Abstract:
The present invention provides a system and method for providing certified voice and/or multimedia mail messages in a broadband signed communication system which uses packetized digital information. Cryptography is used to authenticate a message that has been compiled from streaming voice or multimedia packets. A certificate of the originator&#39;s identity and electronic signature authenticates the message. A broadband communication system user may be provisioned for certified voice and/or multimedia mail by registering with a certified mail service provider and thereby receiving certification. The called system user&#39;s CPE electronically signs the bits in received communication packets and returns the message with an electronic signature of the called system user to the calling party, along with the system user&#39;s certificate obtained from the service provider/certifying authority during registration. The electronic signature is a cryptographic key of the called party.

Description:
RELATED APPLICATIONS 
     This application is a continuation of patent application Ser. No. 11/237,573, entitled “Broadband Certified Mail,” filed Sep. 28, 2005, and issued on Dec. 2, 2008 as U.S. Pat. No. 7,461,254, which is a continuation of patent application Ser. No. 09/544,236, entitled “Broadband Certified Mail,” filed Apr. 7, 2000, and issued on Jan. 4, 2006 as U.S. Pat. No. 6,990,581. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to communication between users in communication systems, and more particularly, to providing certified mail in a communication system including broadband communications. 
     BACKGROUND OF THE INVENTION 
     Present day telephony networks, typically have end-to-end networks built around circuit switches, end offices, a toll network, tandem switches, and twisted wires. These networks are commonly referred to as a public switched telephone network (PSTN) or plain old telephone service (POTS). Due to bandwidth limitations of plain old telephone service (POTS), there is an inherent inability to efficiently integrate multiple types of media such as telephony, data communication for personal computers (PC), and television (TV) broadcasts. Further, the type of customer services and feature/function capability that may be implemented in a PSTN is somewhat limited relative to a broadband communication system. Accordingly, new broadband architectures are developing which transmits voice, data, and multimedia (video and audio) communications using, for example, communication information packets. These communication packets may be constructed in one or more packet protocols such as Internet Protocol (IP) or Asynchronous Transfer Mode (ATM). These new architectures gives rise to a new array of user services and capabilities not previously available with PSTN. One such new service and system capability of a packet based broadband communication system is provided by the present application for certified mail. 
     Present PSTN voice mail systems do not readily provide a method that enables a caller to prove that they have left a voice mail or multimedia mail message for the called party, or for proving the content of that voice mail or multimedia mail, i.e., certified mail. Further, present PSTNs voice mail systems do not automatically include the digital representation of the message left that would enable electronic certification of a broadband communication mail message. The present PSTN infrastructure will not support certified mail. However, with the development of packet based broadband communication systems, certified voice and multimedia mail is possible to implement. Certified voice and multimedia mail represents a value to consumers as a means to enable a calling party to prove that they left a message for a called party on the called parties voice and/or multimedia mail system and establish the content of that message. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system and method for providing certified mail messages in a broadband communication system which uses packetized information. According to the invention, a broadband communication system user may be provisioned for certified voice and/or multimedia mail by registering with a certified mail service provider and thereby receiving certification including a certificate. The registration process may include the system user&#39;s broadband equipment providing a cryptographic public key to the service provider. In one variation, the system user&#39;s customer premises equipment and cryptography software will generate a private key (used to electronically sign messages) and a public key (used to verify the electronic signature) for the user. In this case, the system user controls the private key and keeps it secret. In another variation, a service provider/certifying authority may provide the system user a unique public key and private key. In either case, the service provider/certifying authority issues a digital certificate certifying authenticity of the system user&#39;s identity and public key. The certificate may include, for example, the user&#39;s name and the user&#39;s public key, and is signed with the public key of the service provider/certifying authority. Further, the Certifying Authority may choose to include other information in the certificate, such as an expiration time, and the organization that the individual belongs to. The public key of the service provider/certifying authority may be well known so the user and a caller requesting certified mail may open the certificate. For example, it could be built into the customer premises equipment (CPE) of both parties to the call. 
     Once the broadband communication system user has registered with a service provider for certified voice mail and/or multimedia mail and received the certificate, their CPE, for example a broadband telephone interface (BTI), will be capable of offering certified voice and multimedia mail to a calling party. When a caller communicates with a system user that is registered for certified mail, by for example making a call, he may be given the option of leaving regular voice or multimedia mail or certified voice or multimedia mail. If the certified mail option is active and selected, then the caller and/or the called system user&#39;s CPE keeps track of the information packets (e.g. IP voice packets) used in the call. The called system user&#39;s CPE may then digitally sign the bits in the communication packets with a cryptographic electronic signature and return the signed message to the calling party, along with the system user&#39;s certificate obtained from the service provider/certifying authority during registration. The calling party may then use its copy of the message, a copy of the message signed with the called parties electronic signature, and the certificate, to prove to anyone in possession of the service provider&#39;s public key, that he left the particular voice mail or multimedia mail message for the called party. The service provider/certifying authority may be notified and charge a fee each time the certified mail feature is utilized. Therefore, the caller can undeniably prove that the call happened and that the content of the message left was what he claims it to be. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic representation of a broadband network (e.g., broadband IP based network) in accordance with a preferred embodiment of aspects of the present invention. 
         FIG. 2  shows an information flow diagram for registration of a system user according to a preferred embodiment of the present invention. 
         FIG. 3  shows an information flow diagram of broadcasting a system user&#39;s public key according to a preferred embodiment of the present invention. 
         FIG. 4  shows an information flow diagram of certifying a voice mail message according to a preferred embodiment of the present invention. 
         FIG. 5  shows an information flow diagram of dispute resolution of a certified voice mail message according to a preferred embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certified mail according to the present invention serves purposes similar to “certified mail” offered by the United States Postal Service or any other postal service in that it provides a mechanism by which a person can prove that they had a particular communication with another person. However, the present invention extends the idea of certified mail to all types of electronic communications performed on a broadband communication system. For example, some preferred embodiments of the present invention are directed to certified voice mail and certified multimedia (video and audio) mail. 
     In general, the present invention provides a mechanism for callers to provide proof that they left a message for a particular party which that party cannot deny. The proof covers the content of the message as well as the fact that the communication was made. As packetized information traffic including, for example, voice and multimedia traffic, begins to be carried on broadband communication systems in digital form as packets, e.g., IP voice or multimedia packets, the number of services and features that can be offered increases. The present invention, referred to herein as broadband communication certified mail, is an example of such a service. Although the following preferred embodiments are directed particularly to certified voice mail, one skilled in the art will recognize that the invention is generally applicable to certifying multimedia mail including voice, video, and/or text messages communicated via a broadband communication system. 
     To achieve certified mail messages the present invention uses cryptography as a method of authenticating the identity of the recipient of the message and the contents of the message. A system user may subscribe to a service provider/certifying authority and select a public key which will be use in certifying received voice or multimedia messages. This public key and a system user&#39;s related private key may be generated using cryptography software, for example, Pretty Good Privacy (PGP) or S/MIME. Although, the invention is not limited to these particular software packages. The system user may provide the service provider/certifying authority with its public key at the time they subscribe for certified mail service. Alternatively, the service provider/certifying authority may generate and provide the user with a public key and a private key for use in the certification process. In either case, the private key is used to electronically sign any certified mail message which the system user receives and the public key is used to electronically verify the electronic signature. The system user&#39;s identification (e.g., name) and public key may be included in a certificate generated by the service provider/certifying authority which is electronically signed using the service provider/certifying authority&#39;s public key. When a certified mail message is created, an electronically signed copy of the certified mail message and a copy of the certificate are sent to the party who wishes to leave a certified mail message. The electronically signed message and the certificate may be subsequently used to undeniably prove that the party actually left the message and its contents with the person whom they claim to have left the message. 
     One preferred embodiment of a broadband communication system architecture in which the present invention may be implemented is illustrated in  FIG. 1 . Although the invention will be describe herein using the broadband communication system illustrated in  FIG. 1 , it is understood that the invention may be implemented in any number of different broadband communication systems or variations of the broadband communication system illustrated in  FIG. 1 . Some other possible broadband communication system architectures in which the present invention may be implemented include those shown in, for example, U.S. patent application Ser. No. 09/475,661 and U.S. patent application Ser. No. 09/475,294 filed Dec. 30, 1999, hereby incorporated by reference for all purposes. 
     As illustrated in  FIG. 1 , the broadband communication system may include plurality of customer premise equipment (CPE)  110  and  120  used to interface with a broadband communication system, for example, Internet/broadband network  130 . The CPEs  110  and  120  may include, for example, a cable modem (CM)  111  and  121  coupled to the Internet/Broadband Network  130  via a communication interface  115  and  125 , respectively. The communication interfaces  115  and  125  may be, for example, a coaxial cable, optical fiber, radio waves, etc, as long as it can handle broadband communications. Further, the CPEs  110  and  120  may include a personal computer (PC)  114  and  124 , a broadband telephone interface (BTI)  112  and  122 , and a telephone,  113  and  123 . The cable modem  111  (or  121 ) and the broadband telephone interface  112  (or  122 ), may be separate or integral in a single box such as a broadband residential gateway (BRG), and may further include a television interface. Likewise, the CM  111  (or  121 ) and/or BTI  112  (or  122 ) may be included in the PC  114  (or  124 ). 
     The CPE  110  and  120  may further include a means for generating cryptographic keys such as cryptography software, for example, Pretty Good Privacy (PGP). The means for generating cryptographic keys may be contained in any of the CPE  110  and  120 , for example in the PC  114  and  124  or in the BTI  112  and  122 . Further, the means for generating cryptographic key may include both hardware and software or may reside somewhere else in the broadband communication system. In any case, the cryptographic keys may include both private and public keys and will provide electronic signature and verification means for certified mail. The private key may be a first algorithm that encodes the voice mail or multimedia mail message and the public key may be a second algorithm, related to the first algorithm, that decodes the voice mail or multimedia mail message so that the original message can be recaptured from the signed message. 
     The Internet/broadband network  130  may include a plurality of cable modem termination systems (CMTS)  131  and  132  to couple to the plurality of cable modems (e.g., CMs  111  and  121 ) coupled to the broadband communication system and one or more gate controllers  133  to coordinate communication traffic throughout the broadband system. The Internet/broadband network  130  may be coupled to a PSTN  160  via a gateway (GW)  165 . Further, the broadband communication system may include a service provider/certifying authority  140  coupled to the Internet/broadband network  130  which provides the certified mail feature according to the present invention. The service provider/certifying agent  140  may include a server and appropriate software to operate the certified mail feature of the present invention, and may be located anywhere in the broadband communication system. The service provider/certifying agent  140  may include a means for placing an electronic signature on a certificate that certifies a subscriber&#39;s identity and public key, for example cryptography software such as PGP. Finally, the broadband communication system may include a judging authority  150  coupled to the Internet/broadband network  130  which may provide a forum for validating the authenticity of a certified mail message according to the present invention. The judging authority  150  may include a server and appropriate software to operate the certified mail feature of the present invention, and may be located anywhere in the broadband communication system. 
     Any broadband communication system user/subscriber who wants to provide certified voice mail or multimedia mail to callers may register or subscribe for the service with the service provider/certifying authority  140 . Referring to  FIG. 2 , in a first embodiment the system user/subscriber  205  enters into a registration process in which the user provides credentials and a cryptographic public key ( 215 ) to the service provider/certifying authority  140 . The credentials may include the users identity (e.g., name), directory number, address (geographical and/or system address (e.g. IP address)), etc., so that the service provider/certifying authority  140  may issue a certificate ( 220 ) which properly identifies the system user/subscriber  205 . As indicated in the figures, the system user/subscriber may send their credentials and public key stored on their BTI  112  or PC  114  using, for example, the PC  114  or telephone  113 , transmitted via the Internet/broadband network  130 , to the service provider/certifying authority  140 . The system user/subscriber  205  may generate, store, and control the private key and keep it secret using the CPE  110 . The service provider/certifying authority  140  issues a digital certificate  220  which may include the system user/subscriber&#39;s  205  credentials and public key, and is electronically signed by the service provider/certifying authority  140  public key. The service provider  140  may also provisions the subscribers  205  CPE  110  to enable use of the certified mail feature. This provisioning may be performed when the system user subscribers for service. For example, the service provider/certifying authority  140  may, for example, separately transmit software that enables the subscriber&#39;s CPE  110  to operate the certified voice mail and multimedia mail message feature. This software may include cryptography software. Alternatively, the certificate  220  may include a program that automatically upon receipt enables the CPE  110  to operate the certified mail feature or the service provider  140 . 
     In a further embodiment of the invention, the public key of the service provider/certifying authority  140  may be well known to other system users so that the various recipients of the certificate can open the certificate and verify its contents. For example, it could be built into the subscriber&#39;s customer premises equipment (CPE). Alternatively, the public key of the service provider/certifying authority  140  may be sent to the various system users upon request. 
     The system user/subscriber  205  then may use his CPE  110  to publish his certified mail public key issue by the service provider/certifying authority  140  so that the rest of the world, e.g., Internet/broadband network subscribers, knows his public key and can verify a certified mail message left for the system user/subscriber  205 . As illustrated in  FIG. 3 , the system user/subscriber  205  broadcasts his certified mail public key to the rest of the world ( 310 ), e.g., Internet/broadband network  130  subscribers. This broadcast may occur in advance of the creation of a certified mail message. Alternatively, the system user/subscriber  205  may transmit his public key at the time a certified mail message is sent and/or at the time they subscribe for the certified mail feature. 
     Once the broadband system user has registered with a certified mail service provider and has received his certification (and if necessary software), the system user may activate or deactivate the certified voice mail and multimedia mail message feature by, for example, entering a particular code into the telephone  113  or selecting an icon on the PC  114 . If the certified mail feature is activated then a telephone caller or a multimedia caller will be provided the option of leaving a certified mail message. One example of an embodiment illustrating the operation of certified voice mail is described below. However, one skilled in the art would understand that the an alternative embodiment of the invention directed to certified multimedia mail is easily achieved by slight modification and the details of such a procedure are thus not included herein. 
     Referring now to  FIG. 4 , the procedure for certified voice mail according to one embodiment of the invention is illustrated. First, a caller  410  places a call  401  to a callee  420  through respective CPEs (i.e., a CPE of a system user/subscriber who has registered for certified mail or who has the necessary cryptographic software) by dialing, for example, a telephone directory number or a system address. The call is carried over a broadband communication system using packetized information, for example, IP, such as the system illustrated in  FIG. 1 . The call might be placed with phone  113  to phone  123  via the respective BTIs and CMs through the Internet/broadband network  130  or via multimedia PCs  114  and  124 . Next, the callee&#39;s CPE  420  presents a menu of options to the caller  410  with a request to select an option  402 . The options may include, for example, (1) leave a message (e.g., voice mail (VM)), (2) forward to another phone (FWD), and (3) leave a certified mail message (e.g., certified voice mail (CVM)) and may be a computer generated or voice recorded message. The select option message may be retained in the callee&#39;s CPE or within a centralized system in the Internet/broadband network  130 . In any case, if the caller  410  chooses to leave a certified mail message by entering an appropriate response, e.g., selecting 3, his CPE sends a response indicating a selection of certified voice mail  403  to the callee&#39;s CPE  420  via the broadband communication system. 
     Then, the callee&#39;s CPE  420  indicates to go ahead by sending the caller  410  a prompt to begin  404 , e.g., sending a beep sound. The caller  410  may then leave a voice message  405 . The voice message, being transmitted in a packet based (e.g., IP) broadband communication system, will be digitized and packetized by the caller&#39;s CPE and sent to the callee  420  over, for example, Internet/broadband network  130 . In one alternative, the caller&#39;s  410  CPE may retain a copy of the message packets being transmitted and recorded as a certified mail message. Next, the callee&#39;s CPE  420  receives the stream of digitized and packetized voice message packets (i.e., digital voice data) as the caller  420  leaves a voice message  405 . Then the callee&#39;s CPE  420  may package the related message packets together so as to return them to the caller  420  as part of a return certified voice message  406 . In one preferred embodiment, the related message packets may be combined and all headers removed so only voice message information data is left. Alternatively, each of the message packets may be electronically signed and sent to the caller&#39;s  410  CPE  110 . 
     In any case, without converting the voice mail message contents to analog, the combined message packets may then be electronically signed using the callee&#39;s  420  private key, designated herein as {M} Pv key . The signed message {M} Pv key  is returned to the caller  410 , along with the certificate  220  from the service provider/certifying authority  140 , as returned certified voice message  406 . The signed message {M} Pv key  and certificate  220  may be saved to memory in the caller&#39;s CPE  410  or may be transmitted to a central network service center for storage until needed if a dispute over whether the message was ever left with the callee  420  ever arises. Subsequently, the caller  410  may verify the certification  407  of the certificate  220 . 
     To verify the certification the caller  410  would open the certificate  220  using the service provider/certifying authority&#39;s  140  public key and confirm that the callee&#39;s  420  credentials stored therein are correct and a public key for the callee  420  was included. Further, the caller  410  would verify the electronic signature of the coded message received by opening the message with the callee&#39;s  420  public key. If the resultant message matches the original message left for the callee  420 , then the verification is complete and the caller  410  has successfully left a certified mail message for callee  420 . Therefore, the caller  410  will have verified the certification from the service provider/certifying authority  140  and the callee&#39;s  420  signature on the message  408 . 
     In another preferred embodiment, the service provider/certifying authority  140  may be notified by, for example a message from the callee&#39;s  420  CPE  110 , and the service provider/certifying authority  140  may charge the callee  420  a fee. This fee for service may occur each time the certified mail feature is utilized, or there could be a subscription for service. 
     In one variation of the invention, the system may facilitate certified voice mail for a voice mail message left by a caller using an off network telephone, for example a POTS telephone or a cell phone originating from, for example, the PSTN  160 . In this case, since the caller will not integrally connected with their own PC  114  or BTI  112  at their customer premises, the system will be constructed and operate so that the signed message packet and certificate are stored at a location which may be designated by the caller. For example, the caller may choose to store the signed message packet(s) and certificate transmitted by the callee&#39;s  420  CPE  120  at their own CPE  110 , the service provider/certifying agent  140 , at the judging authority  150 , or at some other party location on or off the network. The system may automatically determine that the call is originating from an off network telephone by determining that packets are originating from a bridging gateway (GW)  165  and prompt the caller to enter their desired certified mail storage destination by entering, for example, a system name or address, or selecting from a menu of choices. The caller can enter the destination information by, for example, pressing the keypad on a POTS telephone or cell phone or by responding verbally and having a voice recognition system determine the caller&#39;s response. As long as the callee  420  is on a packet based network such as an IP network, at the gateway  165  from the PSTN  160  to the Internet/broadband network, the call will be digitized and packetized. When the voice packets reach the callee&#39;s  420  CPE  120 , the callee&#39;s  420  CPE  120  may sign the digital voice data packets the same way as describe in the above embodiments. The difference in this embodiment is that the signed certified message packet(s) and certificate  220  must now reach an alternative destination, not the gateway  165 , such as the caller&#39;s CPE  120 , because the off network communication device, for example a telephone, is not equipped to verify and store the certified mail information. Therefore, by the caller entering, for example, a code into the off network telephone indicating the alternative certified mail storage location, for example their BTI  112 , the callee&#39;s  420  CPE  120  can send the signed message packet(s) and certificate  220  to the selected location after the call and message is completed. The callee&#39;s  420  CPE  120  could also use caller ID information to route the signed data to a known or predetermined destination previously entered into the system, thus eliminating the requirement that the user enter a code at the time a certified mail message is created. 
     If there is ever a dispute as to whether the caller  410  left the callee  420  a particular voice mail message, the caller may a dispute resolution process by submitting the certified voice mail message {M} Pv key  and certificate to a judging authority  150  so that message authentication and content can be verified. Referring to  FIG. 5 , the certified mail message dispute resolution process begins with the caller  410  sending a complaint  501  including the signed message {M} Pv key  and certificate  220  from received from the callee  420  to a judging authority  150 . This information may be transmitted to the judging authority  150  via the Internet/broadband network  130 . The judging authority  150  may then send a public key query  502  to the service provider/certifying authority  140 , asking for its public key. Next, the service provider/certifying authority  140  sends its public key  503  to the judging authority  150 . However, if the judging authority  150  is a subscriber of the service provider/certifying authority  140 , it may already have the service provider/certifying authority&#39;s  140  public key. In either case, then, the judging authority verifies (step  504 ) the certificate  220  by opening the certificate using the service provider/certifying authority&#39;s  140  public key  503 . Then, the judging authority  150  verifies the signed message {M} Pv key  by recovering the original message from the encoded message using the callee&#39;s  420  public key included in the certificate  220  (step  505 ). Next, the judging authority  150  issues his ruling based on the success or failure of the verification. If the digital representation of the decoded message matches the digital representation of the original message, than the judging authority  150  verifies the authenticity of the message and the identity of the recipient. The judging authority  150  may uses the same signing and verification software used by the caller  410  and the callee  420 . 
     Although particular embodiments of the present invention have been shown and described, it will be understood that it is not intended to limit the invention to the preferred embodiments and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Thus, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention as defined by the claims. For example, the present invention is applicable to any broadband communication system in which cryptography may be used to establish authentication and certification of mail messages transmitted in digital packet formats, such as asynchronous transfer mode (ATM) or Internet Protocol (IP) based broadband communication systems. Further, the present invention may be used to certify all types of electronic mail including voice, text, and multimedia. In addition, the certified mail feature of the present invention may be implemented using software and/or hardware located anywhere within a broadband communication system, for example, in customer premises equipment (CPU) such as a PC, BTI, or BRG, in a service provider/certifying authority server, in a judging authority server, or in a central services server located anywhere within the broadband communication system. 
     All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.