Abstract:
A system and method for detecting and selectively preventing the forwarding of an electronic message, wherein the message is sent by a sender to a recipient, and wherein the message has a message body and a message header. The system comprises a wireless gateway in communication with an electronic mail client; a message database in communication with the gateway for storing a first message identifier associated with the electronic message; and a search module in communication with the message database for determining whether a second message identifier associated with a forwarded electronic message is contained in the message database and, if the message database contains the second message identifier, preventing forwarding of the forwarded message.

Description:
BACKGROUND OF THE INVENTION 
   Email continues to be the fastest growing communication medium for businesses. Using email to transmit sensitive information, however, poses many security issues. Consequently, many business have resorted to perimeter defenses such as firewalls, virtual private networks (VPNs), and intrusion detection systems (IDSs). While these defenses help keep out individuals with malicious intentions, they do not address an obvious security vulnerability: the loss of information through unauthorized forwarding of email. 
   Accordingly, a system and method is needed to selectively prevent forwarding of email communications. The architecture should provide sufficient flexibility to accommodate a variety of email clients and should not require any plugins or other client software installations. Additionally, the solution should be easily deployed in large-scale environments. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a system and method for detecting and selectively preventing the forwarding of an electronic message, wherein the message is sent by a sender to a recipient, and wherein the message has a message body and a message header. The system comprises a wireless gateway in communication with the client; a message database in communication with the gateway for storing a first message identifier associated with the electronic message; and a search module in communication with the message database for determining whether a second message identifier associated with a forwarded electronic message is contained in the message database and, if the message database contains the second message identifier, preventing forwarding of the forwarded message. 

   
     DESCRIPTION OF THE FIGURES 
     For the present invention to be understood clearly and readily practiced, the present invention will be described in conjunction with the following figures, wherein: 
       FIG. 1  is a simplified block diagram of an exemplary environment for operation of one embodiment of the present invention; 
       FIG. 2  is a simplified block diagram of an exemplary environment for operation of one embodiment of the present invention; 
       FIG. 3  is a diagram illustrating a message window displayed by an exemplary electronic mail system; and 
       FIG. 4  is a flow diagram of a process to prevent unauthorized forwarding of email messages according to one embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention while eliminating, for purposes of clarity, other elements. For example, certain network details and modules of certain messaging platforms are not described herein. Those of ordinary skill in the art will recognize, however, that these and other elements may be desirable in a typical communications network. A discussion of such elements is not provided because such elements are well known in the art and because they do not facilitate a better understanding of the present invention. 
   The present invention relates to an interactive wireless communications system in which a sender of an electronic mail message can limit, or even prevent, recipients of that message from forwarding the message to other mail clients. The present invention employs a specially configured gateway to control distribution of email among all applications and devices that communicate with the gateway. 
     FIG. 1  is a simplified schematic diagram of a system  10 , according to one embodiment of the present invention. The system  10  includes a wireless device  110 , a mobile switching center (MSC)  113 , a wireless gateway  115 , an intermediate network  128  (such as the Internet), a foreign network  116 , a foreign mail server  108 , and a foreign client  112 . Wireless device  110  may be any wireless digital processor capable of accessing the Internet such as, for example, a mobile telephone, a personal digital assistant, or a pager such as those sold by Research in Motion (RIM) Inc. 
   Mobile switching center  113  may comprise anyone of a number of known communications switching devices, including those commonly used and known in the art for providing either digital or analog cellular telephone service to a plurality of wireless devices  110 . The mobile switching center  113  performs switching functions to permit communication between the intermediate network  128  and the wireless device  110 . Although only one mobile switching center  113  is shown, it will be understood that system  10  likely includes many more. 
   The wireless gateway  115  refers to a software infrastructure that connects the wireless domain (i.e. wireless device  110  and MSC  113 ) with the intermediate network  128 . Each network in  FIG. 1  may be running a different protocol. Message transfer among users that communicate with different protocols typically must be routed through a network gateway processor that transforms the message from the foreign protocol to the native protocol. Thus, gateways that are used for message transfer among interconnected networks, such as over what is commonly referred to as the “Internet,” accept e-mail messages from other gateways and from connected networks. 
   In that regard, wireless gateway  115  carries out protocol conversions between WAP communication protocols and the Internet communication protocols (e.g. HTTP, TCP/IP). The underlying protocol for packaging and decoding messages sent by wireless device  110  and received by gateway  115  is Simple Mail Transport Protocol (SMTP). The gateway  115  also performs content encoding, such as encoding of WML into binary format and compilation of WMLScripts. Gateway  115  may reside within the wireless carrier&#39;s network but may also reside within a corporate business environment. 
     FIG. 2  shows a more detailed schematic of a wireless network  100 , and especially gateway  115 , according to one embodiment of the present invention. Network  100  includes wireless device  110 , MSC  113 , Nrouters  30  and  32 , protocol handlers  40  and  42 , a user database  50 , a message store  52 , and an Internet mail router  60 . Wireless network  100  may use, for example, Mobitex® technology of the Cingular Interactive Intelligent Wireless Network service provided by Cingular Wireless. The Mobitex® network is a two-way wireless data service that can be connected with other complimentary networks. A wireless data service such as the Mobitex® network includes a hierarchy of communications systems that can provide nationwide wireless service through a network of base stations and local switches under the control of higher order regional switches or exchanges. 
   The components of gateway  115  may be connected over an internal network  102 ,  104 , and  106 , which may be a local area network (LAN). One or more wireless network exchanges such as Mobitex® regional switches  111  and  113 , which may reside at separate locations, communicate with gateway  115  through Nrouters  30  and  32 . The communication between regional switch  113  and the Nrouters may use, for example, an X.25 protocol. Nrouters  30  and  32 , in turn, communicate with protocol handlers  40  and  42  over internal network  102  using, for example, X-sockets. 
   Protocol handlers  40 ,  42  use data from user database machine  50  to communicate externally to gateway  115  via network  106 . An Internet mail router  60  is connected to internal network  106  and handles inbound and outbound communications traffic with an external network such as the Internet  128 , as well as X-sockets traffic. If necessary, a separate X-sockets machine and backup machine (not shown) can be added. 
   Protocol handlers  40  and  42  process information contained in user database machines, such as user database  50 . Additionally, each protocol handler maintains a database cache, i.e., a small, fast memory holding recently accessed data, to speed up internal network communications and to limit database access requests over the LAN. The protocols handled by protocol handlers  40 ,  42  specify that message storage and internal email access may be handled by the UNIX standard Network File System (NFS) distributed file system from SUNSOFT, which allows data to be shared across the network regardless of the protocol. 
   Message store  52  is responsible for, among other things, delivering a mail message to a recipient or receiving a mail message from a sender. Thus, message store  52  may contain various routing and delivery program modules necessary to ensure that a mail message is either delivered to a recipient, or forwarded to other components for delivery to a recipient. 
   According to an embodiment of the present invention, message store  52  includes a module to control mail messages sent from wireless network  104 . Such a module may be implemented using hardware or software. Those skilled in the art will appreciate, however, that the process described below may be implemented at any level, ranging from hardware to application software and in any appropriate physical location. For example, the module may be implemented as software code to be executed by the message store  52  using any suitable computer language such as, for example, microcode, and may be stored in, for example, an electrically erasable programmable read only memory (EEPROM). According to another embodiment, the module may be implemented as software code to be executed using any suitable computer language such as, for example, Java, Perl, C or C++ using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer readable medium, such as random access memory (RAM), read only memory (ROM), a magnetic medium such as a hard-drive or a floppy disk, or an optical medium such as CD-ROM. The module may also be a computer, such as a workstation or a personal computer, a microprocessor, a network server, a Java virtual machine, or an application specific integrated circuit, using any suitable type of computer instruction. 
   In many instances, mail messages and other information that are routed through wireless network  100  may be thought of as a collection of properties. If each mail message is conceptually thought of as a collection of various properties, then the properties may be stored and manipulated. For example, message store  52  may comprise means for storing information so that it can be retrieved later. In one embodiment, message store  52  comprises a database engine that will take properties and store them. Such an approach may be highly useful, for example, for storing either temporarily or on a more permanent basis various mail and other information. 
   Message store  52  may include a database, in the traditional sense of the word, or may be simply locations either in memory or on a mass storage device where information is stored until it needs to be retrieved. According to an embodiment, one or more program modules in message store  52  act as a data store manager that provides an interface to the storage medium. A component wishing to store information in message store  52  would submit the information to the appropriate program module and the program module would save the information to the storage medium. Information may be retrieved in a similar manner. According to an embodiment, such a data store program module is adapted to store message identifiers. 
   According to one embodiment of the present invention, gateway  115  can implement a set of policies to prevent unauthorized forwarding of email messages that pass through gateway  115 . For example, users can establish a default policy that is applied to email messages. Alternatively, users could request that certain policies be applied on a per-message basis. Additionally, these policies could be changed at gateway  115  even after a message has been delivered. By implementing the present invention at gateway  115 , the non-forwarding feature is completely transparent to users and requires no special plug-ins or other software to be deployed on individual client devices. Additionally, these features may be entirely user-initiated and user-controlled. 
   According to one embodiment, users can specify policies on a per-message basis by embedding keywords or commands in the body of the messages. These commands may generate mail headers that, in turn, instruct gateway  115  to control distribution of the associated message. According to such an embodiment, the keywords may be implemented as dot commands. Dot commands take the form of a line beginning with a period, followed by one or more letters. Where the message can be placed in the body of the text message itself, it may be recognized by any interactive wireless system protocol. The text message and related commands may be created and specified, e.g., using any Internet-compatible email service such as Microsoft Outlook. 
     FIG. 3  illustrates an embodiment of a user interface  150  with which users can activate the non-forwarding feature. User interface  150  includes a new message window  12  and a message options window  14  according to an embodiment of the present invention. New message window  12  allows a user to compose a new message  16  in a conventional manner. Options window  14  allows a sender to provide certain instructions to the system  10  in connection with the delivery of the message composed in message window  12 . To display the options window  14 , the sender typically selects Options (not shown) from a View menu  20 . The new message window  12  and options window  14  represent Microsoft Outlook 2000® windows for illustration purposes. Those skilled in the art will recognize, however, that these examples do not limit the invention to a particular electronic mail system, but that the invention is applicable to any electronic mail system. 
   According to such an embodiment, the sender may block forwarding of the message  16  by selecting a “do not forward” option  22 . According to such an embodiment, the sender may activate the “do not forward” option under, for example, the voting and tracking options section of message options window  14 . The “do not forward” option  22  must be checked before the message is sent to activate the anti-forwarding functionality. Once activated, recipients of message  16  will be permitted to read message  16  but not forward it through gateway  115 . According to another embodiment, certain controls necessary to activate the present invention could be located in the user&#39;s email toolbar. 
   According to one embodiment of the present invention, gateway  115  consults a database of blacklisted message identifiers to determine whether the sender had requested the non-forwarding feature. In other words, gateway  115  could be configured to look up the message identifier of a forwarded email message, and reject the forwarded message if the blacklist database indicates that the message identifier has an active non-forwarding option. According to such an embodiment, a message identifier may be, for example, an identification string derived from the SMTP header of the message itself that uniquely identifies the message. 
     FIG. 4  is a simplified flow diagram that illustrates a process  200  for controlling the distribution of electronic mail according to an embodiment of the present invention.  FIG. 4  is entered at step  210 , and in step  212 , a wireless subscriber (hereafter “the sender”) uses wireless device  110  to compose and transmit an electronic message  16  in a conventional manner. Message  16  is sent from the wireless device  110  to gateway  115  using wireless session protocols, essentially a binary version of HTTP. In step  214 , gateway  115  determines whether the sender has requested that message  16  not be forwarded. If so, in step  216 , gateway  115  stores the message identifier associated with message  16  in a storage medium  218 . Message  16  then works its way through system  10 , as shown in  FIG. 1 , in a manner well know to those skilled in the art until it reaches client device  112  of the addressee or message recipient in step  220 . 
   If the recipient forwards message  16  to a third party in step  222 , gateway  115  will interrupt the process and read the message identifier associated with message  16  and, in step  224 , search storage medium  218  for a matching entry. If, in step  226 , message  16  has an active non-forwarding request (i.e., gateway  115  finds a matching entry in storage medium  218 ), gateway  115  blocks forwarding of message  16  in step  228  and, optionally, notifies the sender of the forwarded message in step  230  before proceeding to an end in step  232 . If no matching entry is found in storage medium  218 , gateway  115  routes message  16  in a conventional manner in step  234 . 
   The present invention has been described with reference to the SMTP mail protocol and the wireless application protocol (WAP) standards as a basis for transmitting electronic mail from a wireless device. It will be recognized, however, that these standards are used by way of example only, and that the concepts utilized here are equally applicable in other environments that do not operate in accordance with these particular standards. 
   It should also be understood that the invention is not limited by the foregoing description, but embraces all such alterations, modifications, and variations in accordance with the spirit and scope of the appended claims.