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<h2 class="hd hd-2 unit-title">Internet</h2>
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<h4>Internet</h4>
<p>Networking Overview</p>
<p><br />Any set of two of more entities, which can exchange information with one another, be they human, machine, animal or otherwise, are part of a communication network. Communication networks have always been an important part of human survival and success, be it coordinating a hunt on the savanna, or planning out a defensive strategy during a sports match. As technology has developed however, people and machines are now communicating in unprecedented volumes, over incredible distances, and in a multiplicity of forms ranging from simple text, to live video streams. Indeed, one might argue that the digital components of communication are becoming even more critical to human interaction and progress than the traditional face-to-face mode. <br /><br />Given its clear importance, this section will describe the two most heavily utilized faces of digital communication networks: (1) the Internet and (2) the mobile cellular network. More specifically, this section will elucidate the technical fundamentals facilitating these two modes of communication, review the availability of the services in low, and middle income countries, and discuss the utility of these networks in the context of global health.</p>
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<h4>Connecting to the Internet</h4>
<p><br />At its core, the Internet is simply a massive global system of interconnected computers. Just like a human network, computers need a common language to understand one another. The language that is used by computers to communicate over the Internet is called the Transmission Control Protocol/Internet Protocol (TCP/IP). TCP/IP allows any device to remotely connect to any other devices from around the world that also uses it. <br /><br />There are two ways to connect to the Internet: (1) through a fixed connection and (2) via a mobile connection.</p>
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<p>For an overview of networking, please see: <a href="https://www.youtube.com/watch?v=CQQvT7Y-3dk" target="[object Object]">https://www.youtube.com/watch?v=CQQvT7Y-3dk</a></p>
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<h2 class="hd hd-2 unit-title">Accessing The Internet Globally</h2>
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<h4>Accessing The Internet Globally</h4>
<h5>Distribution of Internet Access</h5>
<p><img src="/assets/courseware/v1/f0300aeae1672016b1932c171f16694b/asset-v1:MITx+HST.936x+1T2019+type@asset+block/image11_1.png" alt="Global Internet Access Map" type="saveimage" target="[object Object]" height="600" width="514" /></p>
<h6>Figure: Popularity of fixed and mobile broadband Internet access around the world. The legend indicates the percentage of people in the country with a particular form of access. In some cases, this may be over 100% when, on average, there is more than one access point per person. Data source: International Telecommunications Union</h6>
<p></p>
<p>Figure (a) illustrates Internet access volumes across the world using fixed broadband connections. Importantly, the figure illustrates that while Internet access is common in developed countries, it is still fairly scarce in the developing world. Particularly, there is a paucity of access in sub-Saharan Africa and central Asia. Figure (b) illustrates access volumes using mobile broadband connections. Note that the access volumes using mobile connections differ from those shown in Figure (a). In the developed countries, we see that high volumes of fixed connection tend to correlate well with high volumes of mobile connections. In the developing world, however, areas with low volumes of fixed connections often exhibit higher volumes of mobile access. This interesting result is a consequence of the reality that developing countries often lack the infrastructure to install and maintain fixed connections, while mobile solutions are cheaper, and often easier to deploy. A single cell phone tower can provide service to hundreds of customers, and requires little maintenance. In Egypt, for instance, only 2.7% of the populations have fixed broadband service at home, but nearly 10 times as many Egyptians have Internet access using a cell phone. The story is similar in Ghana, Uzbekistan, Indonesia, South Africa, and Nigeria.</p>
<p>Yet despite the relative advantages of the mobile solution over fixed broadband, many developing areas still lack access to the Internet. The issue is not one of demand, nor one of supply as many individuals in the third world are eager to get connected, and many Telecom carriers or service providers would love to set-up the fixed or mobile broadband connection infrastructures in these untapped markets. Issues ranging from political instability to infrastructure have kept access limited. Most of all it has been shown that approaches which provide full coverage are not economically feasible in low density areas . One potential solution is the deployment of wireless local area networks (also known as WLAN, or wireless LAN).</p>
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<h5>Cost and Capacity of Internet</h5>
<p>The supply of international connectivity has expanded dramatically since 2009, when several submarine fiber cables came online, connecting even the poorest countries in Africa to the Internet. As shown previously, with only a few exceptions, nearly every developing country now has some form of competitive market for broadband services. Nevertheless, one should not easily conclude that the differences in connectivity are narrowing between developed and developing countries. To have a more complete understanding of the current connectivity status of developing regions, we need to take into consideration the connection capacity (or bandwidth) and costs. </p>
<p>In 2011, Hilbert et al conducted a survey to compare the differences in connectivity between developed and developing countries over the last decade. The OECD (Organization for Economic Co-operation and Development) countries were selected to represent the developed countries, which were then compared against the rest. Network connectivity was measured both in terms of the subscription rate per capita and the network capacity (in kilobits/second) per capita. The gap in subscription rate have been closing over the years. On the other hand, the gap in capacity per capita has increased exponentially.</p>
<p>In addition to the constrained capacity, cost is another barrier for populations in developing regions to get connected to the Internet. As defined by the UN Broadband Commission, an affordable entry-level Internet service should be priced at less than 5 percent of average monthly income. According to The Affordability Report by the Alliance for Affordable Internet (A4AI), only a small number of developing countries are close to achieving the UN Broadband Commission standard. In 50 of the studied countries, the cost of entry-level Internet services were priced at more than 40% of the populations’ average monthly income, and in some cases the cost exceeded 80% of monthly income.</p>
<p>Low capacity and high cost of Internet services are difficulties that need to be addressed to facilitate the deployment of Mobile Health technologies in developing regions. However, we may also make use of these constrains to attract participants, test collaborations and attract early adopters by providing them with free or low cost Internet connections. </p>
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<h2 class="hd hd-2 unit-title">Mobile Networking</h2>
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<h4>Mobile Networking</h4>
<h5>Mobile Cellular Network</h5>
<p>The mobile cellular network is a wireless network distributed over land areas called cells, where each cell (as shown in the figure below) is served by at least one fixed-location transceiver, known as the base station. A transceiver is a device, which contains both a transmitter, which sends data, and a receiver, which receives data. Radio waves are used to transmit signals between the mobile phones, the receivers, and the base stations. The transmitting radio frequency bands are a limited, shared resource. To allow multiple callers to use the limited bandwidth of radio with minimum interference, low power transmitters are used. Not surprisingly, transmitters and receivers have limitations as to the volume of data they can send and receive. To solve this issue, a method call packet or circuit switching is employed. In packet switching, messages are collected from several transmitters, broken into small chunks, and transited as packets for reassembly on the receiver end. In circuit switching, a transmitter waits in a queue with other transmitters on the network to establish a dedicated connection with the receiver, and then sends all the data at once. A standard mobile cellular network consists of the following main components:</p>
<ul>
<ul>
<li>A network of radio base stations forming the base station subsystem.</li>
<li>The core circuit switched network for handling voice calls and text</li>
<li>A packet switched network for handling mobile data</li>
<li>The telephone network to connect subscribers to the wider telephony network</li>
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<p></p>
<p>The voice call functionality of the mobile cellular network is, in general, well understood by the public. Therefore, in the following section, we further investigate the text-messaging aspect of the mobile network.</p>
<p><img src="https://studio.edge.edx.org/asset-v1:MITx+HST.936x+3T2016+type@asset+block@image11_2.png" alt="Mobile Network Infrastructure" type="saveimage" target="[object Object]" height="737" width="771" /></p>
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<h5>Short Message Service (SMS)</h5>
<p>Short Message Service is a text messaging service component of the mobile network. It uses standardized communications protocols to allow mobile phone devices to exchange short text messages with each other. The SMS service can be a useful component of global health solutions. </p>
<p>The SMS messages are very small data packages that require minimum bandwidth to transmit. SMS services are also much cheaper to transmit compared to mobile voice calls. It follows that SMS is a highly feasible communication channel in areas where network bandwidth is limited and unstable. Importantly, the SMS messaging service is an attractive option for health care applications, including follow-up appointment and medication reminders, transmitting short health records and brief health care consultancy. </p>
<p>Yet despite the potential of SMS as part of a health care solution, it is worth bearing in mind the limitations of the SMS service. </p>
<p>First, SMS supports a limited message size. Each message carries a maximum of 140 bytes of data. Messages exceeding the quota are broken down into multiple segments for transmissions. If long messages are expected in the application, one needs to incorporate a message reassembling function in the message receivers. </p>
<p>Secondly, SMS message delivery is not guaranteed, and many implementations provide no mechanism through which a sender can determine whether an SMS message has been delivered in a timely manner. Furthermore, SMS messages are generally treated as lower-priority traffic compared to voice messages. Various studies have shown that around 1% to 5% of messages are lost entirely, even during normal operation conditions, and others may not be delivered until long after their relevance has passed. Thus, SMS may be suboptimal in the case of emergency or time sensitive health care situations. </p>
<p>Thirdly, security vulnerabilities are a prominent weakness for SMS. In the GSM, the airway traffic between the Mobile Station (MS) and the Base Station is optionally encrypted and may be easily broken with a stream cipher. The authentication is unilateral and also vulnerable. Such vulnerabilities are inherent to SMS as one of the superior and well-tried services with a global availability in the GSM networks. SMS messaging has some extra security vulnerabilities due to its store-and-forward feature as well. As a result, additional encryption mechanisms are necessary if protected health information is to be transmitted through SMS. </p>
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<legend id="9b5486c42df64e5d940e48c9d2fbc554_2_1-legend" class="response-fieldset-legend field-group-hd">Which of the following is <strong>NOT</strong> a limitation of SMS (Short Message Service)?</legend>
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<h2 class="hd hd-2 unit-title">The Security Dimension</h2>
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<h4>The Security Dimension</h4>
<p>Computer security is normally defined as the ability of a computer system to protect information and system resources. This protection is typically focused on several dimensions: </p>
<ul>
<li>Confidentiality -- Ensuring that information is not accessed by unauthorized persons</li>
<li>Integrity -- Ensuring that information is not altered by unauthorized persons in a way that is not detectable by authorized users</li>
<li>Authentication -- Ensuring that users are the persons they claim to be</li>
<li>Access control -- Ensuring that users access only those resources and services that they are entitled to access and that qualified users are not denied access to services that they legitimately expect to receive </li>
<li>Nonrepudiation -- Ensuring that the originators of messages cannot deny that they in fact sent the message</li>
<li>Availability -- Ensuring that a system is operational and functional at a given moment</li>
</ul>
<p>For each of these elements, there is a wealth of tools and research on how to achieve each goal. However, it must be mentioned again that a computer system is not a singular entity, but a coordinated integration of hardware and software layers (firmware, operating system and applications) connected via an interconnected network infrastructure. This means that the set of threats that one has to guard against, and the security mechanisms to be built, must focus on the physical system components (i.e. hardware), the persistent code built into the startup process (i.e. firmware), the code that makes the device useful (i.e. operating system), the software being on the operating system that makes our lives easier (i.e. applications), the network and networking resources that enable systems to communicate (i.e. network traffic, which includes API use). </p>
<p>This creates a complex landscape that needs to be traversed. Fortunately, a lot of work has gone into solving a lot of these issues at all levels. With this new information, one can see that the constrained nature of a mobile system creates an interesting challenge. </p>
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<p>Bruce Schneier<br />Resilient<br />Berkman Center<br />EFF</p>
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<h3 class="hd hd-2">Privacy Issues with Secondary Use of Health Data</h3>
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<h3 class="hd hd-2">Other aspects of data security: reliability, availability</h3>
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<legend id="743ffcb8ceae42ceb77cb9877df4e4e6_2_1-legend" class="response-fieldset-legend field-group-hd">Which of the following is most correct?</legend>
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<input type="radio" name="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1" id="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_1" class="field-input input-radio" value="choice_1"/><label id="743ffcb8ceae42ceb77cb9877df4e4e6_2_1-choice_1-label" for="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_1" class="response-label field-label label-inline" aria-describedby="status_743ffcb8ceae42ceb77cb9877df4e4e6_2_1"> Computer security means I have secured my application against unauthorized access.
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<input type="radio" name="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1" id="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_2" class="field-input input-radio" value="choice_2"/><label id="743ffcb8ceae42ceb77cb9877df4e4e6_2_1-choice_2-label" for="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_2" class="response-label field-label label-inline" aria-describedby="status_743ffcb8ceae42ceb77cb9877df4e4e6_2_1"> Computer security is a complex multilayer process where system information and resources are protected from multiple different threats.
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<input type="radio" name="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1" id="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_3" class="field-input input-radio" value="choice_3"/><label id="743ffcb8ceae42ceb77cb9877df4e4e6_2_1-choice_3-label" for="input_743ffcb8ceae42ceb77cb9877df4e4e6_2_1_choice_3" class="response-label field-label label-inline" aria-describedby="status_743ffcb8ceae42ceb77cb9877df4e4e6_2_1"> Computer security can be ensured by installing the latest tools.
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<h2 class="hd hd-2 unit-title">The Mobile Platform</h2>
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<h4>The Mobile Platform</h4>
<p>The sensitivity of the data and the interactions on mobile healthcare devices/solutions, as well as the relevant legal mandates that have to be complied with, typically means that developers of mobile apps for health should build systems that 1) securely access medical data from a secured backend database, 2) not store personally identifiable information (or any medical data that may be sensitive in the future) on the device, and 3) ensure that the hardware and software of the mobile device is secure. </p>
<p>This third requirement is the most intense of them all. It requires safeguarding the mobile stack from missing passwords (i.e. lack of authentication), poorly implemented authentication (i.e. the non-use of two-factor, or higher, authentication), application misconfigurations, malware, operating system holes, unauthorized modifications, etc. Fortunately, there is prior work in the space.</p>
<p>In May of 2013, The US Federal CIO Council and the US Department of Homeland security produced the Mobile Security Reference Architecture (MSRA), which provides a solid architectural pattern for developers of mobile solutions in order for them to ensure the confidentiality, integrity, and availability of data accessed through a mobile computing solution.</p>
<p>MSRA assumes an enterprise backend. However, a health mobile solution developer should interpret this as the cloud or server infrastructure that they will be using. The MSRA consists of the following conceptual components:</p>
<ul>
<li>Virtual Private Network</li>
<li>Mobile Device Management</li>
<li>Mobile Application Management</li>
<li>Identity and Access Management</li>
<li>Mobile Application Store</li>
<li>Mobile Application Gateway</li>
<li>Data Loss Prevention</li>
<li>Intrusion Detection System</li>
<li>Gateway and Security Stack</li>
</ul>
<p></p>
<p>We will discuss these in further detail next.</p>
<p>For more details on MSRA, see the detailed report issued by the US Federal CIO Council and the US Department of Homeland Security, <a href="https://cio.gov/wp-content/uploads/downloads/2013/05/Mobile-Security-Reference-Architecture.pdf" target="[object Object]">here</a>.</p>
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<h5>VIRTUAL PRIVATE NETWORKS (VPNS)</h5>
<p>VPNs are a method for creating secure connections between mobile devices and the backend while using public, and often unsecured networks. For the mobile app developer, this is similar to always using a secure channel, with a strong encryption key, to communicate with the backend.</p>
<h5>MOBILE DEVICE MANAGEMENT (MDM)</h5>
<p>Mobile Device Management refers to administration and supervision of the applications, data, and configuration settings on a mobile device. MDM seeks to centralize and optimize the functionality and security management of mobile communications.</p>
<h5>MOBILE APPLICATION MANAGEMENT (MAM)</h5>
<p>Mobile Application Management functionality provides a subset of the operations provided by Mobile Device Management. MAM provides in-depth distribution, configuration, data control, and lifecycle management for specific mobile applications.</p>
<h5>IDENTITY AND ACCESS MANAGEMENT (IAM)</h5>
<p>Identity and Access Management systems are used to integrate and coordinate services such as authentication and authorization across the mobile solution to form a cohesive security profile for each user. </p>
<h5>MOBILE APPLICATION STORE (MAS)</h5>
<p>A Mobile Application Store is a repository of mobile applications. Examples include external application stores like Google Play and Apple’s AppStore. As this repository provides a selection of approved applications that can be downloaded and installed on the device, one can limit the damage done from malicious apps by managing the MAS.</p>
<h5>MOBILE APPLICATION GATEWAY (MAG)</h5>
<p>A Mobile Application Gateway is a piece of software that provides application-specific network security for mobile application infrastructures. The purpose of a MAG is to act as a network proxy, accepting connections on behalf of the application’s network infrastructure, filtering the traffic, and relaying the traffic to mobile application servers. MAGs are often used in place of traditional network protections, such as intrusion detection systems, when application traffic is encrypted or opaque in structure.</p>
<h5>DATA LOSS PREVENTION (DLP)</h5>
<p>DLP focuses on preventing restricted information from being transmitted to mobile devices, or from mobile devices to unauthorized locations outside the organization. A DLP solution monitors all traffic flowing to mobile devices from the organizational infrastructure, validating the traffic against a set of pre-defined words, phrases, images, and patterns that are considered too sensitive to leave the enterprise boundary.</p>
<h5>INTRUSION DETECTION SYSTEM (IDS)</h5>
<p>An IDS is a network appliance that uses a set of heuristics to match known attack signatures against incoming network traffic and raises alerts when suspicious traffic is seen.</p>
<h5>GATEWAY AND SECURITY STACK (GSS)</h5>
<p>Mobile devices, like almost all computing devices, have the capacity to be used to attack other networked devices. The unique dual-connected nature (cellular and wireless Ethernet) of mobile devices makes them ideal platforms for circumventing traditional network security boundary protections. To prevent damage to the backend from a compromised mobile device, access to the enterprise must be restricted through one or more known network routes, i.e. gateways, and inspected by standard network defenses such as stateful packet inspection, intrusion detection, and application and protocol. </p>
<p>Further details of each component can be found in the Mobile Security Reference Architecture document, <a href="https://cio.gov/wp-content/uploads/downloads/2013/05/Mobile-Security-Reference-Architecture.pdf" target="[object Object]">here</a>.</p>
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<legend id="db6fe733985a46feafba700706c2ae16_2_1-legend" class="response-fieldset-legend field-group-hd">In the context of mobile platforms, which of the following would NOT be important for securing the system.</legend>
<p class="question-description" id="description_db6fe733985a46feafba700706c2ae16_1_1"> There may be more than one.</p>
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<input type="checkbox" name="input_db6fe733985a46feafba700706c2ae16_2_1[]" id="input_db6fe733985a46feafba700706c2ae16_2_1_choice_0" class="field-input input-checkbox" value="choice_0"/><label id="db6fe733985a46feafba700706c2ae16_2_1-choice_0-label" for="input_db6fe733985a46feafba700706c2ae16_2_1_choice_0" class="response-label field-label label-inline" aria-describedby="status_db6fe733985a46feafba700706c2ae16_2_1 description_db6fe733985a46feafba700706c2ae16_1_1"> the exclusive use of iOS (iPhone) over Android phones.
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<input type="checkbox" name="input_db6fe733985a46feafba700706c2ae16_2_1[]" id="input_db6fe733985a46feafba700706c2ae16_2_1_choice_1" class="field-input input-checkbox" value="choice_1"/><label id="db6fe733985a46feafba700706c2ae16_2_1-choice_1-label" for="input_db6fe733985a46feafba700706c2ae16_2_1_choice_1" class="response-label field-label label-inline" aria-describedby="status_db6fe733985a46feafba700706c2ae16_2_1 description_db6fe733985a46feafba700706c2ae16_1_1"> the ability to wipe (securely destroy all information) a mobile phone when lost.
</label>
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<input type="checkbox" name="input_db6fe733985a46feafba700706c2ae16_2_1[]" id="input_db6fe733985a46feafba700706c2ae16_2_1_choice_2" class="field-input input-checkbox" value="choice_2"/><label id="db6fe733985a46feafba700706c2ae16_2_1-choice_2-label" for="input_db6fe733985a46feafba700706c2ae16_2_1_choice_2" class="response-label field-label label-inline" aria-describedby="status_db6fe733985a46feafba700706c2ae16_2_1 description_db6fe733985a46feafba700706c2ae16_1_1"> a fast internet connection.
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<input type="checkbox" name="input_db6fe733985a46feafba700706c2ae16_2_1[]" id="input_db6fe733985a46feafba700706c2ae16_2_1_choice_3" class="field-input input-checkbox" value="choice_3"/><label id="db6fe733985a46feafba700706c2ae16_2_1-choice_3-label" for="input_db6fe733985a46feafba700706c2ae16_2_1_choice_3" class="response-label field-label label-inline" aria-describedby="status_db6fe733985a46feafba700706c2ae16_2_1 description_db6fe733985a46feafba700706c2ae16_1_1"> the ability to set controls on who gets access to which system resources.
</label>
</div>
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<input type="checkbox" name="input_db6fe733985a46feafba700706c2ae16_2_1[]" id="input_db6fe733985a46feafba700706c2ae16_2_1_choice_4" class="field-input input-checkbox" value="choice_4"/><label id="db6fe733985a46feafba700706c2ae16_2_1-choice_4-label" for="input_db6fe733985a46feafba700706c2ae16_2_1_choice_4" class="response-label field-label label-inline" aria-describedby="status_db6fe733985a46feafba700706c2ae16_2_1 description_db6fe733985a46feafba700706c2ae16_1_1"> understanding what is normal and abnormal use of the system.
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