form of )/ta;0vta , )/i, I2a1, where t

O+is the version number of the attribute public key, and vta f:R %gis a string corresponding

to t.

$ig. Access policy !ree

(odifications in algorithms3%5 @ $irst, we enable the Create 2( algorithm to uniformly

and randomly generate a hash function Jmki@ f:R %gO+for 2(i, where Jmkiis a random

oracle. Second, we construct another algorithm Create Attribute 0)/ta, mki1, which is e-ecuted

by 2(i whenever it receives a re+uest for )ta, and outputs Jmki0)/ta1): ?%. !herefore, the

first step in the "ncrypt algorithm turns into re+uesting )#values of all attributes in A from the

2(s.When a user is revoked, denoted Q, it is imperative to update public keys of attributes in

SQ, and attribute secret keys for remaining users who possess at least one attribute in SQ, and re#

encrypt data whose access structure specifies at least one attribute in SQ, where the set SQ

contains all attributes associated with Q. If all these tasks are performed by the 2(s themselves,

it would introduce a heavy computing overhead and may also re+uire the 2(s to always be

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online. !herefore, we get the idea to take advantage of the abundant resources in a cloud by

delegating to CS)s most of the computing tasks in revocation.

CHAPTER 3

REUIREMENT ANALYSIS

3.1 SYSTEM REUIREMENTS

3.1.1 H$r+B$re Reuire+

Jard 2isk @ :?7 and Above

NA( @ %?7 and Above

)rocessor @ )entium IQ and Above

(onitor @%GM color

3.1.2 S)B$re Reuire+

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=et 7eans

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3.2 :UNCTIONAL REUIREMENTS

A functional re+uirement defines a function of a software#system or component .A

function is described as a set of inputs, the behavior and outputs. 7ased on the privileges

mentioned the keys is issued to view the contents .In order to download the content the

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encryption key is needed. (oreover revocation rights is issued such that the legitimate user can

attain the rights back.

Eer'$, I'er$ce ReuireFe'"

U"er I'er$ce" %. Cloud service is designed through 6sp.

. System gets the input and delivers through the ?I based.

H$r+B$re I'er$ce"

We can connect your ASK:: to an Integrated Services 2igital =etwork 0IS2=1 for faster,

more accurate data transmission. An IS2= is a public or private digital communications network

that can support data, fa-, image, and other services over the same physical interface. Also, you

can use other protocols on IS2=, such as I2*C and P.G.

S)B$re I'er$ce"

!his software is interacted with the !C)KI) protocol, Socket and listening on unused

ports.

!his software is also interacted with the S(!) protocol, sending and receiving on S(!)

protocol.

3.3 N)'u'ci)'$, ReuireFe'"

Per)rF$'ce ReuireFe'"

We introduced the JAS7" scheme for realiing scalable, fle-ible, and fine#grained

access control in cloud computing. !he JAS7" scheme seamlessly incorporates a hierarchical

structure of system users by applying a delegation algorithm to AS7". JAS7" not only supports

compound attributes due to fle-ible attribute set combinations, but also achieves efficient user

revocation because of multiple value assignments of attributes. We formally proved the security

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of JAS7" based on the security of C)#A7" by 7ethencourt et al.. $inally, we implemented the

proposed scheme, and conducted comprehensive performance analysis and evaluation, which

showed its efficiency and advantages over e-isting schemes.

S$e! ReuireFe'"

!he software may be safety#critical. If so, there are issues associated with its integrity

level

!he software may not be safety#critical although it forms part of a safety#critical

system. $or e-ample, software may simply log transactions.

If a system must be of a high integrity level and if the software is shown to be of that

integrity level, then the hardware must be at least of the same integrity level.

!here is little point in producing 'perfect' code in some language if hardware and

system software 0in widest sense1 are not reliable.

If a computer system is to run software of a high integrity level then that system

should not at the same time accommodate software of a lower integrity level.

Systems with different re+uirements for safety levels must be separated.

&therwise, the highest level of integrity re+uired must be applied to all systems

in the same environment.

S)B$re u$,i! Ari&ue"

:u'ci)'$,i!@ are the re+uired functions available, including Interoperability and security

Re,i$&i,i!@ maturity, fault tolerance and recoverability

U"$&i,i!how easy it is to understand, learn, and operate the software System

Eicie'c!performance and resource behavior.

M$i'$i'$&i,i!@ (aintaining the software.

P)r$&i,i!!he software can easily be transferred to another environment.

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CHAPTER 4

SYSTEM ANALYSIS

4.1 E-ISTING SYSTEM

In the past, software had to be installed in an infrastructure close to end users. In e-isting

system, dont have security for datas. In case any of the corruption might be happened on cloud

mean we cant get the original information, everything will be lost. !here is no privilege for end

users, data owner and data consumer. /ey distribution is ma6or issue. 2ata owners should be

always online to distribute keys. (oreover the session e-piration for the authoried user has also

become an issue.

4.1.1 DISADVANTAGES

/ey distribution Session e-piration

=eed for authority to be online for encrypting and key distributing.

Necovery of lost or damaged data is not possible.

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4.2 PROPOSED SYSTEM

/ey distribution is done with the help of domain authority. !he special authority that

takes responsibility to choose key to generate and distribute to legitimate user, thereby it

increases the security concerns. While uploading the data content the key is provided by the

owner to the domain authority ,so if there is a re+uest by the consumer for a particular file the

link to get the key content, using the key content they can able to get the data of their own

privilege. If there is a case of intruders to hack or damage the information then the original data

content can be recovered back. !he delegation of rights to the legitimate consumers the key

distribution mechanism is made easier to access the data content, the session e-piration is

maintained to provide usage of the data content that has been uploaded. !he proposed model

uses the /)#A7" and pro-y re encryption to enhance the functionality of the access control

scheme of the system.

4.2.2 ADVANTAGES

2istributing keys using the domain authority

Session e-piration is maintained to regenerate for the authoried users

2ata consumers can access only if they satisfy the tree policy attribute

Negenerating the colluded data.

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4.3 MODULES O: THE SYSTEM

Cloud Architecture 2esign

2omain Authority Check and Attribute 7ased "ncryption

Shared resources and !rusted Authority

4.3.1 CLOUD ARCHITECTURE DESIGN

Cloud computing has computational and sociological implications. In

computational terms cloud computing is described as a subset of grid computing concerned with

the use of special shared computing resources. $or this reason it is described as a hybrid model

e-ploiting computer networks resources, chiefly Internet, enhancing the features of the

clientKserver scheme. $rom a sociological standpoint on the other hand, by delocaliing hardware

and software resources cloud computing changes the way the user works as heKshe has to interact

with the FcloudsF on#line, instead of in the traditional stand#alone mode.

4.3.2 DOMAIN AUTHORITY CHEC/ AND ATTRIUTE ASED

ENCRYPTION

!he cloud service provider manages a cloud to provide data storage service. 2ata

owners encrypt their data files and store them in the cloud for sharing with data consumers. !o

access the shared data files, data consumers download encrypted data files of their interest from

the cloud and then decrypt them. "ach data ownerKconsumer is administrated by a domain

authority. A domain authority is managed by its parent domain authority. "ach domain authority

is responsible for managing the domain authorities at the ne-t level or the data

ownersKconsumers in its domain.

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4.3.3 SHARED RESOURCES AND TRUSTED AUTHORITY

!he trusted authority acts as the root of trust and authories the top#level domain

authorities. A domain authority is trusted by its subordinate domain authorities or users that it

administrates, but may try to get the private keys of users outside its domain. sers may try to

access data files either within or outside the scope of their access privileges, so malicious users

may collude with each other to get sensitive files beyond their privileges. !he trusted authority is

responsible for generating and distributing system parameters and root master keys as well as

authoriing the top#level domain authorities. A domain authority is responsible for delegating

keys to subordinate domain authorities at the ne-t level or users in its domain. "ach user in the

system is assigned a key structure which specifies the attributes associated with the users

decryption key.

SYSTEM ARCHITECTURE

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DOMAIN AUTHORITY

CHECK

PRIVILEGES

CLOUD OS

CONSUMER FILE

ATTRIUTE ASED APPLICATION

O!NER FILE

TRUSTED AUTHORITY

APPROVE

CLOUD USERS

$ig.G SS!"( ANCJI!"C!N"

4.4 HASE CHARACTERISTICS

It is generally tree structured, thereby separating the attributes such as team leader,

Juman resources and employee and give them privileges according to the designation. !he

abstraction is done at each level. Separate levels are provided such that to give access

permission with specified constraints.

Cloud computing has emerged as one of the most influential paradigms in the I! industry

in recent years. Since this new computing technology re+uires users to entrust their valuable data

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to cloud providers, there have been increasing security and privacy concerns on outsourced data.

Several schemes employing attribute#based encryption 0A7"1 have been proposed for access

control of outsourced data in cloud computingR however, most of them suffer from infle-ibility in

implementing comple- access control policies. In order to realie scalable, fle-ible, and fine#

grained access control of outsourced data in cloud computing, in this paper, we propose

hierarchical attribute#set#based encryption 0JAS7"1 by e-tending cipherte-t#policy attribute#set#

based encryption 0AS7"1 with a hierarchical structure of users. !he proposed scheme not only

achieves scalability due to its hierarchical structure, but also inherits fle-ibility and fine#grained

access control in supporting compound attributes of AS7". In addition, JAS7" employs

multiple value assignments for access e-piration time to deal with user revocation more

efficiently than e-isting schemes.

We formally prove the security of JAS7" based on security of the cipherte-t#policy

attribute#based encryption 0C)#A7"1 scheme by 7ethencourt et al. and analye its performance

and computational comple-ity. We implement our scheme and show that it is both efficient and

fle-ible in dealing with access control for outsourced data in cloud computing with

comprehensive e-periments.

4.5 REASONS :OR CHOOSING /P@AE

Nandomness to prevent collusion.

ses threshold gates ie checks for constraintsKconditions.

Satisfy the cipher te-t key policy can decrypt its attributes.

2elegation properties handover of rights

4.< /P@AE MECHANISM

Cipher te-t is associated with the set of attributes, decryption key is associated with tree

structure .It provides session e-piration time to deal with user revocation. !he proposed

mechanism provides security based on public and master keys for domain an trusted authorities.

4.= ENCRYPTION ALGORITHM

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!he "l?amal Algorithm provides an alternative to the NSA for public key encryption.

Security of the NSA depends on the 0presumed1 difficulty of factoring large integers.

Security of the "l?amal algorithm depends on the 0presumed1 difficulty of computing

discrete logs in a large prime modulus.

"l?amal has the disadvantage that the cipher te-t is twice as long as the plainte-t.

It has the advantage the same plainte-t gives a different cipher te-t each time it is encrypted.

A chooses

i1 A large prime 0A 0say :: to 9:: digits1,

ii1 A primitive element UA modulo )a1

iii1 A 0possibly random1 integer +A with V dA V pA .

A computes

iv1 XA YA dA 0mod pA1.

A s public key is 60A7 UA7 XA8. Jer private key is +A.

7 encrypts a short message ( 0( Z pA1 and sends it to

A like this@

i1 7 chooses a random integer k 0which he keeps secret1.

ii1 7 computes r Y A

6F)+ 0A8 and Y XA

M 0mod pA1, and then discards k.

7 sends his encrypted message 6r7 8 to A.

E$F0,e@ Alice chooses pA ; %:8, UA ; , dA ; 48, and she computes XA ; 48 Y H 0mod

%:81. Jer public key is 0 pA, UA, XA1 ; 0,48,H1, and her private key is dA ; 48. 7 wants to

send the message F7F 044 in ASCII1 to A.

Je chooses a random integer k ; G and encrypts ( ; 44 as 0r, t1 ; 0UAk, XA k(1 Y 0 pow

G,H pow G 441 Y 62>7 ?8 0mod %:81. Je sends the encrypted message 0D, H1 to Alice. Alice

receives the message 0r, t1 ; 0D, H1, and using her private key dA ; 48 she decrypts to

tr#dA ; H.D pow #48 Y H .D pow0%:4[481 Y H.9 Y O%er$,, De"cri0i)'

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Cloud users store the datas and retrieve the datas from cloud server. 2omain Authority

and !rusted Authority monitor data owner and data consumer and secure the datas. ser depend

upon his privileges retrieve the datas.

Pr)+uc :e$ure"

!o address the critical challenge of keeping cloud secure, Attribute based encryption is

proposed. A Jierarchical Attribute#7ased Solution for $le-ible and Scalable Access Control in

Cloud Computing

U"er C,$""e" $'+ C#$r$ceri"ic"

!here are two main areas that are related to our proposal @

2omainAuthority@ Nesponsible for find the user attributes to give privileges for users.

!rustedAuthority@ Nesponsible for encrypting the datas and give approval for data

consumers.

4.? De"i(' $'+ IF0,eFe'$i)' C)'"r$i'"

C)'"r$i'" i' A'$,!"i"

Constraints as Informal !e-t

Constraints as &perational Nestrictions

Constraints Integrated in "-isting (odel Concepts Constraints as a Separate Concept

Constraints Implied by the (odel Structure

C)'"r$i'" i' De"i('

2etermination of the Involved Classes

2etermination of the Involved &b6ects

2etermination of the Involved Actions

2etermination of the Ne+uire Clauses

?lobal actions and Constraint Nealiation

C)'"r$i'" i' IF0,eFe'$i)'

!he traditional method to protect sensitive data outsourced to third parties

is to store encrypted data on servers, while the decryption keys are disclosed to authorie users

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only. Jowever, there are several drawbacks about this trivial solution. $irst of all, such a solution

re+uires an efficient key management mechanism to distribute decryption keys to authoried

users, which has been proven to be very difficult. =e-t, this approach lacks scalability and

fle-ibilityR as the number of authoried users becomes large, the solution will not be efficient

anymore. In case a previously legitimate user needs to be revoked, related data has to be re#

encrypted and new keys must be distributed to e-isting legitimate users again. *ast but not least,

data owners need to be online all the time so as to encrypt or re#encrypt data and distribute keys

to authorie users.

S!"eF :e$ure"

We e-tend AS7" with a hierarchical structure to effectively delegate the trusted

authoritys private attribute key generation operation to lower#level domain authorities. 7y doing

so, the workload of the trusted root authority is shifted to lower#level domain authorities, which

can provide attribute key generations for end users. !hus, this hierarchical structure achieves

great scalability. u et al.s scheme, however, only has one authority to deal with key generation,

which is not scalable for large#scale cloud computing applications.

CHAPTER VALIDATION TESTING

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At the culmination of integration testing, software is completely assembled as a

package. Interfacing errors have been uncovered and corrected and a final series of software test#

validation testing begins. Qalidation testing can be defined in many ways, but a simple definition

is that validation succeeds when the software functions in manner that is reasonably e-pected by

the customer. Software validation is achieved through a series of black bo- tests that

demonstrate conformity with re+uirement. After validation test has been conducted, one of two

conditions e-ists.

!he function or performance characteristics confirm to specifications and are

accepted.

A validation from specification is uncovered and a deficiency created.

2eviation or errors discovered at this step in this pro6ect is corrected prior to completion

of the pro6ect with the help of the user by negotiating to establish a method for resolving

deficiencies. !hus the proposed system under consideration has been tested by using validation

testing and found to be working satisfactorily. !hough there were deficiencies in the system they

were not catastrophic

=.? USER ACCEPTANCE TESTING

ser acceptance of the system is key factor for the success of any system. !he system

under consideration is tested for user acceptance by constantly keeping in touch with prospective

system and user at the time of developing and making changes whenever re+uired. !his is done

in regarding to the following points.

Input screen design.

&utput screen design.

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CHAPTER >

CONCLUSION

!he main aim of this paper is to increase the performance of cloud, based on customied

Jierarchical Attribute 7ased Solution concepts and to provide additional security for cloud using

Customied JAS7". !he privileges are set by access tree policy which is hierarchically

structured. !he access can be done by the data consumers if and only they satisfy all the

attributes in tree hierarchy. sers may try to access data files either within or outside the scope of

their access privileges, so malicious users may collude with each other to get sensitive files

beyond their privileges. !he regeneration of the colluded data is also recovered.

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CHAPTER ?

:UTURE ENHANCEMENTS

!he /eypolicy #A7" can be enhanced by using different attribute based encryption policy in

order to increase the performance based on the security in cloud computing environment. !he

access policy issues have been overcome but the integrity issues to be rectified using the

homomorphic token generation algorithms.

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APPENDI- I

SNAPSHOTS

1.MAIN PAGE

$ig.% J&(" )A?"

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$ig.%9 ="W S"N N"?IS!NA!I&=

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$I?.% N"?IS!"N"2 S"N J&(" )A?"

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$ig.%G S"NQIC"S )N&QI2"2

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$ig.%4 )*&A2I=? A=2 "=CN)!I&= /"

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$ig.%8 $I*" *IS!

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$ig.%D N"T"S! A=2 A))N&QA*

$ig.%H /" *IS!

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$ig.: $I*" 2"*"!I&=

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