Abstract:
According to an aspect of an embodiment, an electronic apparatus comprises: an electronic apparatus powered by one of a plurality of electric power sources, comprising: a power supply unit for providing the interior of the electronic apparatus with the electric power from one of the electric power sources alternatively; and a controller for requesting user authentication when supply of the electric power to the interior of the electric apparatus is switched from one of the power sources to another.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This art relates to an information processing apparatus for preventing unauthorized access to information stored in the information processing apparatus. 
     2. Description of the Related Art 
     In many electronic apparatuses such as PCs, in order to improve a security level, password authentication can be performed when they are started. 
     In such electronic apparatuses, if a password entered by a user does not match a registered password, the user cannot log in the OS of the electronic apparatus&#39;s and refer to data stored in the electronic apparatus. 
     However, if an electronic apparatus is stolen after a user has logged in the OS of the electronic apparatus using a password, data stored in the electronic apparatus can also be stolen. Thus, the protection of data stored in an electronic apparatus cannot be achieved. 
     An electronic apparatus for preventing unauthorized access, for example, is disclosed in Japanese Laid-open Patent Publication No. 2004-140548. 
     SUMMARY 
     According to an aspect of an embodiment, an electronic apparatus comprises: an electronic apparatus powered by one of a plurality of electric power sources, comprising: a power supply unit for providing the interior of the electronic apparatus with the electric power from one of the electric power sources alternatively; and a controller for requesting user authentication when supply of the electric power to the interior of the electric apparatus is switched from one of the power sources to another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a hardware configuration of an information processing apparatus according to an embodiment of the present invention; 
         FIG. 2  is a diagram illustrating a software configuration of an information processing apparatus according to an embodiment of the present invention; 
         FIG. 3  is a flowchart illustrating a password request process according to an embodiment of the present invention; 
         FIG. 4  is a diagram illustrating a status register according to an embodiment of the present invention; and 
         FIG. 5  is a flowchart illustrating a password request process according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     In this embodiment, in an information processing apparatus  100 , password authentication is performed when an AC adapter  122  is disconnected from a power supply unit  105 . 
       FIG. 1  is a block diagram illustrating a hardware configuration of the information processing apparatus  100  according to an embodiment of the present invention. 
     The information processing apparatus  100  is, for example, a notebook-sized personal computer capable of obtaining power from a plurality of power sources such as a battery and an AC power supply. 
     The information processing apparatus  100  includes a CPU (central processing unit)  101 , a north bridge  102 , a memory  103 , a south bridge  104 , the power supply unit  105 , a battery  106 , a BIOS ROM  107 , a keyboard controller  108 , a mouse  109 , a keyboard  110 , an I/O controller  111 , a serial port  112 , a parallel port  113 , an FDD (Floppy Disk Drive)  114 , a graphic controller  115 , a display  116 , a disk controller  117 , a hard disk  118 , a PC card  119 , and a bus  120 . 
     The north bridge  102  is an LSI chip set that controls information distribution of the information processing apparatus  100  and connects the CPU  101  and the memory  103  to the bus  120 . The south bridge  104  is also an LSI chip set that controls information distribution of the information processing apparatus  100  and connects the power supply unit  105 , the BIOS ROM  107 , the keyboard controller  108 , and the I/O controller  111  to the bus  120 . 
     The BIOS ROM  107  is a storage unit for storing a BIOS (Basic Input/Output System). The keyboard controller  108  controls the mouse  109  and the keyboard  110 . The I/O controller  111  controls the serial port  112 , the parallel port  113 , and the FDD  114 . The graphic controller  115  controls the display  116 . The disk controller  117  controls the hard disk  118 . The BIOS ROM  107  stores a BIOS that is a set of programs executed in the power supply unit  105 , the keyboard controller  108 , the I/O controller  111 , and the graphic controller  115  which are connected to the information processing apparatus  100 . The bus  120  is, for example, a PCI (Peripheral Component Interconnect) bus or a PCI Express bus used for data transfer in the information processing apparatus  100 . The hard disk  118  stores an OS (Operating System), a driver, and user data. 
     The power supply unit  105  controls the switching of a power source between an AC power supply  121  and the battery  106 , and transmits to the OS an SCI (System Control Interrupt) signal representing that a power source (the AC power supply  121  or the battery  106 ) has been changed. The CPU  101  loads the OS, which is stored in the hard disk  118 , into the memory  103  as appropriate so as to control the information processing apparatus  100 . 
       FIG. 2  is a diagram illustrating a software configuration of an information processing apparatus according to an embodiment of the present invention. 
     Upon detecting an SCI signal generated by the power supply unit  105 , an OS  201  requests a BIOS  202  to call an SCI handler. The SCI signal is an interrupt request signal and is transmitted to the OS  201  so as to interrupt processing performed by the OS  201 . The power supply unit  105  generates the SCI signal, which is an interrupt request signal, when the state of a connection between the AC adapter  122  and the power supply unit  105  is changed, and transmits the generated SCI signal to the south bridge  104 . The OS  201  detects the SCI signal and calls the SCI handler that is one of components included in the BIOS  202 . At that time, the OS  201  monitors the state (on/off) of a flag representing whether the south bridge  104  has received the SCI signal. The south bridge  104  has a status register  400  denoting the relationship between an SCI signal  401  and a flag  402 . The flag  402  is set to on when the south bridge  104  has received the SCI signal  401 , and is set to off when the south bridge  104  has not received the SCI signal  401 . 
     The SCI handler determines which one of two types of SCI signals, that is, a signal representing that the AC adapter  122  has been disconnected from the power supply unit  105  and a signal representing that the AC adapter  122  has been connected to the power supply unit  105 , has been received, and transmits the determination result to an application  203  via a driver  204 . 
     The application  203  requests the OS  201  to lock the information processing apparatus  100  and perform password authentication. If an incorrect password is input, the application  203  requests the OS  201  to shut down the information processing apparatus. The information processing apparatus  100  according to this embodiment is compliant with the ACPI (Advanced Configuration and Power Interface) standard that allows the OS  201  to set and manage the power control function of each unit. As a matter of course, the information processing apparatus  100  may be compliant with another power control standard. 
       FIG. 3  is a flowchart illustrating a password request process according to this embodiment. 
     The power supply unit  105  monitors which of the AC power supply  121  and the battery  106  supplies power to the information processing apparatus  100 . In this embodiment, an example in which the information processing apparatus  100  is driven using power supplied from the AC power supply  121  will be described. 
     When a user starts up the information processing apparatus  100 , the OS  201  requests the user to input a login password so as to perform password authentication (step S 301 ). The OS  201  performs the authentication of a password that has been input by the user using the mouse  109  and the keyboard  110 . If the input password is correct, the OS  201  allows the user to log in the OS  201 . On the other hand, if the input password is incorrect, the OS  201  prohibits the user from logging in the OS  201 . After inputting a correct password and logging in the OS  201 , the user performs necessary processing in the OS  201  (step S 302 ). 
     The AC power supply  121  is connected to the power supply unit  105  via the AC adapter  122 , and supplies power so as to start the OS  201 . If the AC adapter  122  is disconnected from the power supply unit  105 , the power supply unit  105  transmits an SCI signal to the south bridge  104  and the OS  201  detects the SCI signal (step S 303 ). The SCI signal is an interrupt request signal for interrupting the processing performed by the OS  201 . Subsequently, the power supply unit  105  changes a power source from the AC power supply  121  to the battery  106 , since power cannot be supplied from the AC power supply  121  to the information processing apparatus  100  via the AC adapter  122  disconnected from the power supply unit  105 . 
     Upon receiving the SCI signal, the OS  201  calls the SCI handler included in the BIOS  202  (step S 304 ). In the BIOS  202 , the SCI handler checks whether the SCI signal, which has been received by the OS  201  from the power supply unit  105 , is an signal representing that the AC adapter  122  has been disconnected from the power supply unit  105  or a signal representing that the AC adapter  122  has been connected to the power supply unit  105  (step S 305 ). If the received SCI signal is the signal representing that the AC adapter  122  has been disconnected from the power supply unit  105 , the BIOS  202  transmits the check result to the application  203  (step S 306 ). 
     The application  203  requests the OS  201  to lock the information processing apparatus  100  and perform password authentication (step S 307 ). Subsequently, the OS  201  requests the user to input a password for password authentication (step S 308 ). The application  203  monitors the user&#39;s input of a password (step S 309 ). 
     The application  203  determines whether a password input by the user is correct (step S 310 ). If the input password is correct, the application  203  allows the user to continuously use the information processing apparatus  100 . On the other hand, if the input password is incorrect, the application  203  requests the OS  201  to shut down the information processing apparatus  100  (step S 312 ). Subsequently, the OS  201  shuts down the information processing apparatus  100  (step S 313 ). 
     Second Embodiment 
     In this embodiment, the information processing apparatus  100  requests a user to input a password for password authentication when the AC adapter  122  is connected to the power supply unit  105 . 
       FIG. 5  is a flowchart illustrating a password request process according to this embodiment. 
     The power supply unit  105  monitors which of the AC power supply  121  and the battery  106  supplies power to the information processing apparatus  100 . In this embodiment, an example in which the information processing apparatus  100  is driven using power supplied from the battery  106  will be described. 
     When a user starts up the information processing apparatus  100 , the OS  201  requests the user to input a login password so as to perform password authentication (step S 501 ). The OS  201  performs the authentication of a password that has been input by the user using the mouse  109  and the keyboard  110 . If the input password is correct, the OS  201  allows the user to log in the OS  201 . On the other hand, if the input password is incorrect, the OS  201  prohibits the user from logging in the OS  201 . After inputting a correct password and logging in the OS  201 , the user performs necessary processing in the OS  201  (step S 502 ). 
     If the AC adapter  122  is connected to the power supply unit  105  after the OS  201  has been driven using power supplied from the battery  106 , the power supply unit  105  transmits an SCI signal to the south bridge  104  and the OS  201  detects the SCI signal (step S 503 ). The SCI signal is an interrupt request signal for interrupting the processing performed by the OS  201 . Subsequently, the power supply unit  105  changes a power source from the battery  106  to the AC power supply  121 . 
     Upon receiving the SCI signal, the OS  201  calls the SCI handler included in the BIOS  202  (step S 504 ). In the BIOS  202 , the SCI handler checks whether the SCI signal, which has been received by the OS  201  from the power supply unit  105 , is an signal representing that the AC adapter  122  has, been disconnected from the power supply unit  105  or a signal representing that the AC adapter  122  has been connected to the power supply unit  105  (step S 505 ). If the received SCI signal is the signal representing that the AC adapter  122  has been connected to the power supply unit  105 , the BIOS  202  transmits the check result to the application  203  (step S 506 ). 
     The application  203  requests the OS  201  to lock the information processing apparatus  100  and perform password authentication (step S 507 ). Subsequently, the OS  201  requests the user to input a password for password authentication (step S 508 ). The application  203  monitors the user&#39;s input of a password (step S 509 ). 
     The application  203  determines whether a password input by the user is correct (step S 510 ). If the input password is correct, the application  203  allows the user to continuously use the information processing apparatus  100 . On the other hand, if the input password is incorrect, the application  203  requests the OS  201  to shut down the information processing apparatus  100  (step S 512 ). Subsequently, the OS  201  shuts down the information processing apparatus  100  (step S 513 ). 
     Thus, the information processing apparatus  100  can be locked for security, even if it is stolen. Accordingly, the leakage of data stored in the information processing apparatus  100  can be prevented. 
     The technical ideas derived from the above-described embodiments of an electronic apparatus will be enumerated below as appendices in the form of claims. The technical ideas according to the present invention may be understood at various levels ranging from a generic concept to a more specific concept. Accordingly, the present invention is not limited to the following appendices.