Abstract:
Disclosed are a method and device for acquiring a message certificate in a vehicle networking system, so that the requirement that a message certificate required by a vehicle needing high passing priority is issued to the vehicle in an emergency is solved. The method comprises: receiving, by a BCC, an application license application instruction sent by an OBU, the application license application instruction being used for applying for use of a privilege certificate already written in the OBU to the BCC; and determining, by the BCC, the valid time for the OBU to use a designated privilege certificate, generating an application control instruction according to the determined valid time, and sending the generated application control instruction to the OBU, the application control instruction being used for indicating that the OBU uses the designated privilege certificate within the valid time, so that the OBU can use the privilege certificate designated by the BCC within the valid time determined by the BCC so as to enable the OBU to have the passing priority within the valid time determined by the BCC.

Description:
[0001]    This application claims the benefit of Chinese Patent Application No. 201410012806.2, filed with the State Intellectual Property Office of People&#39;s Republic of China on Jan. 10, 2014 and entitled “Method and device for obtaining a message certificate in an internet of vehicles system”, which is hereby incorporated by reference in its entirety. 
       FIELD 
       [0002]    The present invention relates to the field of internet of vehicles, and particularly to a method and device for obtaining a message certificate in an internet of vehicles system. 
       BACKGROUND 
       [0003]    The internet of vehicles is primarily applied for the purpose of reducing the number of traffic accidents occurring. In the internet of vehicles system, an On-Board Unit (OBU) on a vehicle monitors the position and traveling information of the vehicle, and broadcasts the information to the surrounding vehicles, and also the OBU on the vehicle further receives the information sent by the OBUs on the other vehicles; and the OBU on the vehicle analyzes the traveling information of the current vehicle and the other vehicles, and notifies a driver of a possible accident threat in a timely manner. 
         [0004]    For the sake of security, in the internet of vehicles system, a certificate for the vehicle to issue a message broadcasted by the vehicle is referred to as a message certificate. Respective privileges possessed by the vehicle are typically stored in the message certificate, e.g., an internet of vehicles specific certificate defined in the IEEE 1609.2. The message certificate is typically sent to the receiver together with the issued message so that the message receiver can authenticate the received message. The message certificate includes a public key for verifying a signature of the message, and a description of the privileges of the sender. In the internet of vehicles system, each of the vehicles possesses a normal message certificate describing the lowest pass privilege. In addition to the normal message certificate, a special vehicle possessing a higher pass privilege possesses a special message certificate describing its higher pass privilege. In this case, the privileges possessed by the special vehicle are the sum of the privileges described by all its message certificates. The respective message certificates applied in the internet of vehicles system are issued by a Certificate Authority (CA) in some flow which particularly includes requesting, reviewing, issuing, distributing, and other processes. 
         [0005]    However in some urgent cases, for example, if there is a serious patient to be delivered to a hospital, there is some special material to be transported, etc., then a civilian vehicle may also need a priority pass privilege. A message certificate required for the vehicle needing the high priority pass privilege can not be issued to the vehicle in the existing message certificate issuing flow in the urgent case because it may take such a long period of time for requesting for the certificate in which the urgent event can not be handled in a timely manner; and furthermore if required data communication means is unavailable (for example, data can not be transmitted between the OBU and the CA) while the event is occurring, then the message certificate can not be issued in the prior art. 
         [0006]    At present, the internet of vehicles is being investigated and the related standards thereof are being developed, so numerous issues thereof have been ignored. None of the related technological standards has been concerned so far with a technical solution to issue a message certificate required for a vehicle needing a high priority pass privilege in an urgent case, and no related research effort has been identified to address this issue. 
       SUMMARY 
       [0007]    Embodiments of the invention provide a method and device for obtaining a message certificate in an internet of vehicles system so as to address the problem of issuing a message certificate required for a vehicle needing a high priority pass privilege in an urgent case. 
         [0008]    The invention provides a method for obtaining a message certificate at the BCC side in an internet of vehicles system, the method including: 
         [0009]    receiving, by a BCC, an application grant request instruction sent by an On-Board Unit (OBU), wherein the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU; and 
         [0010]    determining, by the BCC, a valid time in which the OBU applies the specified privilege certificate, generating an application control instruction according to the valid time, and sending the generated application control instruction to the OBU, wherein the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0011]    In the invention, the BCC receives the application grant request instruction sent by the OBU, and the BCC determines the valid time in which the OBU applies the specified privilege certificate, generates the application control instruction according to the determined valid time, and sends the generated application control instruction to the OBU, so that the OBU can apply the privilege certificate specified by the BCC in the valid time determined by the BCC, and thus the OBU can have a priority pass privilege in the valid time determined by the BCC. 
         [0012]    In an embodiment, receiving, by the BCC, the application grant request instruction sent by the OBU includes: 
         [0013]    receiving, by the BCC, the application grant request instruction sent by the OBU over a data transmission link; or receiving, by the BCC, the application grant request instruction sent by the OBU through voice transmission. 
         [0014]    In an embodiment, generating, by the BCC, the application control instruction according to the valid time, and sending the generated application control instruction to the OBU includes: 
         [0015]    generating, by the BCC, the application control instruction according to the valid time, encrypting the information included in the application control instruction, and sending the encrypted application control instruction to the OBU. 
         [0016]    Furthermore encrypting, by the BCC, the information included in the application control instruction includes: 
         [0017]    performing, by the BCC, key diversification on a random number, generated by the OBU, carried in the application grant request instruction using a determined privilege certificate management key to generate a session key; 
         [0018]    encrypting, by the BCC, an instruction identifier, in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and a determined valid time, using the generated session key to obtain a cipher text; and 
         [0019]    calculating, by the BCC, an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0020]    In an embodiment, before the BCC receives the certificate application grant request instruction sent by the OBU, the method further includes: 
         [0021]    generating, by the BCC, a key pair corresponding to the privilege certificate of the OBU, wherein the key pair includes a public key and a private key; and 
         [0022]    generating, by the BCC, a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU, and sending the privilege certificate request instruction to a Certificate Authority (CA); and 
         [0023]    receiving and storing, by the BCC, the privilege certificate issued by the CA in response to the privilege certificate request instruction. 
         [0024]    Furthermore after the BCC receives the privilege certificate issued by the CA, and before the BCC receives the application grant request instruction sent by the OBU, the method further includes: 
         [0025]    receiving, by the BCC, the privilege certificate request instruction sent by the OBU, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0026]    generating and sending, by the BCC, a write control instruction to the OBU, wherein the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0027]    In an embodiment, generating and sending, by the BCC, the write control instruction to the OBU includes: 
         [0028]    generating, by the BCC, the write control instruction, encrypting the information included in the generated write control instruction, and sending the encrypted write control instruction to the OBU. 
         [0029]    Furthermore encrypting, by the BCC, the information included in the generated write control instruction includes: 
         [0030]    performing, by the BCC, key diversification on a random number generated by the OBU, carried in the write control instruction using a determined privilege certificate management key to generate a session key; and 
         [0031]    encrypting, by the BCC, an instruction identifier, in the write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and 
         [0032]    calculating, by the BCC, an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0033]    Further to the embodiment above, before the BCC receives the certificate application grant request instruction sent by the OBU, the method further includes: 
         [0034]    generating, by the BCC, at least one privilege certificate management key corresponding to the OBU according to its at least one master key, and the identifier of the OBU, and sending the at least one privilege certificate management key to the OBU. 
         [0035]    The invention provides a method for obtaining a message certificate at the OBU side in an internet of vehicles system, the method including: 
         [0036]    if an OBU needs to issue a message using a privilege certificate, then sending an application grant request instruction to a Background Control Center (BCC), wherein the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU; and 
         [0037]    upon reception of an application control instruction sent by the BCC, issuing, by the OBU, the message using the privilege certificate specified by the BCC in a valid time specified by the BCC according to the application control instruction, and broadcasting the issued message to the other OBUs than the OBU. 
         [0038]    In an embodiment, sending, by the OBU, the application grant request instruction to the BCC includes: 
         [0039]    sending, by the OBU, the application grant request instruction to the BCC over a data transmission link; or 
         [0040]    sending the application grant request instruction to the BCC through voice transmission. 
         [0041]    In an embodiment, after the OBU receives the application control instruction sent by the BCC, the method further includes: 
         [0042]    authenticating and decrypting, by the OBU, the application control instruction to obtain and store the information included in the application control instruction. 
         [0043]    Furthermore authenticating and decrypting, by the OBU, the application control instruction includes: 
         [0044]    selecting, by the OBU, a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the application control instruction; 
         [0045]    performing, by the OBU, key diversification on a random number carried in the application grant request instruction using the selected privilege certificate management key to generate a session key; 
         [0046]    calculating, by the OBU, an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; 
         [0047]    decrypting, by the OBU, the cipher text in the application control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the number of the specified privilege certificate, and a determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and 
         [0048]    storing, by the OBU, the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction. 
         [0049]    In an embodiment, before the OBU sends the application grant request instruction to the BCC, the method further includes: 
         [0050]    sending, by the OBU, a privilege certificate request instruction to the BCC, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0051]    receiving, by the OBU, a write control instruction sent by the BCC, and storing the privilege certificate requested by the BCC for the OBU, and a key pair generated by the BCC for the privilege certificate, carried in the write control instruction. 
         [0052]    Furthermore after the OBU receives the write control instruction, the method includes: 
         [0053]    authenticating and decrypting, by the OBU, the write control instruction to obtain and store the information included in the write control instruction. 
         [0054]    Furthermore authenticating and decrypting, by the OBU, the write control instruction includes: 
         [0055]    selecting, by the OBU, a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the write control instruction; 
         [0056]    performing, by the OBU, key diversification on a random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; 
         [0057]    calculating, by the OBU, an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; 
         [0058]    decrypting, by the OBU, the cipher text in the write control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the privilege certificate requested by the BCC for the OBU, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and 
         [0059]    storing, by the OBU, the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier corresponding to the privilege certificate upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU. 
         [0060]    Further to the embodiment above, before the OBU sends the application grant request instruction to the BCC, the method further includes: 
         [0061]    receiving and storing, by the OBU, at least one privilege certificate management key sent by the BCC. 
         [0062]    The invention provides a BCC including: 
         [0063]    a receiving and sending module configured to receive an application grant request instruction sent by an OBU, wherein the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU; and 
         [0064]    a processing module configured to determine a valid time in which the OBU applies the specified privilege certificate, to generate an application control instruction according to the valid time, and to send the generated application control instruction to the OBU, wherein the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0065]    In an embodiment, the receiving and sending module is configured: 
         [0066]    to receive the application grant request instruction sent by the OBU over a data transmission link; or to receive the application grant request instruction sent by the OBU through voice transmission. 
         [0067]    In an embodiment, in order to secure data transmission, the processing module is configured: 
         [0068]    to generate the application control instruction according to the valid time, to encrypt the information included in the application control instruction, and to send the encrypted application control instruction to the OBU. 
         [0069]    Furthermore the processing module configured to encrypt the information included in the application control instruction is configured: 
         [0070]    to perform key diversification on a random number, generated by the OBU, carried in the application grant request instruction using a determined privilege certificate management key to generate a session key; and 
         [0071]    to encrypt an instruction identifier, in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and a determined valid time, using the generated session key to obtain a cipher text; and to calculate an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0072]    In an embodiment, before the receiving and sending module receives the certification application grant request instruction sent by the OBU, 
         [0073]    the processing module is further configured to generate a key pair corresponding to the privilege certificate of the OBU, wherein the key pair includes a public key and a private key; and to generate a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU; and 
         [0074]    the receiving and sending module is further configured to send the privilege certificate request instruction to a Certificate Authority (CA); and to receive and store, by the BCC, the privilege certificate issued by the CA in response to the privilege certificate request instruction. 
         [0075]    In an embodiment, after the receiving and sending module receives the privilege certificate issued by the CA, and before the receiving and sending module receives the application grant request instruction sent by the OBU, 
         [0076]    the receiving and sending module is further configured to receive the privilege certificate request instruction sent by the OBU, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0077]    the processing module is further configured to generate and send a write control instruction to the OBU, wherein the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0078]    In an embodiment, in order to secure data transmission, the processing module configured to generate and send the write control instruction to the OBU is configured: to generate the write control instruction, to encrypt the information included in the generated write control instruction, and to send the encrypted write control instruction to the OBU. 
         [0079]    Furthermore the processing module configured to encrypt the information included in the generated write control instruction is configured: 
         [0080]    to perform key diversification on a random number generated by the OBU, carried in the write control instruction using a determined privilege certificate management key to generate a session key; and 
         [0081]    to encrypt an instruction identifier, in the write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and 
         [0082]    to calculate an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0083]    Further to the embodiment above, before the receiving and sending module receives the certificate application grant request instruction sent by the OBU, 
         [0084]    the processing module is further configured to generate at least one privilege certificate management key corresponding to the OBU according to its at least one master key, and the identifier of the OBU; and 
         [0085]    the receiving and sending module is further configured to send the at least one privilege certificate management key to the OBU. 
         [0086]    The invention provides an OBU including: 
         [0087]    a receiving and sending module configured, if the OBU needs to issue a message using a privilege certificate, to send an application grant request instruction to a BCC, wherein the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU; and to receive an application control instruction sent by the BCC; and 
         [0088]    a processing module configured, after the receiving and sending module receives the application control instruction sent by the BCC, to issue the message using the privilege certificate specified by the BCC in a valid time specified by the BCC according to the application control instruction, and to broadcast the issued message to the other OBUs than the OBU. 
         [0089]    In an embodiment, the receiving and sending module is configured: to send the application grant request instruction to the BCC over a data transmission link; or to send the application grant request instruction to the BCC through voice transmission. 
         [0090]    In an embodiment, in order to secure data transmission, after the receiving and sending module receives the application control instruction sent by the BCC, the processing module is further configured: to authenticate and decrypt the application control instruction to obtain and store the information included in the application control instruction. 
         [0091]    Furthermore the processing module configured to authenticate and decrypt the application control instruction is configured: 
         [0092]    to select a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the application control instruction; to perform key diversification on a random number carried in the application grant request instruction using the selected privilege certificate management key to generate a session key; to calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; to decrypt the cipher text in the application control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the number of the specified privilege certificate, and a determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and to store the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction. 
         [0093]    In an embodiment, before the receiving and sending module sends the application grant request instruction to the BCC, 
         [0094]    the receiving and sending module is further configured: to send a privilege certificate request instruction to the BCC, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and to receive a write control instruction sent by the BCC; and 
         [0095]    the processing module is further configured: to store the privilege certificate requested by the BCC for the OBU, and a key pair generated by the BCC for the privilege certificate, carried in the write control instruction. 
         [0096]    In an embodiment, in order to secure data transmission, after the receiving and sending module receives the write control instruction sent by the BCC, the processing module is further configured: to authenticate and decrypt the write control instruction to obtain and store the information included in the write control instruction. 
         [0097]    Furthermore the processing module configured to authenticate and decrypt the write control instruction is configured: 
         [0098]    to select a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the write control instruction; to perform key diversification on a random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; to calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; to decrypt the cipher text in the write control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the privilege certificate requested by the BCC for the OBU, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and to store the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU. 
         [0099]    Further to the embodiment above, the receiving and sending module is further configured, before the application grant request instruction is sent to the BCC: to receive and store at least one privilege certificate management key sent by the BCC. 
         [0100]    The invention provides another BCC including a transceiver, at least one processor connected with the transceiver, and a memory connected respectively with the transceiver and the processor: 
         [0101]    the transceiver is configured to receive an application grant request instruction sent by an OBU, wherein the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU; and 
         [0102]    the processor is configured to determine a valid time in which the OBU applies the specified privilege certificate, to generate an application control instruction according to the valid time, and to trigger the transceiver to send the generated application control instruction to the OBU, wherein the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0103]    In an embodiment, the transceiver is configured: to receive the application grant request instruction sent by the OBU over a data transmission link; or to receive the application grant request instruction sent by the OBU through voice transmission. 
         [0104]    In an embodiment, in order to secure data transmission, the processor is configured: to generate the application control instruction according to the valid time, to encrypt the information included in the application control instruction, and to send the encrypted application control instruction to the OBU. 
         [0105]    Furthermore the processor configured to encrypt the information included in the application control instruction is configured: 
         [0106]    to perform key diversification on a random number, generated by the OBU, carried in the application grant request instruction using a determined privilege certificate management key to generate a session key; to encrypt an instruction identifier, in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and a determined valid time, using the generated session key to obtain a cipher text; and to calculate an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0107]    In an embodiment, before the transceiver receives the certification application grant request instruction sent by the OBU, the processor is further configured to generate a key pair corresponding to the privilege certificate of the OBU, wherein the key pair includes a public key and a private key; and to generate a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU; the transceiver is further configured to send the privilege certificate request instruction to a Certificate Authority (CA); and to receive and store, by the BCC, the privilege certificate issued by the CA in response to the privilege certificate request instruction; and the memory is configured: store the privilege certificate issued by the CA, and the key pair generated by the processor for the privilege certificate. 
         [0108]    In an embodiment, after the transceiver receives the privilege certificate issued by the CA, and before the transceiver receives the application grant request instruction sent by the OBU, the transceiver is further configured to receive the privilege certificate request instruction sent by the OBU, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and the processor is further configured to generate a write control instruction, and to trigger the transceiver to send the write control instruction to the OBU, wherein the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0109]    In an embodiment, in order to secure data transmission, the processor configured to generate and send the write control instruction to the OBU is configured: to generate the write control instruction, to encrypt the information included in the generated write control instruction, and to send the encrypted write control instruction to the OBU. 
         [0110]    Furthermore the processor configured to encrypt the information included in the generated write control instruction is configured: to perform key diversification on a random number generated by the OBU, carried in the write control instruction using a determined privilege certificate management key to generate a session key; to encrypt an instruction identifier, in the write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and to calculate an MAC from a version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, wherein the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0111]    Further to the embodiment above, before the transceiver receives the certificate application grant request instruction sent by the OBU, the processor is further configured: to generate at least one privilege certificate management key corresponding to the OBU according to at least one master key stored in the memory, and the identifier of the OBU, and to store the at least one privilege certificate management key in the memory; and the transceiver is further configured to send the at least one privilege certificate management key to the OBU. 
         [0112]    The invention provides an OBU including a transceiver, at least one processor connected with the transceiver, and a memory connected respectively with the transceiver and the processor: 
         [0113]    the transceiver is configured, if the OBU needs to issue a message using a privilege certificate, to send an application grant request instruction to a BCC, wherein the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU; and to receive an application control instruction sent by the BCC; and 
         [0114]    the processor is configured to issue the message using the privilege certificate specified by the BCC in a valid time specified by the BCC according to the application control instruction, and to broadcast the issued message to the other OBUs than the OBU. 
         [0115]    In an embodiment, the transceiver is configured to send the application grant request instruction to the BCC over a data transmission link; or to send the application grant request instruction to the BCC through voice transmission. 
         [0116]    In an embodiment, after the transceiver receives the application control instruction sent by the BCC, the processor is further configured: to authenticate and decrypt the application control instruction to obtain and store the information included in the application control instruction. 
         [0117]    Furthermore the processor configured to authenticate and decrypt the application control instruction is configured: 
         [0118]    to select a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the application control instruction; to perform key diversification on a random number carried in the application grant request instruction using the selected privilege certificate management key to generate a session key; to calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; to decrypt the cipher text in the application control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the number of the specified privilege certificate, and a determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and to store in the memory the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction. 
         [0119]    In an embodiment, before the transceiver sends the application grant request instruction to the BCC, the transceiver is further configured: to send a privilege certificate request instruction to the BCC, wherein the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and to receive a write control instruction sent by the BCC; and the processing module is further configured: to store in the memory the privilege certificate requested by the BCC for the OBU, and a key pair generated by the BCC for the privilege certificate, carried in the write control instruction. 
         [0120]    In an embodiment, after the transceiver receives the write control instruction sent by the BCC, the processor is further configured: to authenticate and decrypt the write control instruction to obtain and store the information included in the write control instruction. 
         [0121]    Furthermore the processor configured to authenticate and decrypt the write control instruction is configured: 
         [0122]    to select a corresponding privilege certificate management key according to a version number of the privilege certificate management key carried in the write control instruction; to perform key diversification on a random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; to calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; to decrypt the cipher text in the write control instruction using the generated session key to obtain an instruction identifier identifying the type of the current instruction, a random number, the privilege certificate requested by the BCC for the OBU, a certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and to store in the memory the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier corresponding to the privilege certificate upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0123]      FIG. 1  is a schematic architectural diagram of a vehicle privilege certification application system in an internet of vehicles system according to an embodiment of the invention; 
           [0124]      FIG. 2  is a schematic diagram of a method for obtaining a message certificate at the BCC side in the internet of vehicles system according to an embodiment of the invention; 
           [0125]      FIG. 3  is a schematic diagram of a process of encrypting information included in an application control instruction by the BCC according to an embodiment of the invention; 
           [0126]      FIG. 4  is a schematic diagram of a process of encrypting information included in a generated write control instruction by the BCC according to an embodiment of the invention; 
           [0127]      FIG. 5  is a schematic diagram of a method for obtaining a message certificate at the OBU side in the internet of vehicles system according to an embodiment of the invention; 
           [0128]      FIG. 6  is a schematic diagram of a process of authenticating and decrypting a received application control instruction by the OBU according to an embodiment of the invention; 
           [0129]      FIG. 7  is a schematic diagram of a process of authenticating and decrypting a write control instruction by the OBU according to an embodiment of the invention; 
           [0130]      FIG. 8  is a schematic structural diagram of a security unit in the OBU according to an embodiment of the invention; 
           [0131]      FIG. 9  is a schematic flow chart according to an embodiment of the invention; 
           [0132]      FIG. 10  is a schematic diagram of a process of encrypting information included in a generated write control instruction by the BCC according to an embodiment of the invention; 
           [0133]      FIG. 11  is a schematic diagram of a process of authenticating and decrypting the write control instruction by the OBU according to an embodiment of the invention; 
           [0134]      FIG. 12  is a schematic diagram of a BCC according to an embodiment of the invention; 
           [0135]      FIG. 13  is a schematic diagram of an OBU according to an embodiment of the invention; 
           [0136]      FIG. 14  is a schematic structural diagram of another BCC according to an embodiment of the invention; and 
           [0137]      FIG. 15  is a schematic structural diagram of another OBU according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0138]    The invention provides a mechanism of requesting for and applying a message certificate, which can issue in advance a privilege certificate with a higher pass privilege to any on-board unit, but authorize the OBU to access the privilege of the privilege certificate only if necessary, so that a normal vehicle can also possess the higher priority pass privilege in an urgent case. 
         [0139]    In the embodiments of the invention, the high pass priority certificate issued to any vehicle will be referred to as a privilege certificate. The structure of the privilege certificate is the same as a normal message certificate, but the privilege certificate shall be issued and applied in compliance with a specialized mechanism. The privilege certificate is typically unavailable, and the application of the privilege certificate shall be authorized by a Background Control Center (BCC), where the privilege certificate can be applied in a specified valid time, and the privilege certificate will automatically become unavailable at the end of the valid time. 
         [0140]    Firstly respective entities involved in the embodiments of the invention will be described below, and  FIG. 1  illustrates the architecture of a vehicle privilege certificate application system in an internet of vehicles system, where the system includes a Certificate Authority (CA), a BCC, and OBUs, where general functions of the respective entities are as follows: 
         [0141]    The CA is responsible for issuing various certificates, e.g., a message certificate, a privilege certificate, etc., to an internet of vehicles device which can include an OBU and a Road Side Unit (RSU); 
         [0142]    The BCC is responsible for generating a key pair for the OBU, and requesting for a certificate from the CA, and then writing the obtained certificate and the key pair into the OBU in a secure manner; and the BCC is further responsible for managing vehicle privilege certificates, where the BCC can grant applications of the privilege certificates as required; and 
         [0143]    The OBU firstly requests the BCC for the privilege certificate desirable thereto, and the key pair corresponding to the privilege certificate, and then requests the BCC for an application grant to the certificate, and thereafter issues a message broadcasted by the OBU using the obtained certificate. 
         [0144]    There are the following flows related to an application of the privilege certificate in the internet of vehicles: 
         [0145]    The privilege certificate is requested for and written: the BCC generates the key pair, and requests the CA for the message certificate using the OBU information, and then writes the certificate and the key pair into the OBU using a dedicated instruction in response to the request of the OBU. 
         [0146]    The application grant to the privilege certificate is requested for and written: the BCC writes the application grant to the privilege certificate into the OBU using a dedicated instruction in response to the request of the OBU. 
         [0147]    The privilege certificate is applied: the OBU issues the message using the currently available privilege certificate, and then broadcasts it to the other OBUs. 
         [0148]    The embodiments of the invention will be further described below in details with reference to the drawings. It shall be appreciated that the embodiments described here are merely intended to illustrate and describe the invention, but not to limit the invention. 
         [0149]    Referring to  FIG. 2 , an embodiment of the invention provides a method for obtaining a message certificate at the BCC side in an internet of vehicles, where the method includes the following steps: 
         [0150]    In the step  101 , a BCC receives an application grant request instruction sent by an OBU, where the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU. 
         [0151]    Before this step, the BCC has requests for at least one privilege certificate for the OBU, and writes both the requested privilege certificate, and a key pair generated by the BCC for each requested privilege certificate into the OBU for storage, but the privilege certificate is normally unavailable to the OBU, and an application of any privilege certificate by the OBU shall be authorized by the BCC, where the privilege certificate can be applied in a limited period of time specified by the BCC, and the privilege certificate will become unavailable again at the end of the valid time. Thus if the OBU needs to apply the privilege certificate, then the OBU will send the application grant request instruction to the BCC to request the BCC for an application of the privilege certificate written into the OBU. 
         [0152]    In this step, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU identifier (ID) identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0153]    Particularly the application grant request instruction includes the CMD, the OBU ID, and the OBU Random, where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0154]    It shall be noted that bidirectional authentication is not required between the BCC and the OBU before this step is performed. 
         [0155]    In the step  102 , the BCC determines a valid time in which the OBU applies the specified privilege certificate, generates an application control instruction according to the determined valid time, and sends the generated application control instruction to the OBU, where the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0156]    Particularly the BCC reviews the application grant request instruction sent by the OBU upon reception of the application grant request instruction of the OBU, and specifies the privilege certificate applicable to the OBU, and the valid time in which the OBU applies the specified privilege certificate upon determining that the OBU can apply the privilege certificate; and then generates and sends the corresponding application control instruction to the OBU to instruct the OBU to apply the specified privilege certificate in the valid time. 
         [0157]    In this step, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0158]    Particularly the application control instruction includes: the OBU Key Version, the CMD, the OBU Random, the Certificate Number, a Start Time, and a Duration, where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0159]    It shall be noted that the valid time in which the privilege certificate can be applied can be represented in another representation in addition to the representation above, for example, the start time and an end time at which the privilege certificate is valid represent the valid time in which the privilege certificate can be applied. 
         [0160]    In an embodiment of the invention, the BCC receives the application grant request instruction sent by the OBU, and the BCC determines the valid time in which the OBU applies the specified privilege certificate, generates the application control instruction according to the determined valid time, and sends the generated application control instruction to the OBU, so that the OBU can apply the privilege certificate specified by the BCC in the valid time determined by the BCC, and thus the OBU can have a priority pass privilege in the valid time determined by the BCC. 
         [0161]    In an implementation, the BCC receives the application grant request instruction sent by the OBU in the step  101  particularly in the following two approaches: 
         [0162]    In a first approach, the BCC receives the application grant request instruction sent by the OBU over a data transmission link. 
         [0163]    This approach will be applicable if there is a network connection between the BCC and the OBU, where the BCC interacts with the OBU by transmitting over the network to thereby authorize an application of the privilege certificate. 
         [0164]    In a second approach, the BCC receives the application grant request instruction sent by the OBU through voice transmission. 
         [0165]    This approach will be applicable if there is no network connection between the BCC and the OBU, where the BCC interacts with the OBU through voice transmission to thereby authorize an application of the privilege certificate. 
         [0166]    In an implementation, in order to secure data transmission, the BCC generates the application control instruction according to the determined valid time, and sends the application control instruction to the OBU in the step  102  particularly as follows: 
         [0167]    The BCC generates the application control instruction according to the determined valid time, encrypts the information included in the application control instruction, and sends the encrypted application control instruction to the OBU. 
         [0168]    Here the BCC encrypts the information included in the application control instruction in the following process as illustrated in  FIG. 3 : 
         [0169]    The BCC performs key diversification on the random number carried in the application grant request instruction according to the determined privilege certificate management key (OBU Key) to generate a session key; and 
         [0170]    The BCC encrypts the instruction identifier, in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and the determined valid time, using the generated session key to obtain a cipher text; and the BCC calculates a Message Authentication Code (MAC) from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0171]    In the process above, the BCC determines the privilege certificate management key particularly as follows: the BCC selects one of its master keys, and performs key diversification on the OBU ID using the selected master key to obtain the privilege certificate management key of the OBU, where the BCC can have a number of master keys with different version numbers, so the BCC can generate a privilege certificate management key for the OBU according to each master key and the OBU ID. 
         [0172]    In the process above, the key for calculating the MAC is the session key; or of course, the key for calculating the MAC can alternatively be a key calculated separately and different from the session key. 
         [0173]    In an implementation, before the BCC receives the certificate application grant request instruction sent by the OBU, the method further includes: 
         [0174]    The BCC generates at least one privilege certificate management key corresponding to the OBU according to its at least one master key, and the identifier of the OBU, and sends the at least one privilege certificate management key to the OBU. 
         [0175]    It shall be noted that the BCC firstly performs key diversification using its master key, and the OBU ID of the OBU to obtain the at least one privilege certificate management key (OBU key) corresponding to the OBU before requesting for the privilege certificate for the OBU, that is, OBU keys of different OBUs are different from each other, and each OBU can also have a number of OBU keys, where the OBU keys corresponding to each OBU are identified by their numbers, and the BCC decides on particularly which one of the OBU keys is to be applied. 
         [0176]    In an embodiment of the invention, before the privilege certificate is granted for authorization, the method further includes a process of requesting for the privilege certificate, and particularly, before the BCC receives the certificate application grant request instruction sent by the OBU, the method further includes: 
         [0177]    The BCC generates the pair key corresponding to the privilege certificate of the OBU, where the generated pair key including a public key and a private key; 
         [0178]    The BCC generates a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU (e.g., the OBU ID, and other information related to requesting for the privilege certificate), and sends the privilege certificate request instruction to the Certificate Authority (CA); and 
         [0179]    The BCC receives and stores the privilege certificate issued by the CA in response to the privilege certificate request instruction. 
         [0180]    Furthermore after the BCC receives the privilege certificate issued by the CA, and before the BCC receives the application grant request instruction sent by the OBU, the method further includes: 
         [0181]    The BCC sends a notification message to the OBU to notify the OBU that the BCC has requested for the privilege certificate of the OBU, so that the OBU sends the application grant request instruction to the BCC. 
         [0182]    In an implementation, after the BCC receives the privilege certificate issued by the CA, and before the BCC receives the application grant request instruction sent by the OBU, the method further includes a process of writing the privilege certificate particularly as follows: 
         [0183]    The BCC receives the privilege certificate request instruction sent by the OBU, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0184]    The BCC generates and sends a write control instruction to the OBU, where the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0185]    In the process above, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0186]    Particularly the privilege certificate request instruction includes the CMD, the OBU ID, and the OBU Random, where the CMD is an instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0187]    In the process above, the write control instruction generated by the BCC includes the version number of the currently used privilege certificate management key, an instruction identifier identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of the start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0188]    Particularly the write control instruction includes the OBU key version, the CMD, the OBU Random, the Certificate Number, the Certificate, the Key Pair, the Start Time, and the Duration, where the CMD is the instruction identifier identifying the current instruction as the write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0189]    It shall be noted that the valid time in which the privilege certificate can be applied can be represented in another representation in addition to the representation above, for example, the start time and the end time at which the privilege certificate is valid represent the valid time in which the privilege certificate can be applied. 
         [0190]    In an implementation, in order to secure data transmission, the BCC generates and sends the write control instruction to the OBU particularly as follows: 
         [0191]    The BCC generates the write control instruction, encrypts the information included in the generated write control instruction, and sends the encrypted write control instruction to the OBU. 
         [0192]    Here the BCC encrypts the information included in the generated write control instruction in the following process as illustrated in  FIG. 4 : 
         [0193]    The BCC performs key diversification on the random number carried in the write control instruction using the determined privilege certificate management key to generate a session key; and 
         [0194]    The BCC encrypts the instruction identifier, in the generated write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and 
         [0195]    The BCC calculates an MAC from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0196]    In the process above, the BCC determines the privilege certificate management key particularly as follows: the BCC selects one of its master keys, and performs key diversification on the OBU ID using the selected master key to obtain the privilege certificate management key of the OBU, where the BCC can have a number of master keys with different version numbers, so the BCC can generate a privilege certificate management key for the OBU according to each master key and the OBU ID. That is, OBU keys of different OBUs are different from each other, and each OBU can also have a number of OBU keys, where the OBU keys corresponding to each OBU are identified by their numbers, and the BCC decides on particularly which one of the OBU keys is to be applied. 
         [0197]    In the process above, the key for calculating the MAC is the session key; or of course, the key for calculating the MAC can alternatively be a key calculated separately and different from the session key. 
         [0198]    In an implementation, before the BCC sends the privilege certificate request instruction to the CA, the method further includes: 
         [0199]    The BCC generates the at least one privilege certificate management key corresponding to the OBU according to its at least one master key, and the identifier of the OBU, and sends the at least one privilege certificate management key to the OBU. 
         [0200]    Based upon the same inventive concept, an embodiment of the invention further provides a method for obtaining a message certificate at the OBU side in an internet of vehicles as illustrated in  FIG. 5 , where the method includes the following steps: 
         [0201]    In the step  201 , if an OBU needs to issue a message using a privilege certificate, then the OBU sends an application grant request instruction to a BCC, where the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU. 
         [0202]    Before this step, the BCC has requests for at least one privilege certificate for the OBU, and writes both the requested privilege certificate, and a key pair generated by the BCC for each requested privilege certificate into the OBU for storage, but the privilege certificate is normally unavailable to the OBU, and an application of any privilege certificate by the OBU shall be authorized by the BCC, where the privilege certificate can be applied in a limited period of time specified by the BCC, and the privilege certificate will become unavailable again at the end of the valid time. Thus if the OBU needs to apply the privilege certificate, then the OBU will send an application grant request instruction to the BCC to request the BCC for an application of the privilege certificate written into the OBU. 
         [0203]    In this step, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU ID identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0204]    Particularly the application grant request instruction includes the CMD, the OBU ID, and the OBU Random, where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0205]    In the step  202 , upon reception of an application control instruction sent by the BCC, the OBU issues the message using the privilege certificate specified by the BCC in the valid time specified by the BCC according to the application control instruction, and broadcasts the issued message to the other OBUs than the OBU. 
         [0206]    In this step, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0207]    Particularly the application control instruction includes: the OBU Key Version, the CMD, the OBU Random, the Certificate Number, a Start Time, and a Duration, where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by a CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0208]    It shall be noted that the valid time in which the privilege certificate can be applied can be represented in another representation in addition to the representation above, for example, the start time and an end time at which the privilege certificate is valid represent the valid time in which the privilege certificate can be applied. 
         [0209]    In an embodiment of the invention, if the OBU needs to issues the message using the privilege certificate, then the OBU will send the application grant request instruction to the BCC, and upon reception of the application control instruction sent by the BCC, the OBU issues the message using the privilege certificate specified by the BCC in the valid time specified by the BCC according to the application control instruction, and broadcasts the issued message to the other OBUs than the OBU, so that the OBU can apply the privilege certificate specified by the BCC in the valid time determined by the BCC, and thus the OBU can have a priority pass privilege in the valid time determined by the BCC. 
         [0210]    In an implementation, the OBU sends the application grant request instruction to the BCC in the step  201  particularly in the following two approaches: 
         [0211]    In a first approach, the OBU sends the application grant request instruction to the BCC over a data transmission link. 
         [0212]    This approach will be applicable if there is a network connection between the BCC and the OBU, where the BCC interacts with the OBU by transmitting over the network to thereby authorize an application of the privilege certificate. 
         [0213]    In a second approach, the OBU sends the application grant request instruction to the BCC through voice transmission. 
         [0214]    This approach will be applicable if there is no network connection between the BCC and the OBU, where the BCC interacts with the OBU through voice transmission to thereby authorize an application of the privilege certificate. 
         [0215]    In an implementation, in order to secure data transmission, after the OBU receives the application control instruction sent by the BCC in the step  202 , the method further includes: 
         [0216]    The OBU authenticates and decrypts the received application control instruction to obtain and store the information included in the application control instruction. 
         [0217]    Here the OBU authenticates and decrypts the received application control instruction as illustrated in  FIG. 6  particularly as follows: 
         [0218]    The OBU selects the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the application control instruction; 
         [0219]    The OBU performs key diversification on the random number carried in the application grant request instruction (i.e., the random number generated by the OBU) using the selected privilege certificate management key to generate a session key; 
         [0220]    The OBU calculates an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; 
         [0221]    The OBU decrypts the cipher text in the application control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the number of the specified privilege certificate, and the determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and 
         [0222]    The OBU stores the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction (i.e., the random number generated by the OBU itself). 
         [0223]    In the process above, if the OBU determines that the calculated MAC is the same as the MAC carried in the application control instruction, then this will indicate that the application control instruction is not tempered with while being transmitted; and if the OBU determines that the calculated MAC is not the same as the MAC carried in the application control instruction, then this will indicate that the application control instruction is tempered with while being transmitted, and the flow will be terminated. 
         [0224]    In the process above, if the OBU determines that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction, then it will indicate that the instruction is generated by the BCC; and if the OBU determines that the random number carried in the application control instruction is not the same as the random number carried in the application grant request instruction, then it will indicate that the instruction is not generated by the BCC, and the flow will be terminated. 
         [0225]    In an implementation, before the OBU sends the application grant request instruction to the BCC, the method further includes: 
         [0226]    The OBU receives and stores the at least one privilege certificate management key sent by the BCC. 
         [0227]    It shall be noted that the BCC firstly performs key diversification using its master key and the identifier of the OBU (OBU ID) to obtain the at least one privilege certificate management key (OBU key) corresponding to the OBU before requesting for the privilege certificate for the OBU, that is, OBU keys of different OBUs are different from each other, and each OBU can also have a number of OBU keys, where the OBU keys corresponding to each OBU are identified by their numbers, and the BCC decides on particularly which one of the OBU keys is to be applied. 
         [0228]    In an embodiment of the invention, before the privilege certificate is granted for authorization, the method further includes a process of requesting for the privilege certificate, and particularly, before the OBU sends the certificate application grant request instruction to the BCC, the method further includes: 
         [0229]    The OBU sends a privilege certificate request instruction to the BCC, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0230]    The OBU receives and stores a write control instruction sent by the BCC, where the write control instruction carries the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0231]    In the process above, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0232]    Particularly the privilege certificate request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0233]    In the process above, the write control instruction generated by the BCC includes the version number of the currently used privilege certificate management key, an instruction identifier identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of the start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0234]    Particularly the write control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Certificate, Key Pair, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0235]    It shall be noted that the valid time in which the privilege certificate can be applied can be represented in another representation in addition to the representation above, for example, the start time and the end time at which the privilege certificate is valid represent the valid time in which the privilege certificate can be applied. 
         [0236]    In an implementation, in order to secure data transmission, the OBU authenticates and decrypts the received write control instruction to obtain and store the information included in the write control instruction. 
         [0237]    Here the OBU authenticates and decrypts the received write control instruction as illustrated in  FIG. 7  particularly as follows: 
         [0238]    The OBU selects the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the write control instruction; 
         [0239]    The OBU performs key diversification on the random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; 
         [0240]    The OBU calculates an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; 
         [0241]    The OBU decrypts the cipher text in the write control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the privilege certificate requested by the BCC for the OBU, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and 
         [0242]    The OBU stores the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier corresponding to the privilege certificate upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU (i.e., the random number generated by the OBU itself). 
         [0243]    Since the OBU authenticates and decrypts the write control instruction in the process above which is similar to the process in which the OBU authenticates and decrypts the received application control instruction, a repeated description thereof will be omitted here. 
         [0244]    In an implementation, the OBU sends the privilege certificate request instruction to the BCC upon reception of a notification message sent by the BCC to notify the OBU that the BCC has requested for the privilege certificate of the OBU 
         [0245]    In an implementation, before the OBU sends the application grant request instruction to the BCC, the method further includes: the OBU receives and stores the at least one privilege certificate management key sent by the BCC. 
         [0246]    The interaction processes between the respective entities in the method for obtaining a message certificate in an internet of vehicles system according to the invention will be described below in details with reference to a particular embodiment thereof. 
         [0247]    In a first embodiment, 3DES-ECB is adopted as data encryption and key diversification algorithms, and 3DEC-CBC is adopted as an algorithm for calculating an MAC. Of course, the embodiment of the invention will not be limited to the algorithm for encryption, and other algorithm algorithms and MAC algorithms can also be applicable thereto, e.g., the Advanced Encryption Standard (AES) encryption algorithms, or the other MAC algorithms introduced in ISO/IEC 9797 defined by the International Standardization Organization (ISO) and the International Electronic Electro-technical Committee (IEC). In this embodiment, the value of the MAC is in four bytes (i.e., the first four bytes in the really calculated value of the MAC), but the invention will not be limited to any particular value of the MAC. 
         [0248]    In this embodiment, the OBU includes a security unit configured to provide a trusted computing environment for a secure application of a privilege certificate, and all the operations by the OBU related to the privilege certificate are performed in the security unit.  FIG. 8  illustrates a structure of the security unit of the OBU, including an operation system of the security unit, a certificate state table storage module, a certificate storage module, a key pair storage module, a key storage module, and a cipher text calculation module. 
         [0249]    The operation system of the security unit is responsible for coordinating the respective operations in the security unit, and configured to interact with the other systems of the OBU; 
         [0250]    The certificate state table storage module is configured to store various information related to an application of each privilege certificate; 
         [0251]    The certificate storage module is configured to store all the privilege certificates of the OBU; 
         [0252]    The key pair storing module is configured to store the public and private key pairs corresponding to the respective privilege certificates; 
         [0253]    The key storage module is configured to storage symmetric keys for performing respective encryption and decryption functions; and 
         [0254]    The cipher text calculation module is configured to perform various encryption and decryption operations, and to generate a random number, in the security unit. 
         [0255]    Data and instructions involved in this embodiment will be described below: 
         [0256]    1. Related data include: 
         [0257]    A master key of the BCC: Master Key=1F1F1F1F1F1F1F1F1F1F1F1F1F1F1F1F (in a hexadecimal representation including 16 bytes in total); 
         [0258]    The identifier of the OBU: OBU ID=3131313131313131 (in a hexadecimal representation including 8 bytes in total, which can be represented as the string of characters 11111111); 
         [0259]    A diversification factor of an OBU key: OBU Key Salt=OBU ID+Invert (OBU ID) An OBU key: OBU Key=6317571AE3F9827DC96AD0B57690235C (in a hexadecimal representation including 16 bytes in total); 
         [0260]    A key version: Key Version=31 (in a hexadecimal representation including 1 byte, which can be represented as the character 1); and 
         [0261]    A certificate number: Certificate Number=32 (in a hexadecimal representation including 1 byte, which can be represented as the string of characters 2). 
         [0262]    2. Relate instruction identifiers include 
         [0263]    A certificate and key pair request instruction identifier: CMD=31 (in a hexadecimal representation including 1 byte, which can be represented as the string of characters 1); 
         [0264]    A certificate and key pair response instruction identifier: CMD=32 (in a hexadecimal representation including 1 byte, which can be represented as the string of characters 2); 
         [0265]    A certificate application grant request instruction identifier: CMD=33 (in a hexadecimal representation including 1 byte, which can be represented as the string of characters 3); and 
         [0266]    A certificate application grant response instruction identifier: CMD=34 (in a hexadecimal representation including 1 byte, which can be represented as the string of characters 4). 
         [0267]    3. Random numbers generated by the OBU include: 
         [0268]    OBU Random1=3232323232323232 (in a hexadecimal representation including 8 bytes, which can be represented as the string of characters 22222222); and 
         [0269]    OBU Random2=3333333333333333 (in a hexadecimal representation including 8 bytes, which can be represented as the string of characters 33333333). 
         [0270]    4. The valid time of the privilege certificate includes: 
         [0271]    Start Time=0309060845 (represented as a BCD code, where each digit occupies 4 bits, thus resulting in 5 bytes in total); and 
         [0272]    Duration=00FF (in a hexadecimal representation including 8 bytes). 
         [0273]    Referring to  FIG. 9 , the interaction processes between the BCC and the CA, and between the BCC and the OBU in this embodiment are as follows: 
         [0274]    In the step  301 , the BCC performs 3DES calculation on the ID of the OBU using the master key possessed by the BCC to obtain the privilege certificate management key (OBU key) of the OBU, and writes the OBU key into the OBU. 
         [0275]    Here the key diversification factor used in the 3DES calculation is “OBU ID+Invert (OBU ID)”; and 
         [0276]    The calculated OBU key is: OBU Key=6317571AE3F9827DC96AD0B57690235C. 
         [0277]    Particularly after the OBU key is generated, the BCC writes the OBU key into the key storage module in the security unit of the OBU in a secure environment, and specifies the version of the key as 01 (in a hexadecimal representation including 1 byte). 
         [0278]    In the step  302 , the BCC generates a key pair including a public key and a private key, and generates a message certificate request using the related information of the OBU. 
         [0279]    In the step  303 , the BCC sends the privilege certificate request to the CA. 
         [0280]    In the step  304 , the CA reviews the message certificate request, and then issues the corresponding privilege certificate, the sequence number of which is 12345678 (which can be displayed as a string of characters). 
         [0281]    In the step  305 , the CA transmits the issued privilege certificate to the BCC, and the BCC numbers the privilege certificate as 32 (in a hexadecimal representation). 
         [0282]    In the step  306 , the OBU sends a certificate and key pair request to the BCC, where the requests include: [CMD, OBU ID, OBU Random]; 
         [0283]    Where CMD=31; 
         [0284]    OBU ID=3131313131313131; and 
         [0285]    OBU Random=3232323232323232. 
         [0286]    In the step  307 , the BCC generates a certificate and key pair write control instruction generally including [CMD, Random, Certificate Number, Certificate, Key Pair, Start Time, Duration]. 
         [0287]    Where CMD=32; 
         [0288]    Random=3232323232323232; 
         [0289]    Certificate Number=02; 
         [0290]    Certificate Serial Number=3132333435363738; 
         [0291]    Key Pair=(Private Key, Public Key); 
         [0292]    Start Time=0000000000; and 
         [0293]    Duration=0000. 
         [0294]    In this step, the control instruction is encrypted as illustrated in  FIG. 10 . Furthermore the BCC sends to the OBU a cipher text instruction including OBU Key Version+Cipher Text+MAC. 
         [0295]    Where OBU Key Version=01. 
         [0296]    In the step  308 , the BCC sends the certificate and key pair write control instruction to the OBU. 
         [0297]    In the step  309 , the OBU receives the certificate and key pair write control instruction, and then authenticates and decrypts the received data (particularly as illustrated in  FIG. 11 ). The OBU writes the various data respectively into the certificate state table storage module, the certificate storage module, and the key pair storage module after authenticating and decrypting the data correctly. 
         [0298]    In this step, the certificate state table after the certificate and key pair write control instruction is executed is as depicted in Table 1. 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 Certificate 
                 Key  
                 Valid  
                 Validity 
               
               
                   
                 Certificate 
                 sequence 
                 pair  
                 start  
                 length  
               
               
                   
                 number 
                 number 
                 address 
                 time 
                 of time 
               
               
                   
                   
               
             
             
               
                   
                 . . . 
                 . . . 
                 . . . 
                 . . . 
                 . . . 
               
               
                   
                 02 
                 12345678 
                 0015 
                 0000000000 
                 0000 
               
               
                   
                   
               
             
          
         
       
     
         [0299]    For example, a user of the OBU has a serious patient to be delivered to a hospital, and calls the 122 alarm service station for help to request for a higher pass priority. The 122 alarm service station give the vehicle (OBU) the higher pass priority after necessarily checking the information or storing the personal/vehicle/phone number information. In this embodiment, for example, while the accident is occurring, the OBU can not automatically request for being authorized, over a wireless data link, but needs to be authorized by phone. Data involved in manually requesting by phone will be the same as the data involved in automatically requesting over a wireless network. 
         [0300]    In the step  310 , the user selects a manual request for authorization via a control interface of the OBU; and the OBU displays a certificate application grant request on a screen. The certificate application grant request includes [CMD, OBU ID, OBU Random], where: 
         [0301]    CMD=3 (which can be displayed as a string of characters); 
         [0302]    OBU ID=11111111 (which can be displayed as a string of characters); and 
         [0303]    OBU Random=33333333 (which can be displayed as a string of characters). 
         [0304]    In this embodiment, the user notifies by phone the 122 alarm service station about the reported information=3+11111111+33333333. 
         [0305]    In the step  311 , a human operator at the 122 alarm service station inputs the strings of digits provided by the user into the BCC; and the BCC generates a certificate application control instruction (calculated similarly to the encryption process as illustrated in  FIG. 10 ). The control instruction generally includes: 
         [0306]    [CMD, Random, Certificate Number, Start Time, Duration]; 
         [0307]    Where CMD=3 (which can be displayed as a string of characters); 
         [0308]    Random=33333333 (which can be displayed as a string of characters); 
         [0309]    Certificate Number=2 (which can be displayed as a string of characters); 
         [0310]    Start Time=0309060845 (which can be displayed as a string of characters); and 
         [0311]    Duration=00FF (which can be displayed as a string of characters, which unit is minute). 
         [0312]    In this step, an OBU key is obtained as a result of key diversification calculation: OBU Key=6317571AE3F9827DC96AD0B57690235C; 
         [0313]    A session key is obtained as a result of key diversification calculation: Session Key=93CDD9BC8B89F9F31132F39C32B252FF; 
         [0314]    A plain text to be encrypted is: Plain Text=333333333333333332030906084500FF; 
         [0315]    A cipher text as a result of encryption is: Cipher text=04142E0A592ADD00F6CA3E95A792F0E3; 
         [0316]    An MAC is calculated: inputs to MAC calculation=31 (Key ID)+Cipher text, and MAC value=6446D536; 
         [0317]    In this step, the control instruction is encrypted, and the MAC is calculated, and then the following cipher text instruction is sent to the OBU: 
         [0318]    1 (Key ID)+04142E0A592ADD00F6CA3E95A792F0E3 (Cipher Text)+6446D536 (MAC value); and 
         [0319]    The length of a generated string of characters for the instruction is 41 bytes. 
         [0320]    In the step  312 , the human operator at the 122 alarm service station notifies the user about the certificate application control instruction generated by the BCC, and the user inputs the instruction into the OBU. 
         [0321]    In the step  313 , the OBU verifies the received certificate application control instruction, and then authenticates and decrypts the received data (which are calculated similarly to the authentication and decryption process as illustrated in  FIG. 11 ). The OBU writes the respective data into the corresponding fields recorded respectively in the certificate state table after authenticating and decrypting the data correctly. 
         [0322]    In this step, the certificate state table after the certificate application control instruction is executed is as depicted in Table 2. 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Certificate 
                 Key  
                 Valid  
                 Validity  
               
               
                   
                 Certificate 
                 sequence  
                 pair  
                 start  
                 length 
               
               
                   
                 number 
                 number 
                 address 
                 time 
                 of time 
               
               
                   
                   
               
             
             
               
                   
                 . . . 
                 . . . 
                 . . . 
                 . . . 
                 . . . 
               
               
                   
                 02 
                 12345678 
                 0015 
                 0309060845 
                 00FF 
               
               
                   
                   
               
             
          
         
       
     
         [0323]    In the step  314 , the OBU signs a message using the privilege certificate in the valid time of the privilege certificate. 
         [0324]    In the step  315 , the OBU broadcasts the signed message to the other OBUs to thereby obtain the priority pass privilege. 
         [0325]    The processing flows of the methods above can be executed in software program which can be stored in a storage medium, where the stored software program can perform the steps of the methods above upon being invoked. 
         [0326]    Based upon the same inventive concept, an embodiment of the invention further provides a BCC, and since the BCC addresses the problem under a principle similar to the method above for obtaining a message certificate at the BCC side in an internet of vehicles, reference can be made to the implementation of the method for an implementation of the BCC, so a repeated description thereof will be omitted here. 
         [0327]    Referring to  FIG. 12 , a BCC according to an embodiment of the invention includes a receiving and sending module  41 , and a processing module  42 . 
         [0328]    The receiving and sending module  41  is configured to receive an application grant request instruction sent by an OBU, where the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU; and 
         [0329]    The processing module  42  is configured to determine a valid time in which the OBU applies the specified privilege certificate, to generate an application control instruction according to the valid time, and to send the generated application control instruction to the OBU, where the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0330]    In an embodiment of the invention, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU identifier (ID) identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0331]    Particularly the application grant request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0332]    In an embodiment of the invention, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0333]    Particularly the application control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0334]    In an implementation, the receiving and sending module  41  is configured: 
         [0335]    To receive the application grant request instruction sent by the OBU over a data transmission link; or 
         [0336]    To receive the application grant request instruction sent by the OBU through voice transmission. 
         [0337]    In an implementation, in order to secure data transmission, the processing module  42  is configured: 
         [0338]    To generate the application control instruction according to the valid time, to encrypt the information included in the application control instruction, and to send the encrypted application control instruction to the OBU. 
         [0339]    Where the processing module  42  configured to encrypt the information included in the application control instruction is configured: 
         [0340]    To perform key diversification on the random number, generated by the OBU, carried in the application grant request instruction according to the determined privilege certificate management key (OBU Key) to generate a session key; 
         [0341]    To encrypt the instruction identifier in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and the determined valid time using the generated session key to obtain a cipher text; and 
         [0342]    To calculate a Message Authentication Code (MAC) from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0343]    In an implementation, before the receiving and sending module  41  receives the certificate application grant request instruction sent by the OBU, 
         [0344]    The processing module  42  is further configured: to generate a key pair corresponding to the privilege certificate of the OBU, where the key pair includes a public key and a private key; and to generate a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU; and 
         [0345]    The receiving and sending module  41  is further configured: to send the privilege certificate request instruction to a Certificate Authority (CA); and to receive and store the privilege certificate issued by the CA in response to the privilege certificate request instruction. 
         [0346]    In an implementation, after the receiving and sending module  41  receives the privilege certificate issued by the CA, and before the receiving and sending module  41  receives the application grant request instruction sent by the OBU, 
         [0347]    The receiving and sending module  41  is further configured: to receive the privilege certificate request instruction sent by the OBU, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0348]    The processing module  42  is further configured: to generate and send a write control instruction to the OBU, where the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0349]    In an embodiment of the invention, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0350]    Particularly the privilege certificate request instruction includes [CMD, OBU ID, OBU Random], where the CMD is an instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0351]    In an embodiment of the invention, the write control instruction includes a version number of a currently applied privilege certificate management key, an instruction identifier identifying the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, a certificate number defined by the BCC for the privilege certificate, a key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of a start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0352]    Particularly the write control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Certificate, Key Pair, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as a write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0353]    In an implementation, in order to secure data transmission, the processing module  42  configured to generate and send the write control instruction to the OBU is configured: 
         [0354]    To generate the write control instruction, to encrypt the information included in the generated write control instruction, and to send the encrypted write control instruction to the OBU. 
         [0355]    Where the processing module  42  configured to encrypt the information included in the generated write control instruction is configured: 
         [0356]    To perform key diversification on the random number generated by the OBU, carried in the write control instruction using the determined privilege certificate management key to generate a session key; and 
         [0357]    To encrypt the instruction identifier, in the write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and 
         [0358]    To calculate an MAC from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0359]    In an implementation, before the receiving and sending module  41  receives the certificate application grant request instruction sent by the OBU, 
         [0360]    The processing module  42  is further configured: to generate at least one privilege certificate management key corresponding to the OBU according to its at least one master key, and the identifier of the OBU; and 
         [0361]    The receiving and sending module  41  is further configured: to send the at least one privilege certificate management key to the OBU. 
         [0362]    Based upon the same inventive concept, an embodiment of the invention further provides an OBU, and since the OBU addresses the problem under a principle similar to the method above for obtaining a message certificate at the OBU side in an internet of vehicles, reference can be made to the implementation of the method for an implementation of the OBU, so a repeated description thereof will be omitted here. 
         [0363]    Referring to  FIG. 13 , an embodiment of the invention provides an On-Board Unit (OBU) including: 
         [0364]    A receiving and sending module  51  is configured, if the OBU needs to issue a message using a privilege certificate, to send an application grant request instruction to a BCC, where the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU; and to receive an application control instruction sent by the BCC; and 
         [0365]    A processing module  52  is configured to issue the message using the privilege certificate specified by the BCC in a valid time specified by the BCC according to the application control instruction, and to broadcast the issued message to the other OBUs than the OBU. 
         [0366]    In an embodiment of the invention, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU ID identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0367]    Particularly the application grant request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0368]    In an embodiment of the invention, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0369]    Particularly the application control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by a CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0370]    In an implementation, the receiving and sending module  51  is configured: 
         [0371]    To send the application grant request instruction to the BCC over a data transmission link; or 
         [0372]    To send the application grant request instruction to the BCC through voice transmission. 
         [0373]    In an implementation, after the receiving and sending module  51  receives the application control instruction sent by the BCC, the processing module  52  is further configured: 
         [0374]    To authenticate and decrypt the application control instruction to obtain and store the information included in the application control instruction. 
         [0375]    Where the processing module  52  configured to authenticate and decrypt the application control instruction is configured: 
         [0376]    To select the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the application control instruction; 
         [0377]    To perform key diversification on the random number carried in the application grant request instruction using the selected privilege certificate management key to generate a session key; 
         [0378]    To calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; 
         [0379]    To decrypt the cipher text in the application control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the number of the specified privilege certificate, and the determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and 
         [0380]    To store the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction. 
         [0381]    In an implementation, before the receiving and sending module  51  sends the application grant request instruction to the BCC, 
         [0382]    The receiving and sending module  51  is further configured: to send a privilege certificate request instruction to the BCC, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and to receive a write control instruction sent by the BCC; and 
         [0383]    The processing module  52  is further configured: to store the privilege certificate requested by the BCC for the OBU, and a key pair generated by the BCC for the privilege certificate, carried in the write control instruction. 
         [0384]    In an embodiment of the invention, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0385]    Particularly the privilege certificate request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0386]    In an embodiment of the invention, the write control instruction includes the version number of the currently used privilege certificate management key, an instruction identifier identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of the start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0387]    Particularly the write control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Certificate, Key Pair, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0388]    In an implementation, after the receiving and sending module  51  receives the write control instruction sent by the BCC, the processing module  52  is further configured: 
         [0389]    To authenticate and decrypt the write control instruction to obtain and store the information included in the write control instruction. 
         [0390]    Where the processing module  52  configured to authenticate and decrypt the write control instruction is configured: 
         [0391]    To select the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the write control instruction; 
         [0392]    To perform key diversification on the random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; 
         [0393]    To calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; 
         [0394]    To decrypt the cipher text in the write control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the privilege certificate requested by the BCC for the OBU, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and 
         [0395]    To store the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier corresponding to the privilege certificate upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU. 
         [0396]    Further to any one of the embodiments above, the receiving and sending module  51  is further configured, before the application grant request instruction is sent to the BCC, to: 
         [0397]    To receive and store at least one privilege certificate management key sent by the BCC. 
         [0398]    A structure of and processing by a BCC according to an embodiment of the invention will be described below in connection with a preferred hardware structure thereof. 
         [0399]    Referring to  FIG. 14 , the BCC includes a transceiver  141 , at least one processor  142  connected with the transceiver  141 , and a memory  143  connected respectively with the transceiver  141  and the processor  142 , where: 
         [0400]    The transceiver  141  is configured to receive an application grant request instruction sent by an OBU, where the application grant request instruction requests the BCC for applying a privilege certificate written in the OBU; and 
         [0401]    The processor  142  is configured to determine a valid time in which the OBU applies the specified privilege certificate, to generate an application control instruction according to the valid time, and to trigger the transceiver to send the generated application control instruction to the OBU, where the application control instruction instructs the OBU to apply the specified privilege certificate in the valid time. 
         [0402]    In an embodiment of the invention, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU identifier (ID) identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0403]    Particularly the application grant request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0404]    In an embodiment of the invention, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0405]    Particularly the application control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0406]    In an implementation, the transceiver  141  is configured: 
         [0407]    To receive the application grant request instruction sent by the OBU over a data transmission link; or 
         [0408]    To receive the application grant request instruction sent by the OBU through voice transmission. 
         [0409]    In an implementation, in order to secure data transmission, the processor  142  is configured: 
         [0410]    To generate the application control instruction according to the valid time, to encrypt the information included in the application control instruction, and to send the encrypted application control instruction to the OBU. 
         [0411]    Where the processor  142  configured to encrypt the information included in the application control instruction is configured: 
         [0412]    To perform key diversification on the random number, generated by the OBU, carried in the application grant request instruction according to the determined privilege certificate management key (OBU Key) to generate a session key; 
         [0413]    To encrypt the instruction identifier, in the application control instruction, identifying the type of the current instruction, the random number carried in the application grant request instruction, the number of the specified privilege certificate, and the determined valid time, using the generated session key to obtain a cipher text; and 
         [0414]    To calculate a Message Authentication Code (MAC) from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted application control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0415]    In an implementation, before the transceiver  141  receives the certificate application grant request instruction sent by the OBU, 
         [0416]    The processor  142  is further configured: to generate a key pair corresponding to the privilege certificate of the OBU, where the key pair includes a public key and a private key; and to generate a privilege certificate request instruction corresponding to the OBU according to the generated public key, and the related information of the OBU; and 
         [0417]    The transceiver  141  is further configured: to send the privilege certificate request PCT Original instruction to a CA; and to receive the privilege certificate issued by the CA in response to the privilege certificate request instruction; and 
         [0418]    The memory  143  is configured: to store the privilege certificate issued by the CA, and the key pair corresponding to the privilege certificate, generated by the processor  142 . 
         [0419]    In an implementation, after the transceiver  141  receives the privilege certificate issued by the CA, and before the transceiver  141  receives the application grant request instruction sent by the OBU, 
         [0420]    The transceiver  141  is further configured: to receive the privilege certificate request instruction sent by the OBU, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and 
         [0421]    The processor  142  is further configured: to generate a write control instruction, and to trigger the transceiver  141  to send the write control instruction to the OBU, where the write control instruction includes at least the privilege certificate requested by the BCC for the OBU, and the key pair generated by the BCC for the privilege certificate. 
         [0422]    In an embodiment of the invention, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0423]    Particularly the privilege certificate request instruction includes [CMD, OBU ID, OBU Random], where the CMD is an instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0424]    In an embodiment of the invention, the write control instruction includes a version number of a currently applied privilege certificate management key, an instruction identifier identifying the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, a certificate number defined by the BCC for the privilege certificate, a key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of a start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0425]    Particularly the write control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Certificate, Key Pair, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as a write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0426]    In an implementation, in order to secure data transmission, the processor  142  configured to generate and send the write control instruction to the OBU is configured: 
         [0427]    To generate the write control instruction, to encrypt the information included in the generated write control instruction, and to send the encrypted write control instruction to the OBU. 
         [0428]    Where the processor  142  configured to encrypt the information included in the generated write control instruction is configured: 
         [0429]    To perform key diversification on the random number generated by the OBU, carried in the write control instruction using the determined privilege certificate management key to generate a session key; and 
         [0430]    To encrypt the instruction identifier, in the write control instruction, identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, using the generated session key to obtain a cipher text; and 
         [0431]    To calculate an MAC from the version number of the determined privilege certificate management key, and the obtained cipher text, using the generated session key, where the encrypted write control instruction includes the version number of the determined privilege certificate management key, the obtained cipher text, and the obtained MAC. 
         [0432]    In an implementation, before the transceiver  141  receives the certificate application grant request instruction sent by the OBU, 
         [0433]    The processor  142  is further configured: to generate at least one privilege certificate management key corresponding to the OBU according to at least one master key stored in the memory  143 , and the identifier of the OBU, and to store the at least one privilege certificate management key in the memory  143 ; and 
         [0434]    The transceiver  141  is further configured: to send the at least one privilege certificate management key to the OBU. 
         [0435]    A structure of and processing by an OBU according to an embodiment of the invention will be described below in connection with a preferred hardware structure thereof. 
         [0436]    Referring to  FIG. 15 , the OBU includes a transceiver  151 , at least one processor  142  connected with the transceiver  151 , and a memory  153  connected respectively with the transceiver  151  and the processor  152 , where: 
         [0437]    The transceiver  151  is configured, if the OBU needs to issue a message using a privilege certificate, to send an application grant request instruction to a BCC, where the application grant request instruction requests the BCC for applying the privilege certificate written in the OBU; and to receive an application control instruction sent by the BCC; and 
         [0438]    The processor  152  is configured to issue the message using the privilege certificate specified by the BCC in a valid time specified by the BCC according to the application control instruction, and to broadcast the issued message to the other OBUs than the OBU. 
         [0439]    In an embodiment of the invention, the application grant request instruction includes an instruction identifier identifying the type of the current instruction, an OBU ID identifying the OBU uniquely, and a random number (Random) generated by the OBU. 
         [0440]    Particularly the application grant request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the application grant request instruction. 
         [0441]    In an embodiment of the invention, the application control instruction includes: a version number of a currently applied privilege certificate management key (OBU Key Version), an instruction identifier identifying the current instruction, the random number carried in the application grant request instruction, a certificate number (Certificate Number) of the currently applied privilege certificate, and the valid time. 
         [0442]    Particularly the application control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the application control instruction, the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by a CA; and the Start Time and the Duration represent the valid time, where the Start Time represents a start time at which the privilege certificate is valid, and the Duration represents the length of time for which the privilege certificate is valid. 
         [0443]    In an implementation, the transceiver  151  is configured: 
         [0444]    To send the application grant request instruction to the BCC over a data transmission link; or 
         [0445]    To send the application grant request instruction to the BCC through voice transmission. 
         [0446]    In an implementation, after the transceiver  151  receives the application control instruction sent by the BCC, the processor  152  is further configured: 
         [0447]    To authenticate and decrypt the application control instruction to obtain and store in the memory  153  the information included in the application control instruction. 
         [0448]    Where the processor  152  configured to authenticate and decrypt the application control instruction is configured: 
         [0449]    To select the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the application control instruction; 
         [0450]    To perform key diversification on the random number carried in the application grant request instruction using the selected privilege certificate management key to generate a session key; 
         [0451]    To calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the application control instruction using the generated session key; 
         [0452]    To decrypt the cipher text in the application control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the number of the specified privilege certificate, and the determined valid time, upon determining that the calculated MAC is the same as an MAC carried in the application control instruction; and 
         [0453]    To store in the memory  153  the obtained number of the specified privilege certificate, and determined valid time upon determining that the random number carried in the application control instruction is the same as the random number carried in the application grant request instruction. 
         [0454]    In an implementation, before the transceiver  151  sends the application grant request instruction to the BCC, 
         [0455]    The transceiver  151  is further configured: to send a privilege certificate request instruction to the BCC, where the privilege certificate request instruction requests for writing the privilege certificate requested by the BCC into the OBU; and to receive a write control instruction sent by the BCC; and 
         [0456]    The processor  152  is further configured: to store in the memory  153  the privilege certificate requested by the BCC for the OBU, and a key pair generated by the BCC for the privilege certificate, carried in the write control instruction. 
         [0457]    In an embodiment of the invention, the privilege certificate request instruction includes an instruction identifier identifying the type of the current instruction, the OBU identifier identifying the OBU uniquely, and the random number generated by the OBU. 
         [0458]    Particularly the privilege certificate request instruction includes [CMD, OBU ID, OBU Random], where the CMD is the instruction identifier identifying the current instruction as the privilege certificate request instruction. 
         [0459]    In an embodiment of the invention, the write control instruction includes the version number of the currently used privilege certificate management key, an instruction identifier identifying the type of the current instruction, the random number carried in the privilege certificate request instruction, the requested privilege certificate, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and a time identifier identifying the valid time of the privilege certificate, where the time identifier includes the identifier of the start time at which the privilege certificate is valid, and the identifier of the validity length of time of the privilege certificate. 
         [0460]    Particularly the write control instruction includes [OBU Key Version, CMD, OBU Random, Certificate Number, Certificate, Key Pair, Start Time, Duration], where the CMD is the instruction identifier identifying the current instruction as the write control instruction, and the Certificate Number is an internal number used between the BCC and the OBU to identify the privilege certificate issued by the CA. 
         [0461]    In an implementation, after the transceiver  151  receives the write control instruction sent by the BCC, the processor  152  is further configured: 
         [0462]    To authenticate and decrypt the write control instruction to obtain and store in the memory  153  the information included in the write control instruction. 
         [0463]    Where the processor  152  configured to authenticate and decrypt the write control instruction is configured: 
         [0464]    To select the corresponding privilege certificate management key according to the version number of the privilege certificate management key carried in the write control instruction; 
         [0465]    To perform key diversification on the random number carried in the privilege certificate request instruction using the selected privilege certificate management key to generate a session key; 
         [0466]    To calculate an MAC from the version number of the privilege certificate management key, and a cipher text, in the write control instruction using the generated session key; 
         [0467]    To decrypt the cipher text in the write control instruction using the generated session key to obtain the instruction identifier identifying the type of the current instruction, the random number, the privilege certificate requested by the BCC for the OBU, the certificate number defined by the BCC for the privilege certificate, the key pair generated by the BCC for the privilege certificate, and the time identifier identifying the valid time of the privilege certificate, upon determining that the calculated MAC is the same as an MAC carried in the write control instruction; and 
         [0468]    To store the obtained privilege certificate, number of the privilege certificate, and key pair and time identifier corresponding to the privilege certificate in the memory  153  upon determining that the random number carried in the write control instruction is the same as the random number carried in the privilege certificate request instruction sent by the OBU. 
         [0469]    Those skilled in the art shall appreciate that the embodiments of the invention can be embodied as a method, a system or a computer program product. Therefore the invention can be embodied in the form of an all-hardware embodiment, an all-software embodiment or an embodiment of software and hardware in combination. Furthermore the invention can be embodied in the form of a computer program product embodied in one or more computer useable storage mediums (including but not limited to a disk memory, a CD-ROM, an optical memory, etc.) in which computer useable program codes are contained. 
         [0470]    The invention has been described in a flow chart and/or a block diagram of the method, the device (system) and the computer program product according to the embodiments of the invention. It shall be appreciated that respective flows and/or blocks in the flow chart and/or the block diagram and combinations of the flows and/or the blocks in the flow chart and/or the block diagram can be embodied in computer program instructions. These computer program instructions can be loaded onto a general-purpose computer, a specific-purpose computer, an embedded processor or a processor of another programmable data processing device to produce a machine so that the instructions executed on the computer or the processor of the other programmable data processing device create means for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0471]    These computer program instructions can also be stored into a computer readable memory capable of directing the computer or the other programmable data processing device to operate in a specific manner so that the instructions stored in the computer readable memory create an article of manufacture including instruction means which perform the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0472]    These computer program instructions can also be loaded onto the computer or the other programmable data processing device so that a series of operational steps are performed on the computer or the other programmable data processing device to create a computer implemented process so that the instructions executed on the computer or the other programmable device provide steps for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. 
         [0473]    Although the preferred embodiments of the invention have been described, those skilled in the art benefiting from the underlying inventive concept can make additional modifications and variations to these embodiments. Therefore the appended claims are intended to be construed as encompassing the preferred embodiments and all the modifications and variations coming into the scope of the invention. 
         [0474]    Evidently those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus the invention is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the invention and their equivalents.