A SIM card orSubscriber Identity Module is a portable memory chip used in some models of cellular telephones. The SIM card makes it easy to switch to a new phone by simply sliding the SIM out of the old phone and into the new one. The SIM holds personal identity information, cell phone number, phone book, text messages and other data. It can be thought of as a mini hard disk
that automatically activates the phone into which it is inserted.

A SIM card, also known as a subscriber identity module, is a subscriber identity module application on a smartcard that stores data for GSM/CDMA Cellular telephone subscribers. Such data includes user identity, network authorization data, personal security keys, contact lists and stored text messages. Security features include Authentication and encryption to protect data and prevent eavesdropping. The smartcard with Subscriber identity module application is generally known as SIMCARD. But, In reality, the SIM is effectively a mass-market smartcard. When the SIM is viewed as a smartcard, it opens up security possibilities that resonate far beyond the mobile world.

The GSM standards as specified by ETSI requires authentication of a mobile subscriber through a secure device (the SIM card). Subscriber information, such as the IMSI (International Mobile Subscriber Identity), is stored in the Subscriber Identity Module (SIM). The Subscriber Identity Module (SIM) can be used to store user-defined information such as phonebook entries. One of the
advantages of the GSM architecture is that the SIM may be moved from one Mobile Station to another. This makes upgrades very simple for the GSM telephone user. Why the SIM is card secure? SIM card in reality is a mass market smartcard with a subscriber identity module application. SIM Cloning cannot be confused with smartcard cloning. It is not possible to clone the smartcard and only data can be read when application allows the reading of the data.(SIM Cloning is covered below) Smartcard is very secure and provides:

  • The secure loading of the applications
  • Secure data storage for the application data and application cryptographic keys
  • Secure Crypto operation support. However, Application security depends on the application design and smartcard only provides a secure platform for developing secure applications.

The security of smart card is similar to the security offered by HSM (Hardware security module). Security of Subscriber Identity Module(SIM application) The Presence of Cryptographic algorithm and secret key in SIM card makes the SIM card secure. The most sensitive information of SIM card is the cryptographic algorithm A3, A8, secret Ki, PIN, PUK and Kc. A3, A8 algorithm were written into the SIM card in the producing process, and most people could not read A3, A8 algorithm. HN code could be settled by the phone owners. PUK code is held by the operator. Kc was derived in the process of encryption from Ki. The other factors which make the SIM secure are PIN and PUK:

  • PIN –Personal Identification Number 2 PINs exist (PIN 1 and PIN2) Limited attempts on PIN access
  • PUK –PIN Unblocking Code Resetting PUK, resets PIN and the attempt counter Too many attempts on PUK blocks use permanently.


The IMEI (International Mobile Equipment Identity) is a unique 17 or 15 digit code used to identify an individual mobile station to a GSM or UMTS network. The IMEI number provides an important function; it uniquely identifies a specific mobile phone being used on a mobile network.

The IMEI is a useful tool to prevent a stolen handset from accessing a network and being used to place calls. Mobile phone owners who have their phones stolen can contact their mobile network provider and ask them disable a phone using its IMEI number. With an IMEI number, the phone can be blocked from the network quickly and easily.

It is important to note that swapping a SIM card will not stop a phone from being banned. IMEI numbers are stored in the phones themselves, not on the SIM cards. An IMEI is only used to identify the device and does not relate to a specific individual or organization. Other numbers such as the ESN (Electronic Serial Numbers) and MEID (Mobile Equipment Identifiers) can link an individual to a phone. Usually, an IMSI number stored on a SIM card can identify the subscriber on a network.

There are several ways in which you can locate your mobile phone’s IMEI number. The IMEI can usually be found on the handset, beneath the battery, sometimes printed on a small white label. Another way to easily locate your IMEI phone is to dial the following sequence of numbers into the handset: *#06#. If you have a Sony Ericsson mobile phone, you can retrieve the IMEI by pressing the following key sequence: right,*, left, left,*, left, *, left.


A mobile operating system, also known as a mobile OS, mobile software platform or a handheld operating system, is the operating system that controls a mobile device or information appliance— similar in principle to an operating system such as Windows, Mac OS X, or Linux distributions that controls a desktop computer or laptop. However, they are currently somewhat simpler, and deal more with the wireless versions of broadband and local connectivity, mobile multimedia formats, and different input methods.

Typical examples of devices running a mobile operating system are smartphones, personal digital assistants (PDAs), tablet computers and information appliances, or what are sometimes referred to as smart devices, which may also include embedded systems, or other mobile devices and wireless devices.



Android is a Linux-based operating system designed primarily for touch screen mobile devices such as smartphones and tablet computers. Initially developed by Android, Inc., whom Google financially backed and later purchased in 2005, Android was unveiled in 2007 along with the founding of the Open Handset Alliance: a consortium of hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices. The first Android-powered phone was sold in October 2008. Most recent release is 4.2.1 (jelly bean) on November 27, 2012.

Android Architecture
Android is a software stack for mobile devices that includes an operating system, middle ware and key applications. The following diagram shows the major components of the Android operating system.


Figure: Android Architecture


Applications: These are applications written in Java. Some of basic applications include a calendar, email client, SMS program, maps, making phone calls, accessing the Web browser, accessing your contacts list and others.If you are an average user, this is the layer you will us most, rest all layers are used by Google programmers, developers and hardware manufacturers.

Application Framework: This is the skeleton or framework which all android developers has to follow. The developers can access all framework APIs an manage phone‘s basic functions like resource allocation, switching between processes or programs, telephone applications, and keeping track of the phone‘s physical location.Thearchitectureis well designed to simplify the reuse of components. Think of the application framework as a set of basic tools with which a developer can build much more complex tools.

Libraries: This layer consists of Android libraries written in C, C++, and used by various system. These libraries tells the device how to handle different kinds of data and are exposed to Android developers via Android Application framework. Some of these libraries includes media , graphics, 3d,SQLite,web browser library etc.The Android runtime layer which includes set of core java libraries and DVM (Dalvik Virtual Machine) is also located in same layer.

Runtime Android: This layer includes set of base libraries that are required for java libraries. Every Android application gets its own instance of Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently and it executes files in executable (.Dex) optimized for minimum memory.


Android GUI is single-threaded, event-driven and built on a library of nest able components. The Android UI framework is organized around the common Model-View-Controller pattern.

The Model: The model represents data or data container. You can see it as a database of pictures on your device. Say, any user wants to hear an audio file, he clicks play button and it triggers an event in your app, now the app will get data from data store or database and as per input and creates data to be sent back to the user. You can refer this data as Model.

The View: The View is the portion of the application responsible for rendering the display, sending audio to speakers, generating tactile feedback, and so on. Now as per above example, the view in a hypothetical audio player might contain a component that shows the album cover for the currently playing tune. User will always interact with this layer. User actions on this layer will trigger events that will go to the application functions.

The Controller: The Controller is the portion of an application that responds to external actions: a keystroke, a screen tap, an incoming call, etc. It is implemented as an event queue. On User‘s action, the control is passed over to controller and this will take care of all logic that needs to be done and prepare Model that need to be sent to view layer.


The operating system used by BlackBerry devices is a proprietary multitasking environment developed by RIM. The operating system is designed for use of input devices such as the track wheel, track ball, and track pad. The OS provides support for Java MIDP 1.0 and WAP 1.2. Previous versions allowed wireless synchronization with Microsoft Exchange Server email and calendar, as well as with Lotus Domino email. OS 5.0 provides a subset of MIDP 2.0, and allows complete wireless activation and synchronization with Exchange email, calendar, tasks, notes and contacts, and adds support for Novell GroupWise and Lotus Notes. The Blackberry Curve 9360, Blackberry Torch 9810, Bold 9900/9930, and Torch 9850/9860 contains feature of Blackberry OS 7 & most recent release is (BlackBerry Bold 9900) on November 28, 2012.


BlackBerry OS is programmed to carry out multiple tasks at a time. It uses some special input devices like the scroll wheel, the trackball and the track pad which are present on the phone. The operating system supports the Java mobile information device profile (MIDP) 1.0 and the Wireless Application Protocol (WAP) 1.2. Java has MIDP as a specification which is used for mobile devices. WAP is a protocol that supports the WAP browser. The WAP browser is similar to the web browsers used on a computer. The WAP technology is used to access internet from the mobile phones. A complete wireless synchronization is permitted by the BlackBerry OS with the calendar, tasks, contacts, exchange e-mail and notes.

These functions are performed by a software, BlackBerry Enterprise Server (BES) that is a part of the OS. An alternative to BES is the BlackBerry Internet Service (BIS). It allows internet access to the users. Also the user can make use of POP3, IMAP and Outlook web access e-mail accounts without even logging in through a BES. The push technology of RIM is used in this service. BIS is the service that in actual is run by RIM but it is provisioned to you through your mobile service provider. There are automatic updates for the BlackBerry OS available from wireless carriers that support the over the air software loading (OTASL) service provided by BlackBerry OS. The BlackBerry OS has an Application Programming Interface (API). Using API classes, third-party
programmers can write the source code for their application programs. The BlackBerry OS uses a Graphical User Interface (GUI). The GUI enables the users to carry out interaction with applications and softwares on your mobile phone in ways other than typing.


iOS (formerly known as iPhone OS) is Apple’s mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple, Inc. devices such as the iPod Touch, iPad, and Apple TV. Apple, Inc. does not license iOS for installation on third-party hardware. As of October 4, 2011, Apple, Inc.’s App Store contained more than 500,000 iOS applications, which have collectively been downloaded more than 18 billion times. It had a 26% share of the smartphone operating system units sold in the last quarter of 2010, behind both Google’s Android and Nokia’s Symbian. In May 2010 in the USA, it accounted for 59% of mobile web data consumption (including use on both the iPod Touch and the iPad).

The user interface of iOS is based on the concept of direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. The response to user input is immediate and provides a fluid interface. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multitouch interface. Internal accelerometers are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode). The most recent stable release for iPhone and iPod Touch, iOS 13.3, was released on December 10, 2019.


Symbian is a mobile operating system (OS) and computing platform designed for smartphones and currently maintained by Accenture.The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user interface component based on S60 5th Edition. The latest version, Symbian^3, was officially released in Q4 2010, first used in the Nokia N8. In May 2011 an update, Symbian Anna, was officially announced, followed by Symbian Belle in August 2011.

Symbian OS has a microkernel architecture, which means that the kernel responsibilities are reduced to an essential minimum to improve robustness, availability, and responsiveness. It contains a scheduler, memory management, and device drivers. The Kernel Services layer includes the core kernel services (e.g. memory management, process management, and power management) as well as the device drivers and kernel extensions. The Base Services Layer is the lowest level reachable by user-side operations; it includes the File Server and User Library, telephony services, the Plug-In Framework, Store, Central Repository, DBMS (Database Management System), and cryptographic services.Other services like graphics, PC connection (Bluetooth, IrDA, and USB), networking and multimedia support are placed in the OS Services Layer.

The application services provide middleware functionality to manage user data. Symbian provides an API (Application Programming Interface) that allows programmers leverage the functionality and incorporate it into their applications. These services are personal information management, messaging, browsing and data synchronization.Symbian OS is designed to emphasize compatibility with other devices; especially removable media file systems (e.g. memory cards like secure digital cards (SD cards) or multimedia memory cards (MMC)).

There is a large networking and communication subsystem, which has three main servers – ETEL (EPOC telephony), ESOCK (EPOC sockets) for TCP/IP connections and C32 (responsible for serial communication like IrDA or USB). All Symbian applications are built up from three classes defined by the Application Architecture: an application class, a document class, and an application user interface class.Once developed, Symbian OS applications are packaged in files with SIS-extension, which may be installed over-the-air, via PC connect, via Bluetooth or memory cards. Mobile devices with Symbian OS are able to communicate with desktop PCs – data backup, transformation of documents from formats of PC applications to Symbian OS formats, up to synchronization of the desktop PCS and mobile devices with Symbian OS at home and at work.

These requirements have been considered at creation of Symbian OS The most subject to virus attacks and the most vulnerable for them is the Symbian platform. Usually the viruses send themselves from phone to phone via Bluetooth. None of them have taken advantage of any flaws in Symbian OS – instead of this, they have all asked the user whether they would like to install the software. The new version 9.X of Symbian OS has the Platform Security in comparison to old Symbian versions. Symbian is able to detect unauthorised access to hardware and attempts to read or write restricted data etc. Capabilities protect the APIs (Application programming interface) against access to confidential user data, changing the network configuration and access network services like Bluetooth connections to other phones.


Windows Mobile is an operating system combined with a suite of basic applications for mobile devices based on the Microsoft Win32 API. It is designed to be similar to desktop versions of Windows. Originally appearing as the Pocket PC 2000 operating system, Windows Mobile has been updated several times, with the current version called Windows Mobile 6. Windows Mobile runs on multiple hardware platforms including Pocket PCs,mobile phones, Portable Media Centre, and automotive applications. Pocket PC 2000, was released in April of 2000, was based on Windows CE 3.0 and was intended basically for Pocket PC devices.

The single resolution supported by this release was 240×320 (QVGA – Quarter Video Graphics Array). Supported removable storage cards were Compact Flash (CF) and Multimedia Card (MMC). Pocket PC 2002 (released in October 2001) was used the first time for smartphones. Windows Mobile 2003 (released in June 23 2003) was the first release under the name Windows Mobile. The next version (Windows Mobile 5.0) was released in May 2005, powered by Windows CE 5.0 and used the .NET Compact Framework 1.0. The version of Windows Mobile platform (Windows Mobile 6) was released on February 12, 2007 and is available with three different versions:”Windows Mobile 6 Standard” for mobile phones without touchscreens, “Windows Mobile 6 Professional” for Pocket PCs with phone functionality and “Windows Mobile 6 Classic” for Pocket PCs without cellular radios and with touchscreen.

  • Customizable screen shows the current date, owner information, upcoming appointments, e-mails, and tasks
  • Office Mobile, including Word Mobile, Excel Mobile and Power Point Mobile. These versions include many of the features, which are used in desktop versions. ActiveSync has capabilities, which convert desktop versions of files to Office Mobile compatible versions.
  • Outlook Mobile with POP31 (Post Office Protocol version three) and IMAP42 (Internet Message Access Protocol version four) access
  • Windows Media Player supporting music and video files
  • Client for PPTP VPNs (Point-to-Point Tunneling Protocol, Virtual Private Network)
  • VoIP (Internet calling)
  • Enhanced Microsoft Bluetooth Stack
  • Storage Card Encryption (encryption keys are lost if device is cold-booted).


Bada (stylized as bada; Korean: 바다) is an operating system for mobile devices such as smartphones and tablet computers. It is developed by the Samsung Electronics. Its name is derived from “바다 (bada)”, meaning “ocean” or “sea” in Korean. It ranges from low-end feature phones to high-end smartphone.


The Samsung S8500 Wave was launched with version 1.0 of the Bada operating system. Soon after the launch, Samsung released version 1.0.2, which included minor fixes for European users. It will be available for the rest of the world in the near future. The latest version 1.2 was released with the Samsung S8530 Wave II phone. The alpha-version of Bada 2.0 was introduced on February 15, 2011, with Samsung S8600 Wave III 7.

The device-side of bada has an architecture that consists of four layers (presented here from bottom up):

This layer contains either the real-time operating system or the Linux kernel, depending on device hardware configuration.

This layer contains the core functions of the mobile device platform that are provided by the device operating system, graphics and multimedia functionality, and communication components. These functions include, for example, telephony, security, graphics, and event and window management.

This layer contains the service-oriented functions that are provided by application engines and server-assisted components. The application engines provided by the service layer include Contact and Messaging engines. The server-assisted features are provided by RESTful Web- service components that inter-connect with the service components of the bada Server. This enables applications to manage data that is stored on remote servers, such as geographic information and user presence information. Access to the server-assisted features is possible through APIs on the Framework layer.

This layer contains the open API framework of bada. It consists of the application framework, as well as interfaces and classes that provide access to the functionality on the underlying layers. The application framework provides features for application life-cycle management, event handling and application controls. The interfaces provided by the open API framework include several basic interfaces that are needed by all applications for handling data types, utilities, basic device features and application state and for creating the graphical user interface. The API framework also contains interfaces related to UI, multimedia, communication, internationalization, location, security, commerce and Web browsing, as well as interfaces that provide access to the services provided by the underlying service layer.


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