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SoK: Remotely Wiping Sensitive

Data on stolen Smartphones

Sahiti Koganti

University of Texas at San Antonio

sahiti745@gmail.com

ABSTRACT

Now-a-days technology is trending up higher. Of

all the technological innovations mobile phones

and especially Smartphones are becoming

immensely popular and very much helpful to

people. It is playing a vital role in everyone’s life.

They contain huge amount of personal data like

contacts, messages, photos, credit card

information, passwords and much more.

Sometimes people may sync their office laptops

to their smartphones so that they will be able to

work from outside of the office. But if the device

is lost the adversary can be able to get a lot of

information. To prevent the data to be stolen

even if the device is stolen some techniques have

been proposed. My paper will discuss about these

techniques. These are mainly cloud based

techniques. But all these mechanisms cannot be

used in some situations. My paper will also

discuss the challenges of those techniques.

INTRODUCTION

Enormous developments in technology have made

different transitions. Today’s mobile phones and

in particular Smartphones have taken over

desktops as primary computing platform as they

are becoming very powerful. Smartphones are

creating a great trend in today’s market. Despite

its great advantages they are bringing in new

challenges. They became an attractive entity to

everyone and hence they are more stolen either

for its huge price value or for the huge amount of

information it contains. Some mechanisms have

been proposed and implemented for post-theft

control of data on these smartphones. In this paper

I will discuss a few of them and also briefly

describe my thoughts as one of these mechanisms.

With this systemization of knowledge paper I will

make the following contributions:

Develop a general model of all the

mechanisms for wiping of sensitive data

on smartphones.

Discuss briefly about how each

mechanism works on wiping of sensitive

data.

Discuss about the disadvantages of the

mechanisms and in what type of situations

they might not be useful

Discuss some of the unwanted sensitive

data removal mechanisms to reduce the

sensitive data exposed to theft.

SYSTEMIZATION MODEL OF MY PAPER

The whole paper has been modeled and figure 1

illustrates this model. It starts with mobile phones,

and as this paper mainly focuses on the

smartphones, the flow goes like this. The

smartphones have diversity of usages and hence

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Figure 1: Systemization Model

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have to become smarter and responsible devices.

Due to its mobility and great usage flexibility

there have been many risks. One of the greatest

risks is loss of sensitive data when the device is

lost or stolen. To reduce this risk “Theft

Abatement” can be done. There are many types of

theft abatement and a few of them are idle

timeout, remotely erase sensitive data, password

access and failed password attempts. This paper is

mainly focused on remotely erasing sensitive data.

Remotely erasing can be done by directly using

anti-theft protection apps which can be available

to the user directly on smartphones. Since these

are not having so much extensive capability some

anti-theft mechanisms like CleanOS, SafeCode,

SMS, Remote control system, Remote lock and

wipe with integrity checking, Emergency call

mechanism. There are some general mechanisms

that can be used as well. Some of them are

Shredding, Vanish, SafeVanish, Keypad,

Revocable backup system. This can all be done by

using Cloud. But people feel that home is much

safer than cloud due to its limitations like privacy

and security. Hence this paper also discusses

some techniques to improve privacy and security

on cloud like CloudViews, User driven privacy

enforcement, Data security and privacy in cloud

computing, Cloud data protection for masses,

Cloudsec.

DIVERSITY OF USAGE

Different people use Smartphones in a different

manner. They interact with them in a myriad of

ways. The way they interact and the applications

they use are very much diversified. This is proved

by a research conducted by Dr. Hossein Falaki

and his team.

MOBILE PHONES TO RESPONSIBLE

DEVICES

Applications running on mobile phones in the past

are very limited. Today’s mobile phones are

replacing desktop PCs and are becoming more

powerful. But mobile phone operating systems

currently lack the mechanisms to adequately

protect these increasingly capable devices. As a

result an adversary may be able to not only cause

numerous violations of user’s data confidentiality

and integrity, but also cause significant problems

for the cellular networks themselves. That is these

mobile phones are introducing a variety of ways

for attackers to exploit applications and the

network infrastructure itself. But these known

techniques will provide security but some

mechanisms have to be implemented to protect

these minimum critical systems.

Hence some mechanisms have been proposed that

makes mobile phones smarter and responsible

devices that are capable of intelligently operating

in order to remain as mission critical devices. This

is done by providing these devices with more

capable and reliable trusted computing bases, so

as to greatly increase their ability to protect key

applications and create predictable network

impact. These mechanisms use the combination of

mediation, access control, resource management

and quality of service etc. But these are not

perfect and needs to be improvised.

THE SMARTPHONE AND ITS RISKS

The desktop PCs, laptops and servers have more

protection mechanisms than mobile phones, since

they are used from a long time. Many researchers

have come up with different solutions. They are

well implemented and are working good for now.

But mobile phones are emerging into trend now

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and hence protection mechanisms are still in the

research stage. Also the mobility, convenience

and capabilities of mobile phones especially the

smartphones potentially open new types of risks.

There are several key scenarios to consider to

limit the risks:

1. The smartphones gets lost or stolen and

subsequently there is unauthorized access

to the smartphone, unauthorized access to

data and unauthorized calls

2. Unauthorized access to the network

3. Administrative control to computer

systems are lost

4. Sensitive data is accessed

5. Inappropriate use of the internet

THEFT ABATEMENT

The keystone of the smartphone security model is

avoiding loss or theft. For an unsecure phone, loss

or theft of the device leads to security issues

potentially impacting members, the internal

network and the company’s reputation. These

risks can be reduced by applying some security

controls and policies already available for these

devices. Fundamental security elements to reduce

risk of data theft are:

1. Remotely erase data – to reduce the risk of

sensitive data being accessible, enable the

“remote wipe” functionality to delete the

contents of a smartphone that was lost or

stolen.

2. Password access – enable a password

policy on the smartphone.

3. Failed password attempts – to reduce the

risk of unauthorized access to data on the

smartphone, configure the device to

perform a data wipe after predefined

number of failed logon attempts.

4. Idle timeout – enable password protected

screen lockout or screen saver mode when

a specified duration of non – use is

reached.

REMOTELY ERASE DATA

The best way to approach is to erase the sensitive

data on the smartphones remotely using the

services provided by cloud. Also some

mechanisms use the others like password access,

failed password attempts and idle timeout by itself

or can be done remotely. There are two ways to

deal with this.

1. Use of Anti-theft protection apps

2. Use of Anti-theft mechanisms

ANTI-THEFT PROTECTION APPS FOR

SMARTPHONES

Most smartphones have native remote wipe

capabilities. They are inbuilt or available to the

users in the form of apps. There are a number of

apps out there that can locate, lock and/or erase

the wireless device if it gets lost or stolen. If these

features aren’t enough, then they can be

supplemented with cloud. Several popular cloud

services offer remote data wipe options for iOS or

android devices. Apple iOS users who register

with iCloud can do so through the FindMyPhone

app, as long as it was enabled before the device

got lost. Android users may register with the

cloud services that their wireless carrier or device

manufacturer offers. For example Samsung’s

DIVE remote control app can remotely invoke

factory reset. These are just a few of the mainly

available consumer cloud services that support

end-user remote find and wipe.

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ANTI-THEFT PROTECTION

MECHANISMS

These mechanisms use either the Wi-fi or Internet

connection, SMS service, SIM card for cellular

network connection to work.

1. CleanOS

CleanOS identifies and tracks sensitive data in

RAM and on stable storage, encrypts them with

key and evicts that key to the cloud when data is

not in active use on the device

Methodology: CleanOS is a new Android-based

Operating System that minimizes sensitive data

exposure by evicting it to a trusted cloud

whenever the data is not under active usage. It

implements sensitive data objects (SDOs) which

identifies locations of sensitive data in RAM and

stable storage, monitors its use by applications,

and evicts sensitive data to cloud whenever it is

not under active use. The cloud intermediates all

accesses to unused SDOs and can offer a lot of

useful post-loss functions like:

Disable SDO access after theft

Audit SDO exposures and access

Rate – limit SDO accesses

Basic Functioning: Applications create SDOs

and add sensitive data to them. An SDO is a

logical collection of java objects that contain

sensitive data and that are related somehow.

CleanOS implements three functions for SDOs :

Tracks data in SDOs using taint tracking

Evicts SDOs to a trusted cloud whenever

idle

Decrypts SDO data when it is accessed

again

The following diagram gives an illustration of

SDO object:

Figure 1: Illustration of SDO object

Evict – Idle Garbage Collection: To evict SDOs,

a new type of java garbage collector named as

evict-idle garbage collector (eiGC) was

introduced. A traditional garbage collector de-

allocates only the objects which will never be

used in the future but the eiGC evicts objects that

have not been used for a period of time, even if

they might be used again in the future. eiGC is run

periodically to evict idle SDOs. For any java

object that is tainted with an idle SDOs ID, the

eiGC “evicts” that object, setting its E bit in the

tag.

Disadvantage: Requires network connectivity

with cloud all the time hence needs internet

connection.

2. Safecode

Safecode is a PIN-based user extended security

mechanisms which wipes out data automatically

after a certain number of attempts from iOS

devices.

An adversary who gets the phone might in

common put the device in silent mode, switch off

the device, remove the battery from the device,

place the device in a faraday cage. This

mechanism proposed SafeCode as a system that

prevents the device from being “switched off” or

“silenced” by the adversary, when the device is

stolen. In the best case, it also extends the

opportunity of recovering the stolen device.

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Disadvantage: It augments the probability of

remotely wiping the device by accidental deletion

of user data by the user itself.

3. SMS

This is a model for remote access and protection

of smartphones using the short message service on

the smartphone. This mechanism is used in

controlling a stolen smartphone remotely by using

the short message service (sms).

Basic Methodology: There will be a client

interface, a client service and a server service. The

commands are requested from the client interface

through an SMS and the server service interprets

these and performs the particular action

interpreted in the command on the user data. All

the actions by the server are done remotely.

Disadvantage: This technique will not work if

SIM card is removed from the stolen device. The

adversary might remove the sim card as soon as

he gets the phone.

4. Remote Control System

This is a design of remote control system for data

protection and backup in mobile devices. This

technique communicates with remote device

through the internet and prevents unauthorized

usage of mobile handsets and personal

information by a remote control when the lock

function is not set before they are lost.

Basic Methodology: The remote control service

server can be utilized by the lost mobile devices

which can be shown in steps below: (a) Initially is

the authentication step, in which the user accesses

the remote control services server (b) Next is the

identification step, in which it is checked to see if

the owner of the communication channel is real or

not. (c) Then the next one is the transmission step,

which an access code is sent to the mobile device

to utilize the remote control program on the

device. (d) In the reception step a mobile device

with an identification number is recognized which

is associated with the access code transmitted by

the transmission step. (e) This step is utilized to

select one of the remote control services and run

the selected one on the terminal (f) This step is to

receive the completion code which indicates that

the remote service is normally processed.

Disadvantage: This technique works only when

the devices have internet connection. The

adversary might disconnect it once stolen.

5. Remote lock and wipe with Integrity

Checking

This mechanism presents a system with Message

Authentication Code (MAC) - based integrity

checking mechanism of SMS notification using

Password-Based Key Derived Function (PBKDF).

The remote lock and wipe system consists of a

remote control module on a server and a

command handling module on a smartphone.

Using these, the remote system sends either of the

two commands lock or wipe to a smartphone by

SMS push notification message. When the user

sends a lock command to the smartphone by using

remote control module, the remote handling

module will enable the password locking function

to lock the smartphone. Similarly, when a wipe

command is sent it wipes out all the personal data

on the smartphone. This can be used mostly when

the device is lost or stolen.

The integrity checking will check if the

commands were coming from a trusted server or

trusted service provider. This might stop the

commands sent from malicious users.

Basic methodology: This mechanism employs

password-based key derived function (PBKDF)

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which requires the users to put in a password and

get a 20 bytes long authentication code which is

the Hash-based Message Authentication Code

(HMAC).

Generating Message Authentication Code:

Initially the SMS notification is sent and the

remote control module first creates a secret key

from the password using PBKDF. Using HMAC

function with the secret key, the message

authentication code is generated on the command

message along with the timestamp. Then the

command message is sent with the MAC to the

designated smartphone.

Verifying Message Authentication Code: When

an authenticated SMS notification is received the

command handling module decodes it and checks

the MAC. Also the command handling module

computes a secret key from the passwords using

PBKDF and generates a MAC. Both the decoded

MAC and the re-generated MAC are compared

and the command is executed if they are equal and

ignored if they are not equal.

6. A BETTER APPROACH – Use Emergency

call mechanisms

The above described mechanisms works better

only when there is Wi-Fi or Internet connection,

SMS service, SIM card for cellular network

connection. But once a device is stolen an

adversary might initial either remove the SIM

card or disable the Wi-Fi. Hence a better approach

was designed. This approach utilizes the

“Emergency call mechanisms” to wipe of the data

on the stolen device.

Basic Idea: The basic idea of this approach is to

allow the smartphone use emergency call channel

of the cellular network to receive remote

commands. No normal calls are allowed when sim

card is unplugged, but they still can make

emergency calls such as 911 in the US. When the

smartphone detects the removal of the SIM card,

it will initiate a stealthy emergency call to the

wipe-out service provider, who will send back a

wipe-out command after confirming that the

phone has been lost or stolen. This whole process

is not known to the adversary.

Assumptions: In order to test how this approach

works the authors have made certain assumptions.

It was assumed that the adversary removes the

SIM card from a stolen smartphone and turn off

the Wi-Fi. Adversary is interested in obtaining its

locally stored data, but has not extract the storage

chips or transferred the user data before removing

the SIM card. Adversaries should not keep a

stolen smartphone switched off or position the

phone in an electromagnetic shielding

environment or keep the battery unplugged all the

time. The operator accepts the emergency call that

uses the IMEI as the identification. This number is

used to uniquely identify a stolen smartphone in

most countries. The SIM card used represents all

similar components which have the same

functionality in different networks.

Wipe-out system design: To enable wipe-out

service backstage application needs to be

installed. When the SIM card is removed it is

implied that the phone is stolen and the backstage

application asks for data erasure through making a

customized emergency call automatically and

stealthily. To remotely wipe sensitive data on a

stolen smartphone, the owner interacts with the

service provider as follows:

The owner subscribes to the remote wipe-

out service from the service provider and

registers his/her phone before it is stolen.

After a successful registration, the service

provider records the IMEI number of the

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phone in the IMEI database and marks its

state as normal.

The owner reports the loss and asks for

erasing the data on the device, as soon as

he realizes the lost of the smartphone.

After authenticating the user, the service

provider tags the associated item of the

reported phone as stolen in the IMEI

database.

Figure 2: Remote wipe – out framework

Procedure:

The smartphone attaches a deletion

indicator to an emergency call, and makes

this customized emergency call attempt on

the mobile cellular network. The IMEI is

used as the equipment identication.

The call control entity checks the state of

the smartphone in the IMEI database of

the service provider, after receiving the

request for setting up a customized

emergency call.

If the smartphone is tagged as stolen in the

database, the call control entity sends the

wipe-out command to the smartphone.

Otherwise, the call control entity responds

with a call accepted message which is the

same as the access permission for a normal

legal emergency call.

Device Registration: To remotely wipe sensitive

data on a stolen phone without the SIM card and

the WiFi connection, a user needs to subscribe to

the remote wipe-out service before the

smartphone gets lost. The owner registers the

service with identification information (e.g., ID

card information) that can uniquely identify

himself to the service provider and installs this

application on the smartphone. The service

provider records the IMEI number of the

registered smartphone and marks its state as

normal in the IMEI database.

Report of Lost Smartphone: If the smartphone

is stolen, the owner could request wipe-out

through a service call or web interface or sms.

Each service provider can implement his own

specific way and hence it depends on service

provider. Service provider must authenticate the

user before recording the report and perform

follow-up procedure. This is required because it

might be malicious users who requested the wipe

out. Hence the user needs to provide identity

information for authentication. When the user

reports the theft and the identity is verified

successfully, the service provider updates the

record of the stolen device in the IMEI database

by tagging its state as stolen.

RemoteWipe-Out: Emergency channel is used to

remotely control a stolen smartphone. Once the

smartphone detects the absence of the SIM card, it

asks for data erasure through emergency call. The

deletion indicator is attached to the emergency

call. The author states that just minimal

modifications are required for current protocols in

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implementation of this mechanism. The call

control entity checks the IMEI number in the

IMEI database of the service provider confirming

the state of the phone, and then decides whether

the device needs to be wiped out. If returned state

is stolen in the IMEI database, the call control

entity sends a wipe-out command to the device.

Security Analysis: The service provider verifies

the reporter's identity when a smartphone is

reported stolen. This prevents a malicious attacker

from misusing this system to falsely wipe another

user's smartphone. The user uses PIN code for

extra security which prevents the service provider

to wipe data accidently. This mechanism uses

secure deletion, but smartphone should not be

switched off or out of battery. When power is

back it continues secure deletion till it wipes off

all data.

Disadvantage: This mechanism only works when

the adversary removes the sim card. Also if the

user was not able to detect his lost of phone

before the adversary removes the sim card this

mechanism will not work. Also the adversary

should not keep the phone switched off.

MECHANISMS FOR REMOVING

UNWANTED SENSITIVE DATA

The sensitive data may be scattered widely

throughout the devices. Sometimes it may sit on

the devices even after it has been used and will no

longer be used or it might be used later in the

future but there is no certainty. Then in such type

of situations it is better to remove the unwanted

sensitive data from the devices so that there will

be less sensitive data on the devices that is

exposed to theft.

1. Shredding your garbage

Some sensitive data like passwords, social

security numbers, credit card numbers and

confidential documents often permeates systems

throughout user and kernel space for long periods

of time. The implications of all this sensitive data

being accessible past the end of its useful life will

be high, like, increasing the risk of losing the data

when the devices are lost, stolen or compromised.

This mechanism uses a strategy called secure

deallocation which reduces the lifetime of the

sensitive data in memory. In this the data is

removed from the memory after its last use.

Data life cycle has been used to provide a

conceptual framework for understanding the

lifetime of the data. By doing this we can

determine the effectiveness of secure deallocation.

Its mechanism is to do a First write after

allocation until explicit deallocation.

Secure deallocation zeros out sensitive

information when it’s finished being used that is it

clears the data at deallocation or within a short

time afterwards, which minimizes the data

lifetime. The best place to do deallocation is on

every layer. This Layered clearing of data makes

the secure deallocation worthy. It’s because

layered clearing ensures that data is cleared at

every layer of the system including user

applications, user libraries, and the OS Kernel.

Applications generally have good amount of

knowledge regarding the details of the sensitive

data like what data are sensitive, where the

sensitive data is and when the best time to clear

them is. But finding all the places where sensitive

data is situated and removing them all is a little

complex process. Hence it is complex and

laborious to identify all spots for deallocation.

Compilers handle all the implicit allocations

performed by programs like local variables

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allocated on the stack and hence they can handle

clearing data that the programs do not explicitly

control. But clearing data at this level can be

expensive.

Libraries handle the dynamic memory requests

made by the programs which can be considered as

the best place for clearing these requests. The

drawback here is that the programs have to

deallocate the data explicitly and as promptly as

possible.

Operating system kernels handles all of the

resources and acts as a final safety net for clearing

all the unused data which was not done in

previous stages.

The secure deallocation has also been evaluated

and it showed that it makes data last about 1.35

times longer on average than ideal case but much

less time than natural lifetime would be.

2. Vanish

Data privacy is becoming more concerning factor

in today’s society. Two formidable challenges to

privacy are Data lives forever and Retroactive

disclosure of both data and user keys has become

commonplace.

We have to empower users to control the lifetime

of data. This introduces the concept of Self-

destructing data. The goals of self-destructing data

model are:

Until timeout, users can read original

message.

After timeout, all copies become

permanently unreadable

even for attackers who obtain an

archived copy and user keys

without requiring explicit delete

action by user/services

without having to trust any

centralized services.

Traditional solutions like PGP, centralized data

management services, forward-secure encryption

are not sufficient for self-destructing data. Hence

we leverage peer to peer systems to Vanish.

Vanish combines global-scale Distributed Hash

Tables (DHTs) with secret sharing to provide self-

destructing data. It causes the sensitive

information, such as emails, files, or text

messages, to irreversibly self-destruct, without

any action on the user’s part and without any

centralized or trusted system.

There are a few limitations for DHTs when used

for vanish like applications.

3. SafeVanish

SafeVanish is an extension of Vanish which

includes some extra features to improve self-

destruction for protecting data privacy. It consists

of mainly three features.

First is Cascade, which is an extensible

framework for integrating multiple key-storage

mechanisms into a single self-destructing data

system. It enhances resistance to attack by

combining the security advantages of a diverse set

of key-storage approaches.

Second is Tide, a new key-storage system for self-

destructing data that leverages the ubiquity and

easy deployment of Apache Web Servers

throughout the Internet. It combines the

advantages of DHTs, such as wide scale

distribution, with advantages of centralized

systems, such as resistance to crawling attacks.

Third is to harden Vaze DHT used in the Vanish

and other DHTs against data harvesting attacks.

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4. Keypad

Keypad provides an auditing file system for theft-

prone devices. This mechanism provides two most

important features. First is, auditabiity and second

is, remote data control. With auditabiity we can

achieve fine grained file auditing which means a

user can know if the files have been accessed after

a device has been lost or stolen. With remote data

control, keypad gets the feature of disabling

future file accessing capability after a device is

lost. This can be done on the device even when

there is no network connectivity.

To get these features keypad uses encryption

combined with remote key storage. This means

that files are encrypted locally but encryption keys

are stored remotely. The basic idea of keypad is:

(1) encrypts each file with its own symmetric key,

(2) stores all keys on a remote audit service, (3)

downloads the key for a file each time it is

accessed and (4) destroys the key immediately

after use.

Also keypad uses an audit server with every

protected file access. This will prevent the new

accesses to the files if the device is stolen.

The primary goal of keypad is to provide strong

audit security. If the attacker gets access to a file

from a device and if the file is being protected by

the keypad’s remote audit server, the audit server

has to maintain at least one log entry and should

not be available to the attacker to tamper with.

5. Revocable Backup System

A revocable backup system enables the user to

remove files from both the file system and all

backup tapes. This means that the user has remove

files from file system and all backup tapes without

ever mounting a single tape.

In order to achieve this it uses cryptography. Here

cryptography is used to erase the information

rather than to protect it. The basic idea of

revocable backup system is: (1) the file will be

encrypted using a randomly generated key and

then written to tape (2) when the user wants to

remove the file from the backup tape he instructs

the system to “\forget” the key used to encrypt the

file. Now the data on the tape becomes useless

and cannot be accessed even by the owner of the

file. (3) Hence the file has been erased from the

tape.

CLOUD SERVICES

Cloud is an emerging trend. Several popular cloud

services offer remote data wipe options for

smartphones.

Issues with cloud

Some people don’t trust cloud. A paper “Home is

safer than Cloud” was published, which after

made an extensive research states that many

people would like to save their sensitive data on

the home storage rather than in cloud.

Mechanisms to improve security and privacy

in cloud

But recently many mechanisms have been

proposed and implemented to secure data which is

on cloud. Hence people started to use all the

capabilities and features provided by cloud

providers. The following are few mechanisms that

will improve privacy and security in cloud

1. CloudViews

To simplify the construction of web services

sharing is the key feature. There are mainly three

technological features for a shared-cloud, (1) free,

efficient, and plentiful network bandwidth that

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supports tighter and larger-scale web service

integration (2) a shared storage system that can

provide powerful abstractions for convenient,

efficient, and large-scale inter-service data sharing

and (3) the potential for a rich run-time ecosystem

consisting of many “utility” web services that act

as building blocks for other services and greatly

facilitate their implementation.

CloudViews provides a convenient, scalable and

efficient data sharing in public clouds. These can

be achieved by the Cloud DB, which takes

advantage of cloud technologies to support

sharing. The basic idea here is to provide

enhanced DB-style views for sharing, capabilities

for protection, query admission control and QoS

for resource allocation.

2. User driven privacy enforcement

Internet of things and cloud computing are an

emerging trend. But privacy is becoming a huge

hindrance in combining both these together from

both end user perspective and that of the service

providers’ perspective. In order to overcome these

privacy concerns and considerations User driven

Privacy Enforcement for Cloud-based services in

the Internet of things has been presented. In

includes mainly three things, which becomes the

backbone for UPECSI and they are privacy

enforcement points, model-driven privacy, and

user interaction. Configuring these on different

layers of abstraction minimizes critical privacy

concerns of different user groups and helps to

increase user acceptance promoting to use this

mechanism in further application areas.

3. Data security and privacy in cloud

computing

Data security and privacy are the two most

important factors considered by the cloud users

because data is stored in different places far from

the user. Security and privacy issues in cloud are

relevant to both hardware and software in the

cloud architecture. a number of techniques have

been proposed by researchers to address these

issues.

Data integrity which is the most critical factor in

cloud computing means, protecting data from

unauthorized deletion, modification, or

fabrication. By using a single database data

integrity can be maintained. Also by avoiding

unauthorized access, which can be checked for

with the help of monitoring the accesses, data

integrity can be achieved. Also the users have to

verify integrity of data in the cloud before

deploying the applications.

Data confidentiality is another important factor

because users have to store their most valuable

and sensitive data in cloud. This can be achieved

when the users store their data in encrypted form

rather than storing it directly. Techniques like

homomorphic encryption, encrypted search and

database, distributive storage, hybrid technique,

three layered data security technique, an event

based isolation, data concealment, deletion

confirmation can be used to achieve data

confidentiality.

Data availability is another important factor that

will make the data of the users always available to

them. Especially when the data is damaged

accidentally by hard disk damage, IDC fire, or

network failure, how soon the data can be

recovered and to what extent the users use the

data is data availability. Hence the service

provider has to offer reliable storage agreement

and reliability of hard drive.

Data privacy is the most important factor as this

provides authorization to access the stored data.

Only those users who have valid authorization

13

should access the data. The main privacy issues

are how to enable users to have control over their

data, how to guarantee the consistency of

replicated data, who is responsible for ensuring

legal requirements for personal information and if

any subcontractors are involved, to what extent

they can be involved. To overcome these issues

the cloud provides identity management, which

allows only trusted users to access the cloud and

their data.

These techniques will make the cloud service

consumers to accept the cloud services and use

them.

4. A secure cloud backup system with deletion

and version control

Data backups are very important for organizations

and they usually require huge space and costs to

store them. Hence the backups are now being

stored in cloud at a low cost. But providing

security to this data is important. For this a secure

cloud backup system that acts as a security layer

on top of today’s cloud storage services known as

FadeVersion has been proposed. Here the backups

are stored in cryptographic form and old versions

of backups are deleted and made inaccessible to

everyone. This is known as fine-grained assured

deletion.

FadeVersion is a secure cloud backup system that

serves as a security layer on top of today’s cloud

storage service. FadeVersion constitutes of two

independent systems to store data backups, a

version control system and an assured deletion

system and the main goal of this is to make these

systems compatible with each other into a single

design. The main advantage of using this is it

eliminates storage of redundant data and adds

minimal performance overhead.

5. Cloud data protection for masses

Cloud offers lower costs, scaling, easier

maintenance, service availability but the key

challenge for the cloud will be to keep data

secure. In order to improve security and privacy

for user data, a new cloud computing paradigm

named as data-protection-as-a-service has been

proposed.

Data protection as a service (DPaaS) enforces

fine-grained access control policies on data units

through application confinement and information

flow checking. It employs cryptographic

protections and offers robust logging and auditing

to provide accountability. It also reduces the per-

application development effort required to offer

data protection while still allowing rapid

development and maintenance. Cloud platform

providers have to provide the DPaas along with

the existing hosting environment.

CONCLUSION

There are many uses of mobile phones and hence

are the risks. Remotely wiping of data from lost

smartphones is a better approach to control the

loss of sensitive data. Hence few mechanisms

have been proposed which implements this

strategy. These techniques provide a good way of

wiping off the sensitive data on smartphones

which are stolen. These also have some

disadvantages. Some techniques can be combined

together to get the best of them.

FUTURE WORK

All the anti-theft mechanisms have some

disadvantages. Two possible solutions that might

be feasible are:

14

1. To have an internal sim so that it cannot be

seen and removed out.

2. To have all the data stored to the normal

sim card, so that as soon as the sim card is

removed no data can be seen on the

mobile phone as it stays with the sim card.

RELATED WORK

Remotely erasing data on smartphones is

becoming very important to remove sensitive

data. Many anti-theft schemes have been

proposed. CleanOS [6] is designed to limit mobile

data exposure with idle eviction. SafeCode [7] is

designed to safeguard security and privacy of user

data on stolen iOS devices using a PIN-based

security mechanism. SMS [9] provides a model

for remote access and protection of smartphones

using the short message service. Remote control

system [8] is designed for data protection and

backup in mobile devices. Remote lock and wipe

with Integrity Checking [10] erases the data by

sending lock and wipe commands to smartphones

from a remote machine with integrity checking.

But all these mechanisms should have internet

connection or cellular network connection. To

come across this use of emergency call

mechanism [5] has been proposed. This approach

uses emergency call channel to establish

connection with a service provider in order to

verify the state of phone and perform remote

action. There are some general techniques as well

which can be used for mobile devices. Shredding

[11] uses secure de-allocation to reduce lifetime

of sensitive data in memory. Vanish [12] uses a

self-destructing model for protecting data privacy.

SafeVanish [13] is an extension of vanish.

Keypad [14] is an auditing file system for theft-

prone devices. Revocable backup system [15]

enables user to remove files from both the file

system and all backup tapes.

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