Patent Publication Number: US-2013247174-A1

Title: Authentication system, processor, and computer-readable recording medium storing therein program

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-058307, filed on Mar. 15, 2012, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiment discussed herein is an authentication system, a processor, and a computer-readable recording medium storing therein a program. 
     BACKGROUND 
     Unauthorized use of an information processor, such as a personal computer, is avoided by user authentication using a password, biological data, and an ID (identification) card, so that use of the information processor is restricted. 
     However, user authentication performed only once when the user starts using the processor is incapable of grasping whether the same user is continuously using the processor after the authentication. For the above, a demand arises for managing and confirming the state of using an information processor. 
     For example, one of the known methods of avoiding unauthorized use of an information processor is to intermittently authenticate the current user at a predetermined time period or at predetermined operation timings. 
     [Patent Literature 1] Japanese Laid-open Patent Publication No.2002-55956 
     [Patent Literature 2] Japanese Laid-open Patent Publication No. 2005-115480 
     However, when the cycle of user authentication is set to be short in order to accurately detect replacement of a user, such a method of avoiding unauthorized use frequently demands authentication. When the authentication adopts face authentication, authentication is not successful if the user is facing right/leftward and downward, and therefore the user needs to face the camera. Accordingly, the user of the information processor is annoyed by frequent demand for facing the camera for authentication. Furthermore, since authentication fails if user is not facing the camera when the authentication is carried out, the convenience user is impaired. 
     When face authentication for user authentication is substituted by another manner using, for example, a fingerprint and the cycle of authentication is set to be short in order to surely detect invalid replacement of the user, the user is frequently requested to undergo fingerprint authentication, which declines the convenience of the user. 
     SUMMARY 
     For the above, an authentication system including: an authenticator that collates an object that is to be authenticated to determine whether the object is valid and sets, when the object is determined to be valid, an authentication state for the object; a detector that continuously detects, after the setting by the authenticator, the presence of the object; and an authentication canceller that cancels, when the detector detects the absence of the object, the authentication state set for the object. 
     A processor including: a detector that continuously detects, after an object that is to be authenticated is determined to be valid as a result of collation and an authentication state is set for the object determined to be valid, the presence of the object; and an authentication canceller that cancels, when the detector detects the absence of the object, the authentication state set for the object. 
     A computer-readable recording medium having stored therein a program that causes a computer to execute a process comprising: after an object that is to be authenticated is determined to be valid as a result of collation and an authentication state is set for the object determined to be valid, continuously detecting the presence of the object; and cancelling, when detecting the absence of the object, the authentication state set for the object. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram schematically illustrating an example of the configuration of an information processor according to a first embodiment of the present invention; 
         FIG. 2  is a diagram schematically illustrating an example of the hardware configuration of an information processor of the first embodiment of the present invention; 
         FIG. 3  is an example of log data of an information processor of the first embodiment; 
         FIG. 4  is a flow diagram denoting a succession of procedural steps performed by an information processor of the first embodiment; and 
         FIG. 5  is a flow diagram denoting a succession of procedural steps of personal authentication by an information processor of the first embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENT(S) 
     Hereinafter, description will now be made in relation to an authentication system, a processor, and a program according to a first with reference to the accompanying drawings. However, it should be noted that the following embodiment is an example, and there is no intention to exclude modifications and application of techniques that are not mentioned in the following embodiment and a modification thereof. In other words, the following embodiment and modification can be changed or modified without departing from the concept of the present invention. Furthermore, the accompanying drawings may of course include additional elements and functions to those illustrated in the drawings. 
       FIG. 1  is a diagram schematically illustrating an example of the functional configuration of an information processor of the first embodiment; and  FIG. 2  is a diagram illustrating an example of the hardware configuration of the information processor. 
     An example of an information processor (authentication system, processor)  1  is a laptop or desktop computer. As illustrated in  FIG. 2 , the information processor  1  includes a Central Processing Unit (CPU)  201 , a Random Access Memory (RAM)  202 , a Read Only Memory (ROM)  203 , a camera  204 , a display  205 , a keyboard  206 , a mouse  207 , a memory  209 , and a microphone  210 . 
     The ROM  203  is a memory device that stores various pieces of data and programs. The RAM  202  is another memory device in which data and program are temporarily stored when the CUP  201  is calculating. 
     The keyboard  206  and the mouse  207  are input devices with which a user (object to be authenticated) inputs various data. A user inputs a password (collation information) using the keyboard  206  or the mouse  207 . The password input is used as collation information in user authentication by the authenticator  12 , which will be detailed below. Namely, the keyboard  206  and the mouse  207  function as a collation information inputting unit  11  that inputs collation information. 
     An example of the camera  204  is a WebCamera and takes a photograph of a user of the information processor  1 . The camera  204  is incorporated in or attached to the frame or another part of the display  205  so as to face the user. Specifically, the camera  204  takes a photograph of a user at a predetermined position in front of the information processor  1  and preferably takes a photograph of the face of the user. 
     Here, the predetermined position is a position where the user can visually recognize the contents displayed on the display  205  and also operate keyboard  206  and mouse  207 . For example, if a seat is disposed at such a predetermined position, a user sitting on the seat can visually recognize the contents on the display  205  and can operate the keyboard  206  and the mouse  207 . The camera  204  is disposed at a position where a user sitting on the seat can be recorded. 
     The camera  204  of the information processor  1  is capable of taking both still image and moving image. 
     The image (still image, moving image) taken by the camera  204  is sent to the CPU  201 . The camera  204  functions as a detection sensor  13  that continuously detects the presence of the user, and also functions as an ambient information obtaining unit  15  that obtains information (ambient information) of the surrounding of the information processor  1 . The image obtained by the camera  204  is stored in the memory  209 . 
     The microphone  210  is, for example, incorporated in or attached to the frame or other part of the display  205 , and obtains sound information of the ambient sounds and voices of the information processor  1 . The microphone  210  also functions as the ambient information obtaining unit  15  that obtains information (ambient information) of the surrounding of the information processor  1 . The sound information obtained by the microphone  210  is also stored in the memory  209 . 
     The display  205  is, for example, a monitor such as a Liquid Crystal Display, and is a device that displays thereon results of calculations by the CPU  201  and information to be provided to the user. 
     The memory  209  is a memory device that stores various pieces of data and programs, and is exemplified by a Hard Disk Drive (HDD) or a Solid State Drive (SSD). In addition, registration information (not illustrated) that the authenticator  12  to be detailed below uses for user authentication is stored in the memory  209  beforehand. An example of the registration information is a password (registered password) that each individual user has determined and registered and is associated with identification information (user ID) to specify the user. This means that the memory  209  function also as a registration information memory that records registration information. 
     The memory  209  keeps log data  30  that stores recorded data including image taken by the camera  204  and sound information collected by the microphone  210 . Namely, the memory  209  functions also as a log memory (ambient information memory)  18  that records the ambient information of the surrounding of the information processor  1 . 
     The CPU  201  achieves various calculations and controls by executing an Operating System (OS) and various programs stored in the ROM  203  and the memory  209 . Execution of the program in the memory  209  by the CPU  201  causes the information processor  1  of the first embodiment to function as the authenticator  12 , a detector  14 , a memory controller  16 , and an authentication canceller  17  that are illustrated in  FIG. 1 . 
     The program to achieve the functions of the authenticator  12 , the detector  14 , the memory controller  16 , and the authentication canceller  17  is provided in the form of being stored in a computer-readable recording medium such as a flexible disk, a CD (e.g., CD-ROM, CD-R, CD-RW), and a DVD (e.g., DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, HD DVD), a Blu-ray disk, a magnetic disk, an optical disk, and a magneto-optical disk. The computer reads the program from the recording medium and forwards and stores the program into an internal or external memory for future use. The program may be stored in a storage device (recording medium), such as a magnetic disk, an optical disk, and a magneto-optical disk, and may be provided to a computer from the storage device through a communication route. 
     The functions of the authenticator  12 , the detector  14 , the memory controller  16 , and the authentication canceller  17  are achieved by a microprocessor (corresponding to the CPU  201  of the first embodiment) executing a program stored in an internal memory (corresponding to the RAM  202  or the ROM  203  in the first embodiment). Alternatively, a computer may read a program stored in a recording medium and execute the read program. 
     In the first embodiment, a computer is a concept of a combination of hardware and an Operating System (OS), and means hardware which operates under control of the OS. Otherwise, if a program operates hardware independently of an OS, the hardware corresponds to the computer. Hardware includes at least a microprocessor such as a CPU and means to read a computer program recorded in a recording medium. In the first embodiment, the information processor  1  serves to function as a computer. 
     The authenticator  12  authenticates an object to be authenticated to determine whether the object is valid. In the first embodiment, a user of the information processor  1  corresponds to an object to be authenticated. For example, the authenticator  12  compares (collates) a password (collation information) input using the collation information inputting unit  11  (the keyboard  206  or the mouse  207 ) by a user with a registration password (registered password) stored in the memory  209  in association with the identification data of the user to be authenticated. When the input password matches the registered password, the authenticator  12  determines that the user input the password is the valid user (valid object). Except for the above, the authenticator  12  may adopt various manners of authentication known to the public, the description of which is however omitted here. Hereinafter, the authentication carried out by the authenticator  12  to authenticate a user will be sometimes referred to as “personal authentication”. 
     The authenticator  12  carries out collation of a user as the above and, when the result of the collation determines that the user is valid, set an authentication state for the user determined to be valid. For example, when a user is determined to be valid as a result of the collation, the authenticator  12  sets “1” in an authentication flag that indicates whether the object to be authenticated is valid and that is reserved at a predetermined memory region of the RAM  202  or the memory  209 . 
     Under the state where the authentication flag is set to “1” (i.e., under the authentication state), the current user of the information processor  1  is determined to have valid authority and is provided with authority to use the information processor  1 . Specifically, a log-in process is carried out using the account of the user, so that various functions provided for the valid authorized user come to be enabled. In contrast, under the state where the authentication flag is not set to “1” (i.e., set to be “ 0 ”), the current user of the information processor  1  is determined not to have valid authority and a non-illustrated security function limits predetermined one or more functions. For example, under a state where the authentication flag is not set to “1”, the functions other than the function of authenticating by the authenticator  12  are disabled to lock the information processor  1  (i.e., locking state). 
     Under the locking state, part of functions, such as the function of authenticating by the authenticator  12 , is enabled while data access to, for example, the memory  209  is disabled. The user is not allowed to use the information processor  1  unless the authenticator  12  authenticates the user again and sets “1” in the authentication flag. 
     The functions that can be used by a valid authorized user and the functions disabled for a user determined not to be valid may be modified. 
     The authenticator  12  authenticates the user at various predetermined timings of, for example, powered-on or restart of the information processor  1 , restoration from a power-saving mode, restoration from a locking state, and execution of the program to activate the authenticator  12 . 
     The detector  14  continuously detects the presence or the absence of the user. Specifically, the detector  14  detects, on the basis of the image data obtained by the detection sensor  13  (the camera  204 ), whether the user is present at the predetermined position in front of information processor  1 . For example, the detector  14  has a function of analyzing image and determines whether the image obtained by the camera  204  includes the image of the user. When the obtained image includes the image of the user, the detector  14  detects the presence of the user whereas when the obtained image does not include the image of the user, the detector  14  detects the absence of the user. 
     While a user have a seat disposed at the predetermined position in front of the information processor  1 , the image obtained by the camera  204  includes the image of the user. When the user leaves the seat, the image obtained by the camera  204  does not include the image of the user. Namely, the detector  14  detects the presence or the absence of the user sitting on the seat disposed at the predetermined position of the information processor  1 . 
     Alternatively, the detector  14  may detect the presence or the absence of a user on the basis of the silhouette or a change in color histogram in the image obtained by the camera  204 . 
     The detector  14  starts recording the image of the user through the use of the camera  204  and determining the presence or the absence of the user on the basis of the image obtained by the camera  204  when, for example, the information processor  1  is powered on. 
     After the authenticator  12  authenticates the user, the detector  14  continuously detects the presence and the absence of the user on the basis of the image obtained by the camera  204 . 
     The detector  14  serves to function as a continuous recognizing section that continuously recognizes the presence of the user, and detects (recognizes) that the user is continuously present after the authentication by the authenticator  12 . 
     When detecting the absence of the user from the predetermined position with reference to the image obtained by the camera  204 , the detector  14  notifies the authentication canceller  17  and the memory controller  16  of the detection of the absence of the user. Hereinafter, detection of the absence of the user is sometimes referred to as detection of leaving. 
     Furthermore, when detecting the presence of a user at the predetermined position under a state where a user is absent, the detector  14  notifies the authentication canceller  17  and the memory controller  16  of the detection of the presence of a user. Hereinafter, detection of the presence of the user under a state where a user is absent is sometimes referred to as detection of seating. 
     The detector  14  may detect replacement of the user present at the predetermined position with another person. For example, the detector  14  can detect the replacement by recognizing the face of the user in the face image obtained by the camera  204 . The recognition of the face based on a face image can be achieved by various known manners, and the detailed description thereof is omitted here. Hereinafter, detection of replacement of the user by another person is sometimes referred to as detection of replacement. 
     The image of a user that is to be used for detection of the presence of the absence of the user is obtained by the camera  204  when, for example, the authenticator  12  in the information processor  1  authenticates the user. Alternatively, the image of a user may be registered beforehand, and various modifications are suggested. 
     The detector  14  has a function of detecting a peep by a person except for the user by detecting, in the image obtained by the camera  204 , another person directing toward the display  205  in addition to the user at the predetermined position. For example, when the image recorded by the camera  204  contains two or more face image having a predetermined size or larger, the detector  14  detects a peep. The recognition of the presence of two or more faces in an image can be achieved by various known manners, and the detailed description thereof is omitted here. Hereinafter, detection of peeping by another person is sometimes referred to as detection of a peep. 
     Hereinafter, the detections of seating, leaving, replacement, and a peep by the detector  14  are sometimes referred to collectively as trace. 
     The authentication canceller  17  cancels, upon receipt of the notification of detection of the absence of the user from the detector  14 , the authentication state that the authenticator  12  set for the user. Specifically, when receiving the notification of detecting the absence of the user from the detector  14 , the authentication canceller  17  cancels the authentication flag set by the authenticator  12  (i.e., sets “0” in the flag). 
     Thereby, the information processor  1  is, for example, locked, so that the functions except for the function of authenticating by the authenticator  12  are disabled. This means that the user is locked out. 
     The memory controller  16  obtains ambient information of the surrounding of the information processor  1  using the ambient information obtaining unit  15  (the microphone  210  and the camera  204 ), and registers the obtained ambient information (recorded data) into the log data  30 . Specifically, the memory controller  16  causes the microphone  210  to collect sound (including voice) of the surrounding of the information processor  1  and registers the sound information, as the recorded data, into the log data  30  of the memory  209 . The memory controller  16  also causes the camera  204  to take still or moving images of the surrounding of the information processor  1 , and registers the image data into the log data  30 . 
     When a particular event occurs in the information processor  1 , the memory controller  16  records the occurrence of the event into the log data  30 . For example, when the detector  14  notifies detection of leaving, seating, or a peep when the authenticator  12  starts authentication of a user, or when the user opens an important document, the memory controller  16  records the respective events into the log data  30 . 
     Opening an important document corresponds to a time when data attached thereto specifying data as an important document in advance is selected and executed (opened) on the information processor  1 . 
       FIG. 3  is a table denoting an example of the log data  30  of the information processor  1  of the first embodiment. 
     In the example of  FIG. 3 , the log data  30  is constructed by associating time data, user data, event data, and recorded data with one another. 
     Here, the event data represents the contents of respective events occurred. Examples of an event are detection of seating; detection of leaving; detection of a peep; success or failure of password authentication by the authenticator  12 ; and open of an important document. In particular, since detection of leaving accompanies operation by the authentication canceller  17 , an event of cancellation of the user authorization or log-off is also recorded. 
     The time data is information that specifies the date and the time when the event occurs. The user data is information that specifies the user using the information processor when the event occurs. For example, the name of a user authenticated by the authenticator  12  is registered as the user. The term “unknown” is registered in the user data for an event the user of which is unknown, such as the start of trace upon detection of leaving or seating. 
     The recorded data is data of still and moving image obtained by the camera  204  and data of sounds collected by the microphone  210 , and is data being recorded by the camera  204  and for  210 . The record data represents the ambient status of the surrounding of the information processor  1  when the corresponding event is occurring. 
     For example, the memory controller  16  causes the camera  204  to take moving image only when an event determined to need a high security level is occurring while take only still image when other events are occurring. This can reduce the data size of the log data  30 . In the example of  FIG. 3 , “open an important document” and “detection of a peep” are regarded as events need a high-security level and moving image of only these two events are recorded in the log data  30 . 
     Particular events recorded through obtaining moving image are not limited to “open an important document” and “detection of a peep”, and various modifications can be suggested. 
     The log data  30  is stored into a non-illustrated external server (backup server) at predetermined timings. 
     In the log data  30  of  FIG. 3 , for example, trace is started at May 25, 2011, 14:55:30, and still image (photograph) and sounds (including voice) of the user are recorded. After that, the user is identified to be user A as a result of authentication by the authenticator  12  at May 25, 2011 14:55:30, and still image (photograph) and sounds of the user are recorded. 
     From the table of  FIG. 3 , user A is confirmed to have a seat in front of the information processor  1  until leaving is detected at May 25, 2011 14:55:30. 
     For example, the detector  14  detects a peep at May 25, 2011 18:15:30, and the camera  204  obtains still and moving images and the microphone  210  records voices. 
     The first embodiment assumes that the log data  30  is included in the memory  209  of the information processor  1 . However, the configuration is not limited to this. For example, the log data  30  may be included in an external device, such as an external server and a storage system connected to the information processor  1  via a network. 
     Description will now be made in relation to a succession of procedural steps performed in the information processor  1  of the first embodiment with reference to a flow diagram (steps A 10 -A 90 ) of  FIG. 4   
     For example, when the information processor  1  is powered on, the detector  14  starts recording an image of a user with the camera  204  (step A 10 ). 
     The detector  14  detects the presence or the absence of an user (step A 20 ). The detector  14  may detect the presence of a user on the basis of an image recorded by the camera  204  or detect the presence of a user when detecting input from the keyboard  206  or the mouse  207 . 
     When a user is absent (“ABSENT” route in step A 20 ), step A 20  is repeated until the detector  14  detects the presence of a user at the seat. 
     When the detector  14  detects the presence of a user at the seat (“PRESENT” route in step A 20 ), the detector  14  determines whether the user left the seat or replaced with anther person on the basis of the image recorded by the camera  204  in the ensuing step A 30 . When leaving or replacement is not detected (NO route in step A 30 ), Step A 30  is carried out again after a predetermined time period (step A 90 ). Specifically, the detector  14  continuously detects the presence of a user, which makes it possible to periodically confirm that the user is continuously present (at predetermined intervals). The predetermined time period is shorter than time that a user takes to leave the seat, so that the detector  14  certainly detects leaving of the user. 
     Setting a time interval (predetermined time period) for detection at step A 90  to be short, e.g., several milliseconds, makes substantially continuous detection of leaving and replacement of the user possible. This improves the security level. 
     In parallel with a procedural loop of detecting the presence of a user in steps A 30  and A 90 , the authenticator  12  authenticates the user (personal authentication). The user inputs the password along with the user ID using the keyboard  206  and the mouse  207 . The authenticator  12  authenticates the user by comparing (collating) the input password with a registered password previously stored in association with the user ID. 
     Even when the user is replaced with another person after the detection of the presence of the user at step A 20  and during the authentication by the authenticator  12 , this personal authentication makes it possible to detect the replacement, which improves the reliability of the information processor  1 . 
     As a result of the personal authentication by the authenticator  12 , the user is specified and the value “1” is set in the authentication flag, so that the user is authorized to use the information processor  1 . The personal authentication by the authenticator  12  will be described below with reference to  FIG. 5 . 
     The first embodiment records the image of the user with the camera  204  in step A 10 , which is carried out before the authentication by the authenticator  12  at step A 30 . The timing of recording is not however limited to this. 
     The detection (trace) of the presence of the user by the detector  14  at step A 30 , which is carried out in parallel with the personal authentication, continuously detects the presence of the user under a state where the current user of the information processor  1  is specified. 
     When the detector  14  detects leaving or replacement of the user (YES route in step A 30 ), the detector  14  notifies the memory controller  16  and the authentication canceller  17  of the leaving or the replacement. The memory controller  16  obtains the ambient information (sounds and image) of the surrounding of the information processor  1  using the microphone  210  and the camera  204 , and records the obtained ambient information into the log data  30  (step A 40 ). 
     The authentication canceller  17 , for example, cancels the authentication state set for the user by canceling the authentication flag set by the authenticator  12  (i.e., set the value “0” in the flag) (step A 50 ). This prevents the user from using the information processor  1 . In order to use the information processor  1  again, the user needs undergo the personal authentication once again, so that unauthorized use by third party during the absence of the user can be avoided. 
     The authentication canceller  17  locks the information processor  1 , also shuts off the display  205 , and further makes the user in the log-off state (step A 60 ). In order to use the information processor  1  again, the user needs undergo the personal authentication again, so that unauthorized use by third party during the absence of the user can be avoided. 
     After that, the detector  14  confirms the presence or the absence of the user (step A 70 ). When the detector  14  detects the presence of the user (“PRESENT” route in step A 70 ), the procedure returns to step A 30 . Conversely, when the detector  14  detects the absence of the user (“ABSENT” route in step A 70 ), the detector  14  stops recording the user with the camera  204 , so that the continuous detection of the user is terminated (step A 80 ). After that, the information processor  1  is powered off and the procedure is terminated. 
     Next, description will now be made in relation to a manner of personal authentication of the information processor  1  of the first embodiment with reference to a flow diagram (steps B 10 -B 50 ) of  FIG. 5 . 
     For example, to start personal authentication, a message to encourage the user to input the collation password is displayed on the display  205  and causes the user to input the password (step B 10 ). The authenticator  12  authenticates the user by collating the input password with the password previously registered (step B 20 ). 
     When the input password does not coincide with the registered password, that is, when the user is not identified to be the registered user as a result of the collation (NO route in step B 20 ), the memory controller  16  obtains the ambient information of the surrounding of the information processor  1  using the microphone  210  and the camera  204 . The obtained ambient information is registered into the log data  30  in association with the time of event and event information including the fact of failure in password authenticate (step B 50 ). 
     When the input password coincides with the registered password, that is, when the user is authenticated to be the user him/herself as a result of the collation (YES route in step B 20 ), the memory controller  16  obtains the ambient information of the surrounding of the information processor  1  using the microphone  210  and the camera  204 . The obtained ambient information is registered in the log data  30  in association with the time of the event and the event information including the fact of success in password authentication (step B 30 ). 
     After that, the user logs in the information processor  1  using the account of the user, so that various function allowed for valid authority come to available (step B 40 ), and the personal authentication is completed. 
     As the above, in the information processor  1  of the first embodiment, the detector  14  detects whether the user is continuously seating after the authenticator  12  authenticates the user, which makes it possible to prove the continuous seating. Accordingly, there is no need to, for example, intermittently confirm whether the current user of the information processor  1  is a valid user, and this authentication manner is convenient. 
     Furthermore, since the detector  14  determines the presence or the absence of a user on the basis of the image obtained by the camera  204 , the detection of a user can accomplished at a low cost without preparing a dedicated device. 
     When the detector  14  detects an event of leaving, replacement, or the like of the user, the memory controller  16  obtains the ambient information (voice and image) of the surrounding of the information processor  1  using the microphone  210  and the camera  204  and registers the obtained ambient information into the log data  30 . The ambient state of the information processor  1  when an event is occurring can be confirmed by examining the recorded data in the log data  30 , so that unauthorized access can be easily detected. 
     When the detector  14  detects an event of leaving, replacement, and others of the user, the authentication canceller  17  cancels the authentication state set for the user by the authenticator  12 . This prevents the user from using the information processor  1 . In order to use the information processor  1  again, the user needs undergo the personal authentication again, so that unauthorized use by third party during the absence of the user can be avoided. 
     Furthermore, when the detector  14  detects an event of leaving, replacement, and others of the user, the information processor  1  is powered off, so that unauthorized use by third party can surely avoided. 
     The technique disclosed above is not limited to the foregoing embodiment, and various changes and suggestions can be suggested without departing the gist of the first embodiment. 
     For example, in the first embodiment, the authenticator  12  authenticates a user on the basis of the password that the user inputs with the keyboard  206 . However, the manner of authentication is not limited to this. 
     Alternatively, the information processor  1  may further include a fingerprint sensor (biological data obtaining device) serving as a collation information inputting unit  11 , and the authenticator  12  may authenticate a user on the basis of a fingerprint image (biological data) obtained by the fingerprint sensor. 
     Further alternatively, the fingerprint sensor may be substituted with a palmprint sensor, a retina sensor, a microphone that obtains voice, which are to be used as the collation information inputting unit  11  that obtains other biological data. The collation information is not limited to a password input by a user, and alternative may be a palmprint, a retina, a voice print and others. Various examples of the collation information can be suggested. 
     Further, the camera  204  may be used as the collation information inputting unit  11  and personal authentication may be achieved by face authentication using the face image (collation information) of the user obtained by the camera  204 . 
     In the above first embodiment, the information processor  1  uses the camera  204  as the detection sensor  13 , and the presence of the user is detected on the basis of the image of the user obtained by the camera  204 . However, the manner of the detection is not limited to this. 
     For example, the information processor  1  may further include a motion sensor utilizing infrared or ultrasound, which serves as the detection sensor  13 . Alternatively, the presence of the user may be detected on the basis of typing of the keyboard  206  and inputting from the mouse  207 . Namely, the function of the detection sensor  13  may be achieved by a program that detects inputting through the keyboard  206  and the mouse  207 . Furthermore, at least two of the camera  204 , various motion sensors, the program, and others may be used as the collation information inputting unit  11  in combination with each other. 
     In the above first embodiment, the information processor  1  includes the authenticator  12 , the detector  14 , the memory controller  16 , and the authentication canceller  17 , but the functional elements of the information processor  1  are not limited to these. At least part of these functions may be included in another information processor, such as a server. 
     The above first embodiment assumes that an object to be authenticated is a user of the information processor  1 . However, the object to be authenticated is not limited to a user. Alternatively, an object to be authenticated may be animal or plants other than human or may be an inorganic article. Various changes and modifications of an object to be authenticated can be suggested. 
     For example, when an object to be authenticated is animal or plant, an IC tag may be attached to the object and the authenticator  12  may determine whether the object is valid on the basis of the information read from the IC tag. 
     In particular, when an object to be authenticated is a vehicle, the authenticator  12  may determine whether the vehicle is valid (valid object) by collation using a vehicle registration number read from the plate of the vehicle. 
     The respective functional elements and the respective procedural steps of the first embodiment may be opted for or out according to the requirement. 
     Those ordinarily skilled in the art easily carry out and produce the first embodiment from the above disclosure. 
     The technique disclosed above has an advantage of avoiding unauthorized use of an authentication system. 
     All examples and conditional language recited herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although an embodiment of the present inventions has been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.