Patent Publication Number: US-2023144008-A1

Title: Techniques to lock and unlock displays of vehicle entertainment systems for commercial passenger vehicles

Description:
TECHNICAL FIELD 
     This document is directed generally to systems, methods, and apparatus to lock displays of an in-vehicle entertainment system for a commercial passenger vehicle. 
     BACKGROUND 
     Commercial travel has evolved to provide entertainment options to passengers traveling to their destinations. For example, in an airplane or train, entertainment options are provided on displays located on the back of seats, where the displays can enable passengers to watch movies or television shows as they travel to their destinations. The displays can also provide travel related information to the passengers. For example, passengers can view a map with the current location of the airplane or train and an estimated time of arrival to their destinations. Thus, in-vehicle entertainment systems can be designed to provide passengers with a positive travel experience. 
     SUMMARY 
     This patent document describes exemplary systems, methods, and apparatus to allow users to lock and/or unlock their displays associated with an in-vehicle entertainment system in a commercial passenger vehicle. 
     An example system for securing an in-vehicle entertainment (WE) display in a commercial passenger vehicle, the system comprising: a mobile device located in the commercial passenger vehicle and comprising a first processor configured to secure a display located in the commercial passenger vehicle, where the first processor is configured to: obtain a payload; generate a first digitally signed payload as a first output of a first mathematical computation performed on the payload with a secret key; and send a first message comprising the first digitally signed payload and a lock command to instruct the display to lock the display, where the display is located behind a headrest of a seat in the commercial passenger vehicle; a computer located in the commercial passenger vehicle, where the computer is communicably coupled with the display and comprises a second processor configured to: send a first instruction to cause the display to lock in response to a reception of the lock command. 
     In some embodiments, the mobile device comprising the first processor is further configured to: send, after the display is locked, a second message comprising a second digitally signed payload and an unlock command to instruct the display to unlock the display, where the second digitally signed payload is generated as a second output of a second mathematical computation performed on the payload with the secret key, where the first mathematical computation is performed at a first time that is earlier in time than a second time when the second mathematical computation is performed; and the computer comprising the second processor is further configured to: send a second instruction to cause the display to unlock in response to a reception of the unlock command. In some embodiments, the first processor of the mobile device is configured to not store or to discard the payload in the mobile device after the first digitally signed payload is generated. 
     In some embodiments, the first mathematical computation and the second mathematical computation includes a performance of a hash function using the payload the secret key. In some embodiments, when the display is locked, the second processor of the computer is configured to show on the display a volume adjustment menu to adjust an output volume of an audio or video content or to show on the display a brightness adjustment menu to adjust brightness of the display. In some embodiments, when the display is locked, the second processor of the computer is configured to show on the display a reading light control menu to control a light. In some embodiments, the payload is obtained from the computer by the first processor of the mobile device, the first processor being further configured to: transmit, using a first near field communication (NFC) device located in the mobile device, an application identifier (AID) to a second NFC device located in the display or located in another seat; and where the payload is obtained by the first NFC device from the second NFC device in response to the transmit the AID. 
     In some embodiments, the first message comprising the first digitally signed payload, the lock command, and the AID is sent by the first NFC device in the mobile device to the second NFC device in the display or in the another seat, and the second message comprising the second digitally signed payload, the unlock command, and the AID is sent by the first NFC device in the mobile device to the second NFC device in the display or in the another seat. In some embodiments, the display is caused to unlock by the second processor of the computer that is further configured to: receive the second message; and where the second instruction to cause the display to unlock is sent in response to the receive the unlock command and in response to a determination that the second digitally signed payload in the second message matches or is same as the first digitally signed payload in the first message. In some embodiments, the first NFC device is configured to operate in an NFC reader mode and the second NFC device is configured to operate in a host-based card emulation mode before the payload is obtained by the first NFC device. 
     In some embodiments, after the payload is obtained, the first NFC device is configured to operate in a host-based card emulation mode and the second NFC device is configured to operate in an NFC reader mode. In some embodiments, the payload is obtained from a server located in the commercial passenger vehicle by the first processor of the mobile device, the first processor being further configured to: scan a unique code displayed on the display, where the unique code provides an address of a webpage unique to the display; and cause a screen of the mobile device to show the webpage whose address is provided by the unique code, where the webpage is hosted on the server; where the payload is obtained from the webpage, and where the payload is hidden in the webpage. In some embodiments, the first message comprising the first digitally signed payload and the lock command is sent by the mobile device to the server from the address of the webpage that is unique to the display, and where the second message comprising the second digitally signed payload and the unlock command is sent is sent by the mobile device to the server from the address of the webpage that is unique to the display. 
     In some embodiments, the server includes a third processor that is configured to: receive, from the mobile device, the first message comprising the first digitally signed payload and the lock command; and send, in response to the receive the first message, a third message to the computer associated with the display, where the third message comprises the lock command, and where the third message is sent to the computer based on the address of the webpage that is unique to the display. In some embodiments, the server includes a third processor that is configured to: receive, from the mobile device, the second message comprising the second digitally signed payload and the unlock command; and send, upon determining that the second digitally signed payload matches or is same as the first digitally signed payload, a fourth message to the computer associated with the display, where the fourth message comprises the unlock command, and where the fourth message is sent to the computer based on the address of the webpage that is unique to the display. 
     An example computer configured to secure an in-vehicle entertainment (WE) display, the computer comprising a processor configured to: receive, from a near field communication (NFC) device, a first message comprising a first digitally signed payload and a lock command to instruct a display to lock the display, where the computer and the display are located in a commercial passenger vehicle; send a first instruction to cause the display to lock in response to a reception of the lock command; receive, from the NFC device and after the display is locked, a second message comprising a second digitally signed payload and an unlock command to instruct the display to unlock the display; and send a second instruction to cause the display to unlock in response to a reception of an unlock command and in response to a determination that the second digitally signed payload in the second message matches the first digitally signed payload in the first message. 
     In some embodiments, the processor of the computer is configured to: receive an application identifier (AID) from a mobile device; and transmit, in response to the receive the AID, a payload to the mobile device, where the first digitally signed payload is a first output of a first mathematical computation that includes the payload and a secret key of the mobile device, and where the second digitally signed payload is a second output of a second mathematical computation that includes the payload and the secret key of the mobile device. In some embodiments, where the first message comprising the first digitally signed payload, the lock command, and the AID is received by the NFC device, and the second message comprising the second digitally signed payload, the unlock command, and the AID is received by the NFC device. In some embodiments, when the display is locked, the processor of the computer is further configured to show on the display a volume adjustment menu to adjust an output volume of an audio or video content or to show on the display a brightness adjustment menu to adjust brightness of the display. In some embodiments, the second digitally signed payload in the second message is determined to match the first digitally signed payload in the first message by the processor configured to determine that the second digitally signed payload is same as the first digitally signed payload. 
     In yet another exemplary aspect, the above-described methods are embodied in the form of processor-executable code and stored in a non-transitory computer-readable program medium. The code included in the computer readable storage medium when executed by a processor, causes the processor to implement the methods described in this patent document. 
     In yet another exemplary embodiment, a device that is configured or operable to perform the above-described methods is disclosed. 
     The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows an exemplary overview of an in-vehicle entertainment (IVE) system installed in an airplane. 
         FIGS.  2  and  3    show two example flowcharts to lock and unlock a passenger&#39;s IVE display. 
         FIG.  4 A  shows an example flowchart of operations performed by a computer and mobile device to lock and/or unlock a display on a commercial passenger vehicle. 
         FIG.  4 B  shows an example flowchart of operations performed by a computer to lock and/or unlock a display on a commercial passenger vehicle. 
         FIG.  5    shows an exemplary block diagram of a mobile device. 
         FIG.  6    shows an exemplary block diagram of a computer associated with an IVE display. 
         FIG.  7    shows an exemplary block diagram of a server located in a commercial passenger vehicle. 
         FIG.  8    shows an example scenario where an IVE display is locked using a mobile device. 
     
    
    
     DETAILED DESCRIPTION 
     An in-vehicle entertainment (IVE) system that can send entertainment content (e.g., audio, movies, television shows, or other videos) to displays located on the back of a headrest of the seats (e.g., known as seatback monitors) in the commercial passenger vehicle. A display located on the back of the headrest of the seat can be referred to as seatback monitor or an IVE display and may be electrically connected to a computer that may be located in the seat (e.g., bottom of the seat). The computer of the seatback monitor may include may utilize a one or more software programs when displaying graphical content on a display screen and outputting sound to one or more output ports, e.g., headphone jack(s). The seatback monitor and the associated computer can be considered a media playback device. 
     WE displays or seatback monitors can offer entertainment and travel experience that are specific to passengers while allowing passengers to provide data about themselves which may be considered personal information. For example, a passenger can use an WE display to enter the passenger&#39;s preferences for music or movies or the passenger can use the IVE display to enter email address or dietary needs. In another example, the passenger may fill out a survey related to the passenger&#39;s travel experience using the IVE display where the answers related to the survey may include personal information. In yet another example, the passenger can use the IVE display to purchase products by entering credit card information or to track an order to keep a tab open for future orders in the passenger vehicle. Thus, an IVE system may offer more features to enhance travel experience by collecting a passenger&#39;s preferences or information so that when the passenger travels again in the future the IVE system can provide travel related options (e.g., meal) and/or entertainment options to the passenger based on the passenger&#39;s preferences or information. 
     A technical problem with current IVE systems is that an IVE display used by a passenger may be accessible by another passenger who may obtain the passenger&#39;s personal information when the passenger is sleeping or is not at the passenger&#39;s seat. Thus, this patent document describes example techniques to lock a IVE display using software by, for example, exchanging digitally signed information between the computer associated with the IVE display and a passenger&#39;s mobile device. 
       FIG.  1    shows an exemplary overview of an IVE system  100  installed in an airplane  102 . The IVE system includes a plurality of seatback monitors  103  that is communicably coupled to a plurality of computers  104 , where each computer may be located in a seat below one or more seatback monitors. For example, one computer may be communicably coupled to one or more seatback monitors located in a row in the airplane  102  so that the computer may be located in a seat below the one or more seatback monitors. In another example, each seatback monitor may be communicably coupled to a computer so that each computer may be located in the seat where the seatback monitor is located. Each of the plurality of computers  104  may include an ethernet connector which allows the plurality of computers  104  to be communicably coupled to the server  106  via, for example, an Ethernet switch. The server  106  may be communicably coupled (e.g., via Ethernet switch) to one or more wireless access points  108 . Thus, in such embodiments, passengers may use their mobile devices  110  to connect to the one or more wireless access points  108  so that the passengers&#39; mobile devices  110  can communicate with the plurality of seatback monitors  103  via the server  106 . 
     In some embodiments, each of the plurality of seatback monitors  103  may include a near-field communication (NFC) device so that a passenger&#39;s mobile device  110  may directly communicate with a computer associated with the seatback monitor via the NFC device. In some embodiments, each seat may include an NFC device (e.g., located on or in the armrest of each seat) that is communicably coupled to a computer. In such embodiments, an NFC device located that may be located in a first seat where a passenger may be seated may be used to secure (e.g., lock/unlock) the passenger&#39;s display that is located in another seat immediately in front of the first seat. for example, a passenger&#39;s mobile device  110  may communicate with a computer via an NFC device located in a first seat, where the computer is communicably coupled with the seatback monitor located on a second seat immediately in front of the first seat. 
       FIGS.  2  and  3    show two example flowcharts to lock and unlock a passenger&#39;s WE display. The flowchart shown in  FIG.  2    uses NFC technology and the flowchart shown in  FIG.  3    uses Wi-Fi technology. One of the technical advantages of the flowcharts of  FIGS.  2  and  3    is that a passenger can lock and unlock the WE display without entering a passcode or a password via the WE display so that other passengers cannot easily lock and unlock the passenger&#39;s WE display using the passcode or the password. While this patent document uses NFC and Wi-Fi technology to explain the locking and unlocking techniques for the seatback display, other technologies can be employed to perform the techniques described in this patent document. For example, a mobile device may use infrared (IR) technology instead of NFC technology to communicate with an IR receiver which may be located on the seatback display. In another example, a mobile device may use cellular technology instead of Wi-Fi technology to communicate with a seatback display via the server that may communicably coupled to a satellite. The example techniques shown in Sections A and B in this patent document are shown for ease of understanding. The techniques shown in Section A can be applied to Section B and vice versa. 
     A. Example Locking and Unlocking Techniques Using NFC Technology 
     In  FIG.  2   , an WE display is locked for the first time by performing operations  206  to  218 , and the WE display is unlocked (after being locked) by performing operations  219  to  222 . 
     At operation  206 , the mobile device  202  opens a software application that is stored in the mobile device  202 . The software application in the mobile device  202  may perform operations associated with a first lock/unlock module (shown as  525  in  FIG.  5   ) as further described in this patent application. The mobile device  202  may also include a first NFC device (shown as  530  in  FIG.  5   ) that the first lock/unlock module initially operates in an NFC reader mode at operation  206 . At operation  206 , a second NFC device (shown as  630  in  FIG.  6   ) located in the WE display  204  or in an armrest of a seat or in the vicinity of the WE display is initially operated in a host-based card emulation mode by a second lock/unlock module (shown as  625  in  FIG.  6   ) of the computer  204 . The computer  204  is communicably coupled to the IVE display may store and operate another software application whose operations are described in this patent application as being associated with the second lock/unlock module. 
     At operation  207 , the computer  204  displays a message to indicate to the passenger to tap or touch the WE display (e.g., with their device). At operation  208 , first and second lock/unlock modules communicate with each other via the first NFC device in the mobile device  202  and the second NFC device in the WE display  204  or in the armrest of the seat or in the vicinity of the WE display using, for example, a pre-determined application identifier (AID). The AID facilitates communication using the first and second NFC devices between the WE display and the mobile device. In some embodiments, the AID may be a custom AID, where the AID is sent by the first lock/unlock module in the mobile device  202  to the second lock/unlock module in the computer  204  at operation  208 . 
     At operation  210 , when the computer  204  determines that a person or a device has physically tapped the second NFC device or has physically tapped or touched the WE display  204 , the second lock/unlock module that is associated with (or registered for) the AID is triggered to operate. When the second lock/unlock module in the computer  204  receives an indication of the tap on the second NFC device or the touch on the WE display  204 , the second lock/unlock module sends an acknowledgement payload (referred to as PayloadA) to first lock/unlock module in the mobile device  202  at operation  210 . 
     At operation  212 , after the second lock/unlock module in the computer  204  sends the acknowledgement payload and after the first lock/unlock module in the mobile device  202  receives the acknowledgement payload, the second lock/unlock module in the computer  204  sends a signal to the second NFC device in the WE display  204  or in the armrest of the seat or in the vicinity of the IVE display to operate in a NFC reader mode, and the first lock/unlock module in the mobile device  202  sends a signal to the first NFC device in the mobile display  202  to operate in the host-based card emulation mode. The first NFC device in the mobile display  202  is operated in the NFC reader mode until it receives the acknowledgement payload at operation  212 . After the computer  204  transmits the acknowledgement payload and after the mobile device  202  receives the acknowledgement payload, the mobile device  202  and the computer  204  switch modes to operate in a host-based card emulation mode and in the NFC reader mode, respectively, at least because the mobile device  202  may send a digitally signed PayloadA to the computer  204  as explained in operation  216 . 
     At operation  214 , a person may be prompted to tap the second NFC device or touch the IVE display using the IVE display&#39;s graphical user interface (GUI) thorough which a message to tap or touch the IVE display can be displayed. At operation  214 , the second lock/unlock module does not display a passcode or password for a user to enter. As mentioned in this patent document, one of the technical advantages of the example flowchart of  FIG.  2    is that a passenger can lock and unlock the IVE display without entering a passcode or a password via the IVE display so that other passengers cannot easily lock and unlock the passenger&#39;s IVE display using the passcode or the password. 
     At operation  215 , when the first lock/unlock module determines that the first NFC device is in proximity of the second NFC device (e.g., by determining that the first NFC device and the second NFC device are communicating the AID with each other), then at operation  216 , the first lock/unlock module sends a first message using the AID and via the first NFC device to the second NFC device. The first lock/unlock module in the mobile device  202  may generate the first message to include a header that may include the AID. The AID in the header indicates that the first lock/unlock module in the mobile device  202  wants to communicate with the second lock/unlock module in the computer  204  associated with the AID. The first message may also include a digitally signed PayloadA, where the first lock/unlock module in the mobile device  202  uses a secret key to digitally sign the PayloadA and adds the digitally signed PayloadA to the first message. The first lock/unlock module may generate and store the secret key in the mobile device  202  and only the first lock/unlock module may know or access the secret key. 
     The first lock/unlock module in the mobile device  202  can generate the digitally signed PayloadA by performing a mathematical calculation, such as by using a hash function to hash PayloadA using the secret key. The output generated by the mathematical calculation can be considered a digitally signed PayloadA. After the digitally signed PayloadA is generated at operation  216 , the first lock/unlock module deletes the PayloadA and does not store PayloadA on the mobile device. The PayloadA that is digitally signed is the same as the one provided to the first lock/unlock module in the mobile device  202  at operation  210 . The first message may also include a lock command that indicates to the second lock/unlock module in computer  204  to lock the WE display. 
     At operation  218 , the second lock/unlock module in the computer  204  locks the WE display in response to determining that the first message comprises the lock command to lock. A locked IVE display may show a lock icon on the display with a black background that does not show any of the entertainment content (e.g., as shown in the IVE display on the right-hand side of  FIG.  8   ), and/or the locked WE display may blur the entertainment content so that the entertainment content may not be seen by any of the passengers. The second lock/unlock module in the computer  204  may store the digitally signed PayloadA in the computer  204  as long as the WE display is locked.  FIG.  8    shows an example scenario where an WE display shown on the right-hand side of  FIG.  8    is locked when a person uses a mobile device  202  to tap or touch the lock icon on the IVE display  204  shown on the left-hand side of  FIG.  8   . 
     In some embodiments, the locked WE display prevents the passenger or another passenger from accessing most of the content on the WE display (e.g., the IVE display does not show entertainment content, etc.,). In some embodiments, the locked WE display prevents the passenger or another passenger from accessing the functionalities of the computer  204  (e.g., the WE display and/or computer cannot perform payment related operations or display or collect passenger information, etc.,). In some embodiments, certain functionalities on the WE display may still be operated by the passenger. For example, when the WE display is locked, the second lock/unlock module in the computer  204  may configure the GUI of the WE display to show a volume adjustment menu to allow a passenger to adjust an output volume of an audio or video content via the GUI of the WE display. In another example, when the WE display is locked, the second lock/unlock module in the computer  204  may allow important audio from the passenger vehicle&#39;s staff (e.g., captain of airplane or member of cabin crew or train operator) to pass through to the headphone jack associated with the WE display. In another example, when the WE display is locked, the second lock/unlock module in the computer  204  may configure the GUI of the IVE display to show a brightness adjustment menu to adjust brightness of the display or to show a reading light control menu to control a light. 
     At operation  219 , when the first lock/unlock module determines that the first NFC device is in proximity of the second NFC device (e.g., by determining that the first NFC device and the second NFC device are communicating the AID with each other), the first lock/unlock module sends a second message at operation  220  via the first NFC device to the second NFC device in the IVE display  204  or in the armrest of the seat or in the vicinity of the IVE display, where the second message includes the AID, the digitally signed PayloadA, and an unlock command. The first lock/unlock module in the mobile device  202  may generate the second message to include the AID in a header of the second message and by including the digitally signed PayloadA in the second message. After the digitally signed PayloadA is generated at operation  220 , the first lock/unlock module deletes the PayloadA and does not store PayloadA on the mobile device. The unlock command indicates to the second lock/unlock module in the computer  204  to unlock the IVE display. 
     At operation  222 , the second lock/unlock module in the computer  204  unlocks the IVE display upon determining that the received second message includes the unlock command and that the digitally signed PayloadA in the second message matches (e.g., is the same as) the digitally signed PayloadA received in the first message. After the IVE display  204  is unlocked at operation  222 , if a person wants to lock the IVE display  204 , the set of operations to re-lock the IVE display can start at operation  206 . In some embodiments, the secret key that may be generated at operation  216  by the first lock/unlock module of the mobile device  202  when a person locks the IVE screen for a first time may be different than another secret key that may be generated at operation  216  by the first lock/unlock module of the mobile device  202  when the person locks the IVE screen for a second time that is later than the first time. Thus, in some embodiments, the secret key that may be generated by the first lock/unlock module can be different every time the operations for locking IVE display is performed. 
     B. Example Locking and Unlocking Techniques Using Wi-Fi Technology 
     In  FIG.  3   , an IVE display is locked by performing operations  304  to  313 , and the IVE display is unlocked (after being locked) by performing operations  314  to  323 . 
     Prior to operation  304 , the IVE display  204  displays a lock icon (e.g., in a corner of the IVE display  204  as shown in the IVE display shown on the left-hand side of  FIG.  8   ). At operation  304 , when a second lock/unlock module of the computer  204  determines that a person has touched the lock icon on the IVE display  204 , the computer  204  displays a unique code for the mobile device  202  to scan. The unique code may include information that indicates to the mobile device  202  an address (e.g., a uniform resource locator (URL)) for a webpage hosted on a server  302  (which may be same as server  106  in  FIG.  1   ) located in the passenger vehicle, and the address may include a unique identifier of the WE display  204  (e.g., a seat number of the WE display). In some embodiments, each WE display is associated with a unique identifier so that each WE display can be uniquely identified. In some embodiments, the unique code may be a quick response (QR) code or a bar code. 
     At operation  306 , the first lock/unlock module of the mobile device  202  can scan the unique code displayed on the WE display using a camera of the module device  202 . At operation  306 , the first lock/unlock module of the mobile device  202  can open a web browser or a software application installed in the mobile device  202  to display the webpage of the address that is associated with the unique code. In some embodiments, the software application in the mobile device  202  may be registered to open the address when the first lock/unlock module scans and determines the address from the unique code. 
     The mobile device  202  and the server  302  are communicably coupled to a wireless access point in the passenger vehicle as explained in  FIG.  1   . At operation  308 , the first lock/unlock module obtains and displays the webpage hosted on the server  302 . The displayed webpage includes an icon to lock the IVE display associated with a seat number. The webpage may also include a hidden payload (e.g., PayloadA) that is obtained by the first lock/unlock module so that the first lock/unlock module can digitally sign the payload when exchanging information between the mobile device  202  and the server  302 . 
     At operation  310 , when the first lock/unlock module in the mobile device  202  determines that a person has selected the icon to lock the WE display via the webpage displayed on the mobile device  202 , the first lock/unlock module in the mobile device  202  sends a first message to the server  302  from the webpage whose address is unique to the WE display and via a wireless access point. The first message comprises a digitally signed payload and a lock command to lock the WE display  204 . The first lock/unlock module in the mobile device  202  uses a secret key to digitally sign the payload and adds the digitally signed payload to the first message. The first lock/unlock module may generate and store the secret key in the mobile device  202  and only the first lock/unlock module may know or access the secret key. The secret key may be stored in the mobile device  202  in a local storage (e.g., memory) or in a cookie. The first lock/unlock module in the mobile device  202  can generate the digitally signed PayloadA by performing a mathematical calculation, such as by hashing PayloadA using the secret key. The output generated by the mathematical calculation can be considered a digitally signed PayloadA. After the digitally signed PayloadA is generated at operation  310 , the first lock/unlock module deletes the PayloadA and does not store (or discards) PayloadA on the mobile device. 
     At operation  312 , a third lock/unlock module (shown as  725  in  FIG.  7   ) of the server  302  saves the digitally signed payload received from the mobile device  202  and the server  302  sends a message to the WE display  204  to lock the WE display. The third lock/unlock module sends the message to the WE display  204  using the address associated with the WE display  204 , which is determined by the third lock/unlock module from the address of the webpage indicated to the mobile device at operation  304 . For example, the third lock/unlock module can determine, based on a look-up table, the IP address of the computer associated with the address of the WE display and can send the message to the IP address at operation  312 . The message comprises the lock command to lock the WE display  204 . At operation  313 , the second lock/unlock module locks the IVE display  204  in response to receiving the message comprising the lock command. 
     At operation  314 , when the WE display  204  is locked, the WE display may show an icon to unlock the WE display. At operation  314 , when the second lock/unlock module determines that a person has clicked on or touched the icon to unlock the WE display, the second lock/unlock module can display the same unique code that was displayed at operation  304 . At operation  316  and  318 , the first lock/unlock module scans the unique code and opens the webpage associated with the address of the unique code. The webpage displayed on the module device  202  can show that the WE display  204  is locked and can show an icon to unlock the WE display  204 . The displayed webpage includes a hidden payload that is the same as the hidden payload in the webpage displayed at operation  308 . 
     At operation  320 , when the first lock/unlock module determines that a person has touched the icon to unlock the WE display, the first lock/unlock module retrieves the secret key stored on the mobile device  202 , obtains the hidden payload from the webpage, digitally signs the payload, and sends a second message comprising the digitally signed payload and a second command to unlock the WE module to the server  302  from the webpage whose address is unique to the WE display and via the wireless access point. After the digitally signed PayloadA is generated at operation  320 , the first lock/unlock module deletes the PayloadA and does not store (or discards) PayloadA on the mobile device. 
     At operations  304  and  314 , the second lock/unlock module does not display a passcode or password for a user to enter. As mentioned in this patent document, one of the technical advantages of the example flowchart of  FIG.  3    is that a passenger can lock and unlock the WE display without entering a passcode or a password via the WE display so that other passengers cannot easily lock and unlock the passenger&#39;s WE display using the passcode or the password. 
     At operation  322 , when the third lock/unlock module receives the second message and determines that the digitally signed payload received at operation  320  matches (e.g., is the same as) the digitally signed payload received at operation  310 , the third lock/unlock module can send another message to the computer  204  to unlock the IVE display. The third lock/unlock module sends the another message to the WE display  204  using the address of the WE display  204 , which is determined by the third lock/unlock module from the address of the webpage indicated to the mobile device at operation  314 . The another message includes an unlock message to unlock the WE display  204 . At operation  322 , the second lock/unlock module can unlock the WE display in response to receiving the unlock command. At operation  323 , the second lock/unlock module unlocks the WE display  204  in response to receiving the another message comprising the unlock command. 
     After the WE display  204  is unlocked at operation  322 , if a person wants to lock the WE display  204 , the set of operations to re-lock the WE display can start at operation  304 . In some embodiments, the secret key that may be generated at operation  310  by the first lock/unlock module of the mobile device  202  when a person locks the WE screen for a first time may be different than another secret key that may be generated at operation  310  by the first lock/unlock module of the mobile device  202  when the person locks the WE screen for a second time that is later than the first time. Thus, in some embodiments, the secret key that may be generated by the first lock/unlock module can be different every time the operations for locking WE display is performed. 
     In some embodiments, a main computer associated with a cabin crew can include an override module configured to control the plurality of seatback monitors. For example, if a passenger accidently locks a seatback monitor, the override module in the main computer can send a signal to unlock the particular seatback monitor by sending a unlock command to unlock to the particular seatback monitor. In some embodiments, the override module in the main computer can reset all of the plurality of seatback monitors by sending a reset command so that if at least some of the plurality of seatback monitors are locked, those locked seatback monitor(s) will be unlocked when the reset command is received. 
       FIG.  4 A  shows an example flowchart of operations performed by a computer and mobile device to lock and/or unlock a display on a commercial passenger vehicle. Operations  402  to  406  can be performed by a mobile device located in the commercial passenger vehicle and comprising a first processor configured to secure a display located in the commercial passenger vehicle, where the display is located behind a headrest of a seat in the commercial passenger vehicle. Operation  408  can be performed by a computer located in the commercial passenger vehicle, where the computer is communicably coupled with the display and comprises a second processor. Operation  402  includes obtaining a payload. Operation  404  includes generating a first digitally signed payload as a first output of a first mathematical computation performed on the payload with a secret key. Operation  406  includes sending a first message comprising the first digitally signed payload and a lock command to instruct the display to lock the display. Operation  408  includes sending a first instruction to cause the display to lock in response to a reception of the lock command. 
     In some embodiments, the mobile device comprising the first processor is further configured to: send, after the display is locked, a second message comprising a second digitally signed payload and an unlock command to instruct the display to unlock the display, where the second digitally signed payload is generated as a second output of a second mathematical computation performed on the payload with the secret key, where the first mathematical computation is performed at a first time that is earlier in time than a second time when the second mathematical computation is performed; and the computer comprising the second processor is further configured to: send a second instruction to cause the display to unlock in response to a reception of the unlock command. In some embodiments, the first processor of the mobile device is configured to not store or to discard the payload in the mobile device after the first digitally signed payload is generated. 
     In some embodiments, the first mathematical computation and the second mathematical computation includes a performance of a hash function using the payload the secret key. In some embodiments, when the display is locked, the second processor of the computer is configured to show on the display a volume adjustment menu to adjust an output volume of an audio or video content or to show on the display a brightness adjustment menu to adjust brightness of the display. In some embodiments, when the display is locked, the second processor of the computer is configured to show on the display a reading light control menu to control a light. In some embodiments, the payload is obtained from the computer by the first processor of the mobile device, the first processor being further configured to: transmit, using a first near field communication (NFC) device located in the mobile device, an application identifier (AID) to a second NFC device located in the display or located in another seat; and where the payload is obtained by the first NFC device from the second NFC device in response to the transmit the AID. 
     In some embodiments, the first message comprising the first digitally signed payload, the lock command, and the AID is sent by the first NFC device in the mobile device to the second NFC device in the display or in the another seat, and the second message comprising the second digitally signed payload, the unlock command, and the AID is sent by the first NFC device in the mobile device to the second NFC device in the display or in the another seat. In some embodiments, the display is caused to unlock by the second processor of the computer that is further configured to: receive the second message; and where the second instruction to cause the display to unlock is sent in response to the receive the unlock command and in response to a determination that the second digitally signed payload in the second message matches or is same as the first digitally signed payload in the first message. In some embodiments, the first NFC device is configured to operate in an NFC reader mode and the second NFC device is configured to operate in a host-based card emulation mode before the payload is obtained by the first NFC device. 
     In some embodiments, after the payload is obtained, the first NFC device is configured to operate in a host-based card emulation mode and the second NFC device is configured to operate in an NFC reader mode. In some embodiments, the payload is obtained from a server located in the commercial passenger vehicle by the first processor of the mobile device, the first processor being further configured to: scan a unique code displayed on the display, where the unique code provides an address of a webpage unique to the display; and cause a screen of the mobile device to show the webpage whose address is provided by the unique code, where the webpage is hosted on the server; where the payload is obtained from the webpage, and where the payload is hidden in the webpage. In some embodiments, the first message comprising the first digitally signed payload and the lock command is sent by the mobile device to the server from the address of the webpage that is unique to the display, and where the second message comprising the second digitally signed payload and the unlock command is sent is sent by the mobile device to the server from the address of the webpage that is unique to the display. 
     In some embodiments, the server includes a third processor that is configured to: receive, from the mobile device, the first message comprising the first digitally signed payload and the lock command; and send, in response to the receive the first message, a third message to the computer associated with the display, where the third message comprises the lock command, and where the third message is sent to the computer based on the address of the webpage that is unique to the display. In some embodiments, the server includes a third processor that is configured to: receive, from the mobile device, the second message comprising the second digitally signed payload and the unlock command; and send, upon determining that the second digitally signed payload matches or is same as the first digitally signed payload, a fourth message to the computer associated with the display, where the fourth message comprises the unlock command, and where the fourth message is sent to the computer based on the address of the webpage that is unique to the display. 
       FIG.  4 B  shows an example flowchart of operations performed by a computer to lock and/or unlock a display on a commercial passenger vehicle. Operation  452  to  458  can be performed by a processor in a computer configured to secure an in-vehicle entertainment (WE) display. Operation  452  includes receiving, from a near field communication (NFC) device, a first message comprising a first digitally signed payload and a lock command to instruct a display to lock the display, where the computer and the display are located in a commercial passenger vehicle. Operation  454  includes sending a first instruction to cause the display to lock in response to a reception of the lock command. Operation  456  includes receiving, from the NFC device and after the display is locked, a second message comprising a second digitally signed payload and an unlock command to instruct the display to unlock the display. Operation  458  includes sending a second instruction to cause the display to unlock in response to a reception of an unlock command and in response to a determination that the second digitally signed payload in the second message matches the first digitally signed payload in the first message. 
     In some embodiments, the processor of the computer is configured to: receive an application identifier (AID) from a mobile device; and transmit, in response to the receive the AID, a payload to the mobile device, where the first digitally signed payload is a first output of a first mathematical computation that includes the payload and a secret key of the mobile device, and where the second digitally signed payload is a second output of a second mathematical computation that includes the payload and the secret key of the mobile device. In some embodiments, where the first message comprising the first digitally signed payload, the lock command, and the AID is received by the NFC device, and the second message comprising the second digitally signed payload, the unlock command, and the AID is received by the NFC device. In some embodiments, when the display is locked, the processor of the computer is further configured to show on the display a volume adjustment menu to adjust an output volume of an audio or video content or to show on the display a brightness adjustment menu to adjust brightness of the display. In some embodiments, the second digitally signed payload in the second message is determined to match the first digitally signed payload in the first message by the processor configured to determine that the second digitally signed payload is same as the first digitally signed payload. 
       FIG.  5    shows an exemplary block diagram of a mobile device. The mobile device  202  includes at least one processor  510  and a memory  505  having instructions stored thereupon. The instructions upon execution by the processor  510  configure the mobile device  202  to perform operations described in  FIGS.  1  to  4   , and to perform the operations described for the first lock/unlock module  525  and/or for the first NFC device  530 . The instructions upon execution by the processor  510  can also configure the mobile device  202  to perform the operations described in the various embodiments described in this patent document. The transmitter  515  transmits or sends information or data to another device (e.g., the server). The receiver  520  receives information from another device (e.g., the server). 
       FIG.  6    shows an exemplary block diagram of a computer associated with an WE display. The computer  204  includes at least one processor  610  and a memory  605  having instructions stored thereupon. The instructions upon execution by the processor  610  configure the computer  204  to perform operations described in  FIGS.  1  to  4   , and to perform the operations described for the second lock/unlock module  625  and/or for the second NFC device  630 . The instructions upon execution by the processor  610  can also configure the computer  204  to perform the operations described in the various embodiments described in this patent document. The transmitter  615  transmits or sends information or data to another device (e.g., to the server or the mobile device). The receiver  320  receives information from another device (e.g., from the server or the mobile device). 
       FIG.  7    shows an exemplary block diagram of a server located in a commercial passenger vehicle. The server  302  includes at least one processor  710  and a memory  705  having instructions stored thereupon. The instructions upon execution by the processor  710  configure the server  302  to perform operations described in  FIGS.  1  and  3  to  4   , and to perform the operations described for the third lock/unlock module  725 . The instructions upon execution by the processor  710  can also configure the server  302  to perform the operations described in the various embodiments described in this patent document. The transmitter  715  transmits or sends information or data to another device (e.g., to the compute associated with the WE display or to the mobile device). The receiver  320  receives information from another device (e.g., from the computer associated with the WE display or from the mobile device). 
     This patent document describes the exemplary techniques to lock and unlock WE displays in the context of a commercial passenger vehicle such as an airplane for ease of description. The exemplary test system could be used to lock and unlock monitors or other display devices in other types of commercial passenger vehicle such as a train, a ship, or a bus. 
     Some of the embodiments described herein are described in the general context of methods or processes, which may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Therefore, the computer-readable media can include a non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer- or processor-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes. 
     Some of the disclosed embodiments can be implemented as devices or modules using hardware circuits, software, or combinations thereof. For example, a hardware circuit implementation can include discrete analog and/or digital components that are, for example, integrated as part of a printed circuit board. Alternatively, or additionally, the disclosed components or modules can be implemented as an Application Specific Integrated Circuit (ASIC) and/or as a Field Programmable Gate Array (FPGA) device. Some implementations may additionally or alternatively include a digital signal processor (DSP) that is a specialized microprocessor with an architecture optimized for the operational needs of digital signal processing associated with the disclosed functionalities of this application. Similarly, the various components or sub-components within each module may be implemented in software, hardware or firmware. The connectivity between the modules and/or components within the modules may be provided using any one of the connectivity methods and media that is known in the art, including, but not limited to, communications over the Internet, wired, or wireless networks using the appropriate protocols. 
     While this document contains many specifics, these should not be construed as limitations on the scope of an invention that is claimed or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. 
     Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.