Abstract:
An Instant Messaging security system that encrypts Instant Messages sent by a Instant Messaging user to an Instant Messaging server by intercepting the messages, negotiating a preferred security algorithm and forwarding the encrypted messages to the server. The security system intercepts and decrypts encrypted messages sent by the server to the user. The security system is able to determine whether a receiving user is equipped with a similar security system without prior knowledge of network addresses, configuration or capability. The security system is transparent to the Instant Message service provider and may provide one or more indicators to users that messages are encrypted during forwarding.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 10/890,394, filed Jul. 12, 2004, now issued as U.S. Pat. No. 8,117,273, which application in turn claims the benefit of U.S. Provisional Patent Application Ser. No. 60/486,873, filed Jul. 11, 2003, each of which is fully incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Generally, the present invention relates to Internet Communications. More specifically, the present invention relates to Instant Messaging systems and secured communications for Instant Messaging systems. 
     2. Description of the Related Art 
     Instant Messaging (“IM”) services provide communications between computer users connected to the Internet. Typically an IM service provider, such as AOL receives a message from a first user and forwards the message to a second user. The first user need not be aware of the location or network address of the second user. Similarly, the second user can respond with a message to the first user, having no knowledge of the location of the first user. The user data contained in the IM messages is encoded within a protocol proprietary to the service provider. 
     IM services are generally Internet-based services and IM messages pass through the Internet, even if the first and second users are physically located within the same building of corporation. Although the users could be sitting next to each other, IM traffic is nevertheless transmitted from the first user over the Internet to the service provider and thence relayed to the second user. Therefore, the security of IM messages depends on the minimal security provided by the Internet. 
     Therefore, what is needed is a system for securing IM traffic as it passes through the Internet. 
     SUMMARY OF THE INVENTION 
     The present invention addresses weaknesses in IM security by providing an IM security system for managing and securing Instant Messaging in an enterprise network. Embodiments of the invention include server software that is deployed near the perimeter of the enterprise network. The server software may also be deployed at a service provider if the connection between the enterprise network and the service provider is secure. The server software monitors and intercepts outbound IM traffic and may secure the content of the IM outbound traffic by, for example, encrypting the IM content. The server software also monitors and intercepts inbound IM traffic and may reverse any security process performed on the content by, for example, decrypting the IM content. 
     The present invention operates independently of IM servers and clients and requires no modifications to either the IM client or the IM server. The IM security system selectively modifies IM content in real-time on a communication channel without the knowledge or consent of the service provider or the transmitting and receiving parties. The ability to selectively modify only the user content without modifying the communications protocol control data ensures that the actions of the IM security system are transparent to the service provider. 
     The IM security system secures IM content after determining whether the destination network is capable of receiving secured IM messages. For example, where two users are collocated on an enterprise network protected by an IM security device, an IM message sent by one user to the second user passes through the IM security device located near the perimeter of the enterprise network. When the IM message is forwarded to an IM service provider and thence forwarded to the second user, it will necessarily pass through the same IM security device. Hence, in the example, the IM content can be secured by the IM security system because both users are protected by an IM security device. IM messages can also be secured in examples where the IM message exits and reenters the enterprise network through different IM security devices or where the IM message originates and terminates on different enterprise networks and the different enterprise networks are each protected by an IM security device. 
     Embodiments of the present invention may discover peer IM entities without prior knowledge of network addresses or location of the peer entities. The peer IM entities may be discovered using a discovery protocol that causes a discovery message to be sent to a receiving IM end-user. When the receiving end-user is connected to a network protected by an IM peer security device, the message may be intercepted by the receiving peer security device and the receiving peer security device responds to the sending peer IM entity indicating that a secured connection is possible. If the end-user is unprotected, the discovery message may be displayed by the IM end-user software. In some embodiments however, the discovery message is sent using one or more covert communication channels that cause the IM end-user software to ignore the discovery message. 
     Embodiments of the present invention may secure communications between IM users without knowing the physical location or network addresses of the IM users. The IM peer entities may use IM messages to exchange security set up information between the IM peer entities. The security set up information may include encryption keys. 
     The present invention includes methods to direct all IM traffic in a network to pass through an embodiment of the invention. In some embodiments, the IM traffic may be directed to an IM security server by modifying the Domain Name Server (DNS) entry for all IM traffic to the address of the IM security server. IM traffic may also be redirected by providing the IM end-user software with the IM security server&#39;s IP address to serve as the address of the end-user&#39;s IM service provider. 
     Embodiments of the invention may also redirect IM traffic using networking equipment such as routers bridges and switches. IM traffic directed toward an IM service provider may be diverted to an IM security server and thence to the IM service provider. By way of example, an IM security server may be inserted directly between the Internet and the enterprise network such that all traffic from the enterprise network must pass through the IM security software. 
     Embodiments of the invention may provide IM users with visible notification indicating that IM messages are either secured or not secured. This aspect of the invention permits end-users to determine the type and sensitivity of information that can be communicated during an IM “conversation.” This aspect of the invention requires no modification to IM client or IM server protocols. In some embodiments the visible notification of security is made by a combination of indicators including appending visible characters to IM content, changing IM text color, modifying buddy icons and adding tags to buddy names. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures, wherein: 
         FIG. 1  illustrates a network configured to incorporate an exemplary embodiment of the invention; 
         FIG. 2  is a chart showing the protocols associated with the exemplary embodiment of the invention; 
         FIG. 3  is a drawing illustrating the method by which IM messages are captured in an exemplary embodiment of the invention; and 
         FIGS. 4-9  are diagrams of the contents of communications packets exchanged in the exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described in detail with reference to the drawings, which are provided as illustrative examples of the invention so as to enable those skilled in the art to practice the invention. Notably, the figures and examples below are not meant to limit the scope of the present invention. Where certain elements of the present invention can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present invention will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the invention. Further, the present invention encompasses present and future known equivalents to the components referred to herein by way of illustration. 
     The exemplary network shown in  FIG. 1  illustrates the operation of an embodiment of the invention. A first computer  142  is connected through a first enterprise network  14  and a first IM security device  140  to the Internet  12 . A second computer  162  is connected through a second enterprise network  16  and a second IM security device  160  to the Internet  12 . An IM service provider  10  is also connected to the Internet  12 . In the example, a first user may send a first IM message from the first computer  142  for delivery to a second user who is logged in at the second computer  162 . The first IM message may be intercepted by the first IM security device  140  which discovers that the destination computer  162  is protected by the second IM security device  160 . The first IM security device  140  may then exchange security information with the second IM security device  160 , where the security information may include identity information, a random unique value (hereinafter “NONCE”), key identifier, key data and authentication information. 
     Having exchanged security information with the second IM security device  160 , the first IM security device  140  may encrypt the content of the first IM message and then transmit the encrypted first message to the IM service provider  10 . The IM service provider  10  forwards the first IM message through the Internet  12  to the second enterprise network  16  where it is intercepted by the second IM security device  160 . The second IM security device  160  decrypts the content of the first IM message and sends the message onward to the second user at the second computer  162 . Thereafter, other messages may be exchanged by the users in this manner. In some embodiments, the exchanged security information may be used to encrypt and decrypt subsequent IM messages transmitted between the first and second computers. 
     Considering now  FIG. 2  together with  FIG. 1 , the protocols used to negotiate security between the IM security devices according to the present invention may be understood. Before security can be added to IM messages, the security devices may execute a discovery protocol  20  to identify the existence and capabilities of other IM security devices visible on the Internet  12 . The first IM security device  140 , hereinafter the “Initiator,” sends a discovery message  200  to indicate the key management capabilities of the Initiator  140 . The discovery message  200  indicates to the second security device  160 , hereinafter the “Responder,” that the Initiator  140  is capable of the Instera Key Management protocol. The Responder  160  sends the Initiator  140  a response  202  that includes the Responder&#39;s  160  identifying information (“ID r ”) and a random unique value (“NONCE r ).” The Initiator  140  then transmits a response  204  including a random unique value NONCE i , the initiator&#39;s  140  identifying information (“ID i ”), a copy of the NONCE r , key identifier (“KEYID”), the initiator&#39;s  140  key data (“KEY i ”), and the initiator&#39;s  140  authentication information (“AUTH i ”), where the RUTH; may include an RSA signature. The responder then replies  206  with the NONCE i , the KEY i , and the Responder&#39;s  160  authentication information (“AUTH r ”), where AUTH r  may include an RSA signature. Thus, in the exemplary embodiment, the Initiator  140  and Responder  160  may establish basic security identification to enable the exchange of one or more secured IM messages. 
     It will be apparent, to one skilled in the art, that the exchange of identifying information may also include information specifying preferred security algorithms, alternatives (such as AES128). It will also be apparent to those skilled in the art that identifying information includes public key certificates and information necessary to validate and identify the certificate and that the key data may include a Diffie-Hellman public key such as the Diffie-Hellman Group 2 Key Exchange. Information may be exchanged with base64 encoded data that is line limited to ensure traversal through an IM server. 
     In some embodiments, the Initiator  140  may request Key information from the Responder  160  to permit the encryption of messages. In the exemplary case, and where both the Initiator  140  and the Responder  160  have a master key, a master key protocol  22  will be followed. The Initiator  140  sends a discovery message  220  to the Responder  160 . The Responder  160  sends the Initiator  140  a response  222  containing the Responder&#39;s  160  ID r  and NONCE r . The Initiator  140  sends a Key information request (“KEYID_REQ”) message  224  to the Responder  160 . The Responder  160  sends a response  226  containing Key information necessary to initiate the secured IM message exchange. 
     In the case that the Initiator  140  has a master key and requests Key information from the Responder  160 , but the Responder  160  does not have a master key, then the sequence of packet exchange will be as shown at  24 . The Initiator  140  sends a discovery message  240  to the Responder  160 . The Responder  160  sends the Initiator  140  a response  242  containing the Responder&#39;s  160  ID r  and NONCE r . The Initiator  140  sends a KEYID_REQ message  244  to the Responder  160 . The Responder  160  sends the Initiator  140  a response  246  containing an Error message. The Initiator  140  sends a message  248  the NONCE i , the ID i , a copy of the NONCE r , the KEYID, the KEY i  and the Initiator&#39;s  140  security signature (“SIGNATURE i ”). The Responder  160  sends a response message  249  containing the NONCE i , the KEYID, the KEY r  and the Responder&#39;s  140  security signature (“SIGNATURE r ”). 
       FIGS. 4-9  show the structure and contents of the packets used to negotiate security between the IM security devices.  FIG. 4  shows the Identification message  202 ,  222  and  242 .  FIG. 5  shows the Identification and Key message  204 .  FIG. 6  shows the Key data message  206 .  FIG. 7  shows the KEYID_REQ message  224  and  244 .  FIG. 8  shows the KEYID_RES message  226 .  FIG. 9  shows the Key Management Error message  246 . 
     Certain embodiments of the invention may use services provided by a selected Instant Message service provider (such as AOL) that publish IM user capabilities to assist in the identification of end-users and facilitate the exchange of security-related information. In other embodiments, the IM protocol may be adapted to provide capabilities including user identification and security key management. 
     It will be appreciated by one skilled in the art that private keys associated with, for example, the Diffie-Hellman public key may be used to generate a session key for message encryption and decryption and for digesting verification of the encrypted data. 
     Referring now to  FIG. 3 , the method by which embodiments of the present invention control IM messaging from an enterprise network  30  may be understood. Generally, connections to the Internet may be controlled by one or more networking devices  300  including routers and switches. In the exemplary embodiment of the invention, the IM security device  302  may act as a filter for IM messages. IM messages are directed to an address on the Internet  12  corresponding to the IM server  10 . The address is known or may be discoverable to a client PC  304  and the client PC  304  directs IM messages to the address. The IM security device captures the messages by capturing enterprise network  30  traffic directed to or from the address of the IM service provider. 
     Network-attached devices including the client PC  304  may resolve network addresses using one or more DNS servers  309 . The one or more DNS servers  309  provide information that permits the client PC  304  to forward IM messages through a network device  300  to the Internet  12 . In embodiments of the invention, the one or more DNS servers  309  are adapted to direct all IM traffic to the IM security device  302 . The DNS servers may accomplish redirection by providing alternative address information when, for example, the client PC logs in to the IM service. The network device  300  may be programmed to block IM traffic or to redirect IM traffic directly to the IM security device  302 . 
     In some embodiments of the invention IM traffic is captured by blocking IP addresses related to known IM servers  10  and redirecting the traffic to the IM security device  302 . To achieve this goal, the one or more network devices  300  are reprogrammed to recognize the IP addresses related to the IM servers  10 . 
     Although the present invention has been particularly described with reference to embodiments thereof, it should be readily apparent to those of ordinary skill in the art that various changes, modifications and substitutes are intended within the form and details thereof, without departing from the spirit and scope of the invention. Accordingly, it will be appreciated that in numerous instances some features of the invention will be employed without a corresponding use of other features. Further, those skilled in the art will understand that variations can be made in the number and arrangement of components illustrated in the above figures. It is intended that the scope of the appended claims include such changes and modifications.