Deleting Secret Data in cloud IEEE PROJECT 2015- 2016
FREE INPLANT TRAINING IN CHENNAI
CHAPTER 1
INTRODUCTION
Cloud
computing is an internet-based computing technology, where shared resources
such as software, platform, storage and information are provided to customers
on demand. Cloud computing is a computing platform for sharing resources that
include infrastructures, software, applications, and business processes. Cloud
Computing is a virtual pool of computing resources. It provides computing
resources in the pool for users through internet. Cloud computing is an emerging
computing paradigm aims to share storage, computation and services
transparently among a set of massive users. The exact definition of cloud
computing is a large-scale distributed computing paradigm that is driven by
economies of scale, in which a pool of abstracted, virtualized, dynamically
scalable, managed computing power, storage, platforms, and services are
delivered on demand to external customers over the Internet [5].
Current
cloud computing systems pose serious limitation to protecting users’ data
confidentiality. Since users’ sensitive data is presented in unencrypted forms
to re-mote machines owned and operated by third party service providers, the
risks of unauthorized disclosure of the users’ sensitive data by service
providers may be quite high. There are many techniques for protecting users’
data from outside attackers. An approach is presented to protecting the
confidentiality of users’ data from service providers, and ensures service
providers cannot collect users’ confidential data while the data is processed
and stored in cloud computing systems. Cloud computing systems provide various
Internet based data storage and services. Due to its many major benefits,
including cost effectiveness and high scalability and flexibility, cloud
computing is gaining significant momentum recently as a new paradigm of
distributed computing for various applications, especially for business
applications along with the rapid growth of the Internet. With the rise of the
era of cloud computing, concerns about Internet Security continue to increase.
Cloud
computing began to get both awareness and popularity in the early 2000s. When
the concept of cloud computing originally came to prominence most people did
not fully understand what role it fulfilled or how it helped an organization.
In some cases people still do not fully understand the concept of cloud
computing. Cloud computing can refer to business intelligence (BI), complex
event processing (CEP), service oriented architecture (SOA), Software as a
Service (SaaS), Web-oriented architecture (WOA), and even Enterprise 2.0.
With the
advent and growing acceptance of cloud-based applications like Gmail, Google
Calendar, Flickr, Google Docs, and Delicious, more and more individuals are now
open to using a cloud computing environment than ever before. As this need has
continued to grow so has the support and surrounding infrastructure needed to
support it. To meet those needs companies like Google, Microsoft, and Amazon
have started growing server farms in order to provide companies with the
ability to store, process, and retrieve data while generating income for
themselves. To meet this need Google has brought on-line more than a million
servers in over 30 data centers across its global network. Microsoft is also
investing billions to grow its own cloud infrastructure. Microsoft is currently
adding an estimated 20,000 servers a month. With this amount of process,
storage and computing power coming online, the concept of cloud computing is
more of a reality than ever before. The growth of cloud computing had the net
effect of businesses migrating to a new way of managing their data
infrastructure. This growth of cloud computing capabilities has been described
as driving massive centralization at its deep center to take advantage of
economies of scale in computing power, energy consumption, cooling, and
administration.
The
architecture of cloud involves multiple cloud components communicating with
each other over the application programming interfaces (APIs), usually web
services. The two most significant components of cloud computing architecture
are known as the front end and the back end. The front end is the part seen by
the client, i.e. the customer. This includes the clients network or computer,
and the applications used to access the cloud via a user interface such as a
web browser. The back end of the cloud computing architecture is the cloud
itself, which comprises of various computers, servers and data storage devices.
The general
architecture of cloud platform is also known as cloud stack given in figure 3.1
[5]. Cloud services may be offered in various forms from the bottom layer to
top layer in which each layer represent one service model. The three key cloud
delivery models are software as a service (SaaS), platform as a service (PaaS),
and infrastructure as a service (IaaS). Infrastructure-as-a-Service (IaaS) is
offered in the bottom layer, where resources are aggregated and managed
physically (e.g., Emulab) or virtually (e.g., Amazon EC2), and services are
delivered in forms of storage (e.g., GoogleFS), network (e.g., Open ow), or
computational capability (e.g., Hadoop MapReduce). The middle layer delivers
Platform-as a-Service (PaaS), in which services are provided as an environment
for programming (e.g., Django) or software execution (e.g., Google App Engine).
Software- as-a Service (SaaS) locates in the top layer, in which a cloud
provider further confines client flexibility by merely offering software
applications as a service. Apart from the service provisioning, the cloud
provider maintains a suite of management tools and facilities (e.g., service
instance life-cycle management, metering and billing, dynamic configuration) in
order to manage a large cloud system.
Cloud
deployment models include public, private, community, and hybrid clouds Public clouds are external or publicly
available cloud environments that are accessible to multiple tenants, whereas
private clouds are typically tailored environments with dedicated virtualized
resources for particular organizations. Similarly, community clouds are
tailored for particular groups of customers [3].
1.1.3. CLOUD SECURITY CHALLENGES
The world
of computation has changed from centralized to distributed systems and now we
are getting back to the virtual centralization which is the Cloud Computing.
Location of data and processes makes the difference in the realm of
computation. We have the cloud computing wherein, the service and data
maintenance is provided by some vendor which leaves the client/customer unaware
of where the processes are running or where the data is stored. So, logically
speaking, the client has no control over it. The cloud computing uses the
internet as the communication media. When we look at the security of data in
the cloud computing, the vendor has to provide some assurance in service level
agreements (SLA) to convince the customer on security issues. Organizations use
cloud computing as a service infrastructure, critically like to examine the
security and confidentiality issues for their business critical in-sensitive
applications.
Traditional
security issues are still present in cloud computing environments. But as
enterprise boundaries have been extended to the cloud, traditional security
mechanisms are no longer suitable for applications and data in cloud.
Traditional concerns involve computer and network intrusions or attacks that
will be made possible or at least easier by moving to the cloud. Cloud
providers respond to these concerns by arguing that their security measures and
processes are more mature and tested than those of the average company. It
could be easier to lock down information if it's administered by a third party
rather than in-house, if companies are worried about insider threats In
addition, it may be easier to enforce security via contracts with online
services providers than via internal controls. Due to the openness and
multi-tenant characteristic of the cloud, cloud computing is bringing
tremendous impact on information security field [2].
Availability
concerns center on critical applications and data being available.
Well-publicized incidents of cloud outages include Gmail. As with the
Traditional Security concerns, cloud providers argue that their server uptime
compares well with the avail-ability of the cloud users own data centers. Cloud
services are thought of as providing more availability, but perhaps not there
are more single points of failure and attack. Third-party data control the
legal implications of data and applications being did by a
third party are complex and not well understood. There is also a potential lack
of control and transparency when a third party holds the data. Part of the hype
of cloud computing is that the cloud can be implementation independent, but in
reality regulatory compliance requires transparency into the cloud [5][6].
1.1.4
CHARACTERISTICS OF CLOUD COMPUTING
Cloud services
exhibitive essential characteristics that demonstrate their relation to, and
differences from, traditional computing approaches: [6]
On-demand self-service - A consumer can unilaterally provision
computing capabilities such as server time and network storage as needed
automatically, without requiring human interaction with a service provider.
Broad
network access - Capabilities are available over the network and accessed
through standard mechanisms that promote use by heterogeneous thin or thick
client platforms (e.g., mobile phones, laptops, and PDAs) as well as other
traditional or cloud based software services.
Resource
pooling - The providers computing resources are pooled to serve multiple
consumers using a multi-tenant model, with different physical and virtual
resources dynamically assigned and reassigned according to consumer demand.
There is a degree of location independence in that the customer generally has
no control or knowledge over the exact location of the provided resources, but
may be able to specify location at a higher level of abstraction (e.g.,
country, state, or datacenter).
Rapid
elasticity - Capabilities can be rapidly and elastically provisioned in some
cases automatically to quickly scale out; and rapidly released to quickly scale
in. To the consumer, the capabilities available for provisioning often appear
to be unlimited and can be purchased in any quantity at any time.
1.2 Need For Study
The
clients concern about data security, data integrity, and sharing data with
specific band of men and women must be addressed. You can find multiple means
of achieving this, example encrypting data on client machine and then storing
the information to cloud storage server, computing hash of the information on
client machine and storing hash of data in client machine, client trying out
the responsibility of sharing the trick key about encryption with specific band
of people. Therefore it becomes more tedious for client to keep these
information and share such information, more over in the event the device which
stores such information is lost or stolen it pose a threat to the total data.
Another way could be same storage cloud provider providing the service for
secured sharing, hashing, encryption/decryption, but since administrative can
have use of both services for maintenance, the security service provided by the
cloud storage provider, the information might be compromised. The
aforementioned approaches burdens the client by which makes it additionally
accountable for securing it data before storing it to the cloud storage.
1.3
Objectives of the study
Our objective is to build a security service which
will be provided with a trusted third party, Detailing it further:
1.To
develop a framework that will maintain the confidentiality of the users’ data.
2.To
build a client application which would use the above framework while uploading/downloading/deleting the data to and
from cloud.
CHAPTER 2
LITERATURE REVIEW
The
cloud computing uses the internet as the communication media. When we look at
the security of data in the cloud computing, the vendor has to provide some
assurance in service level agreements (SLA) to convince the customer on
security issues
Security can be provided in two ways
(1) Hardware security (using TPM)
(2) Software security (using Key
approach)
A Trusted Platform module provides
secure asymmetric key generation. This paper [11] describes the use of a secure
key generating authority in shamir identity based signature scheme
implementation. They proposed an idea of identity-based asymmetric
cryptosystems (IBC) and together with an identity based asymmetric signature.
The proposed IBS scheme in this paper has itself proven secure against forgery
under chosen message attacks. This paper also proposed a new concept that
assigning TPM as key generating authority and list out the various benefits of
implementing it. The paper [12] initially identifies the challenges for
establishing the trust in the cloud and then proposes a secure framework which
helps in addressing those identified challenges. This paper is actually
extension of their previous work. In their previous work they proposed a unique
framework for establishing trust in the cloud environment by extending their
previous work the current paper addresses those issue it clearly covers
applications data and their integration with infrastructure management data.
The proposed framework [2] has four types of software agents, each run on
trusted devices. The paper also explains about the controlled content sharing
between devices.
In
[13] Security is ensured using C-code-like formal modeling at application
level. As a result of this approach, security of the protocol is ensured not
only at the abstract level of protocol l, but also at the concrete level. In [14]
the authors proposes the virtualization of trusted platform module, so than not
only single machine can use the tpm but also any number of virtual machines can
also use the TPM, doing so will support higher level services like remote
attestation and so on. Various challenges are addressed in the following table.
Table 2.1 Challenges in TPM
respectively.
A secret sharing scheme consists of one dealer, n participants (or players), an
original secret, a secret distribution algorithm and a secret reconstruction
algorithm. The dealer shares a secret among a given set of n participants, such
that every k of those participants (k≤n) could reconstruct the secret by their
shares together, while any group of fewer than k participants gets no
information about secret [21-23]. Take
Shamir’s scheme for instance, in this scheme, any t out of n shares may be used
to recover the secret. The system relies on the idea that 2 points are
sufficient to define a line, 3 points are sufficient to define a parabola, 4
points to define a cubic curve and so forth. That is, it takes k points to
define a polynomial of degree (k-1). The method is to create a polynomial of
degree k-1 with the secret as the first coefficient and the remaining
coefficients are picked at random. Next find n points on the curve and give one
to each of the players. When at least t out of the n players reveals their
points, there is sufficient information to fit a (k-1) degree polynomial to
them, the first coefficient being the secret. At the very beginning, the
implicit assumption in the original formulation of secret sharing scheme is
that each participant is either honest or corrupt, and honest participants are
all willing to cooperate when dealer requests reconstruction of the secret.
Such schemes include Shamir’s threshold secret sharing scheme [21] based on
polynomial interpolation, Blakley’s geometric threshold secret sharing scheme [22],
Mignotte’s scheme [24] and Asmuth-Bloom’s scheme [25] based on the Chinese
remainder theorem in 1983. Gradually, researchers began to consider the
security problems of secret sharing itself, such as how to verify dishonest
players. HARN proposed a threshold secret sharing scheme [26] based on digital
signature with certification functions in 1995. HSU and WU’s scheme [27]
improved HARN’s scheme and proposed an encryption secret sharing scheme based
on discrete logarithms with more efficiency for signature verification. Scheme
of Han et al [28] used a certification center to verify dishonest shares. Marsh
and Schneider designed a secret sharing system [29] which was fault-tolerant
and attack-tolerant. All of these made the research on secret sharing scheme
more and more mature. Works [30][31][32] were also secret sharing schemes with
verification mechanisms. Starting with the work of Halpern and Teague [33],
participants in secret sharing are neither honest nor corrupt but are instead
viewed as rational and are assumed to act in their own self-interest. Rational
secret sharing is a problem at the intersection of cryptography and game
theory. In essence, a dealer wishes to engineer a communication game that, when
rationally played, guarantees that each of the players learns the dealer’s
secret. Yet, all solutions proposed so far did not rely solely on the players’
rationality, but also on their beliefs, and were also quite inefficient. Micali
and Shelat exhibited a very efficient and purely rational solution to it with a
verifiable trusted channel in their scheme [14]. Fuchsbauer et al also proposed
a new methodology for rational secret sharing leading to various instantiations
in both the two-party and multi-party settings [15]. Of course, because of its
generality, secret sharing schemes step into many fields, such as image secret
sharing [16][17]. More and more information security applications consider
secret sharing scheme to protect confidential key data, and verifiable and
proactive sharing mechanisms are hotly studied [18-21].
secret
sharing scheme can broadly categorized as follows:
1.
Traditional Secret sharing scheme
2.
Threshold Secret sharing scheme
3.
Threshold Changeable Secret sharing scheme
4.
Verifiable Secret sharing scheme
A
Secret sharing is a technique for protecting sensitive data, such as
cryptographic keys. It is used to distribute a secret value to a number of parts
or shares that have to be combined together to access the original value. These
shares can then be given to separate parties that protect them using standard
means like memorize, store in a computer etc. Secret sharing is used in modern
cryptography to lower the risks associated with compromised data. Sharing a
secret spreads the risk of compromising the value across several parties [27].
Traditional
Secret Sharing Scheme
Shamir
[21] presented the first secret sharing method in1979. Secret sharing involves
transmitting different shares in different channels. With a single share nobody
can see the entire secret message. The general idea behind secret sharing is to
distribute a secret to n different participants so that any k participants can
reconstruct the secret, and any (k - 1) or less participants cannot reveal
anything about the secret. Such schemes are also known as (k, n)
threshold-based scheme. For any secret sharing schemes it has the following two
processes: Distribution Process This process input is the secret k that gets
portioned into n number of shares S1, S2,...Sn that is privately delivered to
the participants. Reconstruction Process It reconstructs the secret when a
suitable set of shares is present using a certain algorithm.
Threshold Secret Sharing
Scheme:
These
schemes are the first kind of schemes that were constructed individually by
both Shamir who uses polynomial interpolation [21] and Blakley who uses finite
geometry [28]. To share a secret we can split the secret and spread the pieces
to all participants. In some schemes, reconstructing the secret needs combining
all shares from participants, but this might not be practical since we might
need the secret reconstructed by some of the participants and not all. The
reason is as follows: Imagine if a country splits the access codes for its
missiles among three officials and they found themselves in a dire need to
access the missiles, but one of the officials is not present or he simply
refuses to attack. Then, we need to have a different scheme where a subset of
the participants can reconstruct the secret. These schemes are secure and do
not require all n shares [24]. For example: Consider the Board of Directors of
Defense ministry would like to protect missiles secret formula. The president
of the company should be able to access the formula when needed, but in an emergency
any 3 of the 12 board members would be able to unlock the secret formula
together. This can be accomplished by a secret sharing scheme with k = 3 and n
= 12, where 3 shares are given to the president, and is given to each board
member. These schemes are further classified depending in the size on the
shares. Perfect Secret Sharing (PSS) These schemes cannot allow the size of
secret shares to become smaller than the size of the secret.Ramp Secret Sharing
(RSS) These schemes achieve the goal of reducing the size of the shares, but at
the cost of some degraded protection on the secret.
Threshold Changeable Secret Sharing
Scheme
Threshold
Changeable secret sharing scheme was invented by the scientist Wang and Wong
for changing thresholds in the absence of secure channels after the setup of
threshold secret sharing schemes[24]. Initially, we construct a perfect (t, n)
threshold scheme that is threshold changeable to t which is optimal with
respect to the share size. But these threshold changeable schemes along with
most previously known schemes turn out to be insecure under the collusion
attack of players holding initial shares [29].
Verifiable Secret Sharing Scheme
This
scheme was first introduced to overcome the problem of dishonest dealers. VSS
schemes lets the participants verify that their shares are consistent, thus
they can properly reconstruct the secret. To get a clear idea about how these
schemes work, let us assume a dealer Trent sends shares to Alice, Bob, Carol
and Dave. The only way they can be sure they have a valid share is to
reconstruct the secret, but it may happen that Trent sent a bogus share to Bob
or Bob received a bad share as a result of a communication error. VSS schemes
allow these participants to validate their shares without the need to
reconstruct the secret [25]. It is designed to resist an adversary who can
corrupt the dealer and some of the participants.VSS requires an additional
algorithm called verify that allows participants to verify their shares before
any reconstructing attempts [26].
PROBLEM
DEFINITION
Cloud service providers request
customers to store their account information in the cloud, cloud service
providers have the access to these information. This presents a privacy issue
to the customer’s privacy information. Many SLAs have specified the privacy of
the sensitive information, however, it is difficult for customers to
make sure the proper rules are enforced. There is a lack
of transparency in the cloud that allows the customers to monitor
their own privacy information. When a customer decide to use multiple cloud
service, the customer will have to store his/her password in multiple cloud,
the more cloud service the customer is subscript to, the more copy of the
user’s information will be. This is a security issue for the customers and
the cloud service providers. For every cloud service, the customer needs to
exchange his/her authentication information. This redundant actions
may lead to an exploit of the authentication mechanism. Cloud service providers
use different authentication technologies for authenticating users, this may
have less impact on SaaS than PaaS and IaaS, but it is present a challenge
to the customers. Inspite of all authenticating mechanisms provided by the
cloud service providers, the customers privacy is highly lost while storing data
in their place. In our project we are providing one secure mechanism in which
the cloud service providers cannot access the customers data without the
knowledge of the customers. If the cloud service providers want to access the
customers data mutual authentication between the customers and cloud service
providers. we are introducing third party authority who generates a long key
and shares the key with the customers and the cloud service providers. We are addressing the solution for the
privacy issue that exists with the customers.
CHAPTER
4
PROPOSED
METHOD
Cloud service providers request
customers to store their account information in the cloud, cloud service
providers have the access to these information. This presents a privacy issue
to the customer’s privacy information. Many SLAs have specified the privacy of
the sensitive information, however, it is difficult for customers to
make sure the proper rules are enforced. There is a lack
of transparency in the cloud that allows the customers to monitor
their own privacy information. We are introducing the third party which
generates a long secret key and shares
the half part of the long key to the cloud service providers and remaining part
of the half key to the customers. Customers once registers for a new account
they can login into the system using their account. Once after login into the
account before performing any operations on file they first request for the
third party to generate a long key. Third party as requested by the customers
generates a long key and shares their corresponding share to cloud service
providers and customers respectively. Now when the cloud service providers
tries to access the file without the knowledge of their customers, immediately
an mail should be sent to the customers indicating that CSP is trying to access
their data. If suppose customers want to share their data to the CSP they can
share their half part of the key to the CSP. CSP inturn combines his half key
with the customers half key which gives
full key which should be verified by the third party. Now the cloud service
provider can access the customers file. In our proposed system we are providing
privacy to customers data assuring that the customers data cannot be viewed
without their knowledge.
But
there is one drawback in this scenario once he got users key he can view the
users file anytime without the users knowledge
To overcome this difficulty we are setting default logout time for admin
and also user once he shares his key with the admin in the certain interval of
time his half portion of the key gets updated
so that even admin has the key obtained from the user it is invalid now.
if he want to see the users file he has to again request the key from the user.
In
our proposed system we are going to implement modified shamir's secret sharing
algorithm to generate a secret key and shares the key to admin and user side .The
following are the list of modules and their functionalities
4.2
Modules:
4.2.1 User side:
4.2.1.1 Data upload scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
before a user upload the files he has to request for the secret key from the
third party
5.
once the user receives the key from the third party he can upload the files to
the cloud
4.2.1.2 Data download scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
once the user receives the key from the third party he can download the files from
the cloud
4.2.1.3 Data delete scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
once the user receives the key from the third party he can delete the files from
the cloud
4.2.2 Admin side
when
the admin wants to see the other user files he has to do the following steps
1.
Admin enters his half key which is provided by the third party
2.
Now he has to request from the user the remaining half key so that by combining
his half key and admin half key to view the file
3.
once the user wants to share his file to the admin they can provide their half
key to admin and grants the admin to view their file
CHAPTER
5
EXPERIMENTAL
RESULTS
5.1.
Hardware/Software requirements
In
order to implement we need
1..
Glassfish Server : to host web service
2.
Java 1.6.
3.
MySQL 5.2.
5.2 Typical Existing Scenarios:
5.2.1
User side
5.2.1.1 Data upload scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
Now a user can upload the files and store it to cloud
5.2.1.2 Data download scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
Now a user can download the files from the
cloud
5.2.1.3 Data Delete scenario
1.
The end user registers for new account
2.
The end user login to the system with his/her username & password.
3.
Once the user is authenticated, separate folder has created for the user which
monitors all the activities of the user
4.
Now a user can delete the files from the cloud
5.2.2 Admin side
1.
Admin login into the system who has the full control over the system
2.Admin
can view all files which is deleted by other users
3.
Admin can select whichever file he wants to recover .he can recover all the
files deleted by other users
Existing shamir secret key
Algorithm:
Divide
data D into n pieces D1,D2….Dn in such a
way that:
Knowledge
of any k or more D pieces makes D easily computable.
Knowledge
of any k -1 or fewer pieces leaves D completely undetermined
This
scheme is called (k,n) threshold scheme.
If k=n then all participants are required
together to reconstruct the secret
Choose
at random (k-1) coefficients
a1,a2,a3…ak-1 , and let S be the a0
CHAPTER
6
CONCLUSION
AND FUTURE WORK
Conclusion
Security is an important issue in any application.
To provide the security, authentication plays very important role.
Authentication is provided through the secret sharing schemes. Cloud service
providers request customers to store their account information in the cloud,
cloud service providers have the access to these information. This presents a
privacy issue to the customer’s privacy information. When a customer decide to
use multiple cloud service, the customer will have to store his/her password in
multiple cloud, the more cloud service the customer is subscript to, the
more copy of the user’s information will be. This is a security issue
for the customers and the cloud service providers. our main idea is to secure
the users data from the cloud service provider
Future Work
we
are implementing a secure framework by proposing a new scheme in our future work so that without the
knowledge of the user the cloud service providers cannot access the customers
data though it is saved in the CSP place
APPENDIX
A
SCREENSHOTS
