Mobile Handsets - Computer Science and Engineering

Mobile Handsets - Computer Science and Engineering

Mobile Handsets: A Panoramic Overview Outline Introduction Handset Architecture Handset Operating Systems Networking Applications Security Risks and Mitigation Strategies

What Is A Mobile Handset? A mobile handset (handset) is an electronic device that provides services to users, e.g.: Managing address book Scheduling calendar Cellular telephony Accessing Internet, email Handsets include smartphones and PDAs

Example handsets: Apple iPhone, BlackBerry Storm, Palm TreoPro Handsets: Your Next Computer? Handsets small form factor, mobility have yielded meteoric sales [1] 3.3 billion mobile phone subscriptions as of Jan. 2008 (how about 2013 or 2014?) 2.7 billion subscriptions correspond to one person; some people have multiple phones! Rapid replacement rate: young adults replace phones every 6 months in South Korea [1] These statistics are just for phones Your handset: your next computer? [2]

Whats Inside a Mobile Handset? Source: [3] Handset Architecture (1) Handsets use several hardware components: Microprocessor

ROM RAM Digital signal processor Radio module Microphone and speaker Hardware interfaces LCD display Handset Architecture (2) Handsets store system data in electronically-erasable programmable read-only memory (EEPROM) Service providers can reprogram phones without requiring physical access to memory chips OS is stored in ROM (nonvolatile memory) Most handsets also include subscriber

identity module (SIM) cards Handset Microprocessors Handsets use embedded processors Intel, ARM architectures dominate market. Examples include: BlackBerry 8700, uses Intel PXA901 chip [4] iPhone, uses Samsung ARM 1100 chip [5] Low power use and code size are crucial [3] Microprocessor vendors often package all the chips functionality in a single chip (package-on-package) for maximum flexibility Example: The iPhones CPU The iPhone: a realworld mobile handset [67]

Runs on Samsung S3C6400 chip, supports ARMv6 architecture Very few details are known about the ARM Core, esp. given Apples secrecy Highly modular architecture Similar to Apples iPod Touch, which lacks telephony capability [8] Source: [6] SIM Cards They include their own microprocessor and 16 KB 4 MB EEPROM They come in two sizes

Their versatility arises from portability of information SIM card identifies subscriber to network Stores personal information, address books, messages, service-related information Other Memory Cards Some handsets include other peripheral memory cards: Compact Flash Multimedia Card Secure Digital Handsets synchronize with a computer Nowadays, computers include slots of various sizes to hold these memory cards Handset Operating Systems

Currently, handsets run several OSes: Symbian OS iPhone OS (an embedded version of OS X) Windows Mobile BlackBerry OS Google Android Platform (based on Linux) With the exceptions of Symbian and Android, these OSes are proprietary [910] Telecom carriers frequently lock down handset firmware, OSes to prevent user modifications

Handset OS Usage According to British analysis firm Canalys, handset OS usage in 3Q 2008 had the following ranking (most to least): [11] 1. 2. 3. 4. 5. 6. Symbian OS iPhone OS

BlackBerry OS Windows Mobile Linux (Android, etc.) Others iPhone OS surged ahead of BlackBerry OS, but with new BlackBerries and Android phones, this ranking may easily change in the future [11] (What is the ranking now?) Well now examine each OS individually Symbian OS Dominant OS in the mobile handset market (This is the case of 2008. How about now? why?) Runs exclusively on ARM processors Owned by British firm Symbian Ltd. Descendant of Psion EPOC OS (dev. in 1990s) Sony Ericsson, Nokia, et al. bought shares in the firm until Nokia bought Symbian in 2008,

formed Symbian Foundation to further future open handset development [12] Nokia plans to open-source the OS by 2009 [9] Design of Symbian OS Based on Psion EPOC; desktop OS features include: [13] Bare-bones microkernel (nanokernel) Pre-emptive multitasking Memory protection Handset-centric design, can operate several months without reboot Supports multiple UIs based on smartphone form factor (e.g., 320 240) Symbian OS Devices Numerous handsets use Symbian OS; UIs

largely based on manufacturer & device Nokia S60: includes J2ME, std. UI (mostly Nokia phones) Nokia S80: QWERTY keyboard, Web browser, enterprise office-doc. support (older Nokia Communicators) Nokia S90: used only on Nokia 7710 UIQ: Sony Ericsson/Motorola GUI platform used primarily on those companies handsets FOMA platform: closed-dev. software platform used by handsets on NTT DoCoMos network (Japan) Symbian OS v9 Architecture Source: [15] (heavily modified) Symbian OS Development

Native language is C++ Nokia provides free Eclipse-based Carbide.c++ development tools, Carbide.vs Visual Studio plugin Mac & Linux development is possible Can program in many other languages: C, Java, Ruby, Python, Perl, OPL, Visual Basic, Simkin Applications needing any capabilities beyond bare minimum must be cryptographically signed (see Can also program in Adobe Flash Lite (mobile version of Flash) iPhone OS Runs on both the iPhone and iPod Touch Variation of Mach microkernel-based OS X that fits in 512 MB flash memory, runs on ARM architecture [21] Four abstraction layers: Core OS, Core

Services, Media, Cocoa Touch [22] Core Animation and PowerVR MBX 3D hardware provide interface animations 320 480 LCD display that supports multi-touch gestures iPhone Developer Program iPhone Developer Program provides dev. tools, iPhone emulator, means to upload to App Store (SDK) To download SDK, you must apply to be a member, pay fees Standard Developer: $99 Enterprise Developer: $299 Exception: Apples free iPhone Developer University Program for higher-ed. institutions [23] SDK only runs on Mac OS X Leopard on Intelbased Macs (go figure)

iPhone Web App Development You can develop Web apps for iPhone so long as they run on Safari [24] Safari features: [2526] Auto-resizes Web pages to fit browser size Multi-touch functionality XHTML 1.1, CSS 2.1, JavaScript, W3C DOM Level 2, AJAX technology, cookies, Does not support Flash or Java iPhone Web apps should: Minimize user awareness of browser experience Reproduce control style, layout, behavior of iPhone apps Integrate with built-in iPhone features & services BlackBerry OS BlackBerry OS is Research in Motions (RIMs) proprietary OS for its BlackBerry

handsets Provides multitasking, heavily uses BlackBerry input devices, e.g., thumbwheel Current OS 4 provides a subset of Javas Mobile Information Device Profile (MIDP) 2.0 Developers can use these APIs, proprietary APIs to write software All applications must be digitally signed so to link an app with the developer BlackBerry Software Email from BlackBerry service, MS Exchange, Domino, Yahoo, etc. can be pushed to the handset Can view PDF, MS Word, Excel, PowerPoint attachments BlackBerry Browser (only supports JavaScript) Other online apps include: BlackBerry Maps Facebook services

Yahoo Messenger, Google Talk Calendar, Address Book, and PIM Sync via USB GPS See for much more information about handset and desktop software BlackBerry Wireless Platform RIM provides standards-based platform and developer tools to develop and deploy custom wireless applications HTML Web browser Java Mobile Edition development tools .NET applications BlackBerry handsets support standard networking protocols and connect to any type of server application

BlackBerry Mobile Data System BlackBerry Mobile Data System (MDS) supports MS Exchange, Lotus Domino, Novell GroupWire, and RIMs own MDS systems for messaging applications BlackBerry Mobile Voice System With this service, theres only one business number BlackBerry users must remember Calls are routed to a BlackBerry handset, regardless of whether the call is directed to an office or mobile phone [27] Provides security and authentication through BlackBerry Enterprise Servers [28] IT administrators can lock down handsets, route calls through their telecom infrastructure, etc. [2728]

BlackBerry Internet Services BlackBerry Internet Service leverages centrallyhosted wireless gateways, allowing users to access up to 10 supported email accounts, browse Internet BlackBerry Developer Tools RIM provides several development tools: BlackBerry MDS Studio Developers can quickly create rich client apps using component-based drag-and-drop approach Tool requires MDS runtime BlackBerry plugin for MS Visual Studio (development on MDS platform) BlackBerry Java Development Environment (JDE) Provides IDE, simulation tools for Java ME app for Java-based BlackBerry so developers can create

standalone or client-server apps Windows Mobile Windows Mobile is powered by Microsofts Windows CE embedded OS; Windows CE runs on x86, MIPS, ARM, Hitachi SuperH processors Latest version, 6.1, includes Windows Live services, Exchange 2007 mail access Designed to closely mimic desktop Windows: Windows Mobile 6.1 includes mobile versions of Office applications, Outlook (w/HTML email), Internet Explorer, Windows Media Player SQL Server 2005 included in ROM .NET Compact Framework 2.0 included Windows Mobile Development (1)

Native code is developed with MS Visual C++ Microsoft strongly recommends development with managed code [19] Managed code is written in one of the .NET framework object-oriented languages Compiled to MS Intermediate Language (MSIL) that all the languages share

At execution time, MSIL is compiled just in time to native object code Contrast with Java: Java code is compiled to Java bytecode Java interpreter interprets bytecode, dynamically compiles frequently-accessed bytecode into native object code (HotSpot) .NET Framework in Context. Source: [19] Windows Mobile Development (2)

Windows Mobile development tools include: Plugins for MS Visual Studio 2005, 2008, etc. SDKs for Windows Mobile-based handsets Microsoft gives away Visual Studio to students for free with its DreamSpark program [20] Android Mobile Handset Platform Android is a software development platform for mobile handsets that is based on Linux

Developed by Google and Open Handset Alliance (OHA) for different handset manufacturers The Alliance includes T-Mobile, Sprint Nextel, Google, Intel, Samsung, Wind River Systems, et al. [29] Its purpose is to build a fully free and open mobile handset platform to facilitate development of handsets, software, services [30] First Android-based handset is T-Mobile G1 [31] Android Architecture

Android Features and Software Features 3D: OpenGL ES 1.0 SQLite: Database engine WebKit: Web browser Dalvik: Register-based VM similar to Java VM [32] FreeType: Bitmap and vector font rendering

Connectivity: Bluetooth, 802.11, GPS Core Applications Email client, SMS program, calendar, Google Maps (and Apps), browser, etc. Written in Java App Framework Full access to same framework APIs Architecture designed for component reuse Runtime Core C++ library Multiple Dalvik VMs run in a process, rely on Linux kernel

for process isolation [32] Android SDK Android SDK provides required tools and APIs to develop apps on Android platform using Java Android is licensed under the Apache opensource license The Android Development Tools (ADT) Eclipse plugin eases development Download the Android SDK at and the Eclipse plugin at A Quick Summary on Handset OSes iOS Android

Windows Phone BlackBerry OS Symbian OS Company Apple Open Handset Alliance, Google Microsoft Research in Motion

Accenture on behalf of Nokia Open Source? No Yes No No Yes OS Family Darwin

Linux Windows NT QNX Psions EPOC Supported CPU Architecture ARM, ARM64 ARM, x86, MIPS, 64-bit variants of each

ARM ARM ARM, x86 Programming Language C, C++, Objective-C, Swift C, C++, Java C# (.NET), VB.NET, C, C++, DirectX

C, C++, HTML5, JavaScript, Java ME C, C++, Java ME, Python Development Cost $0 (univ.), $99/yr. (person), $299/ yr. (corp.) $0 $0

$0 $0 App Store Publishing cost Included in dev. cost $25 one-time $0 (1 yr., student) $19/yr. (person), $99/yr. (corp.) $0

$0 36 Handset Networking Handsets communicate with each other and with service providers via many networking technologies There are two classes of these technologies: Cellular telephony Wireless networking Most handsets support both, some also support physical connections such as USB Cellular Telephony Basics (1) There are many types of cellular services; before delving

into details, focus on basics Cellular telephony is a radio-based technology; radio waves are electromagnetic waves that antennas propagate Most signals are in the 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz frequency bands (Frequency, Bandwidth, Transmission speed?) Cell phones operate in this frequency range (note the logarithmic scale) Cellular Telephony Basics (2) Digital signal processors (DSPs) are key to radio reception in handsets They transform signals from one

form to another, e.g.: Fourier transforms Discrete cosine transform Source: [3] Cellular Telephony Basics (3) Cells and base stations Space is divided into cells, and each cell has a base station (tower and radio equipment) Base stations coordinate themselves so mobile users can access the network

If you move from one cell to another, the first cell notices your signal strength decreasing, the second cell notices your signal strength increasing, and they coordinate handover so your handset switches to the latter cell Cellular Telephony Basics (4) Statistical multiplexing Time Division Multiple Access (TDMA) A 30 kHz-wide and 6.7 ms-long band is split into 3 time slots Each conversation gets the radio 1/3 of the time; voice data is converted to digital information and compressed to use less transmission space

Cellular Telephony Basics (5) Statistical multiplexing contd. Frequency Division Multiple Access (FDMA) Analogous to TDMA, but each conversation uses a different frequency in the same band Code Division Multiple Access (CDMA) [38] Uses spread-spectrum technology and different pseudo-noise codes so multiple users share the same physical channel Cellular Telephony It is useful to think of cellular telephony in terms of generations: [3337]

0G: Briefcase-size mobile radio telephones 1G: Analog cellular telephony 2G: Digital cellular telephony 3G: High-speed digital cellular telephony (including video telephony) 4G: IP-based anytime, anywhere voice, data, and multimedia telephony at faster data rates than 3G (to be deployed in 20122015) Other Handset Networks Many handsets not only support cellular telephony, they support other networking technologies as well: Wireless

Bluetooth (100 m max, 10 m for handsets) IEEE 802.11 (longer range) Infrared Data Association (IrDA) Wired USB, etc. Bluetooth Bluetooth is a technology specification for small form factor, low-cost, short-range wireless links between mobile handsets, Internet connectivity Max range is 100 m in 2.4 GHz frequency band (handsets: 10 m radios) There is possible interference with IEEE 802.11b WLANs operating in this band Max bandwidth is 3 Mbps for Bluetooth 2.x with Enhanced Data Rate

IEEE 802.11 Networks The IEEE 802.11 standards specify how electronic devices communicate with each other in wireless fidelity (Wi-Fi) networks Many handsets can communicate with each other this way There are many 802.11 standards [53]; well only look at 802.11b, 802.11g, and WiMax here Other 802.11 standards provide greater security, which well discuss later IEEE 802.11 & WiMax Specs. 802.11b (1999): [51, 53] Operates in the 2.4 GHz frequency band Provides max 11 Mbps data rate 38 m indoor range

802.11g (2003): [51, 53] Operates in either 2.4 GHz or 5 GHz frequency bands Provides max 54 Mbps data rate 38 m indoor range WiMax (802.16): [52] Operates in 2.3 GHz, 2.5 2.6 GHz frequency bands Provides max 40 Mbps data rate now, 300 Mbps later 3 km cell range Wired Networks: USB The Universal Serial Bus (USB) is a ubiquitous standard for transferring data between computers (including handsets!) [55] By definition, data is transferred one bit at a time USB 1.1 (1998): max 1.5 Mbps (low-speed), 12 Mbps (full-speed)

USB 2.0 (2000): max 480 Mbps USB 3.0 (to be released in 2009 2010): max 5 Gbps Handset Applications Many handset applications mirror those of computers, e.g., managing ones schedule, Web browsing, etc. But handsets mobility is opening up new markets Global mobile gaming market value expected to reach 2.6 billion ($3.27 billion) in 2012 Global mobile advertising market value expected to reach 1.77 billion ($2.23 billion) in 2012 Also, handsets make mobile and locationbased services possible, which well discuss next Mobile & Location-based

Services Mobile social computing Large-scale mobile collaboration Mobile data E-Shadow: An Example of Mobile Social Computing System Key Handset Security Problems At this point, mobile device capability is far ahead of security. Prof. Patrick Traynor, Georgia Tech (emphasis added) [62] Handset information can be stolen [63] Transient information: Enhanced 911 can provide user location information Static information: BlueSnarfing attacks (connection without owners knowledge), cracking Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA) [64]

Theft of service attacks, e.g., premium-rate calls/SMS messages [63] Denial-of-service attacks [63] Flooding attacks overload the handset radio with garbage Power-draining attacks attempt to drain the battery Botnets and DoS attacks against networks are likely in the future [62] Cybercriminals make 10 as much as security researchers! [69] The Challenges Ahead [Because] the mobile communications field is evolving so quickly, it presents a unique opportunity to design security properlyan opportunity we missed with the PC. Prof. Patrick Traynor [62] Since most people buy a new handset every 2 years, its vital to ensure the security of handset hardware, OSes, applications, and networks while maintaining usability [62] One suggested approach is to give handsets a hard power-off

switch so they dont have power when turned off [63]] Academic research will play a key role in this, as will user education to counter social engineering Given the sensitivity of information stored on handsets, cybercriminals may well find effective ways to use them to continue their nefarious acts, e.g., bot herding, data theft, etc., even with different operating systems, power constraints, and carriers Questions? Thank you! Electromagnetic Frequency Spectrum Adapted from References (1)

1. 2. 3. 4. 5. 6. 7. 8. T. T. Ahonen, When there is a mobile phone for half the planet: Understanding the biggest technology, 16 Jan. 2008, brands/2008/01/when-there-is-a.html A. Wolfe, Is the Smartphone Your Next Computer?, InformationWeek, 4 Oct. 2008, showArticl e.jhtml?articleID=210605369 J. L. Hennessy and D. A. Patterson, Computer Architecture: A Quantitative

Approach, 4th ed., Elsevier, 2007 Research in Motion, BlackBerry 8700c Technical Specifications, R. Block, iPhone processor found: 620MHz ARM CPU, Engadget, 1 Jul. 2007, Samsung Semiconductor, Product Technical Brief: S3C6400, Jun. 2007, 8/21/661267ptb_s3c6400_rev15.pdf Wikipedia, iPhone, updated 15 Nov. 2008, Wikipedia, iPod Touch, updated 14 Nov. 2008, Ipod_touch References (2) 9. 10. 11. 12. 13.

14. 15. 16. N. Cubrilovic, Symbian Goes Open Source Courtesy of Nokia, TechCrunchIT, 24 Jun. 2008, urtesy-of-nokia/ Android An Open Handset Alliance Project, Canalys, Global smart phone shipments rise 28%: Nokia retains lead, but Apple moves into number two position, 6 Nov. 2008, Press Release, Nokia, Nokia to acquire Symbian Limited to enable evolution of the leading open mobile platform, 24 Jun. 2008, Press Release, Wikipedia, Symbian OS, updated 13 Nov. 2008, Symbian_os

Symbian Ltd., Symbian OS, B. Morris, Symbian OS Architecture Overview, Wireless Developer Forum UK 06, Symbian Software Ltd., orris.ppt?version=1 Wikipedia, Palm OS, updated 3 Nov. 2008, Palm_os References (3) 17. 18. 19. 20. 21. 22. 23. 24.

Wikipedia, Windows Mobile, updated 13 Nov. 2008, wiki/Windows_mobile Wikipedia, Windows CE, updated 12 Nov. 2008, Windows_CE Microsoft Corp., .NET Framework Conceptual Overview, MSDN, 2008, Microsoft Corp., Microsoft Gives Students Access to Technical Software at No Charge to Inspire Success and Make a Difference, 18 Feb. 2008, Press Release, px K. Haslem, Macworld Expo: Optimised OS X sits on versatile Flash, 12 Jan. 2007, Macworld, index.cfm?newsid=1692 7 Wikipedia, iPhone OS, updated 16 Nov. 2008, IPhone_OS Apple Inc., iPhone Developer University Program, 2008, Apple Inc., Apple Developer Connection Web Apps Dev Center, 2008, References (4) 25. 26. 27. 28. 29. 30. 31. 32. Apple Inc., Apple iPhone Features Safari, 2008, Apple Inc., Safari 3.1 Product Overview, Jun. 2008,

.pdf Research in Motion, BlackBerry Mobile Voice System, 2008, A. Succo, RIM exec sees BlackBerry product as shaping telephony, 22 May 2008, InfoWorld, rry-product-as-shaping-telephony.html Open Handset Alliance, Members, oha_members.html Open Handset Alliance, Overview, oha_overview.html Wikipedia, Android (mobile device platform), updated 16 Nov. 2008, Google Inc., What Is Android?, 2008, References (5) 33. 34.

35. 36. 37. 38. 39. 40. 41. 42. 43. 44. Wikipedia, Mobile radio telephone, updated 6 Jul. 2008, Wikipedia, 1G, updated 6 Aug. 2008, Wikipedia, 2G, updated 18 Nov. 2008, Wikipedia, 3G, updated 19 Nov. 2008, Wikipedia, 4G, updated 11 Nov. 2008, Wikipedia, Code division multiple access, updated 30 Oct. 2008,

Wikipedia, GSM, updated 14 Nov. 2008, Wikipedia, IS-95, updated 10 Oct. 2008, Wikipedia, Short message service, updated 19 Nov. 2008, Wikipedia, Multimedia messaging service, updated 3 Nov. 2008, Wikipedia, Enhanced Data Rates for GSM Evolution, updated 19 Nov. 2008, wiki/Enhanced_Data_Rates_for_GSM_Evolution Wikipedia, CDMA2000, updated 17 Nov. 2008, CDMA2000 References (6) 45. 46. 47. 48. 49. 50. 51.

52. 53. 54. Wikipedia, Universal Mobile Telecommunications System, updated 18 Nov. 2008, Wikipedia, W-CDMA (UTMS), updated 19 Oct. 2008, wiki/W-CDMA_(UMTS) Wikipedia, High Speed Packet Access, updated 15 Oct. 2008, Bluetooth SIG, Basics, 2008, Technology/Basics.htm Bluetooth SIG, Profiles Overview, 2008, Technology/Works/Profiles_Overview.htm Wikipedia, Wi-Fi, updated 18 Nov. 2008, Wikipedia, Wi-Fi technical information, updated 31 Oct. 2008, WiMax Forum, Frequently Asked Questions,

documents/faq/ Wikipedia, IEEE 802.11, updated 16 Nov. 2008, 802.11 Infrared Data Association, Welcome to IrDA, displaycommon.cfm?an=1&subarticlenbr=14 References (7) 55. 56. 57. 58. 59. 60. 61. 62. Wikipedia, Universal Serial Bus, updated 19 Nov. 2008, wiki/Usb Screen Digest, iPhone breathes new life into mobile gaming market, 31 Jul.

2008, Press Release, pr_31_07_2008/view.html Screen Digest, Mobile media advertising opportunities: The market for advertising, 2 May 2008, 08mobilemediaadvert/pdf/08chinacabletv-pdf/view.html B. Krebs, Teen Pleads Guilty to Hacking Paris Hiltons Phone, Washington Post, 13 Sep. 2005, 09/13/AR2005091301423_pf.html D. Emm, Mobile malware new avenues, Network Security, 2006:11, Nov. 2006, pp. 46 M. Hypponen, Malware Goes Mobile, Scientific American, Nov. 2006, pp. 70 77, PandaLabs, PandaLabs Quarterly Report: JanuaryMarch 2008, Quarterly_Report_PandaLabs_Q1_2008.pdf Georgia Tech Information Security Center, Emerging Cyber Threats Report for 2009, References (8)

63. 64. 65. 66. 67. 68. 69. D. Dagon et al., Mobile Phones as Computing Devices: The Viruses are Coming!, IEEE Pervasive Computing, Oct. Dec. 2004, pp. 1115 G. Fleishman, Battered, but not broken: understanding the WPA crack, Ars Technica, 6 Nov. 2008, CSL Unveils Mobile Security Service, China Tech News, 31 Mar. 2008, http:// C. Fleizach et al., Can You Infect Me Now? Malware Propagation in Mobile Phone Networks, Proc. of ACM Workshop on Recurring Malcode (WORM 07), Alexandria, VA, USA, 2 Nov. 2007, pp. 6168. H. Kim et al., Detecting Energy-Greedy Anomalies and Mobile Malware Variants, Proc. of the 6th Intl Conf. on Mobile Systems, Applications, and

Services (MobiSys 08), Breckenridge, CO, USA, 1720 Jun. 2008, pp. 239252. E. Sadun, Programming with Safety Scissors and Glitter Glue, Inside iPhone, 10 Oct. 2008, T. Claburn, The Cybercrime Economy, InformationWeek, 9 Apr. 2008, http:// the_cyber_crime.html

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