Patent Publication Number: US-9838398-B2

Title: Validating the identity of an application for application management

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/898,167, entitled “Validating the Identity of a Mobile Application for Mobile Application Management” and filed on May 20, 2013, which claims priority to U.S. Provisional Pat. App. No. 61/806,557 entitled “Systems and Methods for Enterprise Mobility Management” and filed on Mar. 29, 2013, each of which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     Aspects described herein generally relate to management of mobile applications at mobile computing devices. More specifically, various aspects provide approaches to validating a mobile application operating at an unmanaged device and controlling execution of that mobile application. 
     BACKGROUND 
     The use of mobile computing devices continues to grow. In particular, business and other enterprises have come to rely on mobile computing devices to allow individuals to remotely access various computing resources. Such resources may include, for example, electronic mail services, file services, data, and other electronic resources provided by the computer systems of an enterprise or the mobile device itself. 
     Whether an individual is located locally or remotely relative to computing resources, an enterprise may seek to protect and control access to those resources. Accordingly, an enterprise may implement various technological mechanisms (e.g., gateways and firewalls) as well as access control mechanisms (e.g., user authentication and authorization) in order to ensure an individual can only access the resources that individual is authorized and entitled to access. Such mechanisms may also prevent unauthorized individuals from accessing any of the computing resources. 
     With respect to mobile devices, an enterprise may employ various approaches to control remote access to computing resources from those mobile devices. This endeavor may be referred to as mobile device management. In one approach, an enterprise may provide an individual with a company-owned and company-controlled mobile device. Such a device may be configured such that the enterprise has control over the configuration, functionality, operation, and data of the mobile device. In this regard, the company-controlled mobile device may be referred to as a managed device. The enterprise may remotely control the managed device via, e.g., a client-server architecture. An enterprise server may remotely issue commands to a client application residing at the managed device. Such commands may include, e.g., installing new applications or functionality, updating existing applications or functionality, updating configuration settings, providing data, and so forth. If the managed device is lost or stolen, the enterprise may issue commands to lock or wipe the device in order to prevent an unauthorized individual from gaining access to the device or from gaining access to the resources via the device. 
     Individuals, however, may find it inconvenient to maintain both a company-owned mobile device as well as a personal mobile device. Instead, individuals may prefer to access the resources from their personal mobile devices. This practice may be referred to as BYOD, bring-your-own-device. Because these personal devices may not be company-controlled, such personal devices may be referred to as unmanaged devices. To accommodate this preference, solutions to allow unmanaged devices to access these resources are currently in development. 
     For example, providing a company-controlled mobile application, a managed mobile application, that is configured to operate at an unmanaged device is one approach currently in development. However, challenges remain. For managed mobile applications operating on an unmanaged device to be a viable approach, mechanisms to prevent unauthorized access to or use of resources via the managed mobile application may be needed. In particular, there exists a need to validate the identity of a managed mobile application to ensure the managed mobile application has been altered to circumvent the security mechanisms that protect the resources. In addition, there exists a need to control the operation of the managed mobile application at the unmanaged mobile device. 
     BRIEF SUMMARY 
     The following presents a simplified summary of various aspects described herein. This summary is not an extensive overview, and is not intended to identify key or critical elements or to delineate the scope of the claims. The following summary merely presents some concepts in a simplified form as an introductory prelude to the more detailed description provided below. 
     To overcome limitations in the prior art described above, and to overcome other limitations that will be apparent upon reading and understanding the present specification, aspects described herein are directed towards controlling access to remote computing resources located at an enterprise computing system using managed mobile applications at mobile computing devices. In addition, aspects of the present disclosure are directed towards controlling access to local computing resources at the mobile computing devices themselves. An access manager may perform a validation process that determines whether a mobile application requesting access to computing resources has accurately identified itself and has not been subsequently altered after installation at the mobile computing device. In this way, the access manager may ensure the mobile application requesting access to the computing resource can be trusted and is not attempting to circumvent the security mechanisms used to protect those resources. As a result, individuals associated with the enterprise may advantageously utilize remote and local computing resources with their personal mobile devices. 
     A first aspect described herein provides a method of managing access to computing resources. An access manager may operate at a mobile device to validate a mobile application installed at that mobile device. If the access manager does not successfully validate the mobile application, the access manager may prevent the mobile application from accessing a computing resource. If the access manager does successfully validate the mobile application, then the access manager may identify the mobile application as a trusted mobile application. The access manager may thus permit the trusted mobile application to access the computing resource. 
     A second aspect described herein provides a mobile computing device. The mobile computing device may include a mobile application configured to access a computing resource, stored identification information associated with the mobile application, and an access manager. The access manager may be configured to validate the mobile application and prevent or permit access to the computing resource as described above. 
     A third aspect described herein provides an access manager configured to operate at a mobile device. The access manager may also be configured to validate a mobile application at the mobile device and prevent or permit access to a computing resource via the mobile application as described above. The access manager may further be configured to control operation of the mobile application based on an application policy stored at the mobile application. 
     Some aspects described herein provide that the stored identification information may be an original digital certificate associated and created along with the mobile application. The access manager may validate the mobile application by comparing the original digital certificate created for the mobile application with a digital certificate received from a mobile operating system at the mobile computing device. The computing resources may be located locally or remotely relative to the mobile computing device. Examples of computing resources include a software application operating at the mobile computing device or a remote computing system, a service provided by the mobile computing device or a remote computing system, data stored at the mobile computing device or the remote computing system, hardware at the mobile computing device or the remote computing system, and combinations of such. 
     The stored identification information may also be identification tokens embedded into the mobile application upon creation or derived from the mobile application. An application signature may be constructed based on an arrangement of the embedded and derive identification tokens. The access manager may also provide the mobile application with a nonce during validation, and use the nonce to compute an expected hash value using the application signature and the nonce. The access manager may generate an expected response, e.g., an expected hash value, and compare the expected response to a response received from the mobile application following a challenge from the access manager. 
     These and additional aspects will be appreciated with the benefit of the disclosures discussed in further detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of aspects described herein and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
         FIG. 1  depicts an illustrative computer system architecture that may be used in accordance with one or more illustrative aspects described herein. 
         FIG. 2  depicts an illustrative remote-access system architecture that may be used in accordance with one or more illustrative aspects described herein. 
         FIG. 3  depicts an illustrative virtualized (hypervisor) system architecture that may be used in accordance with one or more illustrative aspects described herein. 
         FIG. 4  depicts an illustrative cloud-based system architecture that may be used in accordance with one or more illustrative aspects described herein. 
         FIG. 5  depicts an illustrative enterprise mobility management system. 
         FIG. 6  depicts another illustrative enterprise mobility management system. 
         FIG. 7  depicts an illustrative mobile device management system. 
         FIG. 8  depicts a block diagram of an illustrative application signature and challenge response for a managed mobile application. 
         FIG. 9  is a flowchart of example method steps for managing a mobile application at an unmanaged mobile device. 
         FIG. 10  is a flowchart of example method steps for preparing a managed mobile application for managed operation at an unmanaged mobile device. 
         FIG. 11  is a flowchart of example method steps for initializing a managed mobile application at an unmanaged mobile device. 
         FIG. 12  is a flowchart of example method steps for validating a managed mobile application at an unmanaged mobile device having a first type of mobile operating system. 
         FIG. 13  is a flowchart of example method steps for validating a managed mobile application at an unmanaged mobile device having a second type of mobile operating system. 
         FIG. 14  is a flowchart of example method steps for enforcing application policies during operation of a managed mobile application. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of the various embodiments, reference is made to the accompanying drawings identified above and which form a part hereof, and in which is shown by way of illustration various embodiments in which aspects described herein may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope described herein. Various aspects are capable of other embodiments and of being practiced or being carried out in various different ways. 
     As a general introduction to the subject matter described in more detail below, aspects described herein are directed towards controlling remote and local access to computing resources at a remotely located enterprise computing system or at mobile computing devices themselves. An access manager may perform a validation process that determines whether a mobile application requesting access to computing resources has accurately identified itself and has not been subsequently altered after installation at the mobile computing device. In this way, the access manager may ensure the mobile application requesting access to the computing resource can be trusted and is not attempting to circumvent the security mechanisms used to protect those resources. As a result, individuals associated with the enterprise may advantageously utilize computing resources at their personal mobile devices. Computing resources may be located locally or remotely relative to the mobile computing device. Examples of computing resources include a software application operating at the mobile computing device or a remote computing system, a service provided by the mobile computing device or a remote computing system, data stored at the mobile computing device or the remote computing system, hardware at the mobile computing device or the remote computing system, and combinations of such. In the present disclosure, computing resources that are remotely located at a computing system of an enterprise are referred to as enterprise resources. 
     It is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Rather, the phrases and terms used herein are to be given their broadest interpretation and meaning. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. The use of the terms “mounted,” “connected,” “coupled,” “positioned,” “engaged” and similar terms, is meant to include both direct and indirect mounting, connecting, coupling, positioning and engaging. 
     Computing Architecture 
     Computer software, hardware, and networks may be utilized in a variety of different system environments, including standalone, networked, remote-access (aka, remote desktop), virtualized, and/or cloud-based environments, among others.  FIG. 1  illustrates one example of a system architecture and data processing device that may be used to implement one or more illustrative aspects of the disclosure in a standalone and/or networked environment. Various network nodes  103 ,  105 ,  107 , and  109  may be interconnected via a wide area network (WAN)  101 , such as the Internet. Other networks may also or alternatively be used, including private intranets, corporate networks, LANs, metropolitan area networks (MAN) wireless networks, personal networks (PAN), and the like. Network  101  is for illustration purposes and may be replaced with fewer or additional computer networks. A local area network (LAN) may have one or more of any known LAN topology and may use one or more of a variety of different protocols, such as Ethernet. Devices  103 ,  105 ,  107 ,  109  and other devices (not shown) may be connected to one or more of the networks via twisted pair wires, coaxial cable, fiber optics, radio waves or other communication media. 
     The term “network” as used herein and depicted in the drawings refers not only to systems in which remote storage devices are coupled together via one or more communication paths, but also to stand-alone devices that may be coupled, from time to time, to such systems that have storage capability. Consequently, the term “network” includes not only a “physical network” but also a “content network,” which is comprised of the data—attributable to a single entity—which resides across all physical networks. 
     The components may include data server  103 , web server  105 , and client computers  107 ,  109 . Data server  103  provides overall access, control and administration of databases and control software for performing one or more illustrative aspects of the disclosure as described herein. Data server  103  may be connected to web server  105  through which users interact with and obtain data as requested. Alternatively, data server  103  may act as a web server itself and be directly connected to the Internet. Data server  103  may be connected to web server  105  through the network  101  (e.g., the Internet), via direct or indirect connection, or via some other network. Users may interact with the data server  103  using remote computers  107 ,  109 , e.g., using a web browser to connect to the data server  103  via one or more externally exposed web sites hosted by web server  105 . Client computers  107 ,  109  may be used in concert with data server  103  to access data stored therein, or may be used for other purposes. For example, from client device  107  a user may access web server  105  using an Internet browser, as is known in the art, or by executing a software application that communicates with web server  105  and/or data server  103  over a computer network (such as the Internet). 
     Servers and applications may be combined on the same physical machines, and retain separate virtual or logical addresses, or may reside on separate physical machines.  FIG. 1  illustrates just one example of a network architecture that may be used, and those of skill in the art will appreciate that the specific network architecture and data processing devices used may vary, and are secondary to the functionality that they provide, as further described herein. For example, services provided by web server  105  and data server  103  may be combined on a single server. 
     Each component  103 ,  105 ,  107 ,  109  may be any type of known computer, server, or data processing device. Data server  103 , e.g., may include a processor  111  controlling overall operation of the rate server  103 . Data server  103  may further include RAM  113 , ROM  115 , network interface  117 , input/output interfaces  119  (e.g., keyboard, mouse, display, printer, etc.), and memory  121 . I/O  119  may include a variety of interface units and drives for reading, writing, displaying, and/or printing data or files. Memory  121  may further store operating system software  123  for controlling overall operation of the data processing device  103 , control logic  125  for instructing data server  103  to perform aspects of the disclosure as described herein, and other application software  127  providing secondary, support, and/or other functionality which may or may not be used in conjunction with aspects of the present disclosure. The control logic may also be referred to herein as the data server software  125 . Functionality of the data server software may refer to operations or decisions made automatically based on rules coded into the control logic, made manually by a user providing input into the system, and/or a combination of automatic processing based on user input (e.g., queries, data updates, etc.). 
     Memory  121  may also store data used in performance of one or more aspects of the disclosure, including a first database  129  and a second database  131 . In some embodiments, the first database may include the second database (e.g., as a separate table, report, etc.). That is, the information can be stored in a single database, or separated into different logical, virtual, or physical databases, depending on system design. Devices  105 ,  107 ,  109  may have similar or different architecture as described with respect to device  103 . Those of skill in the art will appreciate that the functionality of data processing device  103  (or device  105 ,  107 ,  109 ) as described herein may be spread across multiple data processing devices, for example, to distribute processing load across multiple computers, to segregate transactions based on geographic location, user access level, quality of service (QoS), etc. 
     One or more aspects may be embodied in computer-usable or readable data and/or computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices as described herein. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The modules may be written in a source code programming language that is subsequently compiled for execution, or may be written in a scripting language such as (but not limited to) HTML or XML. The computer executable instructions may be stored on a computer readable medium such as a nonvolatile storage device. Any suitable computer readable storage media may be utilized, including hard disks, CD-ROMs, optical storage devices, magnetic storage devices, and/or any combination thereof. In addition, various transmission (non-storage) media representing data or events as described herein may be transferred between a source and a destination in the form of electromagnetic waves traveling through signal-conducting media such as metal wires, optical fibers, and/or wireless transmission media (e.g., air and/or space). Various aspects described herein may be embodied as a method, a data processing system, or a computer program product. Therefore, various functionality may be embodied in whole or in part in software, firmware and/or hardware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA), and the like. Particular data structures may be used to more effectively implement one or more aspects of the disclosure, and such data structures are contemplated within the scope of computer executable instructions and computer-usable data described herein. 
     With further reference to  FIG. 2 , one or more aspects described herein may be implemented in a remote-access environment.  FIG. 2  depicts an example system architecture including a generic computing device  201  in an illustrative computing environment  200  that may be used according to one or more illustrative aspects described herein. Generic computing device  201  may be used as a server  206   a  in a single-server or multi-server desktop virtualization system (e.g., a remote access or cloud system) configured to provide virtual machines for client access devices. The generic computing device  201  may have a processor  203  for controlling overall operation of the server and its associated components, including random access memory (RAM)  205 , read-only memory (ROM)  207 , input/output (I/O) module  209 , and memory  215 . 
     I/O module  209  may include a mouse, keypad, touch screen, scanner, optical reader, and/or stylus (or other input device(s)) through which a user of generic computing device  201  may provide input, and may also include one or more of a speaker for providing audio output and a video display device for providing textual, audiovisual, and/or graphical output. Software may be stored within memory  215  and/or other storage to provide instructions to processor  203  for configuring generic computing device  201  into a special purpose computing device in order to perform various functions as described herein. For example, memory  215  may store software used by the computing device  201 , such as an operating system  217 , application programs  219 , and an associated database  221 . 
     Computing device  201  may operate in a networked environment supporting connections to one or more remote computers, such as terminals  240  (also referred to as client devices). The terminals  240  may be personal computers, mobile devices, laptop computers, tablets, or servers that include many or all of the elements described above with respect to the generic computing device  103  or  201 . The network connections depicted in  FIG. 2  include a local area network (LAN)  225  and a wide area network (WAN)  229 , but may also include other networks. When used in a LAN networking environment, computing device  201  may be connected to the LAN  225  through a network interface or adapter  223 . When used in a WAN networking environment, computing device  201  may include a modem  227  or other wide area network interface for establishing communications over the WAN  229 , such as computer network  230  (e.g., the Internet). It will be appreciated that the network connections shown are illustrative and other means of establishing a communications link between the computers may be used. Computing device  201  and/or terminals  240  may also be mobile terminals (e.g., mobile phones, smartphones, PDAs, notebooks, etc.) including various other components, such as a battery, speaker, and antennas (not shown). 
     Aspects described herein may also be operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of other computing systems, environments, and/or configurations that may be suitable for use with aspects described herein include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. 
     As shown in  FIG. 2 , one or more client devices  240  may be in communication with one or more servers  206   a - 206   n  (generally referred to herein as “server(s)  206 ”). In one embodiment, the computing environment  200  may include a network appliance installed between the server(s)  206  and client machine(s)  240 . The network appliance may manage client/server connections, and in some cases can load balance client connections amongst a plurality of backend servers  206 . 
     The client machine(s)  240  may in some embodiments be referred to as a single client machine  240  or a single group of client machines  240 , while server(s)  206  may be referred to as a single server  206  or a single group of servers  206 . In one embodiment a single client machine  240  communicates with more than one server  206 , while in another embodiment a single server  206  communicates with more than one client machine  240 . In yet another embodiment, a single client machine  240  communicates with a single server  206 . 
     A client machine  240  can, in some embodiments, be referenced by any one of the following non-exhaustive terms: client machine(s); client(s); client computer(s); client device(s); client computing device(s); local machine; remote machine; client node(s); endpoint(s); or endpoint node(s). The server  206 , in some embodiments, may be referenced by any one of the following non-exhaustive terms: server(s), local machine; remote machine; server farm(s), or host computing device(s). 
     In one embodiment, the client machine  240  may be a virtual machine. The virtual machine may be any virtual machine, while in some embodiments the virtual machine may be any virtual machine managed by a Type 1 or Type 2 hypervisor, for example, a hypervisor developed by Citrix Systems, IBM, VMware, or any other hypervisor. In some aspects, the virtual machine may be managed by a hypervisor, while in aspects the virtual machine may be managed by a hypervisor executing on a server  206  or a hypervisor executing on a client  240 . 
     Some embodiments include a client device  240  that displays application output generated by an application remotely executing on a server  206  or other remotely located machine. In these embodiments, the client device  240  may execute a virtual machine receiver program or application to display the output in an application window, a browser, or other output window. In one example, the application is a desktop, while in other examples the application is an application that generates or presents a desktop. A desktop may include a graphical shell providing a user interface for an instance of an operating system in which local and/or remote applications can be integrated. Applications, as used herein, are programs that execute after an instance of an operating system (and, optionally, also the desktop) has been loaded. 
     The server  206 , in some embodiments, uses a remote presentation protocol or other program to send data to a thin-client or remote-display application executing on the client to present display output generated by an application executing on the server  206 . The thin-client or remote-display protocol can be any one of the following non-exhaustive list of protocols: the Independent Computing Architecture (ICA) protocol developed by Citrix Systems, Inc. of Ft. Lauderdale, Fla.; or the Remote Desktop Protocol (RDP) manufactured by the Microsoft Corporation of Redmond, Wash. 
     A remote computing environment may include more than one server  206   a - 206   n  such that the servers  206   a - 206   n  are logically grouped together into a server farm  206 , for example, in a cloud computing environment. The server farm  206  may include servers  206  that are geographically dispersed while and logically grouped together, or servers  206  that are located proximate to each other while logically grouped together. Geographically dispersed servers  206   a - 206   n  within a server farm  206  can, in some embodiments, communicate using a WAN (wide), MAN (metropolitan), or LAN (local), where different geographic regions can be characterized as: different continents; different regions of a continent; different countries; different states; different cities; different campuses; different rooms; or any combination of the preceding geographical locations. In some embodiments the server farm  206  may be administered as a single entity, while in other embodiments the server farm  206  can include multiple server farms. 
     In some embodiments, a server farm may include servers  206  that execute a substantially similar type of operating system platform (e.g., WINDOWS, UNIX, LINUX, iOS, ANDROID, SYMBIAN, etc.) In other embodiments, server farm  206  may include a first group of one or more servers that execute a first type of operating system platform, and a second group of one or more servers that execute a second type of operating system platform. 
     Server  206  may be configured as any type of server, as needed, e.g., a file server, an application server, a web server, a proxy server, an appliance, a network appliance, a gateway, an application gateway, a gateway server, a virtualization server, a deployment server, an SSL VPN server, a firewall, a web server, an application server or as a master application server, a server executing an active directory, or a server executing an application acceleration program that provides firewall functionality, application functionality, or load balancing functionality. Other server types may also be used. 
     Some embodiments include a first server  106   a  that receives requests from a client machine  240 , forwards the request to a second server  106   b , and responds to the request generated by the client machine  240  with a response from the second server  106   b . First server  106   a  may acquire an enumeration of applications available to the client machine  240  as well as address information associated with an application server  206  hosting an application identified within the enumeration of applications. First server  106   a  can then present a response to the client&#39;s request using a web interface, and communicate directly with the client  240  to provide the client  240  with access to an identified application. One or more clients  240  and/or one or more servers  206  may transmit data over network  230 , e.g., network  101 . 
       FIG. 2  shows a high-level architecture of an illustrative desktop virtualization system. As shown, the desktop virtualization system may be single-server or multi-server system, or cloud system, including at least one virtualization server  206  configured to provide virtual desktops and/or virtual applications to one or more client access devices  240 . As used herein, a desktop refers to a graphical environment or space in which one or more applications may be hosted and/or executed. A desktop may include a graphical shell providing a user interface for an instance of an operating system in which local and/or remote applications can be integrated. Applications may include programs that execute after an instance of an operating system (and, optionally, also the desktop) has been loaded. Each instance of the operating system may be physical (e.g., one operating system per device) or virtual (e.g., many instances of an OS running on a single device). Each application may be executed on a local device, or executed on a remotely located device (e.g., remoted). 
     With further reference to  FIG. 3 , a computer device  301  may be configured as a virtualization server in a virtualization environment, for example, a single-server, multi-server, or cloud computing environment. Virtualization server  301  illustrated in  FIG. 3  can be deployed as and/or implemented by one or more embodiments of the server  206  illustrated in  FIG. 2  or by other known computing devices. Included in virtualization server  301  is a hardware layer that can include one or more physical disks  304 , one or more physical devices  306 , one or more physical processors  308  and one or more physical memories  316 . In some embodiments, firmware  312  can be stored within a memory element in the physical memory  316  and can be executed by one or more of the physical processors  308 . Virtualization server  301  may further include an operating system  314  that may be stored in a memory element in the physical memory  316  and executed by one or more of the physical processors  308 . Still further, a hypervisor  302  may be stored in a memory element in the physical memory  316  and can be executed by one or more of the physical processors  308 . 
     Executing on one or more of the physical processors  308  may be one or more virtual machines  332 A-C (generally  332 ). Each virtual machine  332  may have a virtual disk  326 A-C and a virtual processor  328 A-C. In some embodiments, a first virtual machine  332 A may execute, using a virtual processor  328 A, a control program  320  that includes a tools stack  324 . Control program  320  may be referred to as a control virtual machine, Dom0, Domain 0, or other virtual machine used for system administration and/or control. In some embodiments, one or more virtual machines  332 B-C can execute, using a virtual processor  328 B-C, a guest operating system  330 A-B. 
     Virtualization server  301  may include a hardware layer  310  with one or more pieces of hardware that communicate with the virtualization server  301 . In some embodiments, the hardware layer  310  can include one or more physical disks  304 , one or more physical devices  306 , one or more physical processors  308 , and one or more memory  316 . Physical components  304 ,  306 ,  308 , and  316  may include, for example, any of the components described above. Physical devices  306  may include, for example, a network interface card, a video card, a keyboard, a mouse, an input device, a monitor, a display device, speakers, an optical drive, a storage device, a universal serial bus connection, a printer, a scanner, a network element (e.g., router, firewall, network address translator, load balancer, virtual private network (VPN) gateway, Dynamic Host Configuration Protocol (DHCP) router, etc.), or any device connected to or communicating with virtualization server  301 . Physical memory  316  in the hardware layer  310  may include any type of memory. Physical memory  316  may store data, and in some embodiments may store one or more programs, or set of executable instructions.  FIG. 3  illustrates an embodiment where firmware  312  is stored within the physical memory  316  of virtualization server  301 . Programs or executable instructions stored in the physical memory  316  can be executed by the one or more processors  308  of virtualization server  301 . 
     Virtualization server  301  may also include a hypervisor  302 . In some embodiments, hypervisor  302  may be a program executed by processors  308  on virtualization server  301  to create and manage any number of virtual machines  332 . Hypervisor  302  may be referred to as a virtual machine monitor, or platform virtualization software. In some embodiments, hypervisor  302  can be any combination of executable instructions and hardware that monitors virtual machines executing on a computing machine. Hypervisor  302  may be Type 2 hypervisor, where the hypervisor that executes within an operating system  314  executing on the virtualization server  301 . Virtual machines then execute at a level above the hypervisor. In some embodiments, the Type 2 hypervisor executes within the context of a user&#39;s operating system such that the Type 2 hypervisor interacts with the user&#39;s operating system. In other embodiments, one or more virtualization servers  301  in a virtualization environment may instead include a Type 1 hypervisor (not shown). A Type 1 hypervisor may execute on the virtualization server  301  by directly accessing the hardware and resources within the hardware layer  310 . That is, while a Type 2 hypervisor  302  accesses system resources through a host operating system  314 , as shown, a Type 1 hypervisor may directly access all system resources without the host operating system  314 . A Type 1 hypervisor may execute directly on one or more physical processors  308  of virtualization server  301 , and may include program data stored in the physical memory  316 . 
     Hypervisor  302 , in some embodiments, can provide virtual resources to operating systems  330  or control programs  320  executing on virtual machines  332  in any manner that simulates the operating systems  330  or control programs  320  having direct access to system resources. System resources can include, but are not limited to, physical devices  306 , physical disks  304 , physical processors  308 , physical memory  316  and any other component included in virtualization server  301  hardware layer  310 . Hypervisor  302  may be used to emulate virtual hardware, partition physical hardware, virtualize physical hardware, and/or execute virtual machines that provide access to computing environments. In still other embodiments, hypervisor  302  controls processor scheduling and memory partitioning for a virtual machine  332  executing on virtualization server  301 . Hypervisor  302  may include those manufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor, an open source product whose development is overseen by the open source Xen.org community; HyperV, VirtualServer or virtual PC hypervisors provided by Microsoft, or others. In some embodiments, virtualization server  301  executes a hypervisor  302  that creates a virtual machine platform on which guest operating systems may execute. In these embodiments, the virtualization server  301  may be referred to as a host server. An example of such a virtualization server is the XEN SERVER provided by Citrix Systems, Inc., of Fort Lauderdale, Fla. 
     Hypervisor  302  may create one or more virtual machines  332 B-C (generally  332 ) in which guest operating systems  330  execute. In some embodiments, hypervisor  302  may load a virtual machine image to create a virtual machine  332 . In other embodiments, the hypervisor  302  may executes a guest operating system  330  within virtual machine  332 . In still other embodiments, virtual machine  332  may execute guest operating system  330 . 
     In addition to creating virtual machines  332 , hypervisor  302  may control the execution of at least one virtual machine  332 . In other embodiments, hypervisor  302  may presents at least one virtual machine  332  with an abstraction of at least one hardware resource provided by the virtualization server  301  (e.g., any hardware resource available within the hardware layer  310 ). In other embodiments, hypervisor  302  may control the manner in which virtual machines  332  access physical processors  308  available in virtualization server  301 . Controlling access to physical processors  308  may include determining whether a virtual machine  332  should have access to a processor  308 , and how physical processor capabilities are presented to the virtual machine  332 . 
     As shown in  FIG. 3 , virtualization server  301  may host or execute one or more virtual machines  332 . A virtual machine  332  is a set of executable instructions that, when executed by a processor  308 , imitate the operation of a physical computer such that the virtual machine  332  can execute programs and processes much like a physical computing device. While  FIG. 3  illustrates an embodiment where a virtualization server  301  hosts three virtual machines  332 , in other embodiments virtualization server  301  can host any number of virtual machines  332 . Hypervisor  302 , in some embodiments, provides each virtual machine  332  with a unique virtual view of the physical hardware, memory, processor and other system resources available to that virtual machine  332 . In some embodiments, the unique virtual view can be based on one or more of virtual machine permissions, application of a policy engine to one or more virtual machine identifiers, a user accessing a virtual machine, the applications executing on a virtual machine, networks accessed by a virtual machine, or any other desired criteria. For instance, hypervisor  302  may create one or more unsecure virtual machines  332  and one or more secure virtual machines  332 . Unsecure virtual machines  332  may be prevented from accessing resources, hardware, memory locations, and programs that secure virtual machines  332  may be permitted to access. In other embodiments, hypervisor  302  may provide each virtual machine  332  with a substantially similar virtual view of the physical hardware, memory, processor and other system resources available to the virtual machines  332 . 
     Each virtual machine  332  may include a virtual disk  326 A-C (generally  326 ) and a virtual processor  328 A-C (generally  328 .) The virtual disk  326 , in some embodiments, is a virtualized view of one or more physical disks  304  of the virtualization server  301 , or a portion of one or more physical disks  304  of the virtualization server  301 . The virtualized view of the physical disks  304  can be generated, provided and managed by the hypervisor  302 . In some embodiments, hypervisor  302  provides each virtual machine  332  with a unique view of the physical disks  304 . Thus, in these embodiments, the particular virtual disk  326  included in each virtual machine  332  can be unique when compared with the other virtual disks  326 . 
     A virtual processor  328  can be a virtualized view of one or more physical processors  308  of the virtualization server  301 . In some embodiments, the virtualized view of the physical processors  308  can be generated, provided and managed by hypervisor  302 . In some embodiments, virtual processor  328  has substantially all of the same characteristics of at least one physical processor  308 . In other embodiments, virtual processor  308  provides a modified view of physical processors  308  such that at least some of the characteristics of the virtual processor  328  are different than the characteristics of the corresponding physical processor  308 . 
     With further reference to  FIG. 4 , some aspects described herein may be implemented in a cloud-based environment.  FIG. 4  illustrates an example of a cloud computing environment (or cloud system)  400 . As seen in  FIG. 4 , client computers  411 - 414  may communicate with a cloud management server  410  to access the computing resources (e.g., host servers  403 , storage resources  404 , and network resources  405 ) of the cloud system. 
     Management server  410  may be implemented on one or more physical servers. The management server  410  may run, for example, CLOUDSTACK by Citrix Systems, Inc. of Ft. Lauderdale, Fla., or OPENSTACK, among others. Management server  410  may manage various computing resources, including cloud hardware and software resources, for example, host computers  403 , data storage devices  404 , and networking devices  405 . The cloud hardware and software resources may include private and/or public components. For example, a cloud may be configured as a private cloud to be used by one or more particular customers or client computers  411 - 414  and/or over a private network. In other embodiments, public clouds or hybrid public-private clouds may be used by other customers over an open or hybrid networks. 
     Management server  410  may be configured to provide user interfaces through which cloud operators and cloud customers may interact with the cloud system. For example, the management server  410  may provide a set of APIs and/or one or more cloud operator console applications (e.g., web-based on standalone applications) with user interfaces to allow cloud operators to manage the cloud resources, configure the virtualization layer, manage customer accounts, and perform other cloud administration tasks. The management server  410  also may include a set of APIs and/or one or more customer console applications with user interfaces configured to receive cloud computing requests from end users via client computers  411 - 414 , for example, requests to create, modify, or destroy virtual machines within the cloud. Client computers  411 - 414  may connect to management server  410  via the Internet or other communication network, and may request access to one or more of the computing resources managed by management server  410 . In response to client requests, the management server  410  may include a resource manager configured to select and provision physical resources in the hardware layer of the cloud system based on the client requests. For example, the management server  410  and additional components of the cloud system may be configured to provision, create, and manage virtual machines and their operating environments (e.g., hypervisors, storage resources, services offered by the network elements, etc.) for customers at client computers  411 - 414 , over a network (e.g., the Internet), providing customers with computational resources, data storage services, networking capabilities, and computer platform and application support. Cloud systems also may be configured to provide various specific services, including security systems, development environments, user interfaces, and the like. 
     Certain clients  411 - 414  may be related, for example, different client computers creating virtual machines on behalf of the same end user, or different users affiliated with the same company or organization. In other examples, certain clients  411 - 414  may be unrelated, such as users affiliated with different companies or organizations. For unrelated clients, information on the virtual machines or storage of any one user may be hidden from other users. 
     Referring now to the physical hardware layer of a cloud computing environment, availability zones  401 - 402  (or zones) may refer to a collocated set of physical computing resources. Zones may be geographically separated from other zones in the overall cloud of computing resources. For example, zone  401  may be a first cloud datacenter located in California, and zone  402  may be a second cloud datacenter located in Florida. Management sever  410  may be located at one of the availability zones, or at a separate location. Each zone may include an internal network that interfaces with devices that are outside of the zone, such as the management server  410 , through a gateway. End users of the cloud (e.g., clients  411 - 414 ) might or might not be aware of the distinctions between zones. For example, an end user may request the creation of a virtual machine having a specified amount of memory, processing power, and network capabilities. The management server  410  may respond to the user&#39;s request and may allocate the resources to create the virtual machine without the user knowing whether the virtual machine was created using resources from zone  401  or zone  402 . In other examples, the cloud system may allow end users to request that virtual machines (or other cloud resources) are allocated in a specific zone or on specific resources  403 - 405  within a zone. 
     In this example, each zone  401 - 402  may include an arrangement of various physical hardware components (or computing resources)  403 - 405 , for example, physical hosting resources (or processing resources), physical network resources, physical storage resources, switches, and additional hardware resources that may be used to provide cloud computing services to customers. The physical hosting resources in a cloud zone  401 - 402  may include one or more computer servers  403 , such as the virtualization servers  301  described above, which may be configured to create and host virtual machine instances. The physical network resources in a cloud zone  401  or  402  may include one or more network elements  405  (e.g., network service providers) comprising hardware and/or software configured to provide a network service to cloud customers, such as firewalls, network address translators, load balancers, virtual private network (VPN) gateways, Dynamic Host Configuration Protocol (DHCP) routers, and the like. The storage resources in the cloud zone  401 - 402  may include storage disks (e.g., solid state drives (SSDs), magnetic hard disks, etc.) and other storage devices. 
     The example cloud computing environment shown in  FIG. 4  also may include a virtualization layer (e.g., as shown in  FIGS. 1-3 ) with additional hardware and/or software resources configured to create and manage virtual machines and provide other services to customers using the physical resources in the cloud. The virtualization layer may include hypervisors, as described above in  FIG. 3 , along with other components to provide network virtualizations, storage virtualizations, etc. The virtualization layer may be as a separate layer from the physical resource layer, or may share some or all of the same hardware and/or software resources with the physical resource layer. For example, the virtualization layer may include a hypervisor installed in each of the virtualization servers  403  with the physical computing resources. Known cloud systems may alternatively be used, e.g., WINDOWS AZURE (Microsoft Corporation of Redmond Wash.), AMAZON EC2 (Amazon.com Inc. of Seattle, Wash.), IBM BLUE CLOUD (IBM Corporation of Armonk, N.Y.), or others. 
     Enterprise Mobility Management Architecture 
       FIG. 5  represents an enterprise mobility technical architecture  500  for use in a BYOD environment. The architecture enables a user of a mobile device  502  to both access enterprise or personal resources from a mobile device  502  and use the mobile device  502  for personal use. The user may access such enterprise resources  504  or enterprise services  508  using a mobile device  502  that is purchased by the user or a mobile device  502  that is provided by the enterprise to user. The user may utilize the mobile device  502  for business use only or for business and personal use. The mobile device may run an iOS operating system, and Android operating system, or the like. The enterprise may choose to implement policies to manage the mobile device  504 . The policies may be implanted through a firewall or gateway in such a way that the mobile device may be identified, secured or security verified, and provided selective or full access to the enterprise resources. The policies may be mobile device management policies, mobile application management policies, mobile data management policies, or some combination of mobile device, application, and data management policies. A mobile device  504  that is managed through the application of mobile device management policies may be referred to as an enrolled device. 
     The operating system of the mobile device may be separated into a managed partition  510  and an unmanaged partition  512 . The managed partition  510  may have policies applied to it to secure the applications running on and data stored in the managed partition. The applications running on the managed partition may be secure applications. The secure applications may be email applications, web browsing applications, software-as-a-service (SaaS) access applications, Windows Application access applications, and the like. The secure applications may be secure native applications  514 , secure remote applications  522  executed by a secure application launcher  518 , virtualization applications  526  executed by a secure application launcher  518 , and the like. The secure native applications  514  may be wrapped by a secure application wrapper  520 . The secure application wrapper  520  may include integrated policies that are executed on the mobile device  502  when the secure native application is executed on the device. The secure application wrapper  520  may include meta-data that points the secure native application  514  running on the mobile device  502  to the resources hosted at the enterprise that the secure native application  514  may require to complete the task requested upon execution of the secure native application  514 . The secure remote applications  522  executed by a secure application launcher  518  may be executed within the secure application launcher application  518 . The virtualization applications  526  executed by a secure application launcher  518  may utilize resources on the mobile device  502 , at the enterprise resources  504 , and the like. The resources used on the mobile device  502  by the virtualization applications  526  executed by a secure application launcher  518  may include user interaction resources, processing resources, and the like. The user interaction resources may be used to collect and transmit keyboard input, mouse input, camera input, tactile input, audio input, visual input, gesture input, and the like. The processing resources may be used to present a user interface, process data received from the enterprise resources  504 , and the like. The resources used at the enterprise resources  504  by the virtualization applications  526  executed by a secure application launcher  518  may include user interface generation resources, processing resources, and the like. The user interface generation resources may be used to assemble a user interface, modify a user interface, refresh a user interface, and the like. The processing resources may be used to create information, read information, update information, delete information, and the like. For example, the virtualization application may record user interactions associated with a GUI and communicate them to a server application where the server application may use the user interaction data as an input to the application operating on the server. In this arrangement, an enterprise may elect to maintain the application on the server side as well as data, files, etc. associated with the application. While an enterprise may elect to “mobilize” some applications in accordance with the principles herein by securing them for deployment on the mobile device, this arrangement may also be elected for certain applications. For example, while some applications may be secured for use on the mobile device, others may not be prepared or appropriate for deployment on the mobile device so the enterprise may elect to provide the mobile user access to the unprepared applications through virtualization techniques. As another example, the enterprise may have large complex applications with large and complex data sets (e.g. material resource planning applications) where it would be very difficult, or otherwise undesirable, to customize the application for the mobile device so the enterprise may elect to provide access to the application through virtualization techniques. As yet another example, the enterprise may have an application that maintains highly secured data (e.g. human resources data, customer data, engineering data) that may be deemed by the enterprise as too sensitive for even the secured mobile environment so the enterprise may elect to use virtualization techniques to permit mobile access to such applications and data. An enterprise may elect to provide both fully secured and fully functional applications on the mobile device as well as a virtualization application to allow access to applications that are deemed more properly operated on the server side. In an embodiment, the virtualization application may store some data, files, etc. on the mobile phone in one of the secure storage locations. An enterprise, for example, may elect to allow certain information to be stored on the phone while not permitting other information. 
     In connection with the virtualization application, as described herein, the mobile device may have a virtualization application that is designed to present GUIs and then record user interactions with the GUI. The application may communicate the user interactions to the server side to be used by the server side application as user interactions with the application. In response, the application on the server side may transmit back to the mobile device a new GUI. For example, the new GUI may be a static page, a dynamic page, an animation, or the like. 
     The applications running on the managed partition may be stabilized applications. The stabilized applications may be managed by a device manager  524 . The device manager  524  may monitor the stabilized applications and utilize techniques for detecting and remedying problems that would result in a destabilized application if such techniques were not utilized to detect and remedy the problems. 
     The secure applications may access data stored in a secure data container  528  in the managed partition  510  of the mobile device. The data secured in the secure data container may be accessed by the secure wrapped applications  514 , applications executed by a secure application launcher  518 , virtualization applications  526  executed by a secure application launcher  518 , and the like. The data stored in the secure data container  528  may include files, databases, and the like. The data stored in the secure data container  528  may include data restricted to a specific secure application  530 , shared among secure applications  532 , and the like. Data restricted to a secure application may include secure general data  534  and highly secure data  538 . Secure general data may use a strong form of encryption such as AES 128-bit encryption or the like, while highly secure data  538  may use a very strong form of encryption such as AES 254-bit encryption. Data stored in the secure data container  528  may be deleted from the device upon receipt of a command from the device manager  524 . The secure applications may have a dual-mode option  540 . The dual mode option  540  may present the user with an option to operate the secured application in an unsecured mode. In an unsecured mode, the secure applications may access data stored in an unsecured data container  542  on the unmanaged partition  512  of the mobile device  502 . The data stored in an unsecured data container may be personal data  544 . The data stored in an unsecured data container  542  may also be accessed by unsecured applications  548  that are running on the unmanaged partition  512  of the mobile device  502 . The data stored in an unsecured data container  542  may remain on the mobile device  502  when the data stored in the secure data container  528  is deleted from the mobile device  502 . An enterprise may want to delete from the mobile device selected or all data, files, and/or applications owned, licensed or controlled by the enterprise (enterprise data) while leaving or otherwise preserving personal data, files, and/or applications owned, licensed or controlled by the user (personal data). This operation may be referred to as a selective wipe. With the enterprise and personal data arranged in accordance to the examples described herein, an enterprise may perform a selective wipe. 
     The mobile device may connect to enterprise resources  504  and enterprise services  508  at an enterprise, to the public Internet  548 , and the like. The mobile device may connect to enterprise resources  504  and enterprise services  508  through virtual private network connections. The virtual private network connections may be specific to particular applications  550 , particular devices, particular secured areas on the mobile device, and the like  552 . For example, each of the wrapped applications in the secured area of the phone may access enterprise resources through an application specific VPN such that access to the VPN would be granted based on attributes associated with the application, possibly in conjunction with user or device attribute information. The virtual private network connections may carry Microsoft Exchange traffic, Microsoft Active Directory traffic, HTTP traffic, HTTPS traffic, application management traffic, and the like. The virtual private network connections may support and enable single-sign-on authentication processes  554 . The single-sign-on processes may allow a user to provide a single set of authentication credentials, which are then verified by an authentication service  558 . The authentication service  558  may then grant to the user access to multiple enterprise resources  504 , without requiring the user to provide authentication credentials to each individual enterprise resource  504 . 
     The virtual private network connections may be established and managed by an access gateway  560 . The access gateway  560  may include performance enhancement features that manage, accelerate, and improve the delivery of enterprise resources  504  to the mobile device  502 . The access gateway may also re-route traffic from the mobile device  502  to the public Internet  548 , enabling the mobile device  502  to access publicly available and unsecured applications that run on the public Internet  548 . The mobile device may connect to the access gateway via a transport network. The transport network may be a wired network, wireless network, cloud network, local area network, metropolitan area network, wide area network, public network, private network, and the like. 
     The enterprise resources  504  may include email servers, file sharing servers, SaaS applications, Web application servers, Windows application servers, and the like. Email servers may include Exchange servers, Lotus Notes servers, and the like. File sharing servers may include ShareFile servers, and the like. SaaS applications may include Salesforce, and the like. Windows application servers may include any application server that is built to provide applications that are intended to run on a local Windows operating system, and the like. The enterprise resources  504  may be premise-based resources, cloud based resources, and the like. The enterprise resources  504  may be accessed by the mobile device  502  directly or through the access gateway  560 . The enterprise resources  504  may be accessed by the mobile device  502  via a transport network. The transport network may be a wired network, wireless network, cloud network, local area network, metropolitan area network, wide area network, public network, private network, and the like. 
     The enterprise services  508  may include authentication services  558 , threat detection services  564 , device manager services  524 , file sharing services  568 , policy manager services  570 , social integration services  572 , application controller services  574 , and the like. Authentication services  558  may include user authentication services, device authentication services, application authentication services, data authentication services and the like. Authentication services  558  may use certificates. The certificates may be stored on the mobile device  502 , by the enterprise resources  504 , and the like. The certificates stored on the mobile device  502  may be stored in an encrypted location on the mobile device, the certificate may be temporarily stored on the mobile device  502  for use at the time of authentication, and the like. Threat detection services  564  may include intrusion detection services, unauthorized access attempt detection services, and the like. Unauthorized access attempt detection services may include unauthorized attempts to access devices, applications, data, and the like. Device management services  524  may include configuration, provisioning, security, support, monitoring, reporting, and decommissioning services. File sharing services  568  may include file management services, file storage services, file collaboration services, and the like. Policy manager services  570  may include device policy manager services, application policy manager services, data policy manager services, and the like. Social integration services  572  may include contact integration services, collaboration services, integration with social networks such as Facebook, Twitter, and LinkedIn, and the like. Application controller services  574  may include management services, provisioning services, deployment services, assignment services, revocation services, wrapping services, and the like. 
     The enterprise mobility technical architecture  500  may include an application store  578 . The application store  578  may include unwrapped applications  580 , pre-wrapped applications  582 , and the like. Applications may be populated in the application store  578  from the application controller  574 . The application store  578  may be accessed by the mobile device  502  through the access gateway  560 , through the public Internet  548 , or the like. The application store may be provided with an intuitive and easy to use User Interface. The application store  578  may provide access to a software development kit  584 . The software development kit  584  may provide a user the capability to secure applications selected by the user by wrapping the application as described previously in this description. An application that has been wrapped using the software development kit  584  may then be made available to the mobile device  502  by populating it in the application store  578  using the application controller  574 . 
     The enterprise mobility technical architecture  500  may include a management and analytics capability  588 . The management and analytics capability  588  may provide information related to how resources are used, how often resources are used, and the like. Resources may include devices, applications, data, and the like. How resources are used may include which devices download which applications, which applications access which data, and the like. How often resources are used may include how often an application has been downloaded, how many times a specific set of data has been accessed by an application, and the like. 
       FIG. 6  is another illustrative enterprise mobility management system  600 . Some of the components of the mobility management system  500  described above with reference to  FIG. 5  have been omitted for the sake of simplicity. The architecture of the system  600  depicted in  FIG. 6  is similar in many respects to the architecture of the system  500  described above with reference to  FIG. 5  and may include additional features not mentioned above. 
     In this case, the left hand side represents an enrolled mobile device  602  with a receiver  604 , which interacts with a gateway  606  to cloud-based services (a “cloud gateway”) and to access various enterprise resources  608  and services  609  such as Exchange, Sharepoint, PKI Resources, Kerberos Resources, Certificate Issuance service, as shown on the right hand side above. The cloud gateway  606  may also include access gateway and application controller functionality. Although not specifically shown, the mobile device  602  may also interact with an enterprise application store (a “store front”) for the selection and downloading of applications. 
     The receiver  604  acts as the UI (user interface) intermediary for Windows apps/desktops hosted in an enterprise data center, which are accessed using a display remoting protocol such as, e.g., the HDX/ICA protocol available from Citrix. The receiver  604  also supports the installation and management of native applications on the mobile device  602 , such as native iOS or Android applications. For example, the managed applications  610  (mail, browser, wrapped application) shown in the figure above are all native applications that execute locally on the device. The receiver  604  and the mobile application management protocol of this architecture act to provide policy driven management capabilities and features such as connectivity and SSO (single sign on) to enterprise resources/services  608 . One example of a mobile application management protocol is the MDX (mobile experience technology) protocol available from Citrix. The receiver  604  handles primary user authentication to the enterprise, normally to an access gateway (AG) with SSO to other cloud gateway components. The receiver  604  obtains policies from the cloud gateway  606  to control the behavior of the managed applications  610  on the mobile device  602 . 
     The secure inter-process communication (IPC) links  612  between the native applications  610  and receiver  604  represent a management channel, which allows the receiver to supply policies to be enforced by the management framework  614  “wrapping” each application. The management framework  614  may be, for example, the MDX framework available from Citrix. The IPC link  612  also allows receiver  604  to supply credential and authentication information that enables connectivity and SSO to enterprise resources  608 . Finally the IPC link  612  allows the management framework  614  to invoke user interface functions implemented by receiver  604 , such as online and offline authentication. 
     Communications between the receiver  604  and cloud gateway  606  are essentially an extension of the management channel from the management framework  614  wrapping each native managed application  610 . The management framework  614  requests policy information from receiver  604 , which in turn requests it from cloud gateway  606 . The management framework  614  requests authentication, and receiver  604  logs into the gateway services part of the cloud gateway  606 , which may be, e.g., a NetScaler Access Gateway available from Citrix. The receiver  604  may also call supporting services on the cloud gateway  606 , which may produce input material to derive encryption keys for the local data vaults  616 , or provide client certificates which may enable direct authentication to PKI protected resources, as more fully explained below. 
     In more detail, the management framework  614  “wraps” each managed application  610 . This may be incorporated via an explicit build step, or via a post-build processing step. The management framework  614  may “pair” with receiver  604  on first launch of an application  610  to initialize the secure IPC link  612  and obtain the policy for that application. The management framework  614  may enforce relevant portions of the policy that apply locally, such as the receiver login dependencies and some of the containment policies that restrict how local OS services may be used, or how they may interact with the application  610 . 
     The management framework  614  may use services provided by receiver  604  over the secure IPC link  612  to facilitate authentication and internal network access. Key management for the private and shared data vaults  616  (containers) may be also managed by appropriate interactions between the managed applications  610  and receiver  604 . Vaults  616  may be available only after online authentication, or may be made available after offline authentication if allowed by policy. First use of vaults  616  may require online authentication, and offline access may be limited to at most the policy refresh period before online authentication is again required. 
     Network access to internal resources may occur directly from individual managed applications  610  through the access gateway functionality of the cloud gateway  606 . The management framework  614  is responsible for orchestrating the network access on behalf of each application  610 . The receiver  604  may facilitate these network connections by providing suitable time limited secondary credentials obtained following online authentication. Multiple modes of network connection may be used, such as reverse web proxy connections and end-to-end VPN-style tunnels  618 . 
     The mail and browser managed applications  610  have special status and may make use of facilities that might not be generally available to arbitrary wrapped applications. For example, the mail application may use a special background network access mechanism that allows it to access a mail server (e.g., Exchange) over an extended period of time without requiring a full AG logon. The browser application may use multiple private data vaults to segregate different kinds of data. 
     This architecture supports the incorporation of various other security features. For example, the cloud gateway  606  (including its gateway services) in some cases may not need to validate directory service passwords, e.g., Active Directory (AD) passwords. It can be left to the discretion of an enterprise whether directory service password is used as an authentication factor for some users in some situations. Different authentication methods may be used if a user is online or offline (e.g., connected or not connected to a network). 
     Step up authentication is a feature wherein the cloud gateway  606  may identify managed native applications  610  that are allowed to have access to highly classified data requiring strong authentication, and ensure that access to these applications is only permitted after performing appropriate authentication, even if this means a re-authentication is required by the user after a prior weaker level of login. 
     Another security feature of this solution is the encryption of the data vaults  616  (containers) on the mobile device  602 . The vaults  616  may be encrypted so that all on-device data including files, databases, and configurations are protected. For on-line vaults, the keys may be stored on the server (e.g., the cloud gateway), and for off-line vaults, a local copy of the keys may be protected by a user password. When data is stored locally on the device  602  in the secure container  616 , it is preferred that a minimum of AES 256 encryption algorithm be utilized. 
     Other secure container features may also be implemented. For example, a logging feature may be included, wherein all security events happening inside an application  610  are logged and reported to the backend. Data wiping may be supported, such as if the application  610  detects tampering, associated encryption keys may be written over with random data, leaving no hint on the file system that user data was destroyed. Screenshot protection is another feature, where an application may prevent any data from being stored in screenshots. For example, the key window&#39;s hidden property may be set to YES. This may cause whatever content is currently displayed on the screen to be hidden, resulting in a blank screenshot where any content would normally reside. 
     Local data transfer may be prevented, such as by preventing any data from being locally transferred outside the application container, e.g., by copying it or sending it to an external application. A keyboard cache feature may operate to disable the autocorrect functionality for sensitive text fields. SSL certificate validation may be operable so the application specifically validates the server SSL certificate instead of it being stored in the keychain. An encryption key generation feature may be used such that the key used to encrypt data on the device is generated using a passphrase supplied by the user (if offline access is required). It may be XORed with another key randomly generated and stored on the server side if offline access is not required. Key Derivation functions may operate such that keys generated from the user password use KDFs (key derivation functions, notably PBKDF2) rather than creating a cryptographic hash of it. The latter makes a key susceptible to brute force or dictionary attacks. 
     Further, one or more initialization vectors may be used in encryption methods. An initialization vector may cause multiple copies of the same encrypted data to yield different cipher text output, preventing both replay and cryptanalytic attacks. This may also prevent an attacker from decrypting any data even with a stolen encryption key if the specific initialization vector used to encrypt the data is not known. Further, authentication then decryption may be used, wherein application data is decrypted only after the user has authenticated within the application. Another feature may relate to sensitive data in memory, which may be kept in memory (and not in disk) only when it&#39;s needed. For example, login credentials may be wiped from memory after login, and encryption keys and other data inside objective-C instance variables are not stored, as they may be easily referenced. Instead, memory may be manually allocated for these. 
     An inactivity timeout may be implemented, wherein after a policy-defined period of inactivity, a user session is terminated. 
     Data leakage from the management framework  614  may be prevented in other ways. For example, when an application  610  is put in the background, the memory may be cleared after a predetermined (configurable) time period. When backgrounded, a snapshot may be taken of the last displayed screen of the application to fasten the foregrounding process. The screenshot may contain confidential data and hence should be cleared. 
     Another security feature relates to the use of an OTP (one time password)  620  without the use of directory service  622  password for access to one or more applications. In some cases, some users do not know (or are not permitted to know) their directory service password, so these users may authenticate using an OTP  620  such as by using a hardware OTP system like SecurID (OTPs may be provided by different vendors also, such as Entrust or Gemalto). In some cases, after a user authenticates with a user ID, a text is sent to the user with an OTP  620 . In some cases, this may be implemented only for online use, with a prompt being a single field. 
     An offline password may be implemented for offline authentication for those applications  610  for which offline use is permitted via enterprise policy. For example, an enterprise may want the store front to be accessed in this manner. In this case, the receiver  604  may require the user to set a custom offline password and the directory service password is not used. Cloud gateway  606  may provide policies to control and enforce password standards with respect to the minimum length, character class composition, and age of passwords, such as described by the standard Windows Server password complexity requirements, although these requirements may be modified. 
     Another feature relates to the enablement of a client side certificate for certain applications  610  as secondary credentials (for the purpose of accessing PKI protected web resources via the management framework micro VPN feature). For example, an email application may utilize such a certificate. In this case, certificate-based authentication using a mobile data synchronization protocol (e.g., the protocol employed by ActiveSync) may be supported, wherein a certificate from the receiver  604  may be retrieved by the cloud gateway  606  and used in a keychain. Each managed application may have one associated client certificate, identified by a label that is defined in the cloud gateway. 
     The cloud gateway  606  may interact with an enterprise special purpose web service to support the issuance of client certificates to allow relevant managed applications to authenticate to internal PKI protected resources. 
     The receiver  604  and the management framework  614  may be enhanced to support obtaining and using client certificates for authentication to internal PKI protected network resources. More than one certificate may be supported, such as to match various levels of security and/or separation requirements. The certificates may be used by the mail and browser managed applications, and ultimately by arbitrary wrapped applications (provided those applications use web service style communication patterns where it is reasonable for the management framework to mediate https requests). 
     Management framework client certificate support on iOS may rely on importing a PKCS  12  BLOB (Binary Large Object) into the iOS keychain in each managed application for each period of use. Management framework client certificate support may use a HTTPS implementation with private in-memory key storage. The client certificate may not be present in the iOS keychain and may not be persisted except potentially in “online-only” data value that is strongly protected. 
     Mutual SSL may also be implemented to provide additional security by requiring that a mobile device  602  is authenticated to the enterprise, and vice versa. Virtual smart cards for authentication to cloud gateway  606  may also be implemented. 
     Both limited and full Kerberos support may be additional features. The full support feature relates to an ability to do full Kerberos login to directory service  622 , using a directory service password or trusted client certificate, and obtain Kerberos service tickets to respond to HTTP Negotiate authentication challenges. The limited support feature relates to constrained delegation in AFEE, where AFEE supports invoking Kerberos protocol transition so it can obtain and use Kerberos service tickets (subject to constrained delegation) in response to HTTP Negotiate authentication challenges. This mechanism works in reverse web proxy (aka CVPN) mode, and when http (but not https) connections are proxied in VPN and MicroVPN mode. 
     Another feature relates to application container locking and wiping, which may automatically occur upon jail-break or rooting detections, and occur as a pushed command from administration console, and may include a remote wipe functionality even when an application  610  is not running. 
     A multi-site architecture or configuration of the store front and application controller may be supported that allows users to be service from one of several different locations in case of failure. 
     In some cases, managed applications  610  may be allowed to access a certificate and private key via an API (example OpenSSL). Trusted managed applications  610  of an enterprise may be allowed to perform specific Public Key operations with an application&#39;s client certificate and private key. Various use cases may be identified and treated accordingly, such as when an application behaves like a browser and no certificate access is required, when an application reads a certificate for “who am I,” when an application uses the certificate to build a secure session token, and when an application uses private keys for digital signing of important data (e.g. transaction log) or for temporary data encryption. 
     Identification of Managed Mobile Applications 
     In  FIG. 7 , an illustrative mobile device management system  700  is shown. The system  700  may be similar in many respects to the systems  500  and  600  described above with reference to  FIG. 5  and  FIG. 6  respectively. The system  700  may also omit certain components described above for the sake of simplicity and may include additional features not mentioned above. 
     The mobile device management system  700  may include an enterprise system  702  in signal communication with one or more mobile devices  704  via a network  706 . The enterprise system may include an enterprise application server  708 , an access gateway  710 , and one or more computing resources such as enterprise resources  712 . 
     The enterprise application server  708  may be similar in many respects to the application store  578  discussed above with reference to  FIG. 5 . The enterprise application server  708  may provide access to mobile applications  714  available for installation at a mobile device, e.g., the mobile device  704 . As noted above, the mobile applications  714  may include both secured and unsecured mobile applications. Accordingly, the mobile applications  714  may correspond to the unwrapped applications  180  and the pre-wrapped applications  182  described above with reference to  FIG. 5 . As also noted above, a secured mobile application may be wrapped with a secure application wrapper that enables the management of and control over the execution of the secured mobile application. In this regard, a secured mobile application, wrapped mobile application, or enrolled mobile application may also be referred to as a managed mobile application. 
     The enterprise application server  708  may also provide access to application policies  716  and application metadata  718  respectively associated with the mobile applications  714 . An application policy  716  may represent one of the mechanisms through which management of a mobile application is achieved. As noted above, an application policy  716  may define rights and entitlements with respect to which users may utilize a managed mobile application, which computing resources a managed mobile application may access, the features available at a managed mobile application when executing at a mobile device, and combinations of the same. 
     Application metadata  718  refers to information that describes and/or identifies a mobile application. Application metadata  718  may be generated during the build process of a new mobile application and made available via the enterprise application server  708  when the new mobile application is published to the enterprise application server Application metadata  718  may include, for example, the name of the mobile application, the size of the mobile application, a unique identifier for the mobile application, the version of the mobile application, and so forth. As discussed further below application metadata  718  may also include information useful to validate the identity of a mobile application. 
     The access gateway  710  may facilitate access to the enterprise resources  712  from a managed mobile application operating at a mobile device, e.g., the mobile device  704 . The access gateway  710  may be similar in many respects to the access gateway  160  and the cloud gateway  606  described above with reference to  FIG. 5  and  FIG. 6  respectively. The enterprise resources  712  may correspond to the enterprise resources  504  and  608  as well as the enterprise services  508  and  609  as also described above with reference to  FIG. 5  and  FIG. 6  respectively. Once validated, authenticated, and authorized, mobile applications may access the enterprise resources  712  via the access gateway  710  as described above. 
     Both managed mobile applications  720  as well as unmanaged mobile applications  722  may reside at the mobile device  704 . An access manager application  724  may also reside at the mobile device  704  and manage execution of the managed mobile applications  720  on the mobile device. A mobile device that includes both managed and unmanaged mobile applications may be referred to as an unmanaged mobile device as an enterprise may only be equipped to exercise control over the managed mobile applications at that mobile device and may not be equipped to exercise control over other aspects of the mobile device, e.g., the unmanaged applications. Because the mobile device  704  includes a managed mobile application  720  and unmanaged mobile applications  722 , the mobile device shown by way of example in  FIG. 7  may be referred to as an unmanaged mobile device and may represent the personal mobile device of an individual. 
     The access manager application  724  (“access manager”) may be similar in many respects to the Receiver  604  discussed above with reference to  FIG. 6 . As discussed further below, the access manager  724  may manage user authentication, validation of mobile application identity, and enforcement of mobile application policies. A user may access the enterprise application server  708  (e.g., via a web browser) to initially download and install the access manager  724  at the mobile device  704 . As noted above, the access manager  724  may also serve as the interface to the enterprise application server  708  enabling a user to browse, download, and install the mobile applications available from the enterprise system  702 . 
     When the user downloads a managed mobile application  720  to the mobile device  704 , the access manager  724  may also download the application metadata  718  associated with the managed mobile application  720  as well as any application policies  716  associated with the managed mobile application. As noted above, the access manager  724  may receive the application metadata  718  for a mobile application  720  from the enterprise application server  708 . In some example implementations, the access manager  724  may store the application metadata  718  and the application policies  716  at a secure location of the mobile device  704 , e.g., the secure data container  528  of  FIG. 5  and/or the secure data vaults  616  of  FIG. 6 . 
     The access manager  724  may also maintain a list  726  of managed mobile applications currently installed at the mobile device  704  and under management of the access manager. Upon installation of a new managed mobile application, the access manager  724  may add a new entry to the managed mobile application list  726 . The new entry in the list  726  may correspond to the new managed mobile application installed at the mobile device  704 . 
     As noted above, the access manager  724  may be configured to validate the identity of the managed mobile application  720 , e.g., to ensure that the managed mobile application has accurately identified itself and/or to ensure that the managed mobile application has not been altered after installation at the mobile device  704 . The access manager may rely on identification information  728  included in the application metadata  718  to validate the identity of the managed mobile application  720 . In some example embodiments, the access manager  724  may rely on the mobile platform on which the managed mobile application  720  is operating in order to validate the identity of the managed mobile application. The operating system of the mobile platform may produce identification information that the access manager  724  may compare to stored identification information for the managed mobile application. If the stored identification information matches the identification information received from the operating system, then the access manager  724  may identify the managed mobile application  720  as a trusted mobile application and grant access to the enterprise resources  712 . If the stored identification information for the managed mobile application does not match the identification information received from the operating system, then the access manager  724  may identify the managed mobile application  720  as a suspicious or untrustworthy mobile application and deny access to the enterprise resources  712 . As noted above, the access manager  724  may also grant or deny access to local computing resources at the mobile device  704  itself. Local computing resources at the mobile device  704  may include, for example, a camera or other recording hardware; location services such as GPS, network services such as cellular or internet services, communication services such as Bluetooth, interface commands such as the cut-and-paste and screenshot features. 
     In other example embodiments, the access manager  724  may challenge the managed mobile application  720  to identify itself. The access manager  724  may issue a challenge request to the managed mobile application  720  and determine an expected challenge response. The expected challenge response is a response that is expected to be received from a managed mobile application that has accurately identified itself and that has not been altered. As explained further below, only a mobile application that has accurately identified itself and has not been altered may be able to produce the expected challenged response. If the response received from the managed mobile application  720  matches the expected response, then the access manager  724  may identify the managed mobile application  720  as a trusted mobile application. Having identified the managed mobile application  720  as a trusted mobile application, the access manager may provide the managed mobile application with the credentials necessary to access the enterprise resources  712 . If the response received from the managed mobile application  720  does not match the expected response, then the access manager may identify the managed mobile application as a suspicious or untrustworthy mobile application and deny access to the enterprise resources  712 . Again, the access manager  724  may grant or deny access to local computing resources at the mobile device  704  depending on whether the response received from the managed mobile application  720  matches the expected response. 
     The expected response may be based, at least in part, on the identification information  728  included in the application metadata  718  that is associated with the managed mobile application  720 . The identification information may be created when the mobile application itself is created. The identification information may be, for example, an original digital certificate or original information that may be used to generate an application signature. The expected response may thus include or otherwise correspond to the identification information  728 . As explained further below, a mobile application that submits a false identity or a mobile application that has been subsequently altered is unable to generate the expected response and thus unable to gain access to the computing resources. 
     Various approaches may be selectively employed to validate the identity of a managed mobile application. The particular approach ultimately implemented may depend on the mobile platform and operating system of the mobile device  704 . For example, the Android operating system available from Google Inc. of Mountain View, Calif. may include mechanisms through which the access manager may strongly identify a mobile application requesting access to computing resources. Those skilled in the art will recognize that the Android operating system may include built-in mechanisms for requesting the signing certificate of an application, which the access manager  724  may utilize to validate the identity of a managed mobile application requesting access to the computing resources such as enterprise resources  712 . It will also be recognized that the Android operating system may prevent an application from being altered after installation and may prevent a mobile application from using a signing certificate created for a different mobile application. In this way, the access manager  724  may rely on the signing certificates provided by the operating system of the mobile platform in order to validate the identity of a managed mobile application. Validation of application identity using signing certificates will be discussed in further detail below. 
     Other operating systems, however, may not include built-in mechanisms the access manager  724  may rely on to validate the identity of a managed mobile application requesting access to the computing resources. For example, the iOS operating system available from Apple Inc. of Cupertino, Calif. may not include mechanisms to request a signing certificate for the managed mobile application. In addition, the methods available for inter-process communication in iOS, may not include mechanisms to validate the identity of the mobile applications at each end of the communication. Mobile applications operating on the iOS platform may exchange communications, for example, via a copy-and-paste procedure, via an agreed to URL scheme, or via the network. 
     In some example implementations, the access manager  724  and the managed mobile application  720  may be configured to communicate via the network, e.g., via the transmission control protocol (TCP). In this example, the access manager  724  may open a TCP socket and wait to receive a connection request from the managed mobile application  720 . It will be appreciated, however, that TCP does not include a mechanism to identify the managed mobile application requesting the connection to the access manager  724 . Because the iOS platform may not include a mechanism to obtain a signing certificate for the mobile application making the request, additional steps may be employed to validate the identity of the requesting mobile application. Instead of relying on a signing certificate, the access manager  724  in this example, may rely, at least in part, on identification information  732  embedded in and/or derived from the managed mobile application  720  as set forth below. 
     The wrapping process discussed above may configure a mobile application to operate as a managed mobile application. In this regard, the wrapping process may include (e.g., insert, embed, wrap, etc.) a management framework  730  in the managed mobile application  720 . The management framework  730  may correspond to the secure application wrapper  120  and the management framework  614  discussed above with reference to  FIG. 5  and  FIG. 6  respectively. The management framework  730  enables the access manager  724  to manage the operation of the mobile application  720  as discussed above with reference to  FIG. 6 . 
     The managed mobile application  720  may also employ the management framework  730  to identify itself to the access manager  724 . In particular, the management framework  730  may generate the response to the challenge posed by the access manager  724  during the identity validation procedure. 
     In some example implementations, the management framework  730  of the managed mobile application  720  may be configured to generate an application signature. The management framework  730  may also be configured to provide a challenge response that is based, at least in part, on this application signature. The application signature may in turn be based on identification information  732  embedded in and/or derived from the managed mobile application  720 . Stated differently, the management framework  730  may generate an application signature based on static information and dynamic information associated with the managed mobile application  720 . 
     The static information may be secret information that is embedded into the managed mobile application  720  during the wrapping process described above. For example, the secret information may include one or more identification tokens  734  embedded into the application during the wrapping process. The identification tokens  734  may be, e.g., randomized alphanumeric strings embedded into the binary of the managed mobile application  720 . The management framework  730  may be configured to extract the identification tokens  734  when constructing the application signature in order to respond to the challenge received from the access manager  724 . 
     The dynamic information may be identification tokens derived from the managed mobile application  720 . For example, the derived identification tokens may be hash values obtained using selective hash functions on the various components of the mobile application bundle, e.g., the mobile application binary, application icon, application frameworks, and the like. The access manager  724  may derive this dynamic identification information in an ad hoc fashion during the identity validation procedure. One or more selective hash functions may be used to generate one or more selective hash values that represent the derived identification tokens. The access manager may utilize the management framework  730  to help derive the dynamic identification information from the managed mobile application  720  as needed. 
     The management framework  730  may also be configured to construct the application signature used in the response to the challenge received from the access manager  724 . The application signature may comprise a combination of the static information extracted from the managed mobile application  720  as well as the dynamic information derived from the managed mobile application. The management framework  730  may further be configured to arrange the static information and the dynamic information within the application signature in a particular way. Thus, strong identification of the managed mobile application  720  may be achieved through the static information embedded in the managed mobile application, the dynamic information derived from the mobile application, and the arrangement of the static and dynamic information within the application signature. 
     As noted above, the access manager  724  may be configured to generate an expected response when challenging the managed mobile application  720 . Accordingly, the access manager  724  may likewise be configured to construct an expected application signature. The access manager  724  may construct the expected application signature based on the identification information  728  included in the application metadata  718  for the managed mobile application  720 . The access manager may also be configured to dynamically derive the dynamic information from the managed mobile application  720 . Furthermore, the access manager  724  may likewise be configured to arrange the static and dynamic information within the expected application signature in a particular way. 
     In order to guard against replay attacks, the access manager  724  may provide a nonce (e.g., an arbitrary and random number) to the managed mobile application  720  for use in the response to the challenge. The access manager  724  may hash the nonce with the expected application signature to obtain an expected hash value. Similarly, the management framework  730  of the managed mobile application may hash the application signature with the received nonce to obtain a response hash value. In response to the challenge from the access manager  724 , the managed mobile application  720  may thus provide the access manager with the computed hash value obtained from the application signature and the nonce received from the access manager. The access manager may thus compare the expected hash value to the received hash value. The access manager  724  may thus identify the managed mobile application  720  as a trusted mobile application when the expected hash value matches the received hash value. 
     With reference to  FIG. 8  a block diagram of an illustrative application signature and challenge response is shown. As noted above, a managed mobile application  800  may generate an application signature  802  in response to a challenge from an access manager  804 . The application signature  802  may include identification tokens  806  embedded in the managed mobile application  800  as well as identification tokens  808  derived from the managed mobile application. As seen in  FIG. 8 , the managed mobile application  800  may arrange the embedded identification tokens  806  and the derived identification tokens  808  in a particular way within the application signature  802 . As an example, the managed mobile application  800  may concatenate the embedded identification tokens  806  and the derived identification tokens  808  in a particular order to construct the application signature. In another example, the managed mobile application  800  may concatenate portions of the embedded identification tokens  806  and portions of the derived identification tokens  808  to construct the application signature. It will be appreciated that various approaches to constructing the application signature may be selectively employed. As also noted above, the access manager  804  may provide a nonce  810  to the managed mobile application  800 . The managed mobile application  800  may employ a hash function  812  to generate a hash value  814  based on the application signature  802  and the nonce  810 . The managed mobile application  800  may provide the hash value  814  to the access manager  802  in the response  816  to the challenge received. 
     To validate the identity of the managed mobile application  800 , the access manager  804  may construct an expected application signature  818  based on the identification tokens  820  stored with the application metadata  822  and identification tokens  808  derived from the managed mobile application. The access manager  804  may also employ the hash function  812  to generate an expected hash value  824  based on the identification tokens  820  from the application metadata  822  and the nonce  810 . In response to the challenge, the access manager  804  may receive the challenge response  816  and compare the hash value  814  in the challenge response with the expected hash value  824 . 
     With the benefit of the present disclosure, it will be appreciated that only an unaltered mobile application received from the enterprise application server ( 708  in  FIG. 7 ) may generate the expected hash value  824 . It will also be appreciated that the expected application signature  818  may not be stored persistently at the mobile device, but rather reconstructed as needed to verify the identity of the mobile application  800  requesting access to computing resources. The approach set forth above thus represents a mechanism to strongly identify a mobile application in order to determine whether to grant or deny the mobile application access to computing resources. 
       FIGS. 9-14  depict example methods steps related to aspects of validating the identity of a managed mobile application, enforcing application policies once validated, and controlling operation of the managed mobile applications. 
     In  FIG. 9 , a flowchart  900  of example method steps for managing a mobile application at an unmanaged mobile device is shown. An enterprise may create a managed mobile application configured to operate at a mobile device (e.g., an unmanaged mobile device) and configured to access computing resources from the mobile device (block  902 ). The enterprise may also configure the managed mobile application to be managed by an access manager application at the mobile device. As noted above, the enterprise may wrap or otherwise include a management framework (e.g., the MDX framework) that enables the access manager to validate the identity of the managed mobile application and control operation of the managed mobile application. 
     Upon creation of the managed mobile application, the enterprise may also create identification information associated with the managed mobile application (block  904 ). The identification information may be, for example, a signed application certificate and/or application metadata that includes identification tokens. The identification tokens may be embedded into the managed mobile application (e.g., into the application binary) in some example implementations. A user may download and install the access manager at a mobile device (block  906 ). The access manager may provide the user with an interface from which to browse the enterprise application server (e.g., the enterprise application store) and select various managed mobile applications to download to the mobile device. The access manager may require the user to provide access credentials in order to logon to the enterprise application server. The user may be associated with a user profile, and the user profile may be associated with various rights and entitlements. In this way, the managed mobile applications presented to the user as available to download depend upon the rights and entitlements assigned to the user, e.g., the enterprise application server may only present managed mobile applications that the user is entitled to use. 
     Having selected a managed mobile application, the user may download the mobile application via the access managed and install the mobile application at the mobile device (block  908 ). The enterprise application server may also provide the identification information associated with the mobile application as well as an access policy associated with the mobile application. Accordingly, when the user downloads and installs a managed mobile application, the access manager may also download and store the identification information (block  910 ) and the application policy (block  912 ) associated with the mobile application. 
     Having installed the mobile application at the mobile device, the user may utilize the mobile application to access a computing resource. When the mobile application seeks to access the computing resource, the mobile application may check-in with the access manager and request access to the resource (block  914 ). Upon receipt of the request to access the computing resource, the access manager may retrieve the identification information received from the enterprise application server and stored at the mobile device (block  916 ). The access manager may also receive identification information from the mobile operating system, e.g., a signed application certification, or from the mobile application itself, e.g., a hash value based, at least in part, on an application signature (block  918 ). 
     The access manager may then compare the stored identification information to the received identification information (block  920 ). If the received identification information matches the stored identification information (block  922 :Y), then the access manager may determine that the mobile application is valid and identify the mobile application as a trusted mobile application. Accordingly, the access manager may permit the managed mobile application to access the computing resource (block  924 ). The access manager may, for example, provide the mobile application with the access credentials, certificates, keys, and the like necessary to establish a connection with and access an enterprise resource. In some example implementations, the application policy associated with the mobile application may determine the manner in which the mobile application accesses and uses the computing resource. If the received identification information does not match the stored identification information (block  924 :N), then the access manager may determine that the mobile application is invalid and not identify the mobile application as a trust mobile application and thus prevent the mobile application from accessing the computing resource (block  926 ). 
     In  FIG. 10  is a flowchart  1000  of example method steps for preparing a managed mobile application for managed operation at an unmanaged mobile device. As noted above, some mobile operating systems may not provide built-in mechanisms the access manager may employ to validate the identity of the mobile application. Accordingly, the mobile application may be configured such that it can strongly identify itself. The enterprise may use a toolkit to prepare a mobile application as a managed mobile application (block  1002 ). The toolkit may add functionality (e.g., the MDX framework) that transforms the mobile application into a managed mobile application (block  1004 ). The toolkit may also generate and embed identification tokens (e.g., randomized strings) into the managed mobile application (block  1006 ). The functionality added to the managed mobile application may include functionality that enables the managed mobile application to extract, arrange, and combine the embedded identification tokens in order to construct an application signature. The functionality added to the managed mobile application may also include functionality that enables the managed mobile application to derive identification tokens dynamically as well as to arrange and combine the derived identification tokens with the embedded identification tokens when constructing the application signature. Furthermore, the functionality added to the managed mobile application may additionally include functionality that enables the managed mobile application to generate a hash value based, at least in part, on the application signature. 
     The toolkit may also generate application metadata for the managed mobile application that includes the identification tokens embedded into the mobile application (block  1008 ). The enterprise may then publish the managed mobile application to the enterprise application server along with the application metadata and any application policies associated with the mobile application (block  1010 ). The enterprise application server may receive a request from a mobile device to download a selected mobile application (block  1012 ). If the access manager has not yet been installed at the mobile device (block  1014 :N), then the enterprise application server may first download the access manager application to the mobile device (block  1016 ). Once the access manager is installed at the mobile application (block  1014 :Y), the enterprise application server may download the selected mobile application to the mobile device in response to receipt of the request ( 1018 ). As noted above, the enterprise application server may also download to the mobile device the application metadata associated with the selected mobile application for storage at the mobile device. The access manager may have access to the application metadata thereby enabling the access manager to validate the identity of the mobile application associated with the application metadata. 
     In  FIG. 11 , a flowchart  1100  of example method steps for initializing a managed mobile application at an unmanaged mobile device is shown. When the mobile device is first activated and initialized (block  1102 ), the access manager application may be one of the first mobile applications launched (block  1104 ). The access manager may, for example, launch automatically as part of the startup process of the mobile device and/or in response to user input received at the mobile device. When the access manager application launches, the access manager may request access credentials (e.g., a username and password) from the user (block  1106 ). The access manager may then provide the access credentials to the enterprise server for authentication (block  1108 ). If the enterprise server does not authenticate the user (block  1110 :N), then the access manager may prevent any managed mobile applications at the mobile device from accessing the computing resources (block  1112 ). For example, the access manager may refrain from providing mobile applications the access credentials necessary to establish connections with the enterprise resources. 
     If the enterprise server does authenticate the user (block  1110 :Y), then the enterprise server may validate the identity of the access manager itself (block  1114 ) in order to ensure that the access manager application has not been altered. The enterprise server may validate the identity of the access manager in the same manner as the managed mobile application. As an example, a signing certificate used to sign the access manager may be employed to validate the access manager application. For example, the enterprise system may validate the managed mobile application. If the access manager is not validated (block  1116 :N), then the management framework of the managed mobile applications may treat the access manager as missing from the mobile device, and the managed mobile applications may thus be prevented from accessing the computing resources (block  1112 ). 
     If the enterprise server does validate the identity of the access manager application (block  1116 :Y), then a managed mobile application may be initiated (block  1118 ). Upon launch as well as during operation, the mobile application may check-in with the access manager so that the access manager may validate the identity of the managed mobile application (block  1120 ). If the access manager cannot validate the identity of the managed mobile application (block  1122 :N), then the access manager may prevent the managed mobile application from accessing the computing resources (block  1124 ). If the access manager successfully validates the identity of the managed mobile application (block  1122 :Y), then the access manager may identify the managed mobile application as a trusted mobile application (block  1126 ). If the managed mobile application has just launched at the mobile device, then the access manager may update the list of mobile applications managed by the access manager to include the trusted mobile application (block  1128 ). Having validated the identity of the managed mobile application, the access manager may also permit the trusted mobile application to access the computing resources (block  1130 ). 
     In  FIG. 12 , is a flowchart  1200  of example method steps for validating a managed mobile application at an unmanaged mobile device having a first type of mobile operating system is shown. The mobile operating system, in this example, may not include built-in mechanisms the access manager may utilize to validate the identity of a mobile application. The access manager may receive a request from a managed mobile application seeking to access a computing resource (block  1202 ). Upon receipt of the request, the access manager may initiate a handshake with the managed mobile application to start the identity validation process (block  1204 ). The managed mobile application may identify itself to the access manager, e.g., by providing a unique application identifier to the access manager (block  1206 ). In turn, the access manager may utilize the application identifier to retrieve the application metadata associated with the mobile application (block  1208 ). The access manager may also generate a nonce and provide the nonce to the mobile application (block  1210 ). 
     The access manager and the managed mobile application may then begin the process of constructing the application signature and corresponding hash value used to validate the identity of the mobile application and determine whether the mobile application is a trusted mobile application. The mobile application may extract the embedded identification tokens (block  1212 ) and derive the derived identification tokens (block  1214 ) used to construct the application signature. The mobile application may then arrange and combine the embedded identification tokens extracted and the derived identification tokens to obtain the application signature (block  1216 ). The mobile application may then compute a hash value using the application signature and the nonce received from the access manager (block  1218 ). 
     Having provided the nonce to the mobile application, the access manager may retrieve the embedded identification tokens from the application metadata associated with the mobile application (block  1220 ). The access manager may similarly derive the derived identification tokens from the mobile application (block  1222 ) used to construct the expected application signature. The access manager may then arrange and combine the embedded identification tokens retrieved from the application metadata and the derived identification tokens to obtain the expected application signature (block  1224 ). The access manager may then compute an expected hash value using the expected application signature and the nonce provided to the mobile application (block  1226 ). 
     It will be appreciated that the hash value computed by the access manager should be the same as the hash value computed by the mobile application if the embedded identification tokens retrieved from the application metadata are the same as the embedded identification tokens extracted from the mobile application; if the identification tokens derived by the access manager are the same as the identification tokens derived by the mobile; if the expected application signature constructed by the access manager is the same as the application signature constructed by the mobile application; and if the mobile application uses the nonce provided by the access manager to compute the hash value. Accordingly, the mobile application may provide the hash value in a response to the access manager (block  1228 ), and the access manager may compare the expected hash value to the value received from the mobile application (block  1230 ). If the expected hash value does not match the received hash value (block  1232 :N), then the access manager may determine that the mobile application has falsely identified itself, has been altered after installation at the mobile device, and so forth. As a result, the access manager may deny the mobile application access to the computing resources (block  1234 ). If the expected hash value matches the received hash value (block  1232 :Y), then the access manager may identify the mobile application as a trusted mobile application and permit the trusted mobile application to access the computing resources (block  1236 ). 
     In  FIG. 13 , a flowchart  1300  of example method steps for validating a managed mobile application at an unmanaged mobile device having a second type of mobile operating system is shown. The mobile operating system, in this example, may include built-in mechanisms the access manager may utilize to validate the identity of a mobile application. The access manager may receive a request from the managed mobile application to access a computing resource (block  1302 ). The access manager may request from the mobile operating system a unique application identifier for the mobile application (block  1304 ) and receive the application identifier in response (block  1306 ). 
     Based on the application identifier for the mobile application, the access manager may query the list of managed mobile applications ( 1308 ). If the list of managed mobile applications does not include the mobile application requesting access to the computing resource (block  1310 :N), then the access manager may deny the mobile application access to the resource (block  1312 ). If, however, the list of managed mobile applications does include the mobile application requesting access to the computing resource (block  1310 :Y), the access manager may then request from the mobile operating system the application certificate for mobile application (block  1314 ). 
     As noted above, the enterprise application server may provide application certificates for the mobile applications installed at mobile devices. The application certificates may be stored at a secure storage location at the mobile device that is accessible by the access manager. Accordingly, the access manager may receive the requested application certificate from the mobile operating system (block  1316 ) and retrieve the stored application certificate provided by the enterprise application server (block  1318 ). In some example implementations, the access manager may compute respective hash values for each of the certificates (step  1320 ), e.g., using the SHA-1 hash function. The access manager may compare the hash value of the stored certificate to the hash value of the certificate received from the mobile operating system. (block  1322 ). If the hash values match (block  1324 :Y), then the access manager may determine that the mobile application is a trusted mobile application and permit the mobile application to access the computing resources (block  1326 ). If the hash values do not match (block  1324 :N), then the access manager may determine that the mobile application is an untrusted mobile application and deny the mobile application access to the computing resources (block  1312 ). 
     In  FIG. 14 . a flowchart  1400  of example method steps for enforcing application policies during operation of a managed mobile application is shown. As noted above, the enterprise application server may provide application policies associated with the managed mobile applications installed at mobile devices. An enterprise may periodically update the application policies, and the access manager may thus be configured to ensure the most recent and up-to-date application policies are stored at a mobile device before permitting a managed mobile application from accessing the computing resources. In this way, the enterprise may grant or revoke entitlements to applications and application functionalities. 
     After the access manager validates the identity of a managed mobile application (block  1402 ), the access manager may retrieve the application policy associated with the managed mobile application and stored at the mobile device (block  1404 ). The access manager may then query the enterprise application server for policy information associated with the application policy (block  1406 ), e.g., a policy date, a policy version number, and the like. Based on the policy information received from the enterprise application server, the access manager may determine whether the application policy stored at the mobile device is current (block  1408 ). As an example, the access manager may compare the policy date or policy version received from the enterprise application server to the policy date or policy version of the application policy stored at the mobile device. If the policy date or policy version do not match, then the access manager may determine that the application policy stored at the mobile device is not current (block  1408 :N). If the policy date or policy version do match, then the access manager may determine that the application policy stored at the mobile device is current (block  1408 :Y). 
     If the application policy is not current (block  1408 :N), then the access manager may retrieve the current policy associated with the mobile application from the enterprise system, e.g., the enterprise application store (block  1410 ). The access manager may download the current application policy and store the current application policy at a secure storage location at the mobile device (block  1412 ). Once the access manager has obtained the current policy for the mobile application, the managed mobile application may refer to the application policy to determine whether it may access or use the computing resource as intended (block  1414 ). 
     The management framework, for example, may configure the managed mobile application to query the policy before accessing or using a computing resource. As an example, the framework may configure the managed mobile application to query the application policy in order to determine whether data may be copied to another mobile application at the mobile device. In some example implementations, the managed mobile application may only copy the data to other managed mobile applications at the mobile device. As another example, the framework may configure the managed mobile application to query the application policy in order to determine whether the mobile device may capture a screenshot of the managed mobile application. These and other examples will be appreciated with the benefit of this disclosure. 
     If the application policy permits the managed mobile application to access or use computing resource as intended (block  1416 :Y), then the framework may permit the managed mobile application to carry out the intended action (block  1418 ). If, however, the application policy does not permit the managed mobile application to access or use the computing resource as intended (block  1418 :N), then the framework may prevent the managed mobile application from carrying out the intended action (block  1420 ). 
     Mobile Application Management with Mobile Device Management 
     Although mobile application management (MAM) has been discussed in the context of an unmanaged device, aspects of the present disclosure may also be employed with respect to managed devices as well. An enterprise may utilize mobile device management (MDM) in conjunction with mobile application management to further control the operation of the mobile device. In particular, the mobile device may enroll with an MDM system to establish a managed relationship between the MDM system and the mobile device. Once the mobile device is enrolled, the MDM system may leverage the managed relationship to enforce policies, monitor the mobile device, push information to the mobile device, and the like. 
     In sum, the MDM system may obtain information about the mobile device that would otherwise be unavailable absent the managed relationship. Such information may correspond to device-level settings that are not discoverable or readable through applications at the mobile device. Such device-level settings may include PIN or password settings, encryption settings, network-related settings, and the like. Such information may also include information regarding the processes currently running at the mobile device and the mobile applications installed at the mobile device (e.g., the application inventory). The MDM system may further obtain additional or alternative types of information pertaining to the managed mobile device. The MDM system may compare the information obtained from the managed mobile device against various policies and take various actions in response. 
     With respect to a device PIN/password, the MDM system may obtain information that indicates whether the device is secured via a PIN/password, the complexity of the PIN/password, and the age of the PIN/password. Through the managed relationship, the MDM system may obtain information regarding the PIN/password settings of the device. The MDM system may compare this information to policies governing the use of device PINs/passwords. As an example, if a security policy indicates that the mobile device must be secured by a PIN/password and the information obtained from the mobile device indicates that the device PIN/password setting is not enabled, then the MDM system may push notifications to the managed mobile device indicating the security policy regarding device PINs/passwords. As another example, if the MDM system determines that the device PIN/password does not meet the complexity requirements of the security policy, then the MDM system may likewise push a notification to the managed mobile device indicating that a new, more complex PIN/password is required to comply with the security policy. As a further example, if the security policy indicates that device PINs/passwords must be changed periodically, then the MDM system may push a notification to the managed mobile device indicating the need to change the device PIN/password upon determining that the current device PIN/password has expired. 
     With respect to encryption settings, the MDM system may also obtain information that indicates whether the device has hardware encryption enabled. Through the managed relationship, the MDM system may enable hardware encryption at the managed mobile device upon determining that a security policy requires hardware encryption and that hardware encryption is not currently enabled at the mobile device. The MDM system may also set network-related settings at the managed mobile device through the managed relationship. 
     The MDM system may additionally obtain information regarding the processes currently running at the managed mobile device. The MDM system may compare the running processes against a list of malicious applications, programs, or processes in order to identify, e.g., malware at the managed mobile device. Through the managed relationship, the MDM system may kill any processes identified as malware or potentially malicious. The MDM system may also remove the corresponding malicious applications or programs through the managed relationship with the mobile device. 
     Similarly, the MDM system may obtain a list of applications installed at the managed mobile device. The MDM system may compare the list of installed applications to, e.g., an application whitelist or an application blacklist. The application whitelist may be a list of mobile applications permitted to be installed at the mobile device. If the list of installed applications includes an application that does not appear on the mobile application whitelist, then the MDM system may leverage the managed relationship to remove the application. The application blacklist may be a list of mobile applications prohibited from being installed at the mobile device. If the list of installed applications includes an application that appears on the mobile application blacklist, then the MDM system may similarly leverage the managed relationship to remove the application. It will be appreciated that the MDM system may additionally leverage the managed relationship to push mobile applications to the managed mobile device in order to control which mobile applications are installed at the mobile device. In view of this disclosure, it will also be appreciated that the MDM system may exert more robust control over the mobile applications installed at the mobile device. As described above, MAM may disable a mobile application installed at the mobile device upon determination that the application violates a policy. When MDM is used in conjunction with MAM, however, the mobile application may not only be disabled, it may be removed entirely from the mobile device. The MDM system may push other types of information to the managed mobile device. For example, the MDM system may leverage the managed relationship to push application updates or certificates to the mobile device. The certificates may be, e.g., X.509 device certificates. 
     The disclosures provided in this disclosure provide a number of technical advantages. In general, the approaches set forth above enable an enterprise to securely and strongly identify a mobile application regardless of mobile platform. The approaches set forth above also provide an automated way to verify the identity of mobile applications accessing potentially sensitive data such as authentication credentials, digital certificates, enterprise data, and the like. An enterprise implementing the approaches set forth above may also reduce the number of physical devices under its management by allowing individuals to use their personal devices to access enterprise resources. In this regard, an enterprise may avoid having to enroll an entire device into a mobile device management system, and may instead only enroll various mobile applications at a mobile device in a mobile application management system. These and other advantages will be appreciated with the benefit of the disclosures provided above. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example implementations of the following claims.