Method and apparatus for providing secure wireless communication

An approach is provided for securely communicating in a wireless network. A cryptographic server generates a command to enable a secure mode of operation for a wireless device, wherein the wireless device can operate in a secure mode and an unsecure mode in support of two-way messaging. The cryptographic server sends the command to the wireless device to activate the secure mode of operation. The secure mode of operation provides transmission of an encrypted message by the wireless device over the wireless network.

FIELD OF THE INVENTION

The present invention relates to communications, and more particularly, to secure wireless communication.

BACKGROUND OF THE INVENTION

Wireless networks, such as paging systems, permit users to communicate with great convenience on a store-and-forward manner or real-time basis. Because of the broadcast nature of these networks, security is a paramount concern. Traditionally, commercial paging systems lack adequate security or require significant change in the hardware and software infrastructure to effect an acceptable level of security. Inadequacy of security measures has limited the types of service offerings and their appeal to customers who place a high premium on privacy and confidentiality. These customers largely include business entities that process highly confidential data, for example, financial and medical information. A further consideration in deploying effective security mechanisms in a wireless network is the impact on the user device, in terms of user interface. That is, the ease or user friendliness of existing wireless devices must be maintained or enhanced.

Another application for a wireless system is telemetry services, notably fleet and asset management. The management of vehicles within a fleet as well as assets involves obtaining information, generally in real-time, about the location and movement of these objects. The fleet manager utilizes this information to maximize use of fleet resources. Customers may view such information as confidential, and thus, may require that such communication is securely exchanged.

Therefore, there is a need for a security mechanism that can be readily deployed in a wireless network, without altering the existing infrastructure or introducing complexity in the end user devices.

SUMMARY OF THE INVENTION

These and other needs are addressed by the present invention, in which an approach for secure messaging over a wireless network is provided.

According to one aspect of the present invention, a method for communicating in a wireless network is disclosed. The method includes generating a command to enable a secure mode of operation for a wireless device, wherein the wireless device is configured to operate in a secure mode and an unsecure mode in support of two-way messaging. The method also includes transmitting the command to the wireless device to activate the secure mode of operation. The secure mode of operation provides transmission of an encrypted message by the wireless device over the wireless network.

According to another aspect of the present invention, a network apparatus for supporting secure communication over a wireless network is disclosed. The apparatus includes a processor configured to generate a command to enable a secure mode of operation for a wireless device, wherein the wireless device is configured to operate in a secure mode and an unsecure mode in support of two-way messaging. Additionally, the apparatus includes a communication interface configured to transmit the command to the wireless device to activate the secure mode of operation, wherein the secure mode of operation provides transmission of an encrypted message by the wireless device over the wireless network.

According to another aspect of the present invention, a method for communicating in a wireless network is disclosed. The method includes switching from an unsecure mode of operation to a secure mode of operation. The method also includes establishing a shared secret key with a cryptographic server over the wireless network in support of two-way messaging. Further, the method includes generating an encrypted message using the shared secret key.

According to yet another aspect of the present invention, a device for communicating in a wireless network is disclosed. The device includes means for switching from an unsecure mode of operation to a secure mode of operation. The device also includes means for establishing a shared secret key with a cryptographic server over the wireless network in support of two-way messaging. Further, the device includes means for generating an encrypted message using the shared secret key.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An apparatus, method, and software for secure communication over a wireless network are described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It is apparent, however, to one skilled in the art that the present invention may be practiced without these specific details or with an equivalent arrangement. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention.

FIG. 1is a diagram of a wireless network capable of providing unsecure and secure modes of operation, according to an embodiment of the present invention. The system100provides, in an exemplary embodiment, two-way paging services as well as fleet and asset tracking. The system100utilizes a combination of autonomous GPS and Assisted GPS (A-GPS); in particular, mobile-centric A-GPS. The system100includes a Network Operation Center (NOC)101that provides both secure and unsecure over-the-air communications for telemetry devices103and two-messaging devices104. For tracking telemetry devices103, which can be resident within vehicles105. Moreover, it is contemplated that the telemetry device103can be affixed to an asset (or any other object).

A wireless network107supports two-way communication among the telemetry devices103and the NOC101. In an exemplary embodiment, the wireless network107is a two-way paging system employing the ReFLEX™ protocol by Motorola for two-way advanced messaging. The wireless network107provides over-the-air encrypted messages for secure communication through establishment of a highly secure area (SA) in the NOC101. According to one embodiment of the present invention, the system100supports advanced cryptographic techniques for the transfer and administration of complex and highly secure encryption keys. By way of example, the Advanced Encryption Standard (AES) in Counter (CTR) mode is used for over-the-air encryption. AES is detailed in NIST, FIPS PUB 197, entitled “Advanced Encryption Standard (AES),” November 2001; which is incorporated herein by reference in its entirety. CTR mode of AES is well suited for ReFLEX™ network as it does not propagate errors and utilizes minimal overhead. Additionally, only one function (encrypt) is adequate to handle both encryption and decryption. The protocol for the secured messaging can be found in the Paging Technical Committee (PTC) Engineering Standards and Publications document RFC 30 which describes the method identifier “0x61” defining how AES should be implemented in a ReFLEX™ network. This highly secure system100can operate within the constraints, for example, of a micro-powered handheld two-way messaging device, such as devices104, without diminishing the ease of sending or reading messages.

Messages are created on the 2-way messaging device104and readily encrypted for transmission over the network107. Once enabled for a particular customer, all messages delivered to/from the corresponding 2-way messaging devices104will be encrypted. The 2-way messaging device104places the clear-text of the message into the outbox. When the device104is ready to transmit the message, it will be encrypted and sent over the normal wireless network107using the ReFLEX™ protocols. When received by the NOC101, the system100checks to determined whether the received message is a secured message. If the message is secured, the message is sent to a cryptographic server (i.e., crypto server) within the NOC101for decoding along with the address of the sending unit. The operation of the crypto server is more fully described below inFIG. 2. When the 2-way messaging device104receives the secured message, the device decrypts the message, places the clear text of the message into the inbox, and alerts the owner that a message has arrived.

Advantageously, the operation, coordination, and administration of the encryption process is transparent to the end user, and therefore, maintains the existing ease of use of the wireless network107as a paging system.

For secure messages exchanged with the telemetry devices103, the NOC101can accordingly encrypt and decrypt such messages. The telemetry devices103have two modes of operation: autonomous GPS mode, and A-GPS mode. When operating in A-GPS mode, the system100can provide for better in building or obstructed view geolocation with in a paging system zone. When out of network coverage, the autonomous GPS may be used to obtain geolocation data that may be stored on the device for later transmission.

The NOC101provides the necessary fleet and asset management functions, such as user account creation and management, access control, and deployment of business rules. The NOC101also supports remote management capabilities by hosts109over a data network111, such as the global Internet.

To better understand the hybrid A-GPS environment of the system100, it is instructive to describe the operation of the general operation of a mobile-centric A-GPS system. The telemetry device103has GPS hardware and intelligence, whereby the network107in conjunction with the NOC101employs mechanisms for providing GPS aiding data (or assistance data). The network107includes base transmitters and some base receivers containing GPS hardware from which the ephemeris and approximate location can be obtained, constituting a GPS reference network113. The GPS reference network113utilizes multiple GPS satellites115.

The assistance data that is transmitted to the devices103, in an exemplary embodiment, can include ephemeris data differential GPS correct data, timing data and/or other aiding data. Using the aiding (or assistance) data, the telemetry devices103performs geolocation calculations, yielding a number of advantages. For example, the telemetry devices103can generate real-time speed and route adherence alerts. Additionally, transmission of geolocation data need not be frequent. Transmission of geolocation data is more compact because it is true location rather than pseudo range data. Also, the telemetry devices103can more intelligently request assistance data because the devices103themselves can determine when the ephemeris data is no longer valid.

The hybrid A-GPS system100thus permits fast and precise geolocation when in network coverage of the network107, while providing immunity from obstructed view of the sky. Also, when the switch is made to autonomous GPS mode (when outside of the coverage area of the network101), the devices103can still obtain geolocation data. This data can be stored within the device103and transmitted to the NOC101when the associated vehicle105returns to the network coverage area.

As noted earlier, the telemetry devices103may be attached to a host entity such as a vehicle or other valuable asset. The device may be used to track, monitor, and control aspects of the host entity. These devices103are configurable with respect to the existence and number of digital inputs/outputs (I/O), analog inputs/outputs (I/O), and device port interfaces for connection with peripheral devices. By way of examples, the digital inputs can be used to monitor various components of the vehicles105: ignition status, door lock status, generic switch status, headlight status, and seat occupancy status. The digital outputs can be used to control, for example, the starter, and door locks, and to monitor such parameters as engine temperature, cargo temperature, oil pressure, fuel level, ambient temperature, and battery voltage. The exact configuration of the telemetry devices103can be based on cost consideration and/or applications.

The telemetry devices103, in an exemplary embodiment, employ a wireless protocol to receive commands and transmit data and alerts (e.g., high speed alert) over the radio network107. The telemetry devices103can queue alerts, message responses, and scheduled data, whereby if the devices103are unable to send the messages, the messages are queued and sent when the device103returns to wireless network coverage. Prioritized queues are used and include, for example, queues for high, normal, and low priority messages. In the exemplary implementation, critical device status changes are given highest priority, while other alerts and responses are given normal priority. Scheduled data messages are given the lowest priority. The queues are configured, as first in yields first out, wherein new messages are dropped when its corresponding queue is full. This arrangement advantageously allows for the status of the device103at the time of transmission failure to be known even when the data stored in the data log at time of the transmission has been overwritten.

The telemetry devices103can also respond to status (e.g., of position, speed, digital I/O port status, analog input channel status, peripheral status or other device status) queries transmitted by the NOC101. The status query may request either current status or status within a time and date range. The device103responds to the query with either the current status or all status within the date and time range that is currently stored in the device's data log.

As regards data logging, the devices103support use of one or more schedules for the data acquisition. The data logging involves storing of the data locally on the device103. This data, which can include position, speed, digital I/O port status, analog input channel status, peripheral status or other device status is not automatically transmitted over the air. Instead, the data is stored for a finite period of time and made available for use by scheduled data acquisitions, data acquisitions on demand, and data acquisitions associated with alerts. The data log is circular in that when the last available memory for the data logger has been written, the data logger begins recording new data at the first location of memory available for the data logger.

With scheduled acquisitions of the data collected by the data logger, the data within the data log is transmitted by the device103according to a configurable schedule at the configured transmission rate. Multiple schedules may be configured on the device103. Schedules are configured to obtain data at a regular interval based upon calendar time and date. Schedules may be configured such that they are enabled and disabled based upon status of a digital input. For example, an ignition status input may be used to turn a schedule on when the engine is On and turn the schedule off when the engine is Off. A Response (or Data) Message Window value can be configured on the device103, such that the device103delays sending scheduled data using an Offset within the Data Message Window. That is, the scheduled transmit time is adjusted by the Offset, the device103delays queuing the scheduled data until the time is equal to the transmit time plus the Offset. Use of the Data Message Window helps prevent overwhelming the wireless network107when many devices are scheduled to transmit data at the same time. For example, it is likely that many schedules will be based upon transmitting on the hour, half past the hour, or at fifteen minute intervals. Using the Offset ensures that the scheduled data transmissions from all of the devices with similar schedules are not sent at precisely the same time. Given the precision of the telemetry device's clock (as it is based upon GPS time), this randomization of regularly scheduled device transmissions is particularly useful.

The telemetry devices103can be configured to monitor a variety of information relating to the vehicle or asset through the digital I/O and analog I/O. For instance, alerts can be used to indicate status change of the digital inputs. Each Digital Input Status Change Alert can be enabled and disabled through configuration. The alert may be configured to transmit other device status recorded at the time of the alert such as position, speed, status of other digital I/O ports, analog input status, peripheral status, or other device status. As regards the digital output, the status of each available digital output can be changed or read.

Similarly, the statuses of analog inputs of the devices103are monitored for change. In an exemplary embodiment, multiple threshold levels (e.g., high and low) can be set, whereby alerts are generated (e.g., Low Range Entry alert, Low Range Exit, High Range Entry, and High Range Exit). That is, if the value of the Analog Input falls below the Low Threshold, a Low Range Entry Alert is generated. If the value of the Analog Input rises above the Low Threshold plus a Hysteresis is value, a Low Range Exit Alert is generated. In similar fashion, if the value of the Analog Input rises above the High Threshold, a High Range Entry Alert is output from the device103. Also, if the value of the Analog Input falls below the High Threshold minus a Hysteresis value, a High Range Exit Alert is generated. The alert may be configured to transmit other device status recorded at the time of the alert such as position, speed, status of other digital I/O ports, analog input status, peripheral status, or other device status.

By way of example, the devices103can be used to monitor excessive speed via a High Speed Alert Control, whereby a High Speed Threshold can be set by a fleet manager. In addition, a duration parameter (i.e., High Speed Duration) can be utilized to specify the time at which the High Speed Threshold must be exceeded before an alert is generated. Further, a configurable High Speed Hysteresis parameter is set as the delta change below the High Speed Threshold used to determine when the High Speed Threshold has no longer been exceeded. The alert may be configured to transmit other device status recorded at the time of the alert such as position, speed, status of other digital I/O ports, analog input status, peripheral status, or other device status.

The system100also permits users via the hosts109to specify and configure areas of interest within the coverage area of the network101such that alerts can be generated when a device103enters or exits the configured areas. The alert may be configured to transmit other device status recorded at the time of the alert such as position, speed, status of other digital I/O ports, analog input status, peripheral status, or other device status.

It is recognized that a tremendous amount of data and associated alerts can result. Therefore, filtering such data is useful, particularly if the data is inaccurate. Notably, GPS positional data can be erroneous due to environmental conditions, which can cause errors or distortions of the GPS signal received by the devices103. For example, small position changes can sometimes be detected on non-moving vehicles, as well as excessive speeds and erroneous positions. Consequently, such errant information is filtered, in an exemplary embodiment, at a gateway within the NOC101. The data collected and transmitted by the telemetry devices103are processed by the NOC101, the components of which are described inFIG. 2.

FIG. 2is a diagram of a Network Operations Center (NOC) in the system ofFIG. 1, according to an embodiment of the present invention. According to an embodiment of the present invention, each device103,104on the wireless network107has a profile that contains various bits of information about the unit and is maintained by the NOC101. The devices103,104that are capable of decryption and have been enabled for a secure communication service are specified accordingly in their respective profiles. Such devices103,104can receive all of their messages encrypted. The profile optionally can indicate that particular encryption algorithm is being used if multiple cryptographic servers (i.e., “crypto server”) are utilized. For example, a customer may request to have its own crypto server hosted at the NOC101, whereby all of the customer's messages are processed by the particular crypto server for encryption and decryption.

The NOC101utilizes, in this exemplary embodiment, a client-server architecture to support the wireless devices103,104. Specifically, the NOC101houses a messaging server201for sending and receiving messages to the devices103,104over the air, for storing the messages, and routing these messages to their destination. The NOC101provides connectivity via a local area network (LAN) (not shown) for the messaging server103with an A-GPS server203, a routing server205, and a gateway207. The gateway207communicates with a security server (i.e., cryptographic server)209to support encryption and decryption of the messages.

A presentation server211resides within the NOC101to interface with the data network111(e.g., the global Internet), such that the host109can access the services of the fleet and asset management system. The host109under this scenario is loaded with a desktop client213. Although a single server is shown for the presentation server211, in the alternative, the server211can functionally be implemented as three separate servers: a database server, a middleware server, and a web server. The database server is responsible for data storing, data updating, and data retrieval as well as providing a set of interfaces to achieve these functions. The web server is responsible for serving maps, presenting user interfaces to manage and control user administration, device configuration, and etc. The middleware server can be deployed between the database server and the web server, and has the following responsibilities: converting the web server's data retrieval requests to database server Application Programming Interfaces (APIs) and then sending to database server, receiving the responses from the database server and then sending back to web server, receiving data from gateway207and then sending requests to the database to store/update data records. Because of the modularity in this design, these three components can reside on the same machine, as shown inFIG. 2, or reside in multiple platforms.

Messages from the wireless devices103and104are forwarded by the messaging server201to either the A-GPS server203or the routing server205depending on the type of device. For example, in the case of the telemetry devices103, if the message is an assist request, the message is sent to the A-GPS server203. In response to the GPS assist request, the A-GPS server203determines GPS assistance data for transmission to the requesting telemetry device103.

The A-GPS server203obtains ephemeris data from the GPS reference network113, and determines satellite configuration for each of the geographic zones comprising the wireless network. The A-GPS server203also determines the assistance data for each geographic zone. The NOC101then periodically broadcasts the assistance data to each geographic zone. In addition, the A-GPS server203supplies GPS assistance data to any telemetry device103that requests the GPS assistance data. When supporting this request, the NOC101determines approximate location of the requesting device103based upon base receivers that received the request, using a type of triangulation. Subsequently, a GPS Assistance message is generated by the A-GPS server203to send to the telemetry device203based upon its approximate location. The messaging server201sends the GPS Assistance message to the particular telemetry device103.

Thus, the A-GPS server203delivers GPS assistance data through two mechanisms by periodically broadcasting GPS assistance data to all devices103in each of the geographic zones covered by the wireless network107, or by responding to specific requests by the telemetry devices103for GPS assistance data.

The routing server205has responsibility for routing of the messages from the wireless devices103and104, and managing such messages from the devices103,104to their server destinations. Each device103can be configured to have messages directed to one or more destination servers. The routing server205, upon receiving message from the wireless device103and104, determines a destination address that has been configured for the device103and104and modifies the destination address accordingly. The message is then forwarded to the configured destination. According to one embodiment of the present invention, by default, the messages are directed to the gateway207.

The gateway207interfaces with the presentation server211to permit the desktop client213access to the fleet and asset management or messaging services. The gateway207provides translation of wireline messages and commands from the presentation server211to the wireless protocol for communication with the telemetry devices103. For example, the gateway207supports an eXtensible Markup Language (XML) interface, such that XML commands submitted to the gateway207over wireline are converted to the wireless protocol commands and sent over the paging network107to the devices103. In turn, the wireless protocol messages received from the devices103are converted to wireline XML messages. The gateway207provides translation of wireline messages and commands from the host109to the wireless protocol for communication with the telemetry devices103. In turn, the wireless protocol messages received from the devices103are converted to wireline XML messages and sent to host109.

The presentation server211provides the following functions: messaging, fleet and asset tracking, and general purpose I/O monitoring and control. The server211also maintains a database (not shown) for user accounts and other related data (e.g., configuration data, user management information, device management, and data acquired from the devices103). The presentation server211, as mentioned, also generates the maps corresponding to where the devices103are tracked and the mapping preferences configured. Using the desktop client213, a user can even issue requests to command a particular device103, such as requesting location of the device103.

With the presentation server211as a front end, a user via the desktop client213can configure the telemetry devices103via web interfaces. In an exemplary embodiment, the server211is a World Wide Web (“web”) application server to support a web browser based front-end for the desktop clients109. The web application server (not shown) can be deployed to support such web interfaces as a set of Java Server Pages (JSP) and Java Applet to interact with the user on the desktop client213. On the backend, based on data collected by JSP and Java Applet, the web server can generate the proper XML commands that are compliant with Application Programming Interface (API) of the presentation server211. Consequently, the collected records can be stored in the database of the presentation server211. The database also stores the properties of the telemetry devices103, such as the alerts and thresholds.

The desktop client213interfaces to the system100through the presentation server211. From the desktop client213, the user logs in to the system100. The presentation server211can also perform authentication as well as administration tasks such as adding new users or devices103. The user can also configure business rules executed by the presentation server211, wherein the business rules logic uses this user supplied configuration to configure the devices103, acquire, and process data from the devices103.

Additionally, the presentation server211provides a reporting capability based on the stored information in the database. The presentation server211can support standard reports or customize reports to the user via the desktop client213.

Instead of using a desktop client213, the user, if associated with a large organization, can utilize an enterprise server to obtain all of the user functionality through the gateway207using the API of the system100. Accordingly, the enterprise server would possess the functional capabilities of the presentation server211, but would be managed by the customer (or user) at the customer's premise.

As noted, the wireless protocol supports communications between the NOC101and the wireless devices103and104. In an exemplary embodiment, the messaging is performed according the FLEXsuite Uniform Addressing & Routing (UAR) protocol (developed by MOTOROLA). The wireless protocol message, which can be encapsulated with an UAR message, can be unencrypted or encrypted.

As seen inFIG. 2, the NOC101houses a Secure Area (SA)215. The SA215can be implemented as a physically secured area for housing a crypto server209, whereby personnel is screened and will have limited, controlled access. That is, all activity in this area including entry, and exit by users are recorded. Additionally, remote access into the SA215is highly restricted and rigorously monitored.

The crypto server209interacts with a SA (Secure Area) Wireless Communication Transfer Protocol (WCTP) and SA Send A Message (SAM) interface219. The SA WCTP & SA SAM interface219, in an exemplary embodiment, supports the Wireless Communication Transfer Protocol (WCTP) features (inbound & outbound) that are currently supported by WCTP NOC interface. The WCTP is a paging standard for sending paging messages over the Internet111. The crypto server209can receive messages destined for the wireless devices103,104from a NOC interface (e.g., email, web, IVR, and WCTP interfaces), an unsecured device, a secured device, or an interface within the SA215. From the user's perspective, the NOC interfaces are provided for both secure and unsecure communication. These NOC interfaces can be made are optional for secure mode of operation. As a default, all NOC interfaces are enabled. The crypto server209determines whether the recipient device is allowed to receive message from the originating device/interface (e.g., NOC interface and unsecured device). If allowed, the crypto server209encrypts the message with a symmetric key and sends the encrypted message to device.

The SA WCTP & SA SAM interface219provides virtual end-to-end security. In an exemplary embodiment, the interface219provides secure messaging over the Internet111. Messages received via the SA WCTP & SA SAM interface219are passed to the crypto server209, which provides secure messaging over the air. According to one embodiment of the present invention, the interface219and the crypto server209can be implemented on the same physical box. The crypto server209encrypts the clear text message using AES and sends the ciphertext to the wireless device (e.g., telemetry device103or 2-way messaging device104). It is noted that the clear text message, in one embodiment of the present invention, is not logged into a file system or stored in database.

The crypto server209communicates with other components and/or processes of the NOC101via a NOC-to-SA interface225. Namely, the crypto server209communicates with the messaging server201. Additionally, the server209can communicate with other NOC interfaces and databases, without comprising the security of the wireless devices103,104or the messages.

Also, the crypto server209interfaces a database221and a CALEA (Communications Assistance for Law Enforcement Act) interface223. This crypto database221holds device keys and security settings for the wireless devices103,104, but does not store encrypted messages. The CALEA interface223provides clear text message to appropriate government agencies, in accordance with the Law Enforcement Agency (LEA) mandate.

As shown, an RF controller227is provided to support routing of secure messages. In particular, the RF controller227recognizes the key establishment and secure messages, and routes such messages appropriately. In an exemplary embodiment, if the messages originate from the telemetry device103, these messages can be routed to the messaging server201, otherwise, they are routed to the crypto server209. The RF Controller227supports location query request for a particular device (e.g., device104); this mechanism can used by the crypto server209or other subsystems to recover from error scenarios.

In an exemplary embodiment, the gateway207provides various core processes that are responsible for handling error messages received from the wireless devices103,104.

The SA215can be configured for redundancy for high reliability. In accordance with one embodiment of the present invention, to support redundancy, the database221—which holds device keys and security settings—is replicated between two NOCs101,233over a secure link. By way of example, the NOC101can serve as a primary facility, while the NOC233is the secondary facility. In case of an emergency or scheduled maintenance, the secondary NOC233can be designated as the primary facility.

Firewall rules can be deployed between the two NOCs101,233. For example, privileges are appropriately assigned to permit access to the crypto databases only by the respective crypto servers. Also, components with the SA215,231can communicate freely. Messages from the CALEA process (e.g., CALEA223) to a LEA are secured. A secured port is designated for WCTP & SAM messages from the Internet111. For database replication between two the NOCs101,233, a secure link using, for example, a Virtual Private Network (VPN) over dedicated lines within a transport network235, is enabled.

FIG. 3shows a diagram of a wireless device used in the system ofFIG. 1, according to an embodiment of the present invention. By way of example, the components of the telemetry device103are described in the context of a narrowband network, such as a paging system. However, it is contemplated that the components for communications can be tailored to the specific wireless network, and user device (e.g., 2-way messaging device104). The telemetry device103can operate in a secure mode or unsecure mode.

In this exemplary embodiment, the telemetry device103includes a two-way wireless modem301for receiving and transmitting signals over the wireless network107according to the communication protocols supported by the wireless network107, such as the Motorola ReFLEX™ protocol for two-way paging. By way of example, a Karli ReFLEX™ module by Advantra International can be used for the modem301. The two-way wireless modem301couples to a two-way wireless antenna (not shown) that can be placed local to the device103or remote from the device103(e.g., 12 or more feet) to enhance flexibility in installation.

The telemetry device103also contains a GPS module303that is capable of operating in the multiple GPS modes: autonomous GPS mode, and mobile-based A-GPS mode. The GPS module303can employ, for example, a GPS receiver manufactured by FastraX—iTrax02/4. In autonomous mode, GPS data may be acquired with no assistance data provided by the wireless network107. The GPS module303operates in the A-GPS mode when the device103is in wireless network coverage, in which assistance data is supplied and can include ephemeris data and data to obtain location in obstructed view locations (in building, wooded areas, etc.). Further, the assistance can include differential GPS (DGPS) to enhance location accuracy under some conditions. The GPS module303couples to a GPS antenna (not shown) that can be placed local to the device103or remote from the device103(e.g., 12 or more feet) to enhance flexibility in installation.

Attachment of peripheral modules to the telemetry device103are supported by one or more peripheral ports305. The ports305, for example, can be used to connect to intelligent peripherals that operate according to business rules and logic. These business rules and logic can be housed in a vehicle harness (not shown), which include an On-Board Diagnostic (OBDII) interface and intelligence. Under this arrangement, a user (e.g., fleet manager) can query any parameter available through the OBDII interface. For example, data obtained for each tracking record can include any combination of the following items: RPM (Revolutions Per Minute), oil pressure, coolant temperature, etc. Such data recorded by the telemetry device103is stored in memory313. The acquisition period for the data is configurable, as well as the transmission interval to the NOC101. Furthermore, the monitoring and subsequent data exchange can be governed by a configurable schedule, which can specify such parameters as start date, start time, end time, recurrence (e.g., daily, weekly, monthly, etc.), and duration.

Data is logged by a data logger307, made available for use by scheduled data acquisitions, data acquisitions on demand, and data acquisitions associated with alerts. As mentioned, the telemetry device103also can be configured to include digital I/O309and analog I/O311for monitoring and control of the vehicle or asset. The data logger307also collects data associated with these I/O ports309,311.

The telemetry device103also includes a processor323that may handle arithmetic computations, and may support operating system and application processing. The processor323, while shown as a single block, may be configured as multiple processors, any of which may support multipurpose processing, or which may support a single function.

The memory313of the telemetry device103can be organized to include multiple queues for prioritizing the messages to be processed by the device103. In support of secure messaging, the memory313stores one or more cryptographic keys315using indices. Thus, the device103can be motivated to change keys based on received index value. The memory313, while shown as a single block, may be configured as multiple memory devices, any of which may support static or dynamic storage, and may include code for operating system functionality, microcode, or application code.

Crypto logic317supports secure functionality, such as the encryption and key establishment processes, as described with respect toFIGS. 6-8, as well as key management functions. The logic317can perform a specified encryption algorithm, such as AES-CTR. The secure functionality can be enabled or disabled via Over the Air Programming (OTAP) or a programming cable/cradle. According to one embodiment of the present invention, the device103supports the capability of being loaded with a device specific shared secret before the device103is shipped to the end user. This “shared secret” memory location can be loaded with the device serial number when the unit is first shipped from the factory. Whenever the device103is reset to factory fresh conditions, the internal software can automatically load the “shared secret” memory location with a copy of the device serial number. When first registering, the device104coordinate keys per the process ofFIG. 6.

Although the crypto logic317is described with respect to the telemetry device103, it is recognized that the crypto logic317can be deployed in the 2-way messaging device104(e.g., a pager) for secure communication in which a display (e.g., an Liquid Crystal Display (LCD) display). In such an embodiment, the 2-way messaging device104can be capable of receiving both encrypted and unencrypted messages. By way of example, a flag can be used by the crypto server209and the device104to indicate whether or not all messages to or from the device104are encrypted. Once these indications are set, the device104is considered an encrypted device and all messages to/from can be sent encrypted. An icon, such as a lock, can be displayed at the top-level (main) screen indicating that the device is being operated in the secure mode. In addition, an icon (such as lock) can be displayed next to every message that's received or transmitted securely. This refers to messages in the inbox, outbox, or any other folder.

The messages within the 2-way messaging device104, in an exemplary embodiment, is stored unencrypted. This approach simplifies the implementation on existing devices and enhances the user experience; that is, the user would not be impacted by any delay in the decryption process, as the unit need not decrypt each message before displaying. In an alternative embodiment, the messages can be stored encrypted. In such a case, it is imperative that the appropriate keys are maintained, as the messages could be rendered unreadable if a particular key associated with the messages are changed.

As an added measure of security, the 2-way messaging device104provides an over-the-air capability to erase all the memory within the unit. An administrator, for instance, can issue an over-the-air command to remotely erase all messages and keys in the event of loss of the device104. This action returns the device104to the “factory fresh” state.

Returning to the description of the telemetry device103, data recorded by the device103may additionally be stored in a storage medium other than the memory313, such as in a flash memory321. A log (not shown) of information may be kept so that the information may be transmitted according to a schedule, as discussed above, or, e.g., upon receipt of a request to send all data that has been collected. Storage devices have only a finite amount of space for storage of information, and thus the information for only a finite number of messages may be stored in either the memory313or the flash memory321.

To improve availability of the telemetry device103, an internal battery319is optionally included. With the internal battery, the telemetry device103can continue to monitor and transmit alerts and status information to the NOC101even if the electrical system of a vehicle is inoperable. Additionally, the internal battery319can be used by the device103to gracefully report power status wirelessly and shut down gracefully when the energy level of the internal battery is becoming to low to sustain operation of the device

FIG. 4is a flowchart of a forward channel encryption process, according to an embodiment of the present invention. A message arrives at the NOC101(per step401) and is destined for a security enabled device. As discussed, the messages exchanged among the wireless devices103,104and the NOC101are messages compliant with the ReFLEX™ protocol. However, other equivalent protocols can be employed. In an exemplary embodiment, message formatting of secured message are identical to unsecured messages, including reply format, time stamp, stored flag, etc.

The message is first transmitted to the crypto server209. The crypto server209then determines the particular symmetric key corresponding to the device (e.g., 2-way messaging device104) and encrypts, as in step403, the message with the key. The message is then delivered via the wireless network107, per step405. Once the device104receives the coded message, the device decrypts the using the agreed upon symmetric key (i.e., shared secret), as in step407, and then provide the clear text message to the user.

FIG. 5is a flowchart of a reverse channel encryption process, according to an embodiment of the present invention. In addition to receiving encrypted messages, the device104itself is also capable of encrypting messages and forwarding them over the wireless network107. In steps501and503, once a message is ready to be sent, the device104encrypts the message with the symmetric key and sends the secured message over the wireless network107. When the NOC101receives this coded message, the NOC101determines whether the communication from this device104is always encrypted based on the device profile. For the purposes of illustration, in this case, the profile indicates that the messages are encrypted. Consequently, the NOC101forwards the received message to the crypto server209, which decrypts, per step505, the message using the agreed upon symmetric key. The clear text message is processed by the NOC101for normal handling and delivery (step507).

FIG. 6is a flowchart of a process for key establishment, according to an embodiment of the present invention. The system100, according to one embodiment of the present invention, utilizes over-the-air key exchange to minimize the complexity to the end user in terms of ease of use and updating. In an exemplary embodiment, a public/private elliptic curve cryptography (ECC) key encryption system is utilized. Over-the-air key exchange with the device104complies with the communication protocol specified in PTC RFC 41 and the Station-to-Station protocol given in ANSI X9.63 using modified ECC Diffie-Hellman; each of these standards is incorporated herein by reference in their entireties. Because the process of key exchange (shown inFIG. 6) utilizes Public Key encryption and each transfer is digitally signed with the appropriate Private Key, authentication and message integrity is essentially guaranteed. Once the keys are initialized, all messages can be sent encrypted using the coordinated symmetric keys.

In one embodiment of the present invention, when the device104is shipped to the customer, no keys are programmed in the device104. The keys are established over the air on the wireless network107.

When the customer first turns on the 2-way messaging device104, the device104registers with the wireless network107using, for example, the typical ReFLEX registration process. After a successful registration, an OTAP command is sent to the device104to enable security for the device104. After the successful execution of the OTAP command, the 2-way messaging device104sends, per step601, an RFC 41 command 0x20 to inform the crypto server209that the device104is ready to begin the key establishment process. As shown, this key establishment process can be initiated through administration action.

In step603, the crypto server209generates an ECC key pair, and sends a Signature Public Key to the device104(step605). In response, the device104generates the ECC key pair, and sends the Signature Public Key (per steps607and609). In steps611and613, the server209generates the ECC key pair, and sends an Ephemeral Public Key to the device104. Accordingly, the device104generates the ECC key pair, and forwards an Ephemeral Public Key to the server209for calculation of the symmetric key (steps617and619). The random seed for generating elliptic curve key pair can be calculated by XORing static random seed on device104, the serial number of the device104, forward channel address of the device104, system time, and/or signal strength of network107. Use of the signal strength and system time to determine the random seed is further described below inFIG. 7.

In step621, the server209submits a confirmation message to the device104to confirm the Ephemeral Key. In step623, the device104computes the symmetric key. Thereafter, the device104transmits, per step625, a Key Established command at the end of key establishment to inform the crypto server209that the device104received the key index for the symmetric key and is ready for secured messaging.

Thus, the server209sends RFC 41 Commands 1, 3, and 5, and the device104responds with Commands 2, and 4. In addition, the device104sends Command 7 at the end of key establishment (after receiving Command 5) to inform the server209that it received the key index for the symmetric key and is ready for secured messaging.

According to one embodiment of the present invention, during the above key establishment process, the serial number of the device104can be used as the shared secret to minimize the risk of a man-in-the-middle attack. For example, Initialization Vectors (IV) of the device104and the crypto server209can be generated by the crypto server209and sent to the device104via RFC 41 Command 5.

Upon completion of the key establishment process, the device104and the NOC101both will have copies of the symmetric key and IVs to perform encryption.

The key establishment process requires time to execute—potentially in the order a few minutes. As a result, the process is invoked only as necessary, for instance, when the device104is first turned ON or in the event of a total device reset. Restricting this key establishment process to occur only upon being ON advantageously prevents unauthorized use. That is, an authorized user can readily obtain the device104, reset the device104, and read all the new messages. It is noted that an administrator can be authorized by the user to reset the device104, thereby allowing the keys to be re-initiated.

In addition, during this key establishment process, the device104can display textual information that informs the user about the process and to wait patiently. Alternatively, an icon can be used on the main screen to indicate that the key establishment process is taking place. Upon completion of the key establishment process, the icon can be replaced with a different icon that indicates secured.

In an exemplary embodiment, the user is prevented from originating or replying to messages during the key establishment process. Thus, in essence the device104is not operational until the full process is complete. In the event that a timeout takes place, the crypto server209can restart the failed step.

The process ofFIG. 6, in an exemplary embodiment, complies with ANSI X9.63-2001 §6.8 (which is incorporated herein in its entirety). Also, the individual ReFLEX™ messages can be implemented per the Paging Technical Committee (PTC) Engineering Standards and Publications document RFC 41, X9.63 Key Management Protocol; which are incorporated herein by reference in their entireties.

FIG. 7is a flowchart of a process for generating keys based on signal strength, according to an embodiment of the present invention. As mentioned, the random seed for the key pair can be determined by a host of parameters. According to one embodiment of the present invention, the system timing information as well as the signal strength of the network107can be used to determine the random seed. In steps701and703, the signal strength of the network107and the system time (or clocking information of the network107) are acquired. The signal strength can be determined by the wireless device (e.g., telemetry device103and 2-way messaging device104). Thereafter, the random seed is output based on the determined signal strength and the system time, as in step705.

FIG. 8is a state diagram for secure and unsecure device operation, according to an embodiment of the present invention. As shown, a wireless device, such as device104, operating within the wireless network107has two modes of operation: unsecure and secure. The modes of operation is dictated based on whether a security feature on the device104is activated. In an exemplary embodiment, the device104transitions among the following states during the key establishment process: an initialization state801, an unsecured state803, a key establish state805, and a secured state807.

In the unsecured state803, the security feature of the device104is not enabled, thus, the device104communicates over the wireless network107in clear text. That is, all messages to and from the device104can be unencrypted. The device104can decode and display personal and IS messages received in an alphanumeric vector. Binary (personal and IS) messages are ACKed, but not displayed. Also, all Generic Over the Air Programming (GOTAP) commands are processed. Additionally, the device104allows the user to reply to an alphanumeric message with a custom response and/or a ReFLEX multiple-choice response (i.e., Multiple Choice Response (MCR) and canned message).

In the initialization state801, the security feature on the device104can be enabled. However, in this state801, the security keys are not yet established. Hence, the device104does not allow the user to originate or reply to messages. While in this state801, the device104continues to send RFC 41 command 0x2X (e.g., range 0x20˜0x2F). Upon successful transmission of this command, the device104enters into the key establish state805.

In the key establish state805, the symmetric keys used for encryption and decryption can be established, for example, using the station-to-station model of ANSI X9.63 ECC public key cryptography. During this state805, the device104does not permit the user to originate or reply to messages. Upon successful transmission of RFC 41 Command 7, the device104will verify that the symmetric key has been established before moving into the secured state.

As regards error handling in the key establish state805, if the device104cannot interpret the RFC 41 command or cannot validate a command, the device104reports an “invalid command” error to the crypto server209.

In the secured state807, the device104operates in a fully secured mode. All personal messages to and from the device104are encrypted. While in this state807, new symmetric keys can be allowed to be established. If the device104cannot decode a secured message (RFC 30), the device104reports a “decode failure” error to the crypto server209. In other words, if the device104receives a message with no errors and the decrypted message is not a UAR message, the device104reports a “decode failure” error to the crypto server209. In addition, if the TID in UAR does not match, for instance, Analog Display Services Interface (ADSI) IV_offset then the device104reports a “decode failure” error. If the device104receives a secured message with an invalid or un-established key index, the device104reports an “invalid key index” error. If the device104receives a secured message that does not follow the RFC 30 format, the device104generates an “invalid format” error to the crypto server209. If the device104cannot interpret an RFC 41 or cannot validate a command, the device104will report an “invalid command” error to the crypto server209.

In each of the states801,805and807, the device104can decode and display personal and IS messages received in the alphanumeric vector. In addition, these messages, among others, are ACKed, but not displayed. Further, the GOTAP commands can be processed.

After establishment and use of the key, the system100also provides a mechanism for automatically changing the key, as detailed below in FIGS.9and10A-10B.

FIG. 9is a diagram of a process for changing of keys, according to an embodiment of the present invention. Once the symmetric keys are initialized as described earlier, all user messages between the device104and the NOC101can be transferred encrypted using the symmetric key. To provide increased security, the symmetric key are changed based on event or time. The process for changing the key is more straightforward than the key initialization process. Unlike the key initialization process, this process can be transparent to the user.

In steps901and903, the crypto server209generates an ECC key pair in response to some administrative action. The command to change keys is initiated by the crypto server209sending a message containing the Ephemeral Public key to the device104. The messages, in an exemplary embodiment. Upon receipt of the Ephemeral Public key, the device104, as in step907, generates the ECC key pair, and sends the Ephemeral Public key to the server209(step909). In step911, the server209computes the symmetric key, and sends a Confirm Ephemeral Key message to the device104, per step913. In turn, the device104, as in step915, generates the symmetric key. Lastly, the device104issues a Key Established command to the server209, per step917.

FIGS. 10A and 10Bare flowcharts of processes for automatically changing device keys, according to an embodiment of the present invention. This key change process is based on the number of messages exchanged using the established symmetric key. In step1001, the NOC101tracks the number of messages that have been encrypted by the device104utilizing a particular symmetric key. A configurable threshold value can be predetermined; for example, 5000 messages. The NOC101determines whether this message threshold has been exceeded by the device104, as in step1003. If the message threshold is exceeded, the NOC101automatically notifies the device104to change the key, per step1005.

This automatic key change can also be triggered based on time. As shown inFIG. 10B, the NOC101can set a key expiration timer, per step1011, for determining when the key should be changed. The timer can be set, for instance, for 30 days. In step1013, the NOC101checks whether the timer has expired; if not, the NOC101continues to wait (step1015). Otherwise, the NOC101, as in step1017, initiates the automatic changing of the key.

Although the processes ofFIGS. 10A and 10Bare described independently, it is contemplated that both processes can be executed concurrently, such that the key can be automatically changed whenever the number of messages is exceeded or the timer is expired, whichever occurs first.

In addition to supporting a secure mode of communication over the wireless network107, the 2-way messaging device104can be configured to with a menu structure to facilitate the ease of enabling such secure mode of operation.

FIG. 11A-11Dare diagrams of a user interface of the devices used in the system ofFIG. 1, according to an embodiment of the present invention. The menu and user interface ofFIGS. 11A-11Dcan be readily incorporated, as appropriate, into the 2-way messaging device104. The 2-way messaging device104provides an option of allowing users and/or administrators to password protect the unit. The password minimum length is a configurable option.

In one embodiment of the present invention, the secure 2-way messaging device104utilizes a timer that is set to an incorrect password timeout interval for preventing would-be thieves (or otherwise unauthorized users) from attempting repetitive password attacks. When an incorrect password is entered, the device104can “time out” for a period of time before the user can again attempt to enter the password. Each subsequent erroneous attempt will cause the timer to be doubled.

For illustrative purposes, the time out interval can be set to 5 seconds. Therefore, the first time the operator incorrectly enters a password, a wait time of 5 seconds is required before the operator can re-try. After the second unsuccessful attempt, the user will be required to wait for 10 seconds, and 20 seconds after the third attempt, and so on. This time out mechanism thus effectively deters the unauthorized user from gaining access. A suitable error message can be displayed to the user during the period of disablement.

A Preferences menu1101can include the addition of a “Security” item1103for viewing and modifying security settings for the device104. When this item1103is selected, the user can be prompted to re-enter the password per a Password menu1105. This is the device access password and is required to prevent unauthorized changes to the security settings. As the user types the password, the device104does not display the actual characters typed to prevent authorized users nearby from reading the information. If the password entered is incorrect, the device104immediately locks out the user and deposits the user at the top level entry screen and again ask for the user's password. At this point, the incorrect password timeout mechanism can be triggered to prevent access to the device104using repetitive guesses.

Once the password is entered correctly, the user can be presented with a Security Menu1107. Within the Security Menu1107, the user has the ability to enable or disable the Auto Lock mechanism, via an Auto Lock menu item1109, and to set the device access password. The Auto Lock menu item1109allows the user to control access to the device104. This particular item1109can be disabled by an internal flag that is only accessible via OTAP or a programming cable/cradle, thereby permitting security administrators to force their users to utilize the Auto Lock feature. Internally, the administrator can set the auto lock to any of the settings and not allow the user to make changes. When the Auto Lock feature is set by the administrator using the internal flag, the Auto Lock menu item1109is disabled. The device104can accordingly indicate the administrator selected action.

Within an Auto Lock menu1111, the user or administrator can select, in an exemplary embodiment, one of three options: “Never”, “On screen timeout”, or “After preset delay.” If the user selects “Never”, no password is needed to access the device104. “On screen timeout” links the password access to the normal device screen timeout. Once the device screen is blanked, the device104can be locked. In one embodiment of the present invention, the initial factory fresh state of the device104has the Auto Locked set to “Never” and the Password cleared.

The third option permits the user to select a preset delay before the pager is locked. A “Preset Delay” screen1113provides the user with the capability to select either minutes or hours—when one is selected, a scroll wheel (or other mechanism specific to the device) can scroll through the numbers. Valid numbers can be either 1-59 minutes or 1-24 hours. Once selected, the entered delay period will be displayed on the Auto Lock menu screen1111.

In accordance with one embodiment of the present invention, when locked (i.e., “auto lock state”), the device104responds to the following “outside originated” commands: “Reset” to factory fresh condition via OTAP, clearing all of the device's memory; HIX 0 (zero) via OTAP which will completely disable the unit; and “Reset” to factory fresh condition via the programming cable/cradle, clearing all of the device's memory. In the Auto Lock state, no other commands sent via the programming cable/cradle can be responded to or performed. However, the device104can still process all incoming REFLEX messages (including secure, unsecured, IS, and GOTAP) when in the locked state.

From the Security menu1107, a Password menu item1115enables the user to change the device access password. When the user selects the “Password” menu item1115, the user enters a change password screen1117that prompts the user for a new password. It is noted that a prompt for the old password is not needed, as the user gained access to the Security menu1107using the old password. The characters of the new password can be displayed to provide feedback to the user, thereby ensuring accuracy of the entry. It is assumed that the user changes passwords when the user is assured that no unauthorized person is attempting to view the passwords.

Once the password is entered, the device104re-displays the password, in a Confirmation screen1119, to confirm that the user is fully aware of the characters typed. If the new password is not what the user wanted, the user can select “Cancel” and be returned to the “Security” menu1107with the password unchanged. If the password is acceptable, the user selects “SAVE” and is returned to the “Security” menu1107with the password changed.

FIG. 12illustrates a computer system1200upon which an embodiment according to the present invention can be implemented. For example, the client and server processes for supporting fleet and asset management can be implemented using the computer system1200. The computer system1200includes a bus1201or other communication mechanism for communicating information and a processor1203coupled to the bus1201for processing information. The computer system1200also includes main memory1205, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus1201for storing information and instructions to be executed by the processor1203. Main memory1205can also be used for storing temporary variables or other intermediate information during execution of instructions by the processor1203. The computer system1200may further include a read only memory (ROM)1207or other static storage device coupled to the bus1201for storing static information and instructions for the processor1203. A storage device1209, such as a magnetic disk or optical disk, is coupled to the bus1201for persistently storing information and instructions.

The computer system1200may be coupled via the bus1201to a display1211, such as a cathode ray tube (CRT), liquid crystal display, active matrix display, or plasma display, for displaying information to a computer user. An input device1213, such as a keyboard including alphanumeric and other keys, is coupled to the bus1201for communicating information and command selections to the processor1203. Another type of user input device is a cursor control1215, such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor1203and for controlling cursor movement on the display1211.

According to one embodiment of the invention, the processes ofFIGS. 4-10are performed by the computer system1200, in response to the processor1203executing an arrangement of instructions contained in main memory1205. Such instructions can be read into main memory1205from another computer-readable medium, such as the storage device1209. Execution of the arrangement of instructions contained in main memory1205causes the processor1203to perform the process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the instructions contained in main memory1205. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the embodiment of the present invention. Thus, embodiments of the present invention are not limited to any specific combination of hardware circuitry and software.

The computer system1200also includes a communication interface1217coupled to bus1201. The communication interface1217provides a two-way data communication coupling to a network link1219connected to a local network1221. For example, the communication interface1217may be a digital subscriber line (DSL) card or modem, an integrated services digital network (ISDN) card, a cable modem, a telephone modem, or any other communication interface to provide a data communication connection to a corresponding type of communication line. As another example, communication interface1217may be a local area network (LAN) card (e.g. for Ethernet™ or an Asynchronous Transfer Model (ATM) network) to provide a data communication connection to a compatible LAN. Wireless links can also be implemented. In any such implementation, communication interface1217sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information. Further, the communication interface1217can include peripheral interface devices, such as a Universal Serial Bus (USB) interface, a PCMCIA (Personal Computer Memory Card International Association) interface, etc. Although a single communication interface1217is depicted inFIG. 12, multiple communication interfaces can also be employed.

The network link1219typically provides data communication through one or more networks to other data devices. For example, the network link1219may provide a connection through local network1221to a host computer1223, which has connectivity to a network1225(e.g. a wide area network (WAN) or the global packet data communication network now commonly referred to as the “Internet”) or to data equipment operated by a service provider. The local network1221and the network1225both use electrical, electromagnetic, or optical signals to convey information and instructions. The signals through the various networks and the signals on the network link1219and through the communication interface1217, which communicate digital data with the computer system1200, are exemplary forms of carrier waves bearing the information and instructions.

The computer system1200can send messages and receive data, including program code, through the network(s), the network link1219, and the communication interface1217. In the Internet example, a server (not shown) might transmit requested code belonging to an application program for implementing an embodiment of the present invention through the network1225, the local network1221and the communication interface1217. The processor1203may execute the transmitted code while being received and/or store the code in the storage device1209, or other non-volatile storage for later execution. In this manner, the computer system1200may obtain application code in the form of a carrier wave.

While the present invention has been described in connection with a number of embodiments and implementations, the present invention is not so limited but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.