Abstract:
Anonymizing location information of a mobile device by an anonymization provider. The anonymizing provider receives, from the mobile device, location information identifying the location of the mobile device and an anonymity requirement. The anonymization provider selects an obfuscation value indicating an extent of location obfuscation that satisfies the received anonymity requirement. The extent of location obfuscation determines location boundaries within which a generated obfuscated location will reside. The anonymization provider generates an obfuscated location for the mobile device and sends the obfuscated location to the mobile device.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with Government support under contract number W911NF-06-3-0001 awarded by the Army Research Office (ARO). The Government has certain rights to this invention. 
    
    
     BACKGROUND 
     The present invention relates to anonymization of location information of a mobile device and more particularly to anonymization of location information of a mobile device using an anonymization provider supplying anonymization data to the mobile device. 
     In a mobile micro-cloud setting having multiple entities there are various concerns relating to trust and vulnerability. One of these concerns is the release of information about a mobile device user&#39;s location to service providers when using location based services. This may be undesirable and can be avoided by location obfuscation wherein an approximate location may be provided that is sufficiently accurate for the response from the service provider to be useful, but not sufficiently accurate that the precise location may be determined. A location obfuscation module may operate in of the following three layers in a mobile micro-cloud: (i) mobile device, (ii) edge and (iii) core. Each of these solutions has diverse implications on the overall performance of an application (for example, latency), on application quality and on security objectives. For instance, a mobile device based solution has incomplete information (on the location of other devices) and thus may either be over conservative (more obfuscation which leads to poor application quality) or too liberal (less obfuscation and thus fail to meet security requirements). 
     Prior art solutions, typically implemented in smart phones, take the location, identity and query when making a location based service query. By default service providers of location based query services use the location information and hence know where the user&#39;s mobile device is located. This is a major breach of privacy if the user does not want to share the location information. Additionally, the service providers may also misuse the information and pass it on to third party applications who further misuse the location information. 
     PCT patent application WO 2012/170314 A2 discloses that requesting users and applications may be interested in communicating with target users/applications based on the whereabouts of the target user/device without disclosing identities of the parties. For example, a user may want to know if a restaurant is crowded or whether it is worth going to an event. However, there is no way to send a message to “someone located at that location” without exposing the sender&#39;s identity or knowing the identity of the target person(s). This capability is provided by mediating messages between the users (requesting and target) via an anonymous messaging component (e.g., a service) that maintains anonymity of the users relative to one another. The anonymous messaging component does not publish user identities, since the component mediates between the sender (requester) and the receiver(s) (target(s))”. 
     United States Patent Application 2012-0034930 A1 discloses an anonymous location wireless network service that tracks the location and identity of network users, such as networks complying with enhanced 911 standards. The service provides content providers with the location of network users without revealing their identities. The service includes a wireless network having a proxy server, a network communication link to a plurality of web sites, and a wireless communication link to a plurality of handheld devices. The proxy server blocks identity by reading the location and identity information of network devices, generating dummy identifications, relating the dummy identifications to the identity information, storing the relationships in a memory storage, and forwarding the location information and dummy identifications to the global computer network. Upon receiving return messages from the global computer network, the proxy server reads the dummy identifications, looks up the related identity information in the memory storage, and forwards the data to the appropriate network devices. 
     United States Patent Application 2007-0264974 A1 discloses a method of implementing privacy control of location information. Such a method comprises defining a geographic zone for which pseudo-location information is to be reported as the current location of the user, wherein the pseudo-location information is not the current location of the user; receiving the current location of the user; determining that the current location is in the geographic zone; and reporting the pseudo-location information as the current location of the user when the current location is determined to be in the geographic zone. 
     Gedik, B. and Liu, L., “Location privacy in mobile systems: A personalized anonymization model”, Proceedings of the 25th International Conference on Distributed Computing Systems (ICDCS 2005), 2005 discloses a personalized k-anonymity model for protecting location privacy against various privacy threats through location information sharing. A unified privacy personalization framework is provided to support location k-anonymity for a wide range of users with context-sensitive personalized privacy requirements. This framework enables each mobile node to specify the minimum level of anonymity it desires as well as the maximum temporal and spatial resolutions it is willing to tolerate when requesting for k-anonymity preserving location-based services (LBSs). An efficient message perturbation engine is run by the location protection broker on a trusted server and performs location anonymization on mobile users&#39; LBS request messages, such as identity removal and spatio-temporal cloaking of location information. 
     Pierangela Samarati and L. Sweeney, “k-anonymity: a model for protecting privacy”, Proceedings of the IEEE Symposium on Research in Security and Privacy (S&amp;P). May 1998, Oakland, Calif. discloses how k-anonymity can be provided by using generalization and suppression techniques. It introduces the concept of minimal generalization, which captures the property of the release process not to distort the data more than needed to achieve k-anonymity. 
     The k-anonymity solutions described above has a number of problems. Due to the limited number of profiles created it is possible to easily track down the actual requestor and further identify the location of the requestor. It would be desirable to have a mechanism that ensures the inclusion of minimum number of similar profiles. Another problem with k-anonymity solution is that the queries are too specific and hence it is possible for the location service providers to track down the identity of the actual service requestor. 
     SUMMARY 
     Embodiments of the present invention disclose a method, computer program product, and system for anonymizing location information of a mobile device. An anonymizing provider receives, from the mobile device, location information identifying the location of the mobile device and an anonymity requirement. The anonymization provider selects an obfuscation value indicating an extent of location obfuscation that satisfies the received anonymity requirement. The extent of location obfuscation determines location boundaries within which a generated obfuscated location will reside. The anonymization provider generates an obfuscated location for the mobile device and sends the obfuscated location to the mobile device. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. The various features of the drawings are not to scale as the illustrations are for clarity in facilitating one skilled in the art in understanding the invention in conjunction with the detailed description. In the drawings: 
         FIG. 1  shows a block diagram of a prior art mobile micro-cloud architecture; 
         FIG. 2  shows a block diagram of a prior art anonymization session; 
         FIG. 3  shows a block diagram of an anonymization session according to embodiments of the present invention; 
         FIG. 4  shows an interactive map used in a first embodiment of the present invention; 
         FIG. 5  is a flow chart illustrating a method for using an access token, in accordance with an embodiment of the present invention; 
         FIG. 6  shows an interactive map used in a second embodiment of the present invention; and 
         FIG. 7  shows a flow chart of a method of location anonymization according to a second trusted edge server based embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a prior art mobile micro-cloud architecture having a core  102  connected through network links  120 ,  122  to one or more trusted edge servers  104 ,  106  and through further network links  124 ,  126 ,  128 ,  130  to mobile devices  110 ,  112 ,  114 ,  116 . Typically, the core  102  has access to large quantities of static information and the trusted edge servers  104 ,  106  have access to smaller quantities of more real-time and dynamic data. The trusted edge servers  104 ,  106  may be located at a WiFi access point or a cellular base station or the like. Although  FIG. 1  shows two trusted edge servers  104 ,  106  and four mobile devices  110 ,  112 ,  114 ,  116 , the number of each of these elements is purely exemplary and any number of these elements may be used in embodiments of the present invention. The network links  120 ,  122  and  124 ,  126 ,  128 ,  130  may be wired or wireless network links and may use any format which the elements at each end of the link may understand. Although not shown in  FIG. 1 , there may be additional network or other connections between each of the trusted edge servers  104 ,  106 . 
       FIG. 2  shows a block diagram of a prior art anonymization session. The mobile device  110  sends  210  a request to the anonymization provider  202 , which obfuscates the location data contained in the request prior to sending  212  it on to the service provider  204 . The service provider&#39;s  204  response is returned  214  through the anonymization provider  202  which sends  216  the response to the mobile device  110 . There are at least two problems with this prior art anonymization of location data. Firstly, the use of an anonymization provider  202  is revealed to the service provider  204 . The service provider  204  may therefore infer that location data contained in the request has been modified by the anonymization provider  202 . The ability of the service provider  204  to infer this may not be desired by the mobile device  110 . Secondly, there is an additional risk that the anonymization provider  202  directs an attack on session data passing between the mobile device  110  and the service provider  204 , such as a man-in-the-middle attack. The service provider  204  may be a regular web service located at the core  102  or at the trusted edge server  104 ,  106 . The service provider  204  may be located at the mobile device  110  as an “app”. The anonymization provider  202  may be located at the trusted edge server  104 ,  106 . 
     Embodiments of the present invention extend known solutions for anonymizing location data by introducing an additional interaction in the session protocol between the service consumer, for example, a mobile device  110  and the service provider  204 , for example, a web service.  FIG. 3  shows a block diagram of an anonymization session according to embodiments of the present invention. The anonymization session of  FIG. 3  is designed to enforce the privacy requirements of service consumers, such as mobile device  110 , thereby mitigating the first problem identified above. Additionally, the anonymization session of  FIG. 3  helps to mitigate the more traditional information security threat in the second concern identified above. 
     Embodiments of the present invention add an additional interaction in the session protocol between the mobile device  110  and the service provider  204 . The service provider  204  is now unaware of the presence of the anonymization provider  202  by virtue of the breaking of the link between them found in prior art anonymization approaches. In a successful session, the mobile device  110  requests  310  anonymization of location data from the anonymization provider  202  and receives  312  obfuscated location data from the anonymization provider  202 . The mobile device  110  then forwards  314  the obfuscated location data to the service provider  204 . The service provider  204  is unaware of the existence of the anonymization provider  202  in this system by simple analysis of the incoming request. The service provider  204  returns  316  the response back to the mobile device  110 . With appropriate validation at the mobile device  110 , the anonymization provider  202  cannot successfully mount an attack on the data, such as a man-in-the-middle attack because the data passes from the mobile device  110  to the service provider  204  without passing through the anonymization provider  202 . The embodiment of  FIG. 3  preserves the privacy of the location information but is still able to get the results for the query based on the location information. As with the prior art system of  FIG. 2 , the service provider  204  may be a regular web service located at the core  102  or at the trusted edge server  104 ,  106 . The service provider  204  may also be located at the mobile device  110  as an “app”. The anonymization provider  202  may be located at the trusted edge server  104 ,  106 . 
     Two embodiments will now be described. Firstly, a mobile device  110  based embodiment will be described with reference to  FIGS. 4 and 5 . In the first embodiment, the function of the anonymization provider  202  is provided in part at the mobile device  110  and in part at the trusted edge server  104 ,  106 . The service provider  204  may be provided at any of the mobile device  110 , the trusted edge server  104 ,  106 , or the core  102 . If provided at the mobile device  110 , the service provider  204  takes the form of an “app” on the mobile device  110 . If provided at the trusted edge server  104 ,  106  or at the core  102 , the service provider  204  takes the form of a regular web service. 
     Secondly, a trusted edge server  104 ,  106  based solution will be described with reference to  FIGS. 6 and 7 . In the second embodiment, the function of the anonymization provider  202  is provided at the trusted edge server  104 ,  106 . The location of the service provider  204  takes the same form as the first embodiment. 
       FIG. 4  shows an interactive map  400  for use in a first embodiment of the present invention, this embodiment being mobile device  110  based. The interactive map  400  may also include any number of geographical and/or physical features displayed to a user and which are not shown in  FIG. 4  for clarity. The location  402  at which a user has clicked is shown as is an area (described herein as the box  404 ) surrounding the user&#39;s location  402 . Although the “box”  404  is shown as a circle in  FIG. 4 , it may be any shape such as a square, an ellipse, a rectangle or any other shape. The preferred embodiment of the “box” is a circle because it encloses the maximum area for a given maximum distance from the user&#39;s location  402 . The location  420  and the dashed line circle  430  will be explained below with reference to  518  in  FIG. 5 . 
     Referring to  FIG. 5 , a method according to an embodiment of the present invention starts at  502 . At  504 , a user clicks anywhere on the interactive map  400  displayed at the mobile device  110  to indicate the mobile device&#39;s  110  current location. In the example of  FIG. 4 , the user has clicked on the map at location  402 . The current location  402  may be identified by latitude and longitude, by use of grid coordinates or any other way in which a current location  402  may be identified. The current location  402  may be selected by the user or may be directly input using a position location system, such as GPS or by use of identification of a current connection within a cellular wireless network. A user may, optionally, be asked to confirm a position supplied by a position location system. 
     At  506 , the current location  402  of the mobile device  110  is noted by the mobile device  110  and the user is prompted for the desired extent of location obfuscation “l” and the level of anonymity “k”. 
     The desired extent of location obfuscation “l” is expressed in terms of a distance, that is, for example, in meters, such as by supplying a bounding box (such as the circle  404  of  FIG. 4 ) containing the point. The desired extent of location obfuscation “l” identifies the area within which the user would like their location to be provided to a service provider  204 . The level of anonymity “k” means that the location information for the mobile device  110  sent to the service provider  204  is such that the location information cannot be distinguished from at least k−l other mobile devices  110  who may also send location information to the service provider  204 . For example, if a “k” value of 9 is used, then the location information supplied could be associated with at least 8 other mobile devices  112 ,  114 ,  116 . 
     The mobile device  110  does not know where other mobile devices  112 ,  114 ,  116  are located and so cannot realize k-anonymity. The mobile device  110  “hopes” that the extent of location obfuscation “l” supplied (that is, the distance in meters) means that the level of anonymity “k” is enough. That is, that there are enough other mobile devices  112 ,  114 ,  116  within the desired distance “l” of the mobile device  110 . If the extent of location obfuscation “l” for the bounding box is not sufficient, then as described below another iteration with a different value for the extent of location obfuscation “l” is carried out. 
     Once the values for location obfuscation “l” and level of anonymity “k” are entered by the user at the mobile device  110 , then at  508 , the computation of a box is performed at the mobile device  110 . The box  404  is computed based on the values the user entered at  506  for “l” and “k”. For example, a user may enter a latitude of 41.13 degrees North and 73.72 degrees West. The computed box  404  may be 41.08 degrees North and 73.79 degrees West to 41.18 degrees North and 73.65 degrees West. This box  404  is a square of dimensions approximately six miles by six miles, with the position of the mobile device  110  given by the user being located within the box  404 . Embodiments of the present invention are not limited to a box  404  of this size as the box  404  size may be determined by the values provided by the user for “k” and “l”. Additionally, embodiments of the present invention are not limited to the computation of the box  404  being in any particular position with respect to the mobile device  110 , except that the mobile devices&#39;  110  position should be located within the box  404 . In a preferred embodiment, the mobile devices&#39;  110  position is at the center of the box  404 . Further, embodiments of the present invention are not limited to the computed “box” being circular. For example, the “box” may actually be square, rectangular or elliptical. A circular “box” has the advantage that a maximum area is enclosed for a given maximum distance from the center point of the box when compared to any other shape. 
     At  510 , the details are submitted by the mobile device  110  to the trusted edge server  104 ,  106 . In a preferred embodiment, this submission is through a HTTP post. The details may typically include the location, extent of location obfuscation “l” and level of anonymity “k”. The trusted edge server  104 ,  106  may know the location of at least k−l other mobile devices  112 ,  114 ,  116 . 
     At  512 , the trusted edge server  104 ,  106  checks whether the obfuscation is good enough. This check is done by checking if there are “k” other mobile devices  112 ,  114 ,  116  within the box  404  associated with the extent of location obfuscation “l”, including the mobile device  110  requesting the anonymization. If there are “k” other mobile devices  112 ,  114 ,  116  within the box  404 , then the obfuscation is good enough and processing proceeds at  514 . If there are not “k” other mobile devices  112 ,  114 ,  116  within the box  404 , then processing returns to  506 , where the user is asked to enter a different value for “l” in order for a box  404  meeting the extent of location obfuscation “l” and level of anonymity “k” to be computed. The user is not asked to enter a new value for the level of anonymity “k”. 
     Once the obfuscation is good enough, that is there are “k” other mobile devices  112 ,  114 ,  116  within the box  404 , at  514  the obfuscated location  420  is returned by the trusted edge server  104 ,  106  to the mobile device  110  with an indication that the obfuscation is good enough. 
     At  516 , the mobile device  110  can send a query to the service provider  204  including the anonymized obfuscated location  420 . The anonymized obfuscated location  420  is typically a random point in the box  404 . Sending more information, such as the co-ordinates of the box risks undermining the anonymization of the location data. The query may be to a location based service provided by the service provider  204  such as where the nearest coffee shop may be found. 
     At  518 , the results are returned by the service provider  204  to the mobile device  110 . Referring back to  FIG. 4 , the results may be the locations of the nearest coffee shops to the obfuscated location  420 . The results may exclude some coffee shops that are closer to the user&#39;s real location, which is any location within the solid line circle  404  centered on the real location  402 , but outside the dashed line circle  430  centered on the obfuscated location  420 . The results may include other coffee shops that are further from the user&#39;s real location  402 , which is any location within the dashed line circle  430  centered on the obfuscated location  420 , but outside the solid line circle  404  centered on the user&#39;s real location  402 . However, the results will likely include some coffee shops that are closer to the user&#39;s location  402 , that is within both the solid line circle  404  centered on the real location  402  and the dashed line circle  430  centered on the obfuscated location  420 . In the example of  FIG. 4 , the dashed line circle  430  is shown as being the same size as the extent of obfuscation “l”, but in practice it is likely to be different and will likely be provided by the end user when making the request to the service provider. For example, the user may request from the anonymization provider  202  an extent of location obfuscation of 200 meters (the radius of the solid line circle  404  centered on the user&#39;s location  402 ), but desires to know from the service provider  204  of any coffee shops within 500 meters (the radius of the dashed line circle  430  centered on the obfuscated location  420 ). Returning to  FIG. 5 , the method according to an embodiment of the present invention ends at  520 . 
       FIG. 6  shows an interactive map  600  for use in a second embodiment of the present invention, this embodiment being trusted edge server  104 ,  106  based. The interactive map  600  may include any number of geographical and/or physical features displayed to a user which are not shown in  FIG. 6  for clarity. Locations  602  to  618  show locations of mobile device  110 ,  112 ,  114 ,  116  users, comprising the location  606  of the mobile device  110  whose user desires anonymization of data and the locations  602 ,  604 ,  608 - 618  of other mobile device  112 ,  114 ,  116  users. One of the locations  606  is identified as the mobile device  110  of the user who desires anonymization of data, whilst the other locations  602 ,  604 ,  608 - 618  are other mobile device  112 ,  114 ,  116  users. Another of the locations  620  is identified in  FIG. 6  as the obfuscated location to be returned to the mobile device  110  by the anonymization provider  202  for sending as the obfuscated location with the query to the service provider  204 . Typically, the scale of the map will be chosen such that there are about “k” different mobile devices  112 ,  114 ,  116  shown. “k” corresponds to the level of anonymity desired by the user of the mobile device  110 . The solid line circle  625  and the dashed line circle  630  will be explained below with reference to  718  in  FIG. 7 . 
     Referring to  FIG. 7 , a method according to an embodiment of the present invention starts at  702 . At  704 , a user clicks on the interactive map  600  displayed at the mobile device  110  to indicate the position of the user. As explained above with reference to  FIG. 5 , the mobile device  110  user&#39;s current location  606  may be selected by the user or may be directly input using a position location system, such as GPS or by use of identification of a current connection within a cellular wireless network. A user may, optionally, be asked to confirm a position supplied by a position location system. In the example of  FIG. 6 , the user has clicked on the map at location  606 . The locations  602 ,  604  and  608 - 618  of the other mobile devices  112 ,  114 ,  116  do not appear on the map displayed to the user, but are known only to the trusted edge server  104 ,  106 . The desired location  606  may be identified by latitude and longitude, by use of grid coordinates or any other way in which a current location  606  may be identified. At  706 , on clicking on the location of the user&#39;s mobile device  110 , the mobile device&#39;s  110  location will be noted at the mobile device  110 . Also at  706 , the user is prompted at the mobile device  110  for the desired level of anonymity “k”. In a preferred embodiment, a value for the desired extent of location obfuscation “l” is not requested and is not sent. In an alternative embodiment, a value for the desired extent of location obfuscation “l” is also optionally requested from a user and may be sent with the value for the level of desired anonymity “k”. The sending of a value for the desired extent of location obfuscation “l” allows a user to indicate that they desire the obfuscated location  620  to fall within the distance “l” of the user&#39;s actual location  606 . At  708 , the details are submitted by the mobile device  110  to the trusted edge server  104 ,  106 . In a preferred embodiment, this submission is through a HTTP post. The details may typically include the location and level of anonymity “k”. Typically, the details do not include the extent of location obfuscation “l”, although this may optionally be included. The trusted edge server  104 ,  106  knows the location of at least “k”−l other mobile devices  112 ,  114 ,  116 . 
     At  710 , the obfuscated location  620  will be computed using the k-anonymity model. In a typical application, it is desirable that the trusted edge server  104 ,  106  selects a minimum extent of location obfuscation “l” that will satisfy the level of anonymity “k”. However, for some applications, it is desirable to specify a maximum extent of location obfuscation “l” because the utility of the application executing on the mobile device  110  drops sharply beyond that extent. For example, if the location is being provided in order to identify the nearest coffee shop, then whilst a minimum extent of location obfuscation “l” is needed for anonymity, there is a maximum extent of location obfuscation “l” for the response to the query to be useful. An extent of location obfuscation “l” of 50 kilometers will not be very helpful if it means that the response to the query returns a coffee shop that is 49 kilometers away, when there are many other coffee shops that are closer to the mobile device&#39;s  110  real location  606 . 
     At  712 , the obfuscated location  620  is returned by the trusted edge server  104 ,  106  to the mobile device  110 . At  714 , once the obfuscated position is received, it is highlighted on the interactive map  600  at the mobile device  110  by showing the true location  606  and the received anonymized location  620 . The locations  602 ,  604  and  608 - 618  of the other mobile devices  112 ,  114 ,  116  do not appear on the map displayed to the user, but are known only to the trusted edge server  104 ,  106 . 
     At  716 , the mobile device  110  sends a query to the service provider  204  including the anonymized location  620 . The query may be to a location based service such as where the nearest coffee shop may be found. 
     At  718 , the results of the query are returned from the service provider  204  to the mobile device  110 . The results may be the locations of the nearest coffee shops to the obfuscated location  620 . The results may exclude some coffee shops that are closer to the user&#39;s real location, which is any location within the solid line circle  625  centered on the real location  606 , but outside the dashed line circle  630  centered on the obfuscated location  620 . The results may include other coffee shops that are further from the user&#39;s real location  606 , which is any location within the dashed line circle  630  centered on the obfuscated location  620 , but outside the solid line circle  625  centered on the user&#39;s real location  606 . However, the results will likely include some coffee shops that are closer to the user&#39;s location  606 , that is within both the solid line circle  625  centered on the real location  606  and the dashed line circle  630  centered on the obfuscated location  620 . In the example of  FIG. 6 , the dashed line circle  630  is shown as being the same size as the extent of obfuscation “l”, but in practice it is likely to be different and will likely be provided by the end user when making the request to the service provider. For example, the user may request from the anonymization provider  202  an extent of location obfuscation of 200 meters (the radius of the solid line circle  625  centered on the user&#39;s location  606 ), but desires to know from the service provider  204  of any coffee shops within 500 meters (the radius of the dashed line circle  630  centered on the obfuscated location  620 ). The method according to an embodiment of the present invention ends at  720 . 
     The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or trusted edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions and the like can be made without departing from the spirit of the invention, and these are, therefore, considered to be within the scope of the invention, as defined in the following claims.