Patent Publication Number: US-11032592-B2

Title: Systems and methods for securely streaming media content

Description:
This Application is a continuation of U.S. patent application Ser. No. 15/912,345 filed on Mar. 5, 2018, which is a continuation of U.S. patent application Ser. No. 15/359,125 filed Nov. 22, 2016, which is a continuation of U.S. patent application Ser. No. 14/842,452 filed Sep. 1, 2015, which is a continuation of U.S. patent application Ser. No. 14/191,039 (No U.S. Pat. No. 9,143,827) filed on Feb. 26, 2014, which is a continuation of U.S. patent application Ser. No. 12/166,039 (now U.S. Pat. No. 8,667,279) filed Jul. 1, 2008. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to streaming of media content, and more particularly relates to systems and methods for improving the security of media streaming. 
     BACKGROUND 
     Most television viewers now receive their television signals through a content aggregator such as a cable or satellite television provider. For subscribers to a direct broadcast satellite (DBS) service, for example, television programming is received via a broadcast that is sent via a satellite to an antenna that is generally located on the exterior of a home or other structure. Other customers receive television programming through a cable, wireless or other medium. Programming is typically received at a receiver such as a “set top box” (STB) that demodulates the received signals and that converts the demodulated content into a format that can be presented to the viewer on a television or other display. 
     More recently, consumers have expressed significant interest in “place shifting” devices that allow viewing of television or other media content at locations other than their primary television set. Place shifting devices typically packetize media content that can be transmitted over a local or wide area network to a portable computer, mobile phone, personal digital assistant or other remote device capable of playing back the packetized media stream for the viewer. Placeshifting therefore allows consumers to view their media content from remote locations such as hotel rooms, offices, or any other locations where portable media player devices can gain access to a wireless or other communications network. 
     While placeshifting does greatly improve the convenience afforded to the viewer, the inherently insecure nature of many communications networks (such as the Internet) continues to pose challenges. That is, while it remains desirable to allow consumers to place shift their media playing experience, it is also desirable to ensure that only authorized users and players are allowed access to valuable media content. 
     It is therefore desirable to create systems and methods for securely placeshifting media content from a place shifting device to a remote media player. These and other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background section. 
     BRIEF SUMMARY 
     Various systems and methods are provided for securely providing a place-shifted media stream from a place shifting device to a remote player via a communications network. A request for a connection is received from the remote player at the place shifting device via the communications network. In response to the request for the connection, an authorization credential is requested from a central server via the communications network. Further, in response to the authorization credential received from the central server, the place-shifted media stream between the place shifting device and the remote player can be established over the communications network. At least a portion of the place-shifted media stream is encrypted based upon the authorization credential. 
     Other embodiments provide systems for securely providing a place-shifted media stream to a remote player via a communications network. The system comprises a network interface to the communications network and a receiver interface to a medium separate from the communications network. A receiver is configured to receive media content from the receiver interface, and a transcoder is configured to packetize the received media content for transport over the communications network. Control circuitry in communication with at least the network interface and the transcoder is configured to receive a request for a connection from the remote player via the network interface, to request an authorization credential from a central server via the network interface in response to the request for the connection, and, in response to receiving the authorization credential from the central server via the network interface, to establish the place-shifted media stream to the remote player via the network interface. In various embodiments, at least a portion of the place-shifted media stream may be encrypted based upon the authorization credential. 
     Still other embodiments provide a method of presenting a place-shifted media stream to a user of a remote device, wherein the place-shifted media stream is provided from a place shifting device to the remote device over a communications network. The user is authenticated to a central server via the communications network. Upon successful authentication with the central server, a connection to the place shifting device is requested. Upon receiving a response from the place shifting device, authorization is requested to connect to the place shifting device from the central server via the communications network. An authorization response comprising an authorization credential is received from the central server via the communications network, and the place-shifted media stream is established, In various embodiments, at least a portion of the place-shifted media stream may be encrypted based upon the authorization credential. 
     Still other embodiments provided a method of allowing a place-shifted media stream to be provided to a user of a remote device, wherein the place-shifted media stream is provided from a place shifting device to the remote device over a communications network. A first request is received from the remote device via the communications network, wherein the first request comprises a user credential associated with the user. The user credential is verified and, in response to successful verification, a first response is transmitted to the remote device that identifies the place shifting device. An authentication credential is then transmitted to the remote device in response to a second request from the remote device and to the place shifting device in response to a key request from the place shifting device to thereby allow the remote device and the place shifting device to establish the place-shifted media stream based at least in part upon the authentication credential. In various embodiments, at least a portion of the place-shifted media stream may be encrypted based upon the authorization credential. 
     Various other embodiments, aspects and other features are described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       Exemplary embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is a block diagram of an exemplary secure placeshifting system; 
         FIG. 2  is a block diagram of an exemplary placeshifting device; 
         FIG. 3  is a data flow diagram showing exemplary processes for establishing secure placeshifting between a place shifting device and a remote device; and 
         FIG. 4  is a flowchart of an exemplary process for transmitting an encrypted media stream to the remote player. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
     Generally speaking, place shifting of media content is made more secure through the use of various authentication and/or encryption features. In various embodiments, the place shifting device verifies that it has an approved capability to provide placeshifting functions. This verification may be based upon “rights” set or modified on the placeshifting device by a human. Alternatively, placeshifting “rights” may be set or modified based upon information received via a satellite, cable or other connection that also provides programming content to the device. In other embodiments, authentication in real-time (or near real-time) can be performed to authenticate the user to a central server and/or to the placeshifting device, and/or to verify that the requesting remote player/device is authentic and approved to receive placeshifted content. A credential-sharing environment may be further constructed so that the transmitting and receiving devices receive cryptographic keys and/or other credentials from a secure central server. The authentication credentials provided from the central server can be used to encrypt some or all of the placeshifted media stream. In various further embodiments, the amount of encryption is adjusted based upon such factors as the quality of the video stream, the processing capabilities of the remote media player, the bandwidth of the intervening communications links, and/or other factors as appropriate. The various concepts described herein may be deployed independently from one another, or two or more may be combined with each other in any manner to produce an even more secure place shifting environment. 
     The secure mechanisms described herein may find particular benefit when used with hardware capable of both receiving television signals (e.g., signal feeds from a satellite, cable, wireless or other source) and of providing the place shifting function. The invention is not so limited, however; to the contrary, the security features described herein may be used in conjunction with conventional placeshifting systems and devices, including those that interact with other external devices such as television receivers, removable media players, digital or personal video recorders, and/or other sources of programming content. 
     Turning now to the drawing figures and with initial reference to  FIG. 1 , an exemplary placeshifting system  100  suitably includes a placeshifting device  108  that packetizes media content for transmission to a remote device  112  over a communications network  102 . In embodiments that provide enhanced security, a central server  114  that maintains a database  116  of information is also able to communicate with placeshifting device  108  and remote device  112  via network  102 . Although  FIG. 1  shows only a single placeshifting device  108 , a single remote device  112  and a single central server  114 , in practice system  100  may include any number of servers  114  that are able to interact with hundreds, thousands or even more placeshifting device  108 , each of which may be able to stream media content to any number of different remote devices  112 . 
     Network  102  is any digital or other communications network capable of transmitting messages between senders and receivers. In various embodiments, network  102  includes any number of public or private data connections, links or networks supporting any number of communications protocols. Network  102  may include the Internet, for example, or any other network based upon TCP/IP or other conventional protocols. In various embodiments, network  102  also incorporates a wireless and/or wired telephone network, such as a cellular communications network for communicating with mobile phones, personal digital assistants, and/or the like. Network  102  may also incorporate any sort of wireless or wired local area networks, such as one or more IEEE 802.3 and/or IEEE 802.11 networks. Placeshifting device  108  is therefore able to communicate with remote device  112  in any manner. Such communication may take place over a wide area link that includes the Internet and/or a telephone network, for example; in other embodiments, communications between devices  108  and  112  may take place over a wired or wireless local area link incorporated within network  102 , with messages to central server  114  taking place over a wide area link also incorporated within network  102 . 
     Placeshifting device  108  is any component, hardware, software logic and/or the like capable of transmitting a packetized stream of media content over network  102 . In various embodiments, placeshifting device  102  incorporates suitable transcoder logic to convert audio/video or other media data into a packetized format that can be transmitted over network  102 . The media data may be in any format, and may be received from any source such as a broadcast, cable or satellite television programming source, a “video-on-demand” or similar source, a digital video disk (DVD) or other removable media, a video camera, and/or the like. In various embodiments, placeshifter device  108  is any of the various SLINGBOX products available from Sling Media of Foster City, Calif., which are generally capable of receiving media content from an external digital video recorder (DVR), set top box (STB), cable or satellite programming source, DVD player, and/or the like. 
     In further embodiments, placeshifter device  108  may also include content receiving capabilities. That is, device  108  may be a hybrid STB or other receiver that also provides transcoding and placeshifting features, as described more fully below. Such a device may receive satellite, cable, broadcast and/or other signals that encode television programming  105  from an antenna  104 , modem, server and/or other source. The receiver may further demodulate or otherwise decode the received signals  105  to extract programming that can be locally viewed and/or place shifted to a remote viewer  112  as appropriate. Such devices  108  may also include a content database  110  stored on a hard disk drive, memory, or other storage medium to support a personal or digital video recorder (DVR) feature as appropriate. 
     In the exemplary embodiment illustrated in  FIG. 1 , placeshifting device is a hybrid receiver/transcoder that receives digital broadcast satellite (DBS) signals  105  from a satellite  106  at an antenna  104 . Equivalent embodiments, however, could receive programming  105  from a cable connection, broadcast source, removable media, service provider accessible via network  102 , any external device and/or the like. In embodiments that include DVR functionality, programming may be stored in database no as desired (e.g., in response to user/viewer programming instructions) for subsequent viewing on a television or other display located in relatively close proximity; programming need not be stored in all instances or embodiments, however, and programming could be alternately provided in real time. As noted above, content may be presented on a television or other display that is physically connected to device  108 , or may be placeshifted from device  108  to a remote device  112  over network  102 . 
     Remote device  112  is any device, component, module, hardware, software and/or the like capable of receiving a media stream from placeshifting device  108 . In various embodiments, remote device  112  is personal computer (e.g., a “laptop” or similarly portable computer, although desktop-type computers could also be used), a mobile phone, a personal digital assistant, a personal media player (such as the ARCHOS products available from the Archos company of Igny, France) or the like. In many embodiments, remote device  112  is a general purpose computing device that includes a media player application in software or firmware that is capable of securely connecting to placeshifting device  108 , as described more fully below, and of receiving and presenting media content to the user of the device as appropriate. 
     Many different placeshifting scenarios could be formulated based upon available computing and communications resources, as well as consumer demand. In various embodiments, consumers may wish to placeshift content within a home, office or other structure, such as from a placeshifting device  108  to a desktop or portable computer located in another room. In such embodiments, the content stream will typically be provided over a wired or wireless local area network operating within the structure. In other embodiments, consumers may wish to placeshift content over a broadband or similar network connection from a primary location to a computer or other remote device  112  located in a second home, office, hotel or other remote location. In still other embodiments, consumers may wish to placeshift content to a mobile phone, personal digital assistant, media player, video game player, automotive or other vehicle media player, and/or other device via a mobile link (e.g., a GSM/EDGE or CDMA/EVDO connection, an IEEE 802.11 “Wi-Fi” link, and/or the like). Several examples of placeshifting applications available for various platforms are provided by Sling Media of Foster City, Calif., although the concepts described herein could be used in conjunction with products and services available from any source. 
     As noted at the outset, it is generally desirable to maintain security of the placeshifting process to ensure that unauthorized users and unauthorized players do not gain access to programming content. This is particularly true when placeshifting device  108  is an integrated receiver/DVR/placeshifter, since the amount of valuable content available within the device could be significant. To maintain the security of the connection, then, various embodiments establish a logical barrier around a trusted domain or authorized zone  120 , which may include the placeshifter device  118  itself, as well as any backend servers  114 ,  118  that are maintained by service providers or other trusted entities. By requiring users to interact within a secure infrastructure  100 , suitable authentication or other security mechanisms can be implemented to prevent unauthorized access to resources contained within trusted domain  120 . 
     To that end, a service provider may provide a central server  114  that interacts with placeshifting device  108  and/or mobile device  112  over network  102 . Server  114  is any computer system or other computing resources that are able to respond to process requests for information received via network  102 . Server  114  may, for example, maintain a database  116  that includes user account information, as well as cryptographic keys or other authentication credentials associated with the various placeshifting devices  108  as appropriate. 
     Central server  114  facilitates secure transactions between the remote device  112  and the placeshifting device  108  in any manner. In various embodiments, users of remote devices  102  are able to locate placeshifting devices  108  on network  102  by contacting central server  114 , authenticating to server  114  with a userid/password pair or other credential, and then receiving information that allows a subsequent connection request to one or more placeshifting devices  108  associated with the user in database  116 . The remote device  112  is then able to contact the placeshifting device  108  directly via network  102  to request a connection. Upon receiving connection requests from both placeshifting device  108  and remote device  112 , central server  114  suitably provides a cryptographic key or other credential that can be used to establish a secure media stream between devices  108  and  112 , as appropriate, and as more fully described below. Central server  114  is therefore able to greatly assist in maintaining the security of the placeshifted media stream, even though the server  114  need not be logically or physically interposed between the communicating devices  108  and  112 . 
     In further embodiments, a server  114  involved with user authentication and/or key management may communicate with one or more backend servers  118  for additional security. Backend server  118  may have access to billing information, for example, that can be cross-checked against information received at server  114  to ensure that the user requesting services has properly paid for such services, has maintained an account in good standing, and/or the like. Queries to backend server  118  may be processed in real-time (or near real-time) over a secure link apart from network  102 . In various embodiments, backend server  118  may be affiliated with a provider of satellite or cable television signals to device  108 , for example. In such embodiments, server  118  could be used to ensure billing compliance, but could additionally (or alternatively) enable further services to the user in any manner. For example, a user authenticated with server  114  could order services (e.g., enablement of placeshifting features), issue an instruction to purchase a pay-per-view program or to record a program on a DVR associated with device  108 , pay a bill, and/or take some other action with respect to the user&#39;s account with backend server  118  through the convenience of network  102 . In embodiments wherein the user has ordered additional services or content, server  118  may coordinate messages transmitted via satellite  116  (or, equivalently, a cable connection or the like) to update settings on device  108  as appropriate. Because a secure connection within trusted domain  120  exists from server  114  to placeshifting device  108 , new services and features can be enabled without data transmissions across relatively unsecured network  102 . 
       FIG. 2  provides additional detail about an exemplary placeshifting device  108  that includes a receiver  208 , a decoder  214  and a placeshifting transcoder  204 , as appropriate. Although  FIG. 2  describes a hybrid device  108  capable of receiving and decoding content in addition to placeshifting, the concepts set forth herein could be equivalently applied to devices  108  that simply provide placeshifting of media content received and/or decoded at an external receiver, DVR, media player, server and/or the like. Other embodiments may incorporate additional or alternate processing modules from those shown in  FIG. 2 , may omit one or more modules shown in  FIG. 2 , and/or may differently organize the various modules in any other manner different from the exemplary arrangement shown in  FIG. 2 . 
     Device  108  may be logically and physically implemented in any manner.  FIG. 2  shows various logical and functional features that may be present in an exemplary device  108 ; each module shown in the figure may be implemented with any sort of hardware, software, firmware and/or the like. Any of the various modules may be implemented with any sort of general or special purpose integrated circuitry, for example, such as any sort of microprocessor, microcontroller, digital signal processor, programmed array and/or the like. Any number of the modules shown in  FIG. 2 , for example, may be implemented as a “system on a chip” (SoC) using any suitable processing circuitry under control of any appropriate control logic  205 . In various embodiments, control logic  205  executes within an integrated SoC or other processor that implements receiver  208 , transport selector  212 , decoder  214 , display processor  218  and/or disk controller  206 , as appropriate. In such embodiments, the integrated SoC processor may interact with a transcoder module  204  implemented with a separate processor as well as any other input or output devices to produce desired outputs based upon inputs received from local or remote users. In other embodiments, transcoder  204  may also be incorporated into the SoC design. Broadcom Corporation of Irvine, Calif., for example, produces several models of processors (e.g., the model BCM 7400 family of processors) that are capable of supporting SoC implementations of satellite and/or cable receiver systems, although products from any number of other suppliers could be equivalently used. In still other embodiments, various distinct chips, circuits or components may be inter-connected and inter-relate with each other to implement the receiving and decoding functions represented in  FIG. 2 . 
     Various embodiments of device  108  therefore include any number of appropriate modules for obtaining and processing media content as desired for the particular embodiment. Each of these modules may be implemented in any combination of hardware and/or software using logic executed within any number of semiconductor chips or other processing logic. 
     Various embodiments of control logic  205  can include any circuitry, components, hardware, software and/or firmware logic capable of controlling the various components device  108 . Various routines, methods and processes executed within device  108  are typically carried out under control of control logic  205 , as described more fully below. In many embodiments, the various security and authentication features described with respect to  FIG. 3  below are carried out primarily within control logic  205 , which may be executing on any processor within device  108 . 
     As noted above, many embodiments of device  108  include a receiver  208 , which is any hardware, software, firmware and/or other logic capable of receiving media content via one or more content sources  105 . In various embodiments, content sources  105  may include cable television, DBS, broadcast and/or other programming sources as appropriate. Receiver  208  appropriately selects a desired input source and provides the received content to an appropriate destination for further processing. In various embodiments, received programming may be provided in real-time (or near real-time) to a transport stream select module  212  or other component for immediate decoding and presentation to the user. Alternatively, receiver  208  may provide content received from any source to a disk or other storage medium in embodiments that provide DVR functionality. In such embodiments, device  108  may also include a disk controller module  206  that interacts with an internal or external hard disk, memory and/or other device that stores content in a database  110 , as described above. 
     In the embodiment shown in  FIG. 2 , device  108  also includes an appropriate network interface  210 , which operates using any implementation of protocols or other features to support communication by device  108  on network  102 . In various embodiments, network interface  210  supports conventional LAN, WAN or other protocols (e.g., the TCP/IP or UDP/IP suite of protocols widely used on the Internet) to allow device  108  to communicate on network  102  as desired. Network interface  210  typically interfaces with network  102  using any sort of LAN adapter hardware, such as a conventional network interface card (NIC) or the like provided within device  108 . 
     Transport stream select module  212  is any hardware and/or software logic capable of selecting a desired media stream from the available sources. In the embodiment shown in  FIG. 2 , stream select module  212  is able to generate video signals for presentation on one or more output interfaces  228 . In various embodiments, stream select module  212  is also able to provide an encoded video signal  236  to transcoding module  204 , although this feature is entirely optional. In such embodiments, however, transcoding module  204  would decode the video signal  236  for packetizing and subsequent transmittal over network  102 , as described elsewhere. 
     More typically, however, stream select module  212  responds to viewer inputs (e.g., via control logic  205 ) to simply switch encoded content received from a live source  105  or from storage  110  to one or more decoder modules  214 . Device  108  may include any number of decoder modules  214  for decoding, decompressing and/or otherwise processing received/stored content as desired. Generally speaking, decoder module  214  decompresses or otherwise processes received content from stream select module  212  to extract an MPEG or other media stream encoded within the stream. The decoded content can then be processed by a display processor modules  218  to create a display for the viewer in any appropriate format. 
     Display processor module  218  includes any appropriate hardware, software and/or other logic to create desired screen displays at interfaces  242 ,  244 ,  246  as desired. In various embodiments, display processing module  218  is also able to produce on screen displays (OSDs) for electronic program guide, setup and control, input/output facilitation and/or other features that may vary from embodiment to embodiment. Such displays are not typically contained within the received or stored broadcast stream, but are nevertheless useful to users in interacting with device  108  or the like. The generated displays, including received/stored content and any other displays may then be presented to one or more output interfaces  228  in any desired format. In various embodiments, display processor  218  produces an output signal encoded in any standard format (e.g., ITU656 format for standard definition television signals or any format for high definition television signals) that can be readily converted to standard and/or high definition television signals at interface  228 . 
     In hybrid receiver/placeshifter devices  108 , a hardware or software switch  226  may also be provided that allows one or more output channels to be diverted to a transcoding module  204  for placeshifting over network  102 . In such embodiments, switch  226  suitably re-directs output from one of the output channels (e.g., channel  228 ) in decoded and decompressed form to the transcoding module  204  as appropriate. An output signal encoded in ITU656 format, for example, may be provided as an input to transcoding module  204  to support digital-to-digital conversion to a media format that can be readily transmitted on network  102 . In other embodiments, digital or analog signals may be provided to transcoder  204  in any format. 
     To that end, transcoding module  204  is any hardware, software, firmware and/or combination thereof that is capable of producing a media stream capable of being routed on network  102  to a remote device  112 . In various embodiments, transcoding module is implemented in a semiconductor chip having digital signal processing capabilities, such as a DAVINCI model processor available from the Texas Instruments Corporation of Dallas, Tex., although other embodiments may use any sort of processor or other circuitry (including the same processor or other circuitry used to implement any other components shown in  FIG. 2 ) to implement the transcoding function. Generally speaking, transcoding module  204  receives either a decoded signal  234  decoded by decoders  214  or  216  (and optionally further processed by display processors  218  or  220 ) or an already encoded stream  236 , performs a digital-to-digital conversion to create a media stream in a desired format and having desired parameters, and provides the converted stream for transport on network  102 . One example of a placeshifting system that includes transcoding capabilities is described in U.S. Patent Publication 2006/0095471, although other placeshifting and/or transcoding features may be implemented in a wide array of alternate embodiments.  FIG. 2  shows the output  238  of transcoding module  204 , which includes the placeshifted video stream, as being provided for transport using network interface  210 . In an alternate embodiment, a different network interface  210  could be provided, such as a stack residing within module  204  itself. In various embodiments, it may be desirable to secure any inter-chip communications between transcoding module  204  and other components of device  108  through any sort of physical or logical security techniques. Signals  234 ,  236  and/or  238  may be provided on signal pins that are physically embedded within a printed circuit board, for example, to make access to such signals more difficult. Further, signals  234 ,  236  and/or  238  may be encrypted or encoded between modules in any manner to prevent unauthorized usage in the event that such signals are physically intercepted. 
     In operation, then, placeshifting device  108  suitably receives one or more media streams from a DBS, cable or other source  105 , which may be stored in a DVR database  110  or the like as desired. Received and/or stored content may be provided in compressed form (e.g., signal  236 ) and/or decompressed form (e.g., signal  234 ) to transcoding module  204 , which appropriately converts the received signals to a format that can be transmitted to the remote device  112  over network  110 . Control of the placeshifting process, including any communications related to security or authentication, may take place under the direction of control logic  205  executing within device  108 . 
       FIG. 3  shows an exemplary process  300  for securely establishing a placeshifting media stream between a placeshifting device  108  and a remote device  112 .  FIG. 3  shows messages sent and received by each of the entities  108 ,  112 ,  114  involved in the security process  300 , as well as other actions that may be performed by one or more entities within system  100  ( FIG. 1 ). In practice, the overall process  300  may be implemented with various methods executed by one or more entities  108 ,  110 ,  112 , as described more fully below. Generally speaking, each of the method steps shown in  FIG. 3  may be implemented in software or firmware that may be stored in memory, mass storage or any other storage medium available to the executing device, and that may be executed on any processor or control circuitry associated with the executing device. 
     Process  300  typically begins with the remote device  112  contacting the central server with a login request (step  302 ). This may be initiated by, for example, a user of remote device  102  opening a media player application, or otherwise initiating the process of viewing placeshifted media. Step  302  may include providing any sort of identifying information associated with the user, such as any sort of userid/password pair. Alternatively, step  302  could provide a digital signature, any other cryptographic credential, biometric information, and/or any other sort of identifying information to ensure the identity of the user. Step  302  may also include a digital signature, identifier or other credential associated with a media player application or other component of device  112  to ensure that the application is authorized to participate in process  300 . Central server  114  suitably validates the received information (step  303 ) in any manner (e.g., by querying database  116  in  FIG. 1 ). If validation is successful, the user is identified, and a response message may be sent (step  304 ). In the event that the media player application is out of date, such information may be used to prompt the user to obtain updated software, or for any other purpose. 
     Response message  304  includes any information that allows the remote device to establish a connection to a desired placeshifting device  108 . In various embodiments, response  304  may include address information (e.g., an Internet Protocol (IP) address) relating to one or more placeshifting devices  108  associated with the user&#39;s account in a directory or other listing. The response  304  may also include user preferences or other settings established by the user for added convenience. 
     Upon successful authentication with the central server  114 , the remote device  112  is able to request a connection to a particular placeshifting device  108  via network  102  (step  306 ). This request may be sent using any suitable protocol or other format that can be received an interpreted by placeshifting device  108 . In an exemplary embodiment, response  304  includes an IP address or other identifier associated with the placeshifting device  108  that allows the remote device  112  to contact the desired placeshifting device  108  directly via network  102 . 
     Placeshifting device  108  is able to verify the capability to perform placeshifting in any manner (step  307 ). In various embodiments, device  108  receives a flag or other indication via a separate data connection other than network  102  that indicates availability of placeshifting “rights”. For example, in embodiments wherein device  108  includes the ability to receive cable or satellite signals, a placeshifting enablement message may be embedded within signals  105  transmitted to device  108  via the cable or satellite connection, respectively. In other embodiments, a human physically close to device  108  may be alerted by device  108  to authorize placeshifting. In either case, device  108  may not accept placeshifting requests until placeshifting “rights” are expressly enabled on the device. This may be verified by checking that placeshifting is approved (step  307 ) just prior to validating the user&#39;s request for connection, as shown in  FIG. 3 , or by simply ignoring requests  306  for placeshifting connections until approval for placeshifting is received. 
     Placeshifting may be enabled or disabled in any manner, and/or may be differently applied based upon the location or capabilities of remote device  112 . For example, placeshifting device  108  may be configured to recognize several “tiers” of service so that placeshifting is enabled only for local area networks, for example, or only for wide area networks. Such functionality may be implemented by comparing IP or other network addresses of devices  108  and  112 , for example, when limited placeshifting is enabled. Placeshifting within any particular device  108  may be enabled, disabled, or otherwise adjusted in any manner and on any temporal basis by simply updating the placeshifting “flag” or other data provided to device  108 . 
     If placeshifting is enabled on device  108 , then a response message  308  is sent to remote device  112  via network  102 . In various embodiments, device  112  also submits a request  312  to central server  114  for an authorization credential that can be used to secure the placeshifted media stream, as described below. Upon receipt of response  308  from placeshifting device  108 , remote device  112  also submits a request  310  to central server  114  to obtain the authorization credential that permits secure communication with the particular placeshifting device  108 . In various embodiments, the authorization credential is a cryptographic key, such as a symmetric encryption key or the like that permits subsequent secure communications based upon a shared secret. Conventional keys of any length (e.g., 64 or 128 bits) associated with advanced encryption standard (AES) or data encryption standard (DES) algorithms, for example, could be used in various embodiments. In various embodiments, the authorization credential is associated with the particular placeshifting device  108 , and may be updated on any temporal basis. Keys may be updated on a periodic or aperiodic basis, for example, or a unique key may be provided in response to each request  312  for added security. 
     Upon receiving requests  310  and  312 , central server  114  suitably validates and authorizes the placeshifting session (step  314 ). Step  314  may involve querying a backend server  118 , for example, to ensure that the placeshifting is approved for the particular user, remote device  112  and/or placeshifting device  108 . Alternatively, verification may be resolved locally at central server using database  116  ( FIG. 1 ) or the like. If the transaction is approved, then the authorization credential is transmitted from server  114  to the remote device as message  316 , and to the placeshifting device  108  as message  318 . In embodiments wherein the credential is already stored within device  108 , message  318  may not necessarily include another copy of the credential, but may instead provide an indication that placeshifting with remote device  112  is approved. Authorization credentials will typically be provided using relatively secure connections (e.g., secure hypertext transport protocol (HTTPS) or the like) to prevent any third parties from obtaining the credential through eavesdropping or similar techniques. 
     When both placeshifting device  108  and remote device  112  have received authorization  316 ,  318  from the central server  114 , then a secure connection may be established directly between the two devices  108 ,  112  via network  102 . A session key  320  may be generated by each party, for example, using conventional techniques (e.g., as set forth in the AES, DES or other algorithms) and using parameters provided from central server  114 . This session key may be based upon the received authentication credential, for example, to allow for mutual encryption/decryption of ensuing communications. The session key is typically negotiated based upon the received credential, and also based upon one or more other parameters known to the communicating devices. These parameters may be embedded within software previously provided (e.g., within a media player application provided to device  112 , and/or within a firmware update to device  108 ) to further enhance placeshifting security. These parameters may be defined in any manner (e.g., in accordance with well-known encryption protocols such as AES, DES and/or the like) and may be updated on any temporal basis. In the event that the cryptographic systems described in  FIG. 3  become compromised, for example, a firmware update to device  108  and/or a player update to device  112  may be required to update the various parameters prior to receiving any future approvals (e.g, messages  316 ,  318 ) from central server  114 . 
     In various embodiments, a user of remote device  112  may also authenticate separately with placeshifting device  108  (step  324 ) to further enhance the security of process  300 . This authentication may involve providing a userid/password pair, a digital signature, biometric data, and/or any other identifying information associated with the user to placeshifting device  108 . Such information may be configured by the user prior to establishing the placeshifting session in any manner. Although  FIG. 3  shows authentication step  324  as occurring after negotiation of the session key, such authentication may take place at any point within process  300 . Authentication  324  may take place prior to placing of key request  312 , for example. Other embodiments may eliminate the additional authentication in step  324  entirely, or make such authentication optional at the discretion of the user or any administrator. 
     When authentication is complete and the various encryption parameters are properly in place, the placeshifting media stream  326  can be provided over network  102  to remote device  102 . Typically, some or all of the content contained within media stream  326  is encrypted (step  325 ), as described more fully below. Transcoding, encryption and transmission of content in media stream  326  may be adjusted in any manner during operation (step  328 ). In various embodiments, the media player application associated with remote player  112  provides command and control information to device  108  that may be used to adjust or otherwise control transcoding, encryption or transmission as desired. 
     From the varying perspectives of devices  108 ,  112  and central server  114 , then, various methods for establishing a secure placeshifting session are described in  FIG. 3 . With respect to placeshifting device  108 , for example, establishing a secure connection suitably includes the broad steps of receiving a request for connection  306  from the remote device, verifying that a placeshifting feature is available within device  307 , and then requesting approval for the session from the central server (step  312 ). In response to the received approval (step  318 ), which may include a cryptographic key or other authentication credential, placeshifting device  108  is able to establish the secure media stream  326  based upon the received credential. The various steps of this method may be carried out by any processing circuitry or logic associated with device  108 , including control logic  205  shown operating in  FIG. 2 . 
     With respect to the remote device  112 , an initial request is placed to central server  114 , which responds  304  with an address or other information about placeshifting device  108 . The remote device  112  is then able to request a connection (step  306 ) from the placeshifting device, and to request the key or other credential upon receipt of a response  308  from device  108 . The received credential can then be used to negotiate or otherwise establish the parameters of the secure media stream  326 , and to decrypt the content transferred as part of the stream. The various steps of this method may be executed within a media player application or other software executing on remote device  112 . 
     With respect to the central server  114 , the initial request  302  is received from remote device  112  and validated (step  303 ) as appropriate. If the request is valid, information about the placeshifting device  108  is provided (step  304 ) to allow the remote device  112  to contact the placeshifting device  108  directly. Upon receipt of subsequent requests  310 ,  312  from device  112 ,  108  (respectively), central server  114  suitably validates and authorizes the session in any appropriate manner, and transmits the key or other authentication credential to the remote device  112  and/or placeshifting device  112  in any manner. Devices  108  and  112  are then able to independently negotiate the parameters of the secure media stream  326  based upon the shared credential. The various functions and other features of this method may be executed on one or more processors associated with server  114  and/or backend server  118  ( FIG. 1 ), as appropriate. 
       FIG. 4  shows additional detail about an exemplary technique for transmitting a secure media stream  326  from a placeshifting device  108  to a remote device  112 . The various steps shown in  FIG. 4  may be executed in software, firmware and/or hardware logic residing within device  108 , such as control logic  205  shown operating in conjunction with the various other modules (including transcoder module  204 ) in  FIG. 2 . 
     As noted above, placeshifting device  108  receives authentication credentials (e.g., a cryptographic key) in any manner (step  402 ). Unique credentials may be provided for each requested session in some embodiments, or a key/credential may be securely stored within device  108  for use in conjunction with multiple placeshifting sessions. In either event, a session key and/or other parameters for a particular placeshifting session may be negotiated with remote device  112  (step  404 ) based upon the secret information shared between the two devices using any technique, such as conventional AES cryptography. 
     In some embodiments, resources may be available to encrypt the virtual entirety of media stream  326 . In other embodiments (step  406 ), however, it may not be necessary or desirable to encrypt the entire stream. In embodiments wherein the transcoded media stream is of relatively low quality (e.g., a relatively low bit resolution) in comparison to the received signal, for example, cryptography may be reduced or eliminated. Further, when the remote device has limited computing resources (e.g, a mobile phone or the like), the computational demands of strong cryptography may detract from the user experience. Similarly, if the media stream  326  is being transferred over a relatively low bandwidth link (e.g, a relatively slow telephone connection), the added delay imposed by cryptography may be undesirable. As a result, the level of cryptography applied by the placeshifting device may be selected (step  408 ) based upon such factors as the quality of the transmitted media stream, the processing capabilities of remote device  112 , and/or the bandwidth of the intervening communications network  102 . 
     Cryptography may be applied in any manner (step  410 ). In various embodiments, cryptography may be applied in any number of “levels”, ranging from no encryption, to partial encryption, to encryption of the entire stream depending upon the various factors. “Partial encryption” in this sense can refer to encrypting only certain frames of the media stream, and/or to encrypting only certain blocks of one or more frames. That is, by encrypting only a portion of the transmitted media, security can be maintained without unduly increasing computational overhead. In a conventional MPEG-type video stream, for example, the more fundamental video frames (e.g., I-frames) can be encrypted, with reduced encryption applied to the more heavily compressed frames (e.g, P-frames and/or B-frames). Encrypting only a portion of the macroblocks making up the various frames can similarly reduce computational demands. As one example, a “high” level of encryption could encrypt every outgoing frame of media stream  326 , whereas a “medium” level could encrypt a lesser amount, for example between 25-75 percent or so of the blocks in some or all of the I, P and/or B frames. Additional levels could be added for any level of resolution desired. 
     In further embodiments, the particular blocks that are encrypted could be assigned in any manner, including randomly. That is, the particular blocks may be randomly selected to further enhance the security of the system. Randomizing the encrypted blocks could have a further advantage in terms of spreading processor loading as well, thereby further improving system performance during encryption. The particular randomly-selected blocks may be called out to the receiving party in any manner, such as through header identification, control messages and/or the like to facilitate efficient decryption of media stream  326 . 
     Media stream  326  is therefore encrypted and transmitted to remote device  108  in any manner (step  412 ) until the placeshifting session is complete (step  414 ). As noted above, various transcoding, encryption and/or transmission parameters of stream  326  may be adjusted during operation as desired (step  416 ). If the bandwidth of the connection  102  should degrade, for example, or the processing capabilities of remote device  112  become overloaded, it may be desirable to reduce the quality of the media stream and/or to reduce the amount of encryption applied in step  410 . Any of the various parameters used in transcoding and/or encrypting media stream  326  may be adjusted upwardly or downwardly as appropriate to compensate for changing conditions (step  418 ). In an exemplary embodiment, the encryption level may be set and/or adjusted according to the video bitrate and/or video resolution. High definition video, for example, may always be encrypted at a relatively high level, whereas standard definition video may be encrypted at lower levels in some embodiments, particularly if the video bitrate is relatively low. Various encryption parameters and criteria could be established across a wide range of alternate embodiments. 
     Using the various systems, methods and other concepts described herein, a number of advantages may be achieved. By requiring authentication to a central server and/or to the placeshifting device, for example, access to placeshifted content can be limited to authorized users. Moreover, by unauthorized media player applications can be rejected through authentication to the central server and/or the use of system secrets for generating session keys. The use of a central server allows for convenient upgrading/updating of keys or player applications in the event of security breach, thereby greatly enhancing system renewability. Moreover, streaming content is encrypted end-to-end, thereby reducing access by untrusted or unapproved third parties. The level of encryption applied may be adjusted based upon video quality, environmental factors and/or the like, further improving system performance. As noted at the outset, the various features may be selectively applied, and not all features will be found in all embodiments. 
     As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. 
     While the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing various embodiments of the invention, it should be appreciated that the particular embodiments described above are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. To the contrary, various changes may be made in the function and arrangement of elements described without departing from the scope of the invention.