Patent Publication Number: US-8526916-B2

Title: Method and system for multimedia tags

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/605,111, filed on Oct. 23, 2009, which is a continuation of U.S. application Ser. No. 10/504,410, filed Jan. 7, 2005, which is a National Stage of International Application No. PCT/2003/002683, filed Feb. 13, 2003, and a continuation-in-part of U.S. application Ser. No. 10/073,200, filed on Feb. 13, 2002, entitled “Short-Range Wireless System and Method for Multimedia Tags”; which are incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The invention disclosed broadly relates to ubiquitous computing and more particularly relates to improvements in wireless technology. 
     BACKGROUND OF THE INVENTION 
     Short-Range Wireless Systems 
     Short-range wireless systems have a typical range of one hundred meters or less. They often combine with systems wired to the Internet to provide communication over long distances. The category of short-range wireless systems includes wireless personal area networks (PANs) and wireless local area networks (LANs). They have the common feature of operating in unlicensed portions of the radio spectrum, usually either in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band or the 5 GHz Unlicensed-National Information Infrastructure (U-NII) band. Wireless personal area networks use low cost, low power wireless devices that have a typical range of ten meters. The best-known example of wireless personal area network technology is the Bluetooth Standard, which operates in the 2.4 GHz ISM band. It provides a peak air link speed of one Mbps and a power consumption low enough for use in personal, portable electronics such as PDAs and mobile phones. Wireless local area networks (LANs) generally operate at higher peak speeds of between 10 to 100 Mbps and have a longer range, which requires greater power consumption. Wireless local area networks are typically used as wireless links from portable laptop computers to a wired LAN, via an access point (AP). Examples of wireless local area network technology include the IEEE 802.11 Wireless LAN Standard and the HIPERLAN Standard, which operates in the 5 GHz band. 
     The Bluetooth Short-Range Wireless Technology 
     Bluetooth is a short-range radio network, originally intended as a cable replacement. It can be used to create networks of up to eight devices operating together. The Bluetooth Special Interest Group,  Specification of the Bluetooth System , Volumes 1 and 2, Core and Profiles: Version 1.1, Feb. 22, 2001, describes the principles of Bluetooth device operation and communication protocols. The devices operate in the 2.4 GHz radio band reserved for general use by Industrial, Scientific, and Medical (ISM) applications. Bluetooth devices are designed to find other Bluetooth devices within their ten-meter radio communications range and to discover what services they offer, using a service discovery protocol (SDP). 
     The SDP searching function relies on links being established between the requesting Bluetooth device, such as a stationary access point device, and the responding Bluetooth device, such as a mobile user&#39;s device. When the mobile user&#39;s device enters within communicating range of the access point, its Link Controller layer in its transport protocol group handles the exchange of inquiry and paging packets to establish the initial link with the access point device. Then the Logical Link Control and Adaptation Protocol (L2CAP) layer in the transport protocol group passes the link status up to the layers in the middleware protocol group. The SDP searching function in the middleware protocol group can then be used to find out about application programs in the responding Bluetooth device that may provide desired services. 
     Bluetooth usage models are formally specified in application profiles set forth in the  Specification of the Bluetooth System , referred to above. There are 13 application profiles described in Version 1.1 of the specification, including the Generic Access Profile (GAP), Service Discovery Profile (SDP), Generic Object Exchange Profile (GOEP), and Object Push Profile. The Generic Access Profile (GAP) defines how two Bluetooth units discover and establish a connection with each other. The service discovery protocol (SDP) defines the investigation of services available to a Bluetooth unit from other units. Generic Object Exchange Profile (GOEP) describes defines the set of protocols and procedures used by applications in handling object exchanges, e.g. File Transfer Synchronization using the Object Exchange (OBEX) Standard. The OBEX Standard is specified by the Infrared Data Association (IrDA), Object Exchange Protocol, Version 1.2. The OBEX Standard was adopted by Bluetooth as a session-oriented protocol, which allows multiple request/response exchanges in one session as a binary HTTP protocol. The Bluetooth Object Push Profile specification discusses the application of exchanging virtual business cards using the OBEX Standard. 
     The IEEE 802.11 Wireless LAN Standard 
     The IEEE 802.11 Wireless LAN Standard defines at least two different physical (PHY) specifications and one common medium access control (MAC) specification. The IEEE 802.11(a) Standard is designed for either the 2.4 GHz ISM band or the 5 GHz U-NII band, and uses orthogonal frequency division multiplexing (OFDM) to deliver up to 54 Mbps data rates. The IEEE 802.11(b) Standard is designed for the 2.4 GHz ISM band and uses direct sequence spread spectrum (DSSS) to deliver up to 11 Mbps data rates. The IEEE 802.11 Wireless LAN Standard describes two major components, the mobile station and the fixed access point (AP). IEEE 802.11 networks can be configured where the mobile stations communicate with a fixed access point. IEEE 802.11 also supports distributed activities similar those of the Bluetooth piconets. The IEEE 802.11 standard provides wireless devices with service inquiry features similar to the Bluetooth inquiry and scanning features. 
     In order for an IEEE 802.11 mobile station to communicate with other stations in a network, it must first find the stations. The process of finding another station is by inquiring. Active inquiry requires the inquiring station to transmit queries and invoke responses from other wireless stations in a network. In an active inquiry, the mobile station will transmit a probe request frame. If there is a network on the same channel that matches the service set identity (SSID) in the probe request frame, a station in that network will respond by sending a probe response frame to the inquiring station. The probe response includes the information necessary for the inquiring station to access a description of the network. The inquiring station will also process any other received probe response and Beacon frames. Once the inquiring station has processed any responses, or has decided there will be no responses, it may change to another channel and repeat the process. At the conclusion of the inquiry, the station has accumulated information about the networks in its vicinity. Once a station has performed an inquiry that results in one or more network descriptions, the station may choose to join one of the networks. The IEEE 802.11 Wireless LAN Standard is published in three parts as IEEE 802.11-1999; IEEE 802.11a-1999; and IEEE 802.11b-1999, which are available from the IEEE, Inc. web site http://grouper.ieee.org/groups/802/11. 
     High Performance Radio Local Area Network (HIPERLAN) 
     The HIPERLAN standard provides a wireless LAN with a high data rate of up to 54 Mbps and a medium-range of 50 meters. HIPERLAN wireless LANs provide multimedia distribution with video QoS, reserved spectrum, and good in-building propagation. There are two HIPERLAN standards. HIPERLAN Type 1 is a dynamic, priority driven channel access protocol similar to wireless Ethernet. HIPERLAN Type 2 is reserved channel access protocol similar to a wireless version of ATM. Both HIPERLAN Type 1 and HIPERLAN Type 2 use dedicated spectrum at 5 GHz. HIPERLAN Type 1 uses an advanced channel equalizer to deal with intersymbol interference and signal multipath. HIPERLAN Type 2 avoids these interference problems by using OFDM and a frequency transform function. The HIPERLAN Type 2 specification offers options for bit rates of 6, 16, 36, and 54 Mbps. The physical layer adopts an OFDM multiple carrier scheme using 48 carrier frequencies per OFDM symbol. Each carrier may then be modulated using BPSK, QPSK, 16-QAM, or 64-QAM to provide different data rates. The modulation schemes chosen for the higher bit rates achieve throughput in the range 30-50 Mbps. 
     The HIPERLAN Type 1 is a dynamic, priority driven channel access protocol that can form networks of wireless devices. HIPERLAN Type 1 networks support distributed activities similar those of the Bluetooth piconets and IEEE 802.11 independent basic service sets (IBSS). The HIPERLAN Type 1 standard provides wireless devices with service inquiry features similar to those of the Bluetooth inquiry and scanning features and the IEEE 802.11 probe request and response features. An overview of the HIPERLAN Type 1 principles of operation is provided in the publication  HIPERLAN Type  1  Standard , ETSI ETS 300 652, WA2 Dec. 1997. 
     HIPERLAN Type 2 is a reserved channel access protocol that forms networks. HIPERLAN Type 2 networks support distributed activities similar those of the HIPERLAN Type 1 networks, Bluetooth piconets and IEEE 802.11 independent basic service sets (IBSS). HIPERLAN Type 2 provides high-speed radio communication with typical data rates from 6 MHz to 54 Mbps. It connects portable devices with broadband networks that are based on IP, ATM and other technologies. Centralized mode is used to operate HIPERLAN Type 2 as an access network via a fixed access point. A central controller (CC) in the fixed access point provides QoS coordinates the access of the mobile stations support. User mobility is supported within the local service area and wide area roaming mobility can also be supported. An overview of the HIPERLAN Type 2 principles of operation is provided in the Broadband Radio Access Networks (BRAN),  HIPERLAN Type  2;  System Overview , ETSI TR 101 683 VI.I.1 (2000-02) and a more detailed specification of its ad hoc network architecture is described in  HIPERLAN Type  2,  Data Link Control  ( DLC )  Layer ; Part 4. Extension for Home Environment, ETSI TS 101 761-4 V1.2.1 (2000-12). 
     SUMMARY OF THE INVENTION 
     A system and method is disclosed to store and transfer a new type of multimedia data construct called a tag. This system and method may be employed in wireless communications environments. A user can write text, create a voice clip and append it to the text, take a digital picture and append it to the text, to create a multimedia file as the content of a tag. The creation or modifying of the multimedia file can be done in the user&#39;s mobile wireless device or off line and then stored in the mobile device. The multimedia file is then incorporated into the tag or it can be referenced by a pointer in the tag. The multimedia file is artistic expression of the user and the tag uniquely associates the user&#39;s identity with the multimedia file by prohibiting alteration of the content after the user completes its creation. A content-originator flag (CFG) value in the tag is set to “false” during the period when the user is creating or modifying the tag&#39;s content. When the user completes editing the content of the tag, the content-originator flag (CFG) value is set to true, thereby freezing the content. The tag may include the user&#39;s ID, such as his/her international mobile subscriber identity (IMSI) or mobile station integrated services digital network number (MSISDN). Alternatively, the tag may include a tag ID that is derived from the user&#39;s ID. Subsequent viewers of the content can make a copy of the content and can then modify it, but they cannot authentically attribute the modified copy to the original user. 
     The invention can be implemented as a wireless personal area network (PAN) such as provided in Bluetooth Standard or a wireless local area network (LAN) such as provided in the IEEE 802.11 Wireless LAN Standard and the HIPERLAN Standard. This invention can also be implemented, for example, in other wireless communications environments, such as cellular telecommunications networks. In these environments, messaging services, such as the multimedia messaging service (MMS), may be used to transfer tags. 
     In one aspect of the invention, a server is connected to a short-range wireless access point, such as a Bluetooth access point. The access point is typically located at a frequent gathering place, such as a famous landmark, a shopping center, a school, or a home. Users carry Mobile Bluetooth devices, which are programmed in accordance with the invention to enable the users to create tags that contain multimedia messages. The messages are typically aphorisms, notes, jokes, and the like, which the users have previously prepared or spontaneously create. The tags are then uploaded over the Bluetooth link to the server for posting on a virtual “wall” for viewing by other users with Bluetooth viewing devices. The user has effectively “painted the wall” with his/her uploaded tag. 
     In further aspects of the invention, a server is connected to a interface that provides for the exchange of information across one or more wireless communications networks, such as cellular telecommunications networks. Users have communications devices, which are programmed to enable the users to create tags. The tags are then uploaded across the wireless communications network to the server for posting on a virtual “wall” for viewing by other users with tag viewing devices. The user has effectively “painted the wall” with his/her uploaded tag. 
     A user can browse tags that have previously been “painted on the wall”, by viewing a list downloaded from the server, listing the tags stored in the server. The user can also perform a database search for tags using a query specifying particular IMSI or MSISDN values or user names. A list is then downloaded from the server, listing the tags stored in the server having the particular IMSI or MSISDN values or user names. The user may have old tags stored in his/her mobile device, and the IMSI or MSISDN values or user names can be extracted from those tags and used as the query sent to the server. A database in the server stores information about each tag in the server, in a tag record. Each tag record includes the information contained in the corresponding tag, to enable searches to be made on the author&#39;s name, IMSI or MSISDN identity, time that the tag was recorded, and the like. An additional field is included that links the tags forward or backward, if they are part of a sequence of user comments that have been recorded on “the wall”. “The wall” server can be connected to a remote, backup server that stores a copy of all of the tags and the database, to be used in the event of disaster recovery. Additionally, the backup server can provide an accessible, bulk storage for old tags, to reduce the storage requirements on “the wall” server. 
     As an alternative to a user&#39;s ID, a tag may include a tag ID, which is derived from the user&#39;s ID. For example, the tag ID may be generated from the tag identifier with a public key and an asymmetric encryption algorithm, such as an RSA encryption algorithm. A corresponding private key that is maintained in secret is used to derive subscriber IDs from tagIDs. Accordingly, user privacy is protected by not “publicizing” subscriber IDs (e.g., MSISDNs and IMSIs) at locations, such as virtual walls. 
     Tags may include hop counts, but this is not required. When the original user has created the content in his/her mobile wireless device, a hop count value of zero is written into the tag. If the user uploads the tag to the server and writes the tag on “the wall”, the hop count is incremented by one. Whenever a later user downloads a copy of the tag from the server, the hop count is incremented again by one. Alternatively, the hop count may be incremented when uploading, but not when downloading. Similarly, the hop count may be incremented when downloading, but not when uploading. Such techniques prevent a tag&#39;s hop count from being incremented by two when it is transferred between individuals via a wall. 
     When one user sends a copy of the tag to another user, each transmission increments the hop count in the tag by one. This feature makes original copies of the content more valuable, as signified by a low hop count value in the tag. A person-to-person flag (PFG) is also included in the tag. The initial value of the person-to-person flag (PFG) is set to a value of “true” when the originating user creates the tag. The person-to-person flag (PFG) value of “true” verifies that the tag has only been transferred from person-to-person, and has not been downloaded from “the wall” server. When the tag is uploaded to “the wall” server, the value of the person-to-person flag (PFG) is reset to a value of “false”, and can never be returned to a value of “true”. This resetting may be performed by either the person&#39;s device, or by the wall server. Thus, a tag directly received from a famous person will have a person-to-person hop count of one, and thus be an item of value, similar to an original, famous autograph. As long as the tag is not transferred to “the wall” server, the person-to-person flag (PFG) value remains “true” and the tag has a greater value than it would if it had been obtained by downloading it from “the wall” server. 
     One technique for freezing the content of the tag so that later viewers cannot attribute the modified content to the original user, is provided by public key encryption protocols, such as the secure sockets layer protocol. The originating party&#39;s device can compute a message authentication code (MAC) hash value on the content of the tag and then digitally sign the MAC using the originating party&#39;s secret key. Each receiving party&#39;s device decrypts the signed MAC using the originating party&#39;s public key and compares the recovered MAC with a reference MAC computed on the received content of the tag. If the two MAC values are equal, then the receiving party knows that the content has not been modified since it left the device of the originating party. 
     If the user has a Bluetooth equipped cellular telephone, he/she can transmit the multimedia content of a tag over a cellular telephone network to a cellular telephones capable of receiving multimedia files. However, in some embodiments, tags cannot be transmitted in any other manner than over a short-range wireless link, such as a Bluetooth link. In these embodiments, the user of a Bluetooth mobile device must be close enough to another Bluetooth device to directly communicate over the Bluetooth link in order to send a tag. As an example, the user must be at the location of the access point for the “wall” server in order to “paint the wall” with his/her tag. As a further example, the user must be at the location of his/her friend in order to deliver his/her tag to the friend. This requirement of proximity between sender and receiver of a tag may be imposed by the programmed operation of the Bluetooth devices, in accordance with embodiments of the invention. 
     There are two modes that the user can select from to transfer his/her tag to a friend. The first mode is a “tag delivery”, whereby the sending user transfers a copy of the tag in the sender&#39;s device, causing the hop count to be incremented by one in the copy of the tag received by the recipient. The second mode is called “tag give-away”, whereby the sending user transfers the tag currently in the sender&#39;s device, causing the hop count to remain unchanged in the tag received by the recipient. The sender effectively keeps a copy of the tag, and the copy in the sender&#39;s device is incremented by one. 
     In embodiments, messaging services, such as the multimedia messaging service (MMS) may be used to transfer tags. “Messaging tags” may be used that include a content portion and a header portion. The content portion is in a standard messaging format. The header portion includes the flags that are associated with tags, such as CFG, PFG, hop count, tag ID, or subscriber ID. 
     As set forth above, tags may include tag IDs as an alternative to user IDs. A communications device may obtain a tag ID for use in creating and transferring tags from a tag ID processing server. The tag ID processing server is within a trusted domain so that the services it provides can be trusted. For instance, when a user obtains a secured Tag ID, it can trust that it has been calculated correctly, and that no one outside the trusted domain can get the corresponding user ID because the user utilized a service within the trusted domain. Thus the trusted domain provides restrictions on accessibility and exhibits credibility. 
     The tag ID processing server receives a tag identifier configuration request (including a subscriber identifier) from a communications device; generates the tag identifier with an asymmetric encryption algorithm and a public key; and sends the tag identifier to the communications device. In addition, the tag ID processing server may ensure that the communications device is authorized to obtain the tag identifier. The tag identifier configuration request and the tag identifier may each be sent in short messaging service (SMS) messages. Alternatively, these may be sent in other formats, such as MMS messages, etc. 
     The tag ID processing server, in conjunction with a subscriber identification node, may also provide tag identity resolution services. These services allow communications devices to determine subscriber IDs (e.g., MSISDNs and IMSIs) from tag IDs. Accordingly, the tag ID processing server receives a tag identifier resolution request (including a tag identifier) from a communications device, generates a subscriber identifier from the tag identifier with an asymmetric encryption algorithm and a private key; and sends the subscriber identifier to the subscriber identification node. In response, the server receives subscriber-related information from the subscriber identification node; and sends the subscriber-related information to the communications device. In addition, the tag ID processing server may ensure that the communications device is authorized to obtain the subscriber-related information. This subscriber-related information may include, for example, a subscriber name. The tag identifier resolution request and the subscriber-related information may each be sent in short messaging service (SMS) messages. 
     In an alternate embodiment of the invention, the server is programmed to store the tags in association with two dimensional X, Y coordinates, in a tag storage in the server. A user can browse tags that have been posted on “the wall”, by using up/down and left/right controls displayed in the GUI of the user&#39;s device. 
     In another alternate embodiment of the invention, payment may be required before a user is allowed to upload a tag to “paint the wall”. If the user has a communications device, such as a Bluetooth equipped cellular telephone or other wireless device, he/she is required to send a short message service (SMS) charge-authorizing message over the cellular telephone system to an account-charging server, authorizing his/her account to be charged. The account-charging server returns an SMS payment token to the user&#39;s device over the cellular telephone system. The payment token must be received by the user&#39;s device before the user is allowed to upload a tag to “paint the wall”. These payment tokens may also be implemented with premium rate MMS messages. 
     In another alternate embodiment of the invention, payment may be required before a user is allowed to download a tag from the “the wall” server. A digital rights management (DRM) authorization message is sent by the user&#39;s device over the Bluetooth link to “the wall” server. A DRM module in the server is connected over a network such as the Internet, to a DRM account-charging server. The DRM account charging server handles the necessary steps in debiting the user&#39;s account, and then returns an enabling signal to “the wall” server. “The wall” server then downloads over the Bluetooth link, the tag requested by the user. Such features may also be implemented in environments other than ones involving short-range wireless communications. Such features may be implemented with premium rate SMS and MMS messages. 
     In another alternate embodiment of the invention, payment may be required before a user is allowed to download a tag from the “the wall” server. A payment accumulator is included in the user&#39;s device, which accumulates authorized charges for downloading a plurality of tags from one or many “wall” servers over an extended period, such as a month. If the user has a communications device (e.g., a Bluetooth equipped cellular telephone), then at the end of the month, an SMS message containing the monthly total authorized charges is sent by the user&#39;s device over the cellular telephone system to an account charging server, authorizing his/her account to be charged. This feature may also be implemented with premium rate MMS messages. 
     In another alternate embodiment of the invention, payment may be required from a requesting user, before a providing user will transfer a tag to the requesting user. A digital rights management (DRM) module in each mobile wireless device handles the exchange of charge authorization messages over the Bluetooth link between the mobile devices. The DRM module in the requestor&#39;s device sends a charge-authorizing message to the provider&#39;s device. The provider&#39;s device then sends the tag requested by the requestor, over the Bluetooth link. This feature may be implemented with SMS and MMS messages. 
     In another alternate embodiment of the invention, a tag can be automatically transferred from one Bluetooth device to another, whether stationary or mobile. The user&#39;s mobile Bluetooth device can be programmed to listen or scan for any Bluetooth access point device connected to a “wall” server. The SDP message exchange will tell the mobile device of the availability of “the wall” services. When the user&#39;s mobile device recognizes “a wall” within communications range, the user&#39;s mobile device uploads the user&#39;s tag and automatically “paints the wall”. The user&#39;s mobile device can be programmed to automatically send a tag to any other Bluetooth device, including mobile devices. A “tag worm” can be created, wherein the tag automatically propagates from user device to user device, as users walk about. A user can prevent receiving unsolicited tags by turning off this feature. Such features may also be implemented in environments other than ones involving Bluetooth wireless communications. 
     In another alternate embodiment of the invention, a tag can be transferred from the user&#39;s mobile device to a “wall” server in the user&#39;s home, as a “personal or family tag storage”. The personal home “wall” server is programmed to check the IMSI or MSISDN identity (or the secure tag ID) of the mobile device storing the tags, according to an embodiment of the present invention. The user can store and retrieve his/her tags from the personal home “wall” server without changing the hop counts in the tags. If an unauthorized person or device were to attempt retrieving the user&#39;s tags, the personal home “wall” server can prevent downloading the tags, or it can increment the hop counts in copies of the tags that are downloaded. 
     In another alternate embodiment of the invention, “the wall” server includes a queuing management system. In this embodiment, the short-range wireless access point for “the Wall” server is located within the premises of a business. “The wall” server performs the function of establishing a queue of customers waiting for service, such as in a bank or at a funfair or the like. The customer sends his/her Tag (including his/her presence/ID-information) to “the Wall” server. “The wall” server registers the customer as being on a virtual queuing line. When the customer uploads his/her tag to the server, the server can optionally return another tag that is an advertisement message of the business. After registering, the customer can optionally browse other tags from “the Wall” server while awaiting his/her turn within the premises of the business. Alternately, the customer can leave the premises of the business and when his/her turn is reached on the virtual queue, “the wall” server sends a notification message informing the customer that it is his/her turn at the front of the queue. The notification message can be delivered over a cellular telephone network as an SMS message. Alternately, the notification message can be transmitted over a LAN connected to “the wall” server, and delivered over a Bluetooth link to the customer&#39;s device by a Bluetooth access point connected to the LAN. Such features may also be implemented in environments other than ones involving short-range wireless communications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a Bluetooth equipped cellular telephone  100  searching over the Bluetooth link for tags in “the wall” server  150 , using the tag author&#39;s name, IMSI or MSISDN identity, according to an embodiment of the present invention. A list of tags is viewed and the multimedia content of selected tags is viewed in the device&#39;s browser. 
         FIG. 1A  illustrates the Bluetooth equipped cellular telephone downloading over the Bluetooth link selected tags  130  and  132  from “the wall” server, according to an embodiment of the present invention. 
         FIG. 1B  illustrates the Bluetooth equipped cellular telephone downloading over the Bluetooth link a selected tag  134  from “the wall” server, according to an embodiment of the present invention. Tag  134  was found by using a forward pointer from the earlier tag  132 , the forward pointer identifying the later tag  134  as part of a sequence of user comments that have been recorded on “the wall”. 
         FIG. 1C  illustrates the editing buffer  247  in the Bluetooth equipped cellular telephone, wherein a multimedia file  138 ′ is created and then incorporated into a tag  138 , according to an embodiment of the present invention. 
         FIG. 1D  illustrates the Bluetooth equipped cellular telephone uploading over the Bluetooth link the tag  138  to “the wall” server, to “paint the wall”, according to an embodiment of the present invention. 
         FIG. 1E  illustrates the Bluetooth equipped cellular telephone  100  transferring the tag  134  over the Bluetooth link to a second Bluetooth equipped cellular telephone  100 ′, using the “tag delivery” mode, whereby the sending user transfers a copy of the tag in the sender&#39;s device, causing the hop count to be incremented by one in the copy of the tag received by the recipient, according to an embodiment of the present invention. 
         FIG. 1F  illustrates the Bluetooth equipped cellular telephone  100  transferring the tag  134  over the Bluetooth link to the second Bluetooth equipped cellular telephone  100 ′, using the “tag give-away” mode, whereby the sending user transfers the tag currently in the sender&#39;s device, causing the hop count to remain unchanged in the tag received by the recipient, according to an embodiment of the present invention. The sender effectively keeps a copy of the tag, and the copy in the sender&#39;s device is incremented by one. 
         FIG. 1G  illustrates the Bluetooth equipped cellular telephone  100  transferring over the cellular telephone network, the multimedia content  134 ′ to the second Bluetooth equipped cellular telephone  100 ′, according to an embodiment of the present invention. 
         FIG. 1H  illustrates the Bluetooth equipped cellular telephone  100  transferring over the cellular telephone network, the multimedia content  134 ′ to either a cell phone or an Internet protocol gateway, according to an embodiment of the present invention. 
         FIG. 2  illustrates the memory and components of the Bluetooth equipped cellular telephone  100 , according to an embodiment of the present invention. 
         FIG. 2A  is a flow diagram of the mobile wireless device communications processing method  500  in the applications programs  225  of the mobile wireless device  100 . 
         FIG. 3  illustrates the memory and components of the “the wall” server  150 , according to an embodiment of the present invention. 
         FIG. 3A  is a flow diagram of “the wall” server communications processing method  600  in the applications programs  325  of “the wall” server  150 . 
         FIG. 4  illustrates the tag storage  154  in the “the wall” server  150 , according to an embodiment of the present invention. 
         FIG. 5  illustrates the database storage  156  in the “the wall” server  150 , according to an embodiment of the present invention. 
         FIG. 6A  illustrates an alternate embodiment of the invention, with the Bluetooth equipped cellular telephone  100  browsing over the Bluetooth link for tags in “the wall” server  150 , according to an embodiment of the present invention. The server  150  is programmed to store the tags in association with two dimensional X, Y coordinates, in a virtual viewing space. A user can browse tags that have been posted on “the wall”, by using up/down and left/right controls of the user&#39;s Bluetooth device. 
         FIG. 6B  illustrates the virtual, two-dimensional viewing space in the alternate embodiment of the invention, according to an embodiment of the present invention. 
         FIG. 7A  illustrates a Bluetooth equipped cellular telephone  100 ″ uploading the tag  134  over the Bluetooth link to “the wall” server, to “paint the wall”, in the alternate embodiment of the invention, according to an embodiment of the present invention. 
         FIG. 7B  illustrates the Bluetooth equipped cellular telephone  100  downloading tag  134  over the Bluetooth link from “the wall” server, in the alternate embodiment of the invention, according to an embodiment of the present invention. 
         FIG. 8  illustrates another alternate embodiment of the invention, wherein payment is required before user&#39;s device  100  is allowed to upload a tag  138  over the Bluetooth link to “paint the wall” of the server  150 , according to an embodiment of the present invention. The Bluetooth equipped cellular telephone  100  sends an SMS charge authorizing message over the cellular telephone system to an account-charging server, authorizing the account to be charged. The account-charging server returns an SMS payment token to the user&#39;s device over the cellular telephone system. 
         FIG. 9  illustrates another alternate embodiment of the invention, wherein payment is required before a user is allowed to download a tag over the Bluetooth link from the “the wall” server, according to an embodiment of the present invention. A digital rights management (DRM) authorization message is sent by the user&#39;s device  100  over the Bluetooth link to “the wall” server  150 . A DRM module  422  in the server  150  is connected over a network such as the Internet, to a DRM account-charging server  424 . The DRM account charging server handles the necessary steps in debiting the user&#39;s account, and then returns an enabling signal to “the wall” server. “The wall” server then downloads over the Bluetooth link, the tag requested by the user. 
         FIG. 10  illustrates another alternate embodiment of the invention, wherein payment is required before a user is allowed to download a tag over the Bluetooth link from the “the wall” server, according to an embodiment of the present invention. A payment accumulator  430  is included in the user&#39;s device  100 , that accumulates authorized charges for downloading a plurality of tags from one or many “wall” servers  150 , etc. over an extended period, such as a month. At the end of the month, the Bluetooth equipped cellular telephone  100  sends an SMS message containing the monthly total authorized charges, sending it over the cellular telephone system to an account-charging server  406 , authorizing the account to be charged. 
         FIG. 11  illustrates another alternate embodiment of the invention, wherein “the wall” server  150  is connected to a remote, backup server  442  that stores a copy of all of the tags and the database, to be used in the event of disaster recovery, according to an embodiment of the present invention. Additionally, the backup server  442  provides an accessible, bulk storage for old tags, to reduce the storage requirements on “the wall” server  150 . 
         FIG. 12  illustrates another alternate embodiment of the invention, wherein payment is required from a requesting user&#39;s device  100 ′, before a providing user&#39;s device  100  will transfer a tag over the Bluetooth link to the requesting user&#39;s device, according to an embodiment of the present invention. A digital rights management (DRM) module  450  in each mobile wireless device handles the exchange of charge authorization messages over the Bluetooth link between the mobile devices. The DRM module  450 ′ in the requestor&#39;s device  100 ′ sends a charge authorizing message to the provider&#39;s device  100 . The provider&#39;s device  100  then sends the tag requested by the requestor&#39;s device  100 ′, over the Bluetooth link. 
         FIG. 13  is a diagram illustrating the format of an exemplary multimedia content tag  1300  that includes a message portion  1302 , and a header portion  1304 . The header portion includes various fields to facilitate the transfer of tags. In further embodiments, such fields may be embedded inside a standard message structure as an internal header. 
         FIG. 14  is a flowchart illustrating the processing of a multimedia messaging tag by a wireless communications device (WCD). 
         FIGS. 15A and 15B  are diagrams that illustrate relationships between a subscriber ID  1502  and its corresponding tag ID  1504 . This relationship is based on an asymmetric encryption algorithm. 
         FIG. 16  is a block diagram of an operational environment that includes a wireless communications device a tag ID processing server  1616 , and a subscriber identification node  1608 . In this environment, tag ID configuration processes and tag ID resolution services may be performed. 
         FIG. 17  is a flowchart of a tag ID configuration process. This process allows communications devices to receive their tag ID for use in the creation and transmission of tags. 
         FIG. 18  is a flowchart of a tag identity resolution process. This process allows communications devices to determine subscriber IDs from tag IDs. 
         FIG. 19  is a flowchart illustrating the searching of tags. This may be performed at various devices, such as a virtual tag wall server. 
         FIG. 20  is a diagram illustrating an example of tag searching. In this example, a communications device searches for tags contained at a wall server. 
         FIG. 21  is a block diagram of an exemplary computer system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     I. Multimedia Tags 
     In the following description of the preferred embodiment, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. 
     It is human nature to leave one&#39;s mark when visiting a place. Leaving one&#39;s mark can range from signing a guest book to spray-painting a wall. If a person had the possibility to leave an electronic tag commemorating the fact of their visit, such as to the Eiffel Tower, it is natural that they would do it. Leaving an electronic tag would be even more likely if it could be done inexpensively and easily with one&#39;s mobile phone. It would be an attractive feature to be able to commemorate one&#39;s visit to a famous place by leaving an electronic tag that would be retained at that place and be visible years later upon one&#39;s return. A person could write messages to be left for their friends to find, in the classic manner of leaving one&#39;s mark. 
     One aspect of the invention is a system and method to create an electronic tag, which is a personal multimedia message that can only be delivered within a personal area, such as within the range of a personal area network (PAN). The feature of personal area delivery emphasizes that the sender must physically be at a place, or be nearby a person receiving the electronic tag. An electronic tag can only be delivered from one person to another within the personal area. The preferred implementation of the invention is by communication with Bluetooth devices. The sender and the receiver must have their Bluetooth devices physically nearby each other in order to transfer the electronic tag. The invention can be implemented as a wireless personal area network (PAN) such as provided in Bluetooth Standard, Radio Frequency Identification (RFID), and Infrared Data Protocol networks (IrDA) or a wireless local area network (LAN) such as provided in the IEEE 802.11 Wireless LAN Standard and the HIPERLAN Standard. 
     Another aspect of the invention is “the wall” server, a storage device connected to a Bluetooth access point located at a place where people gather. An electronic tag containing a multimedia message can be published at a place, such as the Eiffel Tower, by the sender transmitting it over the Bluetooth link to “the wall” server. To publish in this manner, the sender must physically be there. Electronic tags that are published by uploading them in this manner to “the wall” server, can be browsed and downloaded by others using their Bluetooth devices. 
     In another aspect of the invention, a person having a Bluetooth equipped cellular telephone can publish his/her own content on places where people gather, and thus create circulating content. The multimedia messages contained in an electronic tag can be extracted and relayed over the cellular telephone network as a multimedia message. The best aphorisms, jokes, etc. from “the wall” server can be circulated. It is not the electronic tag, itself, that is transmitted over the cellular network, but the multimedia content of the tag. The electronic tag, itself, can only be transferred over a short-range wireless radio link, such as a Bluetooth link, to preserve the close proximity of the sender and the receiver. 
     The multimedia content of an electronic tag is the artistic expression of its creator. In another aspect of the invention, the electronic tag uniquely associates the creator&#39;s identity with the multimedia content by prohibiting alteration of the content after the user completes its creation. The electronic tag includes the creator&#39;s ID, such as his/her international mobile subscriber identity (IMSI) or mobile station integrated services digital network number (MSISDN). Subsequent viewers of the content can make a copy of the content and can then modify it, but they cannot authentically attribute the modified copy to the original user. 
     In another aspect of the invention, a hop count is contained in the electronic tag. Collectors will attribute greater value to those tags with a low hop count. For example, instead of collecting autographs, one collects electronic tags of famous people that he/she meets. A collector, upon meeting Tina Turner, receives her electronic tag with a hop count of one. The collector will attribute a high value to that tag. The low hop count indicates that the collector actually met Tina Turner. The collector can show the tag to friends. The hop count information indicates that the tag is an original “first generation tag”. If the collector were to give away the tag to a friend, the collector looses the original tag, but retains a copy with an increased hop count. Alternately, if the collector delivers a copy of the tag to a friend, the friend receives the copy with an increased hop count, while the collector retains the original. These transfers of the tag can only occur over a short-range wireless radio link, such as a Bluetooth link, to preserve the close proximity of the sender and the receiver. 
       FIG. 1  illustrates a Bluetooth equipped cellular telephone  100  searching for tags in “the wall” server  150 , using the tag author&#39;s name, IMSI or MSISDN identity, according to an embodiment of the present invention. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. The mobile wireless device  100  of  FIG. 1  is equipped with circuits  103  for short-range wireless systems and circuits  105  for cellular telephone communications systems. Cellular telephone communications systems include GSM, GPRS, UMTS, EDGE, and the like. An example of such a mobile wireless device  100  is a Bluetooth-equipped GSM cellular telephone. 
     During an initial period when the mobile wireless device  100  is within the coverage area of the short range wireless access point  140 , it exchanges inquiry and paging packets and service discovery protocol (SDP) packets with the access point  140 . In this example, the short-range wireless access point  140  is a Bluetooth access point and the short-range wireless circuits in the mobile wireless device  100  are Bluetooth circuits. The user has previously actuated the Bluetooth mode button “BT” on the keypad  104  and the Bluetooth circuits have completed their exchange of inquiry, paging, and service discovery packets with the Bluetooth access point  140 . 
     In this example, the user wishes to search the tags on “the wall” server  150 , using the tag author&#39;s name, IMSI or MSISDN identity, as taken from the old tags  107  and  109  stored in the tag buffer  245 . Tag  107  includes the header  107 ″ containing Max&#39;s ID, which is an IMSI or MSISDN identity, a hop count value of one, a content-originator flag (CFG) value of “true”, a person-to-person flag (PFG) value of “true”, a message authentication code (MAC) and Max&#39;s digital signature (SIG). Tag  107  also includes multimedia content  107 ′. The user wishes to search the tags on “the wall” server  150 , using Max&#39;s IMSI identity. 
     Tag  109  includes a header containing Tina&#39;s ID, which is an IMSI or MSISDN identity, a hop count value of one, a content-originator flag (CFG) value of “true”, a person-to-person flag (PFG) value of “true”, a message authentication code (MAC) and Tina&#39;s digital signature (SIG). Tag  109  also includes multimedia content  109 ′. The user wishes to search the tags on “the wall” server  150 , using Tina&#39;s IMSI identity. The user&#39;s device  100  extracts the IMSI identities from tags  107  and  109  and assembles a query that it sends over the Bluetooth link to the server  150 . In this example the query terms represent Max&#39;s IMSI identity and Tina&#39;s IMSI identity. 
     The “wall server”  150  includes the tag storage  154  and the database storage  156 . Tags  128 ,  130 ,  132 , and  134  are currently in the tag storage  154 , which is shown in  FIG. 4 . A user can browse tags  128 ,  130 ,  132 , and  134  that have previously been “painted on the wall”, using the tag selector  122  on the device  100  to view a list  124  downloaded from the server  150 , listing the tags stored in the server. Since each of the tags  130 ,  132 , and  134  has been uploaded to the server  150 , each has a person-to-person flag (PFG) value of “false”. 
     Alternately, the user can also perform a database search for tags using a query specifying particular IMSI or MSISDN values or user names. The database storage  156  in the server  150  includes database  158  that stores information about each tag in the server, in a tag record. The database  158  is shown in greater detail in  FIG. 5 . Each tag record includes fields for the information contained in the corresponding tag, to enable searches to be made on the author&#39;s name, IMSI or MSISDN identity, the hop count, the content-originator flag (CFG) value, the message authentication code (MAC) of the information in the tag, and the digital signature (SIG) of the author of the tag. 
     Additional fields in the tag record include a time stamp when the tag was recorded in the server  150  and comment chain linking pointers to other tags in the server  150 . In an alternate embodiment, the tag record includes a field for the two dimensional X, Y coordinates of the location of the tag in a virtual viewing space. The comment chain linking field contains pointers linking the tags forward or backward, if they are part of a sequence of user comments that have been recorded on “the wall”. 
     The tag storage  154  includes Tag  132 , which includes Max&#39;s ID which is an IMSI or MSISDN identity. This data is contained in the personal ID field of a tag record in database  158  having a tag index field of “Tag  132 ”. The tag storage  154  also includes Tag  130 , which includes Tina&#39;s ID which is an IMSI or MSISDN identity. This data is contained in the personal ID field of a tag record in database  158  having a tag index field of “Tag  130 ”. The user&#39;s query results in the return of a list  124 , which is downloaded from the server  150 , listing the tags stored in the server having the particular IMSI or MSISDN values or user names. 
       FIG. 1A  illustrates the Bluetooth equipped cellular telephone downloading selected tags  130  and  132  from “the wall” server, according to an embodiment of the present invention.  FIG. 1A  shows Max&#39;s tag  132  downloaded to device  100  and stored in its tag buffer  245 . Note that the hop count value has been incremented by one when the tag was downloaded from the server  150 . Also note that the person-to-person flag (PFG) value is “false”. The multimedia content  132 ′ is shown on the screen  120  of the device  100 . 
     Tina&#39;s tag  130  is downloaded to device  100  and stored in its tag buffer  245 . Note that the hop count value has been incremented by one when the tag was downloaded from the server  150 . Also note that the person-to-person flag (PFG) value is “false”. The multimedia content  130 ′ is also shown on the screen  120  of the device  100 . 
       FIG. 1B  illustrates the Bluetooth equipped cellular telephone downloading a selected tag  134  from “the wall” server, according to an embodiment of the present invention. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. Tag  134  was found by using a forward link from the earlier tag  132 , the forward link identifying the later tag  134  as part of a sequence of user comments that have been recorded on “the wall”. The “comment chain link” field in database  158  contains pointers linking the tags forward or backward, if they are part of a sequence of user comments that have been recorded on “the wall”. The row for Tag  132  includes a forward linking pointer “For_Link to Tag  134 ” to the row for Tag  134 . 
     Referring to server tag storage  154  of  FIG. 4  and the database  158  of  FIG. 5 , Tag  134  was uploaded by its author, Monique, with a time stamp of 18.12.01, wherein its author designated that Tag  134  was a comment on Max&#39;s earlier tag  132 , having a time stamp of 04.12.01. The designation of tag  134  as being a comment about Tag  132 , is stored as the forward linking pointer “For_Link to Tag  134 ” in the row for Tag  132 . A corresponding backward linking pointer “Bak_Link to Tag  132 ” was written by the server in the row for Tag  134 .  FIG. 1B  shows the wireless device  100  sending a query “GET Forward Linked Tags”, which results in the database  156  accessing Monique&#39;s tag  134 , which is downloaded to device  100  and stored in its tag buffer  245 . Note that the hop count value in the header  134 ″ has been incremented by one when the tag was downloaded from the server  150 . Also note that the person-to-person flag (PFG) value is “false”. The multimedia content  134 ′ is shown on the screen  120  of the device  100 . 
       FIG. 1C  illustrates the editing buffer  247  in the Bluetooth equipped cellular telephone  100 , wherein a multimedia content  138 ′ is created and then incorporated into a tag  138 , according to an embodiment of the present invention. A user can write text  250  in step (1), create a voice clip and append it to the text  250  and/or take a digital picture and compress it as a JPEG file  251  and append it to the text  250  in step (2), to create a multimedia file in step (3) as the content  138 ′ of the tag  138 . The creation or modifying of the multimedia content  138 ′ can be done in the user&#39;s mobile wireless device  100  or off line and then stored in the mobile device  100 . 
     The multimedia content  138 ′ is then incorporated into the tag or it can be referenced by a pointer in the tag. In  FIG. 1C , a copy  254  is made of a tag template in step (4), having a header portion  255  and a content portion  256 . The header portion specifies a personal ID field, which is filled with the identity of the author, a hop count field with a default value of zero, a content-originator flag (CFG) field with a default value of “false”, a person-to-person flag (PFG) field with a default value of “true”, a MAC field and a digital signature (SIG) field. 
     The hop count always begins with a value of zero in the author&#39;s wireless device  100 . The content-originator flag (CFG) field remains at a value of “false” during the period while the content portion  256  is being created or modified. The initial value of the person-to-person flag (PFG) is set to a value of “true”. The person-to-person flag (PFG) value of “true” verifies that the tag has only been transferred from person-to-person, and has not been downloaded from “the wall” server. The MAC field and the digital signature (SIG) field are filled in, as described below. 
     When the completed multimedia content is inserted into the portion  256  of the tag and when all of the fields of the portion  255  are completed in step (5), the content-originator flag (CFG) field is set to “true” in step (6), thereby freezing the content of the tag  138 . Subsequent viewers of the content can make a copy of the content and can then modify it, but they cannot authentically attribute the modified copy to the original user. 
     The multimedia content  138 ′ can be in the form of a multimedia messaging service (MMS) message, which is described in the 3GPP Technical Specification entitled  Multimedia Messaging Service  ( MMS )  Functional Description , TS 23.140, V5.1.0 (2001-12). 
     An example of the values inserted into the MAC field and the digital signature (SIG) field of the tag  138  is as follows, using the principles of public key encryption. A hash value is computed on the concatenated multimedia content  138 ′ and the author&#39;s personal ID field, forming the message authentication code (MAC). In this example, it is not necessary to store the unencrypted MAC in the MAC field. Instead, the MAC value and a clear text copy of the author&#39;s ID are encrypted using the author&#39;s secret key, to form a digital signature (SIG), which is written into the digital signature (SIG) field of tag  138 . The MAC is effectively incorporated into the tag in its encrypted (i.e., signed) form as the digital signature. 
     Later, the author&#39;s wireless device  100  delivers a copy of the tag  138  over the Bluetooth link to a second wireless device. The second wireless device decrypts the signed MAC using the author&#39;s public key, recovering the clear text author&#39;s ID and also recovering the MAC. If the recovered author&#39;s ID is readable, then the recipient is certain that the author originated the recovered MAC value. Then, to insure that the multimedia content  138 ′ has not been altered since it was created by the author, the second wireless device computes a reference MAC. The reference MAC is a hash value computed on the concatenated multimedia content  138 ′ and author&#39;s personal ID, both of which have been provided by the tag  138 . The second wireless device compares the recovered MAC with the reference MAC and if the two MAC values are equal, then the receiving party knows that the multimedia content  138 ′ has not been modified since it left the author&#39;s wireless device  100 . 
     In an alternate embodiment, the expression “content-originator flag (CFG)=true” can also be included in the MAC. In this embodiment, a hash value is computed in the author&#39;s device  100  on the concatenated multimedia content  138 ′ and the expression “content-originator flag (CFG)=true”, forming the message authentication code (MAC). Then, the second wireless device decrypts the signed MAC using the author&#39;s public key, recovering the clear text expression “content-originator flag (CFG)=true” and also recovering the MAC. If the recovered expression “content-originator flag (CFG)=true” is readable, then the recipient is certain that the author originated the recovered MAC value and that the author&#39;s wireless device had set the content-originator flag (CFG) value to “true”. 
     Methods to generate and evaluate message authentication codes to insure the integrity of data are described in the book by Stephen Thomas entitled  SSL and TLS , published by John Wiley and Sons, 2000. Two example algorithms for message authentication are RSA&#39;s Message Digest (MD5) and the Secure Hash Algorithm (SHA), both of which are described in the book by Stephen Thomas. Another reference that goes into greater detail in its discussion of data integrity methods is the book by Bruce Schneier entitled  Applied Cryptography -2nd Edition published by John Wiley and Sons, 1996. Methods to generate and evaluate digital signatures to authenticate the originating user as the source of the MAC (or other signed data), are described in the book by Richard E. Smith entitled  Internet Cryptography , published by Addison Wesley, 1997. 
     The multimedia content  138 ′ is artistic expression of its author and the tag  138  uniquely associates the author&#39;s identity with the multimedia content  138 ′ by prohibiting alteration of the content after the author completes its creation or modification. Subsequent viewers of the content can make a copy of the content and can then modify it, but they cannot authentically attribute the modified copy to the original author. 
     When the original user has created the content in his/her mobile wireless device, a hop count value of zero is written into the tag. If the user uploads the tag to the server  150  and writes the tag on “the wall”, the hop count is incremented by one. Whenever a later user downloads a copy of the tag from the server, the hop count is incremented again by one. When one user sends a copy of the tag over a Bluetooth link to another user, each transmission increments the hop count in the tag by one. This feature makes original copies of the content more valuable, as signified by a low hop count value in the tag. 
     A person-to-person flag (PFG) is also included in the tag. The initial value of the person-to-person flag (PFG) is set to a value of “true” when the originating user creates the tag. The person-to-person flag (PFG) value of “true” verifies that the tag has only been transferred from person-to-person, and has not been downloaded from “the wall” server. When the tag is uploaded to “the wall” server, the value of the person-to-person flag (PFG) is reset to a value of “false”, and can never be returned to a value of “true”. Thus, a tag directly received from a famous person, will have a person-to-person hop count of one, and thus be an item of value, similar to an original, famous autograph. As long as the tag is not transferred to “the wall” server, the person-to-person flag (PFG) value remains “true” and the tag has a greater value than it would if it had been obtained by downloading it from “the wall” server. Thus, a tag directly received from a famous person, will have a person-to-person hop count of one, and thus be an item of value, similar to an original, famous autograph.  FIG. 1D  illustrates the Bluetooth equipped cellular telephone uploading the tag  138  to “the wall” server, to “paint the wall”, according to an embodiment of the present invention. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. 
     In an alternate embodiment, when the user uploads a tag  138  to the server  150  and “paints the wall”, the server will return the tag  128  that is a souvenir of visiting the location, such as “Welcome to the Eiffel Tower”. 
       FIG. 1E  illustrates the Bluetooth equipped cellular telephone  100  transferring the tag  134  to a second Bluetooth equipped cellular telephone  100 ′, using the “tag delivery” mode, whereby the sending user transfers a copy of the tag  134  in the sender&#39;s device  100 , causing the hop count to be incremented by one in the copy of the tag received by the recipient&#39;s device  100 ′, according to an embodiment of the present invention. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. If the user has a Bluetooth equipped cellular telephone  100 , he/she can transmit the multimedia content  134 ′ of a tag  134  over a cellular telephone network to a cellular telephones capable of receiving multimedia files. However, the tags, themselves, cannot be transmitted in any other manner than over a short-range wireless link, such as a Bluetooth link. 
     The user of a Bluetooth mobile device  100  must be close enough to another Bluetooth device  100 ′ to directly communicate over the Bluetooth link in order to send a tag  134 . The user must be at the location of the access point for the “wall” server  150  in order to “paint the wall” with his/her tag. The user must be at the location of his/her friend in order for his/her device  100  to deliver his/her tag to the friend&#39;s device  100 ′. This requirement of proximity between sender and receiver of a tag is imposed by the programmed operation of the Bluetooth devices, in accordance with the invention. 
     There are two modes that the user can select from to transfer his/her tag to a friend. The first mode is a “tag delivery”, whereby the sending user transfers a copy of the tag in the sender&#39;s device, causing the hop count to be incremented by one in the copy of the tag received by the recipient. The second mode is called “tag give-away”, whereby the sending user transfers the tag currently in the sender&#39;s device, causing the hop count to remain unchanged in the tag received by the recipient. The sender effectively keeps a copy of the tag, and the copy in the sender&#39;s device is incremented by one. The person-to-person flag (PFG) value of “false” indicates that the tag has been downloaded from “the wall” server at some point after it was created. 
       FIG. 1F  illustrates the Bluetooth equipped cellular telephone  100  transferring the tag  134  to the second Bluetooth equipped cellular telephone  100 ′, using the “tag give-away” mode, whereby the sending user transfers the tag currently in the sender&#39;s device, causing the hop count to remain unchanged in the tag received by the recipient, according to an embodiment of the present invention. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. The sender effectively keeps a copy of the tag, and the copy in the sender&#39;s device is incremented by one. 
       FIG. 1G  illustrates the Bluetooth equipped cellular telephone  100  transferring over the cellular telephone network, the multimedia content  134 ′ to the second Bluetooth equipped cellular telephone  100 ′, according to an embodiment of the present invention. The multimedia content  134 ′ is extracted from the tag  134  in the user&#39;s device  100  and is transmitted via the GSM circuits  105  to the GSM access point  148  as a multimedia messaging service (MMS) message. The GSM access point  148  transfers the multimedia content  134 ′ over the GSM infrastructure network  116  to the remote GSM access point  148 ′, where it is transmitted to the second wireless device  100 ′ via its GSM circuits  105 . There the second wireless device  100 ′ displays the multimedia content  134 ′ on its browser  102  and stores it in its memory  202 .  FIG. 1H  illustrates the Bluetooth equipped cellular telephone  100  transferring over the cellular telephone network  116 , the multimedia content  134 ′ to either a cell phone  117  or an Internet protocol gateway  118 , the Internet  144 , and the recipient&#39;s personal computer  119 , according to an embodiment of the present invention. 
       FIG. 2  illustrates the memory and components of the Bluetooth equipped cellular telephone  100 , according to an embodiment of the present invention. The memory  202  is connected by the bus  204  to the Bluetooth radio  206 , the keypad  104 , the central processor  210 , the display  212 , and the cellular telephone radio  208 . The memory  202  stores programs that are sequences of executable instructions which, when executed in the central processor  210 , carry out the methods of the invention. The memory  202  includes the Bluetooth transport group  214  that includes the link controller  216 , the link manager  218 , and the logical link control and adaptation layer  220 . The memory  202  also includes the GSM protocol group  215 , the HSCSD protocol group  217 , and the GPRS protocol group  219 . The memory  202  also includes the Bluetooth middleware protocol group  224  that includes the RFCOMM, PPP, IP, UDP, and SDP program modules. 
     The memory  202  further includes the application group  235  that includes the application programs  225 . The application programs  225  include create a tag program  222 , download a tag over Bluetooth program  223 , deliver a tag to a friend over Bluetooth program  226 , handle delivered tags received from friends program  228 , write a multimedia note program  230 , paint a tag with a note in a “wall” over Bluetooth program  232 , search tags of friends from the “wall” over Bluetooth program  236 , browse the “wall” over Bluetooth program  238 , and relay multimedia content over GSM network program  240 . The memory  202  also includes a display buffer  244 , a GUI application  234 , the editing buffer  247  (shown in  FIG. 1C ), the tag buffer  245  (shown in  FIG. 1A ), a wireless application protocol (WAP) module and a WAP application environment (WAE) module. 
       FIG. 2A  is a flow diagram of the mobile wireless device communications processing method  500  in the applications programs  225  of the mobile wireless device  100 . The steps in the flow diagram are as follows. 
     Step  502 : Create new tag ( FIG. 1C ) or select tag from tag buffer ( FIG. 1E ,  1 F, or  1 G). 
     Step  504 : Determine if the user has requested transmission over the short-range wireless link to step  505  or alternately over the cellular telephone link ( FIG. 1G ) to step  530 . 
     Step  505 : Determine if the user has requested transmission using the tag delivery mode ( FIG. 1E ) to step  506  or alternately, using the tag give away mode ( FIG. 1F ) to step  516 . 
     Step  506 : If the user has requested transmission using the tag delivery mode, then make a copy of the tag. 
     Step  508 : increment hop count by one in the copy of the tag. 
     Step  510 : Send the copy of the tag over the short-range wireless link. 
     Step  516 : If the user has requested transmission using the tag give away mode, then make a copy of the tag. 
     Step  518 : increment hop count by one in the original tag. 
     Step  520 : Store and keep the copy of the tag with the incremented count. 
     Step  522 : Send the original tag with the original count over the short-range wireless link. 
     Step  530 : If the user has requested transmission over the cellular telephone link, then extract the multimedia content from the tag. 
     Step  532 : Send only the multimedia content over the cellular telephone link. 
       FIG. 3  illustrates the memory and components of the “the wall” server  150 , according to an embodiment of the present invention. The memory  302  is connected by the bus  304  to the Bluetooth access point  140 , hard drive storage  306 , the central processor  310 , and the optional LAN adapter  308 . The memory  302  stores programs, which are, sequences of executable instructions which, when executed in the central processor  310 , carry out the methods of the invention. The memory  302  includes the operating system  316 , the database manager system  318 , the database storage  156  (shown in  FIG. 5 ), the tag storage  154  (shown in  FIG. 4 ), and the application programs  325 . The application programs  325  include manage sending downloaded tag over Bluetooth program  323 , manage receiving painted tag over Bluetooth program  332 , manage searching tags over Bluetooth program  336 , manage browsing over Bluetooth program  338 , manage list view over Bluetooth program  340 , and manage search options over Bluetooth program  342 . The memory  302  also includes the I/O buffer  345 . 
       FIG. 3A  is a flow diagram of “the wall” server communications processing method  600  in the applications programs  325  of “the wall” server  150 . The steps in the flow diagram are as follows. 
     Step  602 : Receive an uploaded tag over the short-range wireless link ( FIG. 1D  or  FIG. 7A ). 
     Step  604 : Set the person-to-person flag (PFG) to the value of “false”. 
     Step  606 : Store the tag in the tag storage ( FIG. 4 ) and store the tag record for the tag in the database storage ( FIG. 5 ). 
     Step  608 : Determine if a request has been received for the tag over the short-range wireless link ( FIG. 1 ). 
     Step  616 : If a request has been received for the tag over the short-range wireless link, then make a copy of the tag. 
     Step  518 : Increment hop count by one in the copy of the tag. 
     Step  510 : Send the copy of the tag over the short-range wireless link ( FIG. 1A  or  FIG. 7B ). 
       FIG. 6A  illustrates an alternate embodiment of the invention, with the Bluetooth equipped cellular telephone  100  browsing for tags in “the wall” server  150 . The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. The server  150  is programmed to store the tags in association with two dimensional X, Y coordinates, in a virtual viewing space shown in  FIG. 6B . Each tag is given a position in the coordinate system at the time it is uploaded and stored in the server  150 . The X, Y coordinates of a tag are with respect to the origin of coordinates X, Y=X0, Y0. For example, the X, Y coordinates of the tag  134  are X, Y=X134, Y134 with respect to the origin of coordinates X, Y=X0, Y0. These coordinates are stored in the tag record  134  of the database  158  of  FIG. 5 . The X, Y coordinates of the screen  120  of the wireless device  100  of  FIG. 6A  are X, Y=X120, Y120 with respect to the origin of coordinates X, Y=X0, Y0. As the user browses tags that have been posted on “the wall” server, he appears to move the viewing area of the screen  120  with respect to the origin of coordinates X, Y=X0, Y0 by using up/down and left/right controls of the user&#39;s Bluetooth device. The screen&#39;s position coordinates X120, Y120 are incremented or decremented as the user presses the up/down and left/right controls, causing the viewing area to pass over and include those tags whose X, Y coordinates are within the viewing area of the screen. A user can browse tags that have been posted on “the wall”, by using up/down and left/right controls of the user&#39;s Bluetooth device  100 . 
       FIG. 7A  illustrates Monique&#39;s Bluetooth equipped cellular telephone  100 ″ uploading her tag  134  to “the wall” server  150 , to “paint the wall” at a position X134, Y134 of the virtual viewing space shown in  FIG. 6B , according to an embodiment of the present invention. Monique uploads her tag  134  on a first occurring day. Note that the person-to-person flag (PFG) has a value of “true” in Monique&#39;s wireless device  100 ″. When the server  150  receives the tag  134 , it resets the person-to-person flag (PFG) to a value of “false”, indicating that the tag  134  has been uploaded to a “wall” server at some time in its life. The database  158  in the server  150  adds a tag record with a tag index for tag  134 . The tag record includes Monique&#39;s name and IMSI or MSISDN identity value+358402370, the hop count=1, the content-originator flag (CFG) value=true, the message authentication code (MAC) of the information in the tag  134 , and the digital signature of Monique. Additional fields in the tag record include a time stamp 18.12.01 when the tag was recorded in the server  150 . The tag record includes a field for the two dimensional X, Y coordinates X134, Y134 of the location of the tag  134  in a virtual viewing space of  FIG. 6B . Tag  134  is uploaded by its author, Monique, with a time stamp of 18.12.01, wherein Monique designates that Tag  134  is a comment on Max&#39;s earlier tag  132 , having a time stamp of 04.12.01. The designation of tag  134  as being a comment about Tag  132 , is stored as the forward linking pointer “For_Link to Tag  134 ” in the record for Tag  132 . A corresponding backward linking pointer “Bak_Link to Tag  132 ” is written by the server in the record for Tag  134 .  FIG. 7B  illustrates the user&#39;s Bluetooth equipped cellular telephone  100  downloading tag  134  from “the wall” server, on a later day 26.01.02, according to an embodiment of the present invention. Note that the hop count value has been incremented by one when the tag was downloaded from the server  150 . Also note that the person-to-person flag (PFG) has a value of “false”, indicating that the tag  134  has been downloaded from a “wall” server at some time in its life. 
       FIG. 8  illustrates another alternate embodiment of the invention, wherein payment is required before user&#39;s device  100  is allowed to upload a tag  138  to “paint the wall” of the server  150 . The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. The Bluetooth equipped cellular telephone  100  sends an SMS charge authorizing message  402  over the GSM cellular telephone access point  148 , GSM infrastructure network  116 , and telephone interface  404  to an account charging server  406 , authorizing the account to be charged. The account charging server  406  returns an SMS payment token  408  over the cellular telephone network to the user&#39;s device  100 . 
       FIG. 9  illustrates another alternate embodiment of the invention, wherein payment is required before a user is allowed to download a tag  134  from the “the wall” server  150 . The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. A digital rights management (DRM) authorization message  420  is prepared in the DRM module  450  in the user&#39;s device  100  and is sent by the user&#39;s device over the Bluetooth link to “the wall” server  150 . A DRM module  422  in the server  150  is connected over a network such as the Internet  144 , to a DRM account charging server  424 . The DRM account charging server  424  handles the necessary steps in debiting the user&#39;s account, and then returns an enabling signal to “the wall” server  150 . 
     The digital rights management (DRM) module  422  in “the wall” server  150  creates a secure environment in the memory  302  of the server  150 , within which the data rights information associated with the tag  134  can be securely written in the “DRM Data” field of the tag  134 . The digital rights management (DRM) module  422  in “the wall” server  150  enters the “Paid” status and additional data rights information in the “DRM Data” field of the tag  134 . The multimedia content  134 ′ can optionally be encrypted by the module  422 . “The wall” server  150  then downloads the tag over the Bluetooth link as requested by the user&#39;s device  100 . The DRM module  450  in the user&#39;s device  100  creates a secure environment in the memory  202  of the device  100 , within which the data rights associated with the tag  134  can be implemented. 
     The DRM data in the tag  134  read by the DRM module  450 , includes rules imposed by its author, Monique, regarding how the tag  134  may be distributed. The rules can include restrictions on copying, transfer, payment for copies, time span allowed for distribution, conditions for distribution of trial samples, allocation of royalties to middleman distributors, and the like. If multimedia content  134 ′ was optionally encrypted by the server  150 , then the DRM module  450  in the user&#39;s device  100  decrypts the multimedia content  134 ′ and permits its display on the screen  120 . Additional description of the principles of digital rights management (DRM) can be found in the book by Bill Rosenblatt, et al., entitled  Digital Rights Management: Business and Technology , published by Professional Mindware, 2001. 
       FIG. 10  illustrates another alternate embodiment of the invention, wherein payment is required before a user is allowed to download a tag from the “the wall” server  150 . The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. A payment accumulator  430  is included in the user&#39;s device  100 , that accumulates authorized charges in a register  432  for downloading a plurality of tags from one or from many “wall” servers  150 , etc. over an extended period, such as a month. At the end of the month, the Bluetooth equipped cellular telephone  100  sends an SMS message  408  containing the monthly total authorized charges, sending it over the cellular telephone system  148 ,  116 , and  404  to an account charging server  406 , authorizing the user&#39;s account to be charged. 
       FIG. 11  illustrates another alternate embodiment of the invention, wherein “the wall” server  150  is connected over a LAN  440  to a remote, backup server  442  that stores a copy of all of the tags  128 ,  130 ,  132 , and  134  and the database  156 / 158 , to be used in the event of disaster recovery. Additionally, the backup server  442  provides an accessible, bulk storage for older tags, to reduce the storage requirements on “the wall” server  150 . 
       FIG. 12  illustrates another alternate embodiment of the invention, wherein payment is required from Max&#39;s requesting device  100 ′, before the providing user&#39;s device  100  will transfer a tag  134  to Max&#39;s requesting device  100 ′. The Bluetooth devices are in close proximity to one another and use the Bluetooth link to exchange tags. A digital rights management (DRM) module  450  in the user&#39;s mobile wireless device  100  and DRM module  450 ′ in Max&#39;s mobile wireless device  100 ′ handle the exchange of charge authorization messages over the Bluetooth link between the mobile devices. The DRM module  450 ′ in Max&#39;s requestor&#39;s device  100 ′ sends a charge authorizing message to the user&#39;s provider device  100 . The user&#39;s provider device  100  then sends the tag  134  requested by Max&#39;s requestor&#39;s device  100 ′, over the Bluetooth link. The digital rights management (DRM) module  450  in the user&#39;s wireless device  100  creates a secure environment in the memory  202  of the device  100 , within which the data rights information associated with the tag  134  can be securely written in the “DRM Data” field of the tag  134 . The DRM module  450  in the user&#39;s wireless device  100  enters the “Paid” status and additional data rights information in the “DRM Data” field of the tag  134 . The multimedia content  134 ′ can optionally be encrypted by the module  450 . The user&#39;s wireless device  100  and then sends the tag  134  over the Bluetooth link in the tag delivery mode as requested by Max&#39;s wireless device  100 ′. The DRM module  450 ′ in Max&#39;s device  100 ′ creates a secure environment in the memory  202  of the device  100 ′, within which the data rights associated with the tag  134  can be implemented. The DRM data in the tag  134  read by the DRM module  450 ′, includes rules imposed by its author, Monique, regarding how the tag  134  may be distributed. The rules can include restrictions on copying, transfer, payment for copies, time span allowed for distribution, conditions for distribution of trial samples, allocation of royalties to middleman distributors, and the like. If multimedia content  134 ′ was optionally encrypted by the user&#39;s wireless device  100 , then the DRM module  450 ′ in Max&#39;s device  100 ′ decrypts the multimedia content  134 ′ and permits its display on Max&#39;s screen  120 . 
     Note that in the example of  FIG. 12 , it is assumed that there has never been an uploading of the tag  134  to a “wall server”. This circumstance is indicated by the person-to-person flag (PFG), which has a value of “true” in the user&#39;s wireless device  100 . The person-to-person flag (PFG) value of “true” verifies that the tag has only been transferred from person-to-person, and has not been downloaded from “the wall” server. The operation of tag delivery from the user&#39;s device  100  to Max&#39;s device  100 ′ does not change the person-to-person flag (PFG), which has a value of “true” in the Max&#39;s wireless device  100 ′. 
     In another alternate embodiment of the invention, a tag can be automatically transferred from one Bluetooth device to another, whether stationary or mobile. The user&#39;s mobile Bluetooth device  100  can be programmed to listen or scan for any Bluetooth access point device  140  connected to a “wall” server  150 . The SDP message exchange will tell the mobile device  100  of the availability of “the wall” services. When the user&#39;s mobile device  100  recognizes “a wall” server  150  within communications range, the user&#39;s mobile device  100  uploads the user&#39;s tag and automatically “paints the wall”. The user&#39;s mobile device  100  can be programmed to automatically send a tag to any other Bluetooth device, including mobile devices such as  100 ′. A “tag worm” can be created, wherein the tag automatically propagates from user device  100  to user device  100 ′, as users walk about. A user can prevent receiving unsolicited tags by turning off this feature. 
     In another alternate embodiment of the invention, a tag can be transferred from the user&#39;s mobile device  100  to a “wall” server  150  located in the user&#39;s home, as a “personal or family tag storage”. The personal home “wall” server  150  is programmed to check the MSISDN identity of the mobile device  100  storing the tags. The user can store and retrieve his/her tags from the personal home “wall” server  150  without changing the hop counts in the tags. If an unauthorized person or device  100 ′ were to attempt retrieving the user&#39;s tags, the personal home “wall” server  150  can prevent downloading the tags, or alternately it can increment the hop counts in copies of the tags that are downloaded. 
     In another alternate embodiment of the invention, “the wall” server  150  includes a queuing management system as one of the application programs  325  in  FIG. 3 . In this embodiment, the short-range wireless access point  140  for “the Wall” server  150  is located within the premises of a business. The queuing management system program of “the wall” server  150  performs the function of establishing a queue of customers waiting for service, such as in a bank or at a funfair or the like. The customer sends his/her Tag similar to Tag  138  shown in  FIG. 1D  (including his/her presence/ID-information) to “the Wall” server  150 . “The wall” server  150  registers the customer as being on a virtual queuing line established by the queuing management system program. When the customer uploads his/her tag to the server  150 , the server  150  can optionally return the tag  128  that is an advertisement message of the business, such as “Welcome to First National Bank. Open an interest-free checking account today.” After registering, the customer can optionally browse other tags from “the Wall” server as shown in  FIG. 1 , while awaiting his/her turn within the premises of the business. Alternately, the customer can leave the premises of the business and when his/her turn is reached on the virtual queue, the queuing management system program of “the Wall” server  150  sends a notification message informing the customer that it is his/her turn at the front of the queue. The notification message can be sent over a cellular telephone network connected to “the wall” server  150 , such as the network  116  in  FIG. 8 , to deliver an SMS message, similar to SMS message  408  shown in  FIG. 8 . Alternately, the notification message can be transmitted over a LAN such as the LAN  440  connected to “the wall” server  150  in  FIG. 11 , and delivered over a Bluetooth link to the customer&#39;s device  100  by a nearby Bluetooth access point connected to the LAN. 
     The resulting invention can be implemented in any suitable short range wireless system, including wireless personal area networks (PANs), such as Bluetooth networks, Radio Frequency Identification (RFID), and Infrared Data Protocol networks (IrDA), and wireless local area networks (LANs), such as the IEEE 802.11 wireless LANs and HIPERLAN networks. 
     I. II. Messaging Tags 
       FIGS. 1-12  involve short-range communications networks, such as Bluetooth. However, tags may be exchanged in other environments, as well. For instance, tags may be exchanged in environments where close physical proximity between devices is not required for communications. For example, messaging services, such as the Multimedia Messaging Service (MMS), may be employed to exchange tags across networks. These networks may involve various wireless technologies. For example, such tags may be exchanged across cellular telecommunications infrastructure. 
     Multimedia messaging service (MMS). provides automatic and immediate delivery of personal messages. MMS is similar in nature to short messaging service (SMS). However, unlike SMS, MMS provides for mobile phone users to enhance their messages by incorporating sound, images, and other rich content. This allows for the exchange of personalized visual and audio messages. In addition to broadening message content, MMS technology allows for flexibility in the source and destination of MMS messages. For instance, in addition to sending MMS messages from one phone to another, MMS messages may also be sent from phone to email, and vice versa. Another feature of MMS is that the message is a multimedia presentation in a single entry, not a text file with attachments. This makes MMS a simple and user-friendly way to exchange multimedia content. Information regarding MMS can be downloaded from the following sites on the Internet: http://www.nokia.com/mms/index.html; and http://www.mobileMMS.com. 
     An MMS message is not sent directly from the sender to the recipient. Rather, it is sent to a multimedia service center (MMSC), which locates the recipient and delivers the message to the recipient (after sending an SMS notification and receiving a request for the message). Thus MMS can provide connectionless messaging communications. 
     Embodiments of the present invention employ message tags that are exchanged according to a messaging service, such as MMS. However, instead of being in conventional message formats (e.g., a standard MMS format), these message tags have formats that are detectable by communications devices, such as cellular telephones. Upon detection of a message tag, these devices can process and transmit the tag according various rules, and restrictions regarding the transfer of tags. An exemplary message tag format is shown in  FIG. 13 . 
       FIG. 13  is a diagram illustrating the format of an exemplary multimedia content tag  1300 . As shown in  FIG. 13 , multimedia content tag  1300  includes a message portion  1302 , and a header portion  1304  that is appended to message portion  1302 . Message portion  1302  is a multimedia message, such as an MMS message. Accordingly, message portion  1302  may include content  1303 , such as images, text, voice, audio, and/or other types of content. 
     Header portion  1304  includes various fields. In particular,  FIG. 13  shows that header portion  1304  includes a tag flag  1310 , a tag ID  1312 , a hop count  1314 , and a person-to-person flag (PFG)  1316 . 
     Tag Flag  1310  may have either a “true” or a “false” value. A “true” value indicates that multimedia content tag  1300  is not a conventional multimedia content message, but a multimedia message tag. Accordingly, when a communications device receives a multimedia message (e.g., an MMS message), it identifies the message as a multimedia content tag if it has a header portion  1304  that includes a tag flag  1310  value of “true”. At this point, the communications device may process and transmit the tag according to rules and conditions associated with the transfer of tags. 
     Tag ID  1312  indicates the originator of MMS tag  1300 . Thus, Tag ID  1312  is a universal identity code for a subscriber that distributes tags. This field may be based on an MSISDN or an encrypted MSISDN associated with the originator. In further embodiments, tag ID  1312  may be based on other subscriber related identifiers, such as IMSIs, e-mail addresses, and Internet Protocol (IP) addresses. 
     Hop count  1314 , indicates the number of times that tag  1300  has been delivered (also referred to herein as “hugged”) since it was originated by its initiator. As described above, a hop count  1314  value of zero is written into the tag when the original user has created the content in his/her device. If the user uploads the tag to the server and writes the tag on “the wall”, hop count  1314  is incremented by one. Whenever a later user downloads a copy of the tag from the server, hop count  1314  is incremented again by one. When one user sends a copy of the tag to another user, each transmission increments hop count  1314  in the tag by one. This feature makes original copies of the content more valuable, as signified by a low hop count value in the tag. 
     Person-to-Person Flag (PFG)  1316  indicates whether tag  1300  has ever been publicly available. For example, PFG Flag  1316  indicates whether tag  1300  has been published on a virtual tag wall (such as wall server  150 ) or similar entity. As described above, the initial value of PFG flag  1316  is set to a value of “true” when the originating user creates the tag. This value of “true” verifies that the tag has only been transferred from person-to-person, and has not been downloaded from a virtual tag wall. When the tag is uploaded to a virtual tag wall, the value of PFG flag  1316  is reset to a value of “false”, and can never be returned to a value of “true”. Thus, a tag directly received from a famous person will have a person-to-person hop count of one, and thus be an item of value, similar to an original, famous autograph. As long as the tag is not transferred to a virtual tag wall, the value of person-to-person PFG flag  1316  remains “true” and the tag has a greater value than it would if it had been obtained by downloading it from a virtual tag wall. 
     As an alternative to the format shown in  FIG. 13 , the information of header portion  1304  may instead be embedded inside a standard MMS structure as an internal header. This internal header can be a portion within a standard message. For example, inside an MMS message, there can be additional fields that are the internal header. Such internal headers may be implemented like normal text input by users, but interpreted by communications devices as a tag header. 
     According to one embodiment of the present invention, parts of the multimedia content tag, such as one or more fields of header portion  1304  may be encrypted during transmission and storage within communications devices. These encrypted parts may be decrypted for various tag processing operations performed by the communications devices. 
     For example, when a tag is created, a value is assigned to its tag ID field. The value of this field cannot be changed later on. Instead, a recipient of the tag may copy its MMS into a newly created tag, and assign a different value to the tag ID field of the new tag. 
     In addition, different transfer modes may be employed, such as the aforementioned tag delivery and tag give-away modes. These transfer modes affect the manner in which a tag&#39;s hop count field is incremented. 
     For instance, in the aforementioned tag delivery mode, a sending user transfers a copy of the tag in the sender&#39;s device, causing the hop count to be incremented by one in the copy of the tag received by the recipient. In the “tag give-away” mode, the sending user transfers the tag currently in his/her device, causing the hop count to remain unchanged in the tag received by the recipient. Thus, the sender effectively keeps a copy of the tag having a hop count that is incremented by one. 
     By incrementing a tag&#39;s hop count during its distribution, the percentage of tags having small hop count values become rare. Thus, a tag having a small hop count indicates that its possessor is familiar with the tag&#39;s originator. 
     Further conditions (restrictions) may be imposed on the transfer of tags. For example, in a cellular communications environment, tag transfer may only be allowed between users that are inside the same network cell. In other words, the exchange of tags between users within different cells would not be enabled. 
       FIG. 14  is a flowchart illustrating the processing of a multimedia messaging tag by a wireless communications device (WCD), such as a cellular telephone. The following description of these steps is made with reference to the format of multimedia content tag  1300 . However, this process may be employed with other tags in various formats. 
       FIG. 14  shows that there are various ways in which tag processing operations may commence. Steps  1401 ,  1402 , and  1403  illustrate three such ways. 
     In step  1401 , the user of the WCD creates a new multimedia message tag. However, in step  1402 , the user of the WCD selects a tag from the tag buffer within the WCD. As shown in  FIG. 14 , a step  1408  follows each of steps  1401  and  1402 . 
     In step  1403 , the WCD receives multimedia content message from a wireless communications network, such as a GSM cellular network. A step  1404  follows step  1403 . In this step the WCD determines whether the received message contains a tag flag  1310  having a value of “true”. If not, then operation proceeds to step  1406 , where the wireless communications device engages in normal multimedia message processing. However, if the received multimedia message contains a Tag Flag  1310 , then operation proceeds to step  1408 . 
     In step  1408 , the WCD determines a mode in which the tag is to be sent. For instance, this step comprises determining whether the tag is sent according to a tag delivery mode or a tag give away mode. This step may comprise the user of the WCD interacting with a user interface to designate the transmission mode. For example, step  1408  may comprise the WCD displaying a menu providing a selection of tag send modes. The user would then select one of the displayed modes. 
     Next, in a step  1410 , the WCD decrypts the multimedia content tag  1300 . At this point, the WCD is able to change the content of fields included in header portion  1304 , such as hop count  1314  and PFG flag  1316 . 
     In a step  1412 , the WCD changes the contents of one or more fields in header portion  1304 . 
     A step  1414  follows step  1412 . In this step, the WCD encrypts the one or more fields of header portion  1304 . 
     Next, in a step  1416 , the WCD sends the multimedia content tag to its destination. 
     II. Encryption 
     As described above, each tag includes a tag ID, which is a universal identity code for the subscriber (user) who distributed the tag. Thus, when a tag is sent to a destination, such as a user&#39;s communication device or a virtual tag wall, its tag ID can be used to identify the person who originated the tag. Accordingly, strategies for searching tags transmitted by certain people may be based on tag IDs. For example, at virtual tag walls, a user (subscriber) can search for the tags of particular individuals, if the user knows the Tag IDs that correspond to these individuals. 
     These tag IDs may be based on subscriber network IDs (e.g., MSISDNs or IMSIs). For instance, tag IDs may be assigned the network IDs of the originating subscribers. Such assignment schemes are convenient for establishing a universal tagging identity, because they associate tag IDs to numbers established by a cellular operator. 
     However, the employment of such ID numbers may create security issues. This is because, in order to distribute tags, users are required to make their subscriber IDs (i.e., their telephone numbers) publicly available. This requirement may reduce people&#39;s willingness to send tags to locations that they visit (i.e., virtual walls), or transfer tags to people that they meet. 
     The present invention provides techniques that eliminate such security issues, while maintaining an association between network subscriber IDs and tag IDs. In addition, the present invention also provides secure techniques for determining the identity of a tag&#39;s originator. 
     For example, instead of making a subscriber&#39;s network ID (e.g., an MSISDN) publicly available as the tag IDs, an asymmetrically encrypted version of the subscriber&#39;s network ID is used. This encryption is done based on a public encryption key. This public key may be distributed among communications devices. Alternatively, this public key may be kept only within a secure trusted domain. A corresponding private key is used for decrypting tag IDs into network subscriber IDs. In embodiments, this private key is kept within a secure trusted domain, and is never published outside of the trusted domain. 
     The public encryption key allows users to derive tag IDs from network IDs that they are aware of. However, by maintaining the corresponding private key in secret, a user cannot derive network IDs from tag IDs without authorization from the trusted domain. 
       FIGS. 15A and 15B  are diagrams that illustrate relationships between a subscriber ID  1502  and its corresponding tag ID  1504 . In these relationships, both a public encryption key and a private encryption key are associated with an asymmetric encryption algorithm  1510 .  FIG. 15A  shows that the public encryption key may be used to derive the tag ID from the subscriber ID. Conversely,  FIG. 15B  shows that the private encryption key may be used to derive the subscriber ID from the tag ID. 
     Asymmetric encryption algorithm  1510  may employ various encryption techniques. One such technique is RSA encryption. RSA encryption is a public-key encryption technology developed by RSA Data Security, Inc. The acronym stands for Rivest, Shamir, and Adelman. The RSA algorithm is based on the fact that there is no efficient way to factor very large numbers. Therefore, deducing an RSA key, would require an extraordinary amount of computer processing power and time. Many software products utilize RSA encryption. 
       FIG. 16  is a block diagram of an operational environment that includes a wireless communications device (e.g., a cellular telephone)  1602 , a trusted domain  1604 , a wireless communications network  1606 , a packet-based network  1607 , and a subscriber identification node  1608 . 
     WCD  1602  may be implemented in a manner that is similar to wireless device  100 . However, as an alternative to exchanging tags across short-range wireless communications links, WCD  1602 , may exchange tags across other types of links, such as cellular communications links. 
     Wireless communications network  1606  is illustrated as a GSM network comprising GSM access point  1610 , a GSM infrastructure network  1612 , and a gateway  1614 . As shown in  FIG. 16  network  1612  is coupled between access point  1610  and gateway  1614 . Gateway  1614  converts between transmission formats used in communications network  1606  and packet-based network  1607 . Although  FIG. 16  shows a particular GSM implementation for communications network  1606 , other implementations are within the scope of the present invention. 
     Packet-based network  1607  is a network, such as the Internet, that provides for the exchange of packets according to one or more protocols. Examples of such protocols include the Internet Protocol (IP), and the Transmission Control Protocol (TCP). 
     Trusted domain  1604  includes a tag ID processing server  1616 . As shown in  FIG. 16 , server  1616  is coupled to gateway  1614  by network  1607 . This allows information to be exchanged between WCD  1602  in the form of requests and responses. Tag ID processing server  1616  provides tag ID configuration services and tag ID resolution services to devices, such as WCD  1602 . Tag ID configuration services enable a subscriber to obtain a tag ID for use in tags that it may create and/or transmit. Such a tag ID may be based on subscriber identification information, such as an MSISDN or an IMSI. 
     Tag ID resolution services provide mappings from Tag IDs to corresponding subscriber identity information (e.g., a subscriber&#39;s name). This feature advantageously enables subscribers to ascertain the source of information. For example, if a subscriber receives a multimedia content tag that includes an autographed image of a celebrity, the subscriber may determine whether the tag was actually originated by the celebrity. To determine this, the subscriber can send the tag ID of the received tag to server  1616  for identity resolution. In response, server  1616  will respond with information that identifies the subscriber that transmitted the tag. If this subscriber is the celebrity, then the tag can be considered an authentic autograph. However, if the subscriber is someone else, then the tag can be viewed as an unauthentic autograph of lesser intrinsic value. 
     Tag ID processing server  1616  operates in a trusted domain  1606 . Trusted domain  1606  allows the services that are provided by tag ID processing server  1616  to be accessible only to authorized subscribers. Accordingly, trusted domain  1606  may be implemented through authentication techniques that control which subscribers have access to information and services provided by, for example, server  1616 . 
     An example of such authentication techniques include requiring a password from WCD  1602  to verify that its user is authorized to utilize the services of server  1616 . Transmissions involving this password may be encrypted. Such authentication may be provided by server  1616 , or a separate authentication server (not shown) within trusted domain  1606 . This encryption may be based on a key provided, for example, by either server  1616  or the separate authentication server. 
     As shown in  FIG. 16 , subscriber identification node  1608  is coupled to tag ID processing server  1616  by network  1607 . However, in alternative embodiments, these elements may be coupled by other means. Node  1608  may include one or more telephony databases  1609  that store subscriber-related information. For example identification node  1608  may include a telecommunications operators  118  service which identifies the person associated with an subscriber ID, such as an MSISDN. 
       FIGS. 17-18  illustrate processes involving the operational environment of  FIG. 16 . In particular,  FIG. 17  shows a tag ID configuration process that allows communications devices to receive their tag ID for use in the creation and transmission of tags.  FIG. 18  shows a tag identity resolution process that allows communications devices to determine subscriber IDs from tag IDs. Although  FIGS. 17-18  are described with reference to the environment of  FIG. 16 , these processes may also be performed in other environments. 
     The process shown in  FIG. 17  begins with a step  1702 . In this step, WCD  1602  transmits a configure tag ID request to server  1616  within trusted domain  1606 . This message includes an identification number associated with the user (subscriber) of WCD  102 , such as an MSISDN or an IMSI. 
     Next, in a step  1704 , tag ID processing server  1616  receives and processes the configure tag ID request. This processing results in a tag ID being derived from the identification number included in the configure tag ID request. As shown in  FIG. 17 , step  1704  includes using an asymmetric encryption algorithm (e.g., RSA) and a public key to encrypt this identification number. Since server  1616  is within trusted domain  1604 , step  1704  may also include engaging in an authentication procedure with WCD  1602  to ensure that the user of WCD  1602  is authorized to utilize the services of processing server  1616 . 
     A step  1706  follows step  1704 . In step  1706 , tag ID processing server  1616  sends a tag ID configuration message. This message includes the tag ID generated in step  1704 . Next in step  1708 , WCD  1602  may automatically insert this tag ID into tags that it creates and transmits. 
     The process of  FIG. 17  involves the exchange of messages between WCD  1602  and tag ID processing server  1616 . These messages may be in various formats. For example, these messages may be SMS messages. 
     As an alternative to the process shown in  FIG. 17 , WCD  1602  may independently derive a tag ID from subscriber-related identification numbers. To perform this operation, WCD  1602  possesses the public key and functionality to perform the asymmetric encryption algorithm described above. This functionality may be implemented with hardware, software, firmware, or any combination thereof. WCD  1602  may store the public key in memory such as RAM. In such implementations, WCD  1602  may receive the public key from server  1616  in response to a key request that it transmits. 
       FIG. 18  is a diagram illustrating a tag identity resolution process. In this process, the user of WCD  1602  desires to know a tag originator&#39;s identity, such as his name. This process begins with a step  1802 , in which WCD  1602  sends a tag ID resolution request to tag ID processing server  1616  within trusted domain  1606 . 
     Next, in a step  1804 , tag ID processing server  1616  receives and processes the tag ID resolution request. This processing results in a subscriber related identification number (e.g., MSISDN or IMSI) being derived from the tag ID included in the configure tag ID message. As shown in  FIG. 18 , step  1704  includes using an asymmetric encryption algorithm (e.g., RSA) and a private key to decrypt this identification number. Since server  1616  is within trusted domain  1604 , step  1804  may also include engaging in an authentication procedure with WCD  1602  to ensure that the user of WCD  1602  is authorized to utilize the services of processing server  1616 . 
     A step  1806  follows step  1804 . In this step, the identification number derived in step  1804  is transmitted to subscriber identity node  1608 . In a step  1808 , subscriber identity node  1608  receives and processes this identification number. This processing may include obtaining subscriber identity information (e.g., a subscriber&#39;s name) that is associated with this identification number. 
     Next, in a step  1810 , this subscriber identity information is transmitted to tag ID processing server  1616 . In a step  1812 , this subscriber identity information is forwarded to WCD  1602  across wireless communications network  1606 . 
       FIG. 19  is a flowchart illustrating the searching of tags according to embodiments of the present invention. 
     In a step  1902 , the user of WCD  1602  identifies one or subscriber IDs. These subscriber IDs may selected, for example, from a personal phonelist, or a published phone directory. 
     In a step  1904 , WCD converts these subscriber IDs into corresponding tag IDs. This step comprises using a designated asymmetric encryption algorithm and a designated public key to derive tag IDs from subscriber IDs. Accordingly, this step  1904  may comprise performing the tag ID configuration process described above with reference to  FIG. 17 . Alternatively, in embodiments, where WCD  1602  possesses the public key and the asymmetric encryption algorithm, step  1904  may comprise WCD  1602  converting these subscriber IDs into Tag IDs itself. 
     A step  1906  follows step  1904 . In step  1906 , WCD  1602  transmits a query containing the one or more derived tag IDs to a remote device, such as a virtual tag wall. In a step  1908 , the remote device sends any tag(s) containing tag ID fields that match the one or more tag IDs sent in step  1906 . 
       FIG. 20  is a diagram illustrating a tag searching example. In this example, WCD  1602  searches for tags contained at a wall server  150 ′. Wall server  150 ′ is similar to wall server  150 , as described above. However, wall server  150 ′ includes a messaging interface  2002  that provides for the exchange of messaging tags, such as MMS tags. Moreover, instead of including a database  156 , which contains entries having personal IDs (e.g., IMSI or MISDN), wall server  150 ′ includes a database  156 ′. Database  156 ′ contains entries that are indexed according to tag IDs that are encrypted according to the techniques described herein. 
     As shown in  FIG. 20 , WCD  1602  searches for tags associated with three different MSISDN numbers: 358405694771, 358506455371, and 358405694771. These MSISDNs are encrypted with the public key to obtain the corresponding tag IDs: Kg75kHtTwe, eo983ck45h, and kHtO7GQhtr. 
     These tag IDs are sent in a query to wall server  150 ′. Upon receipt of this query, wall server  150 ′ searches database  156 ′ for the tag IDs contained in the query. As shown in  FIG. 20 , a match is found in tag  130 . Accordingly, tag  130  is transmitted to WCD  1602  according to the tag transfer techniques described herein. 
     The example of  FIG. 20  shows that subscriber ID numbers (e.g., MSISDNs) associated with the search never left WCD  1602 . This feature advantageously provides enhanced security and privacy. 
     III. Computer System 
     Various elements described herein, such as tag ID processing server  1616 , subscriber identification node, and server  150 ′, may implemented with one or more computer systems. An example of a computer system  2101  is shown in  FIG. 21 . Computer system  2101  represents any single or multi-processor computer. Single-threaded and multi-threaded computers can be used. Unified or distributed memory systems can be used. 
     Computer system  2101  includes one or more processors, such as processor  2104 . One or more processors  2104  can execute software implementing processes, such as the ones described above with reference to  FIGS. 17 ,  18 , and  19 . Each processor  2104  is connected to a communication infrastructure  2102  (for example, a communications bus, cross-bar, or network). Various software embodiments are described in terms of this exemplary computer system. After reading this description, it will become apparent to a person skilled in the relevant art how to implement the invention using other computer systems and/or computer architectures. 
     Computer system  2101  also includes a main memory  2107  which is preferably random access memory (RAM). Computer system  2101  may also include a secondary memory  2108 . Secondary memory  2108  may include, for example, a hard disk drive  2110  and/or a removable storage drive  2112 , representing a floppy disk drive, a magnetic tape drive, an optical disk drive, etc. Removable storage drive  2112  reads from and/or writes to a removable storage unit  2114  in a well known manner. Removable storage unit  2114  represents a floppy disk, magnetic tape, optical disk, etc., which is read by and written to by removable storage drive  2112 . As will be appreciated, the removable storage unit  2114  includes a computer usable storage medium having stored therein computer software and/or data. 
     In alternative embodiments, secondary memory  2108  may include other similar means for allowing computer programs or other instructions to be loaded into computer system  740 . Such means can include, for example, a removable storage unit  2122  and an interface  2120 . Examples can include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an EPROM, or PROM) and associated socket, and other removable storage units  2122  and interfaces  2120  which allow software and data to be transferred from the removable storage unit  2122  to computer system  2101 . 
     Computer system  2101  may also include a communications interface  2124 . Communications interface  2124  allows software and data to be transferred between computer system  2101  and external devices via communications path  2127 . Examples of communications interface  2127  include a modem, a network interface (such as Ethernet card), a communications port, etc. Software and data transferred via communications interface  2127  are in the form of signals  2128  which can be electronic, electromagnetic, optical or other signals capable of being received by communications interface  2124 , via communications path  2127 . Note that communications interface  2124  provides a means by which computer system  2101  can interface to a network such as the Internet. 
     The present invention can be implemented using software running (that is, executing) in an environment similar to that described above with respect to  FIG. 21 . In this document, the term “computer program product” is used to generally refer to removable storage units  2114  and  2122 , a hard disk installed in hard disk drive  2110 , or a signal carrying software over a communication path  2127  (wireless link or cable) to communication interface  2124 . A computer useable medium can include magnetic media, optical media, or other recordable media, or media that transmits a carrier wave or other signal. These computer program products are means for providing software to computer system  2101 . 
     Computer programs (also called computer control logic) are stored in main memory  2107  and/or secondary memory  2108 . Computer programs can also be received via communications interface  2124 . Such computer programs, when executed, enable the computer system  2101  to perform the features of the present invention as discussed herein. In particular, the computer programs, when executed, enable the processor  2104  to perform the features of the present invention. Accordingly, such computer programs represent controllers of the computer system  2101 . 
     The present invention can be implemented as control logic in software, firmware, hardware or any combination thereof. In an embodiment where the invention is implemented using software, the software may be stored in a computer program product and loaded into computer system  2101  using removable storage drive  2112 , hard drive  2110 , or interface  2120 . Alternatively, the computer program product may be downloaded to computer system  2101  over communications path  2127 . The control logic (software), when executed by the one or more processors  2104 , causes the processor(s)  2104  to perform the functions of the invention as described herein. 
     In another embodiment, the invention is implemented primarily in firmware and/or hardware using, for example, hardware components such as application specific integrated circuits (ASICs). Implementation of a hardware state machine so as to perform the functions described herein will be apparent to persons skilled in the relevant art(s). 
     IV. Conclusion 
     Although specific embodiments of the invention have been disclosed, it will be understood by those having skill in the art that changes can be made to those specific embodiments without departing from the spirit and the scope of the invention. 
     For example, while the encryption and security techniques of the present invention are described in the context of messaging tag, they may also be employed with short-range tag implementations involving technologies, such as Bluetooth.