Patent Publication Number: US-2005141705-A1

Title: Verification method of mobile communication system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This Application claims priority to Taiwan Patent Application No. 092137657 entitled “Verification Method of Mobile Communication System,” filed Dec. 31, 2003.  
     FIELD OF INVENTION  
      A security verification method of a mobile communication system is provided in the present invention. By transmitting and verifying the encrypted messages between the mobile device and the security unit of the system, the method ensures a secured usage of the mobile communication device.  
     BACKGROUND OF THE INVENTION  
      With the development and broad application of mobile communication technology, mobile communication has significantly influenced people&#39;s lives. Security issues regarding the mobile communication system and the mobile device are becoming more and more important to modern people.  
      In some designs that prevent non-authorized users from accessing the mobile communication device, users have to input a password manually to pass the verification to access the mobile device. Some other designs permit or reject an access request based on the comparison of the device identification (device ID) stored both in the mobile device and in the communication host, as proposed in the Japanese Patent with publication number JP 11-018147. But the aforementioned solutions based on the device ID do not involve the security verification method.  
      In terms of securing the mobile communication network, some methods involve transmitting and receiving messages encrypted or decrypted by a specific key (as shown in U.S. published patent application number U.S. 2003/0112977). Another solution is applying a specific algorithm to encrypt and decrypt messages in the communication protocols (see, for example, U.S. Pat. No. 6,237,093).  
      In terms of securing the mobile communication device, one design involves permitting access to the device only after an encrypted message is transmitted from the mobile device to and verified by the communication system (as shown in U.S. published patent application number U.S. 2002/0081993). Another security design disposes a remote control to restrict the operating range of the electronic device (as disclosed in U.S. published patent application number U.S. 2003/0095044).  
     SUMMARY OF THE INVENTION  
      The present invention provides a verification method of a mobile communication system to ensure the security of the mobile communication system and the mobile device.  
      The present invention also provides a mobile communication system that operates in coordination with the foregoing verification method to ensure the security of the mobile communication system and the mobile device.  
      The mobile communication system in the present invention includes a mobile device and a security unit. The mobile device includes an input device, a first wireless interface and a first processor. The security unit includes a second wireless interface and a second processor.  
      The method includes: (1) A first key and a second key are generated and stored, respectively, in the first processor and the second processor; (2) when the input device receives a request, the first processor generates a first message and encrypts the first message into a first encrypted message with the first key; (3) the first encrypted message is transmitted to the second processor by the first wireless interface and the second wireless interface; (4) the second processor decrypts the first encrypted message and generates a second message with the second key; (5) the second processor encrypts the second message to a second encrypted message with the first key; (6) the second encrypted message is transmitted to the first processor by the second wireless interface and the first wireless interface; and (7) the first processor decrypts the second encrypted message to a third message with the second key, and the request is allowed only when the third message is verified by the first processor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a schematic diagram of the mobile communication system of the present invention.  
       FIG. 2  shows a flow chart of another embodiment of the present invention.  
       FIG. 3  shows a schematic diagram of another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
      The present invention provides a verification method of a mobile communication system to ensure the security of the mobile communication system and the mobile device.  
       FIG. 1  shows a schematic diagram of the mobile communication system of the present invention. As shown in  FIG. 1 , the mobile communication system  100  includes a mobile device  101  and a security unit  103 . The mobile device  100  includes an input device  11  for users to input instructions, a first wireless interface  15  transmitting and receiving wireless signals, a first processor  13  with encrypting, decrypting and storing functions and a timer  12  connected to the first processor  13 . The security unit includes a second wireless interface  19  for transmitting and receiving wireless signals and a second processor  17  with encrypting, decrypting and storing functions.  
      When the mobile communication system is initialized, the first processor  13  generates a first key and a second key from a random number (or according to other algorithms) and stores them in the first processor  13 . The first key and the second key are a couple of encrypting-decrypting keys, with the first key encrypting information and the second key decrypting it. The first key and the second key are transmitted to the second processor  17  by the first wireless interface  15  and the second wireless interface  19 . In other embodiments, the second processor  17  can also generate the first key and the second key and transmit them to the first processor  13 . It is permitted that the first processor  13  and the second processor  17  generate the same keys respectively.  
      After the mobile communication system is initialized, the security verification procedure proceeds as the user tries to access the mobile device  101 . When the input device  11  receives an access request, the first processor  13  generates a first message and encrypts the first message into a first encrypted message  14  with the first key. The first encrypted message  14  is transmitted to the second processor  17  by the first wireless interface  15  and the second wireless interface  19 . Then, the second processor  17  decrypts the first encrypted message  14  with the second key and generates a second message. The second processor  17  can embed device identification (device ID) in the second message to avoid error message transmission. The mobile device  101  stores and confirms the mentioned device ID, as the mobile device  101  receives the messages from the security unit. The second processor  17  encrypts the second message into a second encrypted message  16  with the first key, and then transmits the second encrypted message  16  to the first processor  13  by the second wireless interface  19  and the first wireless interface  15 .  
      The first processor  13  decrypts the second encrypted message  16  into a third message with the second key and verifies the third message. The request is allowed and executed if the third message passes the verification of the first processor  13 . The method of verification is to compare the outgoing and incoming message. If the result is the same, the access request is allowed; if the result is not the same, the access request is denied. In addition, the first message generated by the first processor  13  can be a time-varying parameter or a parameter chosen from a plurality of predetermined parameters. The choice from different parameters before transmission makes the verification procedure safer. If the first processor does not receive the second encrypted message  16  transmitted back from the second processor  17  (for examples, due to a weak wireless signal or the mobile device  101  being out of range), the request is rejected. In other words, if the mentioned verification procedure fails, the access request will be denied. Two exceptions are: (1) the request is an emergency call (for example,  112 ); and (2) the user passes a predetermined password verification to allow the rejected request. The predetermined password verification here includes inputting a password into the mobile device via the input device  11 . The mentioned design provides quick access to the mobile device  101  to an authorized user in times of emergency.  
      As shown in  FIG. 1 , the mobile device  101  includes a timer  12  connected to the first processor  13 , and the timer  12  counts down for a predetermined time interval after the mobile device  101  finishes a task. After the time interval, the verification procedure of the mobile communication system is required. In other words, it helps to reduce power consumption and allows the user to decide whether to activate the verification procedure or not.  
       FIG. 2  shows a flow chart of another embodiment of the present invention. The mobile communication system  100  in the present invention takes the following steps; Step  201 : a first key and a second key are generated and stored, respectively, in the first processor and the second processor; Step  203 : when the input device receives a request, the first processor generates a first message and encrypts the first message into a first encrypted message with the first key; Step  205 : as the input device receives a request, the first processor generates a first message and encrypts the first message into a first encrypted message with the first key; Step  207 : the second processor decrypts the first encrypted message and generates a second message with the second key; Step  209 : the second processor encrypts the second message to a second encrypted message with the first key; Step  211 : the second encrypted message is transmitted to the first processor by the second wireless interface and the first wireless interface; Step  213 : the first processor decrypts the second encrypted message to a third message with the second key, and the request is allowed after the third message is verified by the first processor. Executing the foregoing steps of the verification of the present invention ensures the security of the communication system. In other embodiments, the verification method also includes: (1) the first key and the second key are generated and stored in the first processor when the mobile communication system is initialized; (2) the second processor receives and stores the first key and the second key transmitted by the first wireless interface and the second wireless interface; (3) the request is rejected when the first processor does not receive the second encrypted message; (4) a password can be inputted into the mobile device to allow the rejected request; (5) the request is rejected when the third message is not verified by the first processor.  
       FIG. 3  shows a schematic diagram of another embodiment of the present invention. As shown in  FIG. 3 , the mobile device  301  includes an input device  31 , a first processor  33 , a first wireless interface  35  and an encrypting/decrypting unit  32 . The security unit  302  includes a second wireless interface  37 , a second processor  39  and an encrypting/decrypting unit  34 . In this embodiment, when the security verification system is initialized, the input device  31  receives a user&#39;s request and the first processor  33  generates an encrypted message  36  with the encrypting/decrypting unit  32 . The encrypted message  36  is transmitted to the second processor  39  by the first wireless interface  35  and the second wireless interface  37 . The second processor  39  decrypts the encrypted message  36 , embeds a device ID in it, and transmits it back to the first processor  33  by the first wireless interface  35  and the second wireless interface  37 . The first processor  33  decrypts the encrypted message  36  by the encrypting/decrypting unit  32  and verifies it. If it passes the verification, the user&#39;s request will be executed. In yet another embodiment, the mobile communication system also includes a timer (not illustrated) connected to the first processor  33 , and the timer counts down for a predetermined time interval. During the time interval, the verification procedure is not activated.  
      While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.