Abstract:
A method and system for authenticating a user to access a computer system. The method comprises communicating security information to the computer system, and providing the computer system with an implicit input. The method further comprises determining whether the security information and implicit input match corresponding information associated with the user. The method further comprises granting the user access to the computer system in the event of a satisfactory match. When authenticating the user, the method and system consider the possibility of the user being legitimate but subject to duress or force by a computer hacker.

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
       [0001]    Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates generally to methods of accessing a secure computer system. More particularly, this invention relates to a method and system for authenticating an identity of a user before accessing a computer system. 
         [0004]    Description of the Related Art 
         [0005]    In today&#39;s information age, a user is generally required to execute or pass some form of a security step, such as entering a private identification code or password, to access a computer system. As the computer stored information or application becomes more sensitive or valuable, greater security measures are desired to verify the identity and legitimacy of the user before allowing access to the computer system that contains such information or application. The use of a password alone, however, has become less reliable to authenticate the user. The reduced reliability of using a password alone has been due to a computer hacker&#39;s ability to locate, copy, or electronically identify or track the required password using specialized software programs. In some cases, computer hackers are simply able to obtain the user&#39;s password by exercising duress or force. Accordingly, the use of a password alone to authenticate the user for access to the computer system has not been very reliable. 
         [0006]    Instead of or in combination with entering a password, some computer systems are designed to authenticate the user by requiring the user to turn a conventional key or swipe a machine readable card. These techniques, however, are still subject to the same weaknesses as those identified for using a password. Recently, some computer makers considered using the user&#39;s fingerprint to authenticate and grant access to the computer system. In such a system, a peripheral device, such as a mouse, includes a fingerprint acquisition module that provides to the computer a signal representative of the fingerprint of the user. The computer compares the user&#39;s fingerprint signal to a list of signals stored in its memory. If the user&#39;s fingerprint signal matches a signal that is stored in the computer memory, the user is granted access to the computer system, otherwise access is denied. For further details about such computer system, reference is made to U.S. Pat. No. 5,838,306 issued to O&#39;Connor et al. on Nov. 17, 1998, which is incorporated in its entirety by reference. Using a fingerprint is still not immune to the computer hacker&#39;s ability to force the user to place his/her finger on the acquisition device. Moreover, a sophisticated computer hacker may be able to copy the user&#39;s fingerprint and provide a simulated signal to the computer system to obtain access. 
         [0007]    Therefore, the above-described authentication techniques do not overcome a computer hacker&#39;s ability to access the computer by forcing the user to enter a password, turn a key, swipe a card, or place the user&#39;s finger on a fingerprint acquisition device. There is a need in the computer technology to provide an implicit authentication technique that is immune to force or theft by computer hackers. 
       SUMMARY OF THE INVENTION 
       [0008]    To overcome the above-mentioned limitations, the invention provides a method and system for authenticating a user to access a computer system. The method comprises communicating security information to the computer system, and providing the computer system with an implicit input. The method further comprises determining whether the security information and implicit input match corresponding information associated with the user. The method further comprises granting the user access to the computer system in the event of a satisfactory match. 
         [0009]    The system comprises a user interface configured to communicate security information and an implicit input to the computer. The system further comprises a compare circuit that is operationally coupled to the user interface. The compare circuit is configured to determine whether the security information and implicit input match corresponding information associated with the user. The system further comprises a process circuit that is operationally coupled to the compare circuit. The process circuit is configured to grant the user access to the computer in the event of a satisfactory match. In another embodiment, the system comprises means for interfacing the user with the computer. The interfacing means is configured to communicate security information and an implicit input to the computer. The system further comprises means, operationally coupled to the interfacing means, for comparing the security information and implicit input with corresponding information associated with the user. The system further comprises means, operationally coupled to the comparing means, for processing the compared information and granting the user access to the computer in the event of a satisfactory match. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The above and other aspects, features, and advantages of the invention will be better understood by referring to the following detailed description, which should be read in conjunction with the accompanying drawings, in which: 
           [0011]      FIG. 1  is a block diagram showing one embodiment of a computer system in accordance with the invention. 
           [0012]      FIG. 2  is a perspective view of a peripheral device that may be used with the invention. 
           [0013]      FIGS. 3A, 3B, 3C, and 3D  illustrate exemplary patterns that are recognized by the computer system of  FIG. 1 . 
           [0014]      FIG. 4  is a flowchart describing one embodiment of the method of authenticating a user in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. 
         [0016]      FIG. 1  is a block diagram showing one embodiment of a computer system  100  in accordance with the invention. As shown in  FIG. 1 , the computer system  100  comprises a user interface  110  that is operationally connected to a process circuit  120 . The user interface  110  may be any input device that is used to enter or communicate information to the computer system  100 , such as a keyboard, mouse, trackball, pointer, touch-screen, remote terminal, audio sensor, optical scanner, telephone, or any similar user interface. The user interface may provide input signals to the computer system  100  in an analog form, which typically requires conversion to digital form by the computer system  100 , or in a digital form. For example, when using a keyboard, a computer user (not shown in this figure) may enter a password representing a unique series of keys. When using a mouse or trackball, the user may enter a unique series of clicks using left, center, and/or right buttons of the mouse. Alternatively, the user may enter a unique geometric pattern (see  FIGS. 3A-3D ) concurrently with or shortly after entering the password. When using an audio sensor, such as a microphone, the user may enter audio information, such the user&#39;s voice, which may be uniquely identified by the computer system  100 . When using an optical scanner, the user may scan his/her fingerprint or other physical feature such as the retina into the computer system  100  for authentication. 
         [0017]    Any, a combination, or all of the above-described types of input signals may be used to authenticate a user. For example, the computer system  100  may be designed to receive a combination of input signals in a form of a password from a keyboard, in a form of a fingerprint scan from an optical scanner (e.g., placed on the keyboard or mouse), and in a form of a geometric pattern from a mouse or trackball. The user may input these signals substantially concurrently, or in any agreed upon sequence. For example, the user may enter a password through the keyboard and, within a predetermined duration of time (e.g., 5 seconds), place his/her finger on the mouse to be scanned while moving the mouse in a specified pattern, e.g., clockwise circle. As further described below, before granting the user&#39;s request for access, the computer system  100  may be configured to recognize the combination of a password, fingerprint, and a particular pattern that is unique to each user. 
         [0018]    The process circuit  120  is configured to receive input signals from the user interface  110  for processing. If the input signals are in analog form, the process circuit  120  converts the input signals to digital form for further processing. If desired or necessary, the process circuit  120  filters undesired components of the input signals, so that only components that are necessary for identification are passed on. The process circuit is operationally connected with a timer  130  that measures time duration between the various input signals. As noted above, the computer system  100  may be configured to recognize and accept for processing input signals (e.g., password) that occur within a predetermined duration of time from other input signals (e.g., fingerprint scan or pattern). Accordingly, the process circuit  120  may instruct the timer  130  to measure time between input signals to determine whether the user is an authorized user. For example, the duration between entering a password and performing a fingerprint scan and/or pattern may be set to a maximum of 10 seconds. If, after entering a legitimate password, the user takes too long (i.e., greater than 10 seconds) to perform a fingerprint scan and/or pattern, the process circuit  120  may deny access to the computer system  100 , as described for the method of  FIG. 4 . 
         [0019]    If, on the other hand, the user performs a fingerprint scan and/or pattern within the designated time, the process circuit  120  communicates the input signals to a compare circuit  150  for authentication. The compare circuit  150  is operationally coupled to a memory  140 , which stores a list of legitimate user identifications (ID&#39;s) with respective passwords, fingerprint, pattern, or any other type of information (“security information”) for recognition by the computer system  100 . The process circuit  120  may instruct the memory  140  to communicate security information to the compare circuit  150  for authentication. The compare circuit  150  also receives and compares input information from the process circuit  120  with the security information received from the memory  140 . If there is a match between the input and security information, the compare circuit  150  issues a “pass” signal to the computer system  100  (e.g., a host processor) indicating acceptance of and authorizing access by the user. If the input and security information do not match, the compare circuit issues a “flag” signal indicating denial of access by the user. 
         [0020]    In one embodiment, the user is always required to perform an implicit, invisible, or non-apparent act (the “implicit” act or input). The implicit input may include an active and/or a passive act. For instance, in performing the active act, the user may generate a geometric pattern (e.g., using a mouse) when requesting access to the computer system  100 . The computer system  100  may be configured to recognize a particular geometric pattern under the condition that the user performs such pattern concurrently with, or after a predetermined duration from, scanning his/her fingerprint. In performing the passive act, the user may wait a predetermined time intervals between entry of various components of the security information or, for instance, may skip a predetermined letter of each component of the security information. In heightened security applications, it may be desirable to configure the computer system  100  to issue a security alert to the responsible authority (e.g., security guards or law enforcement personnel) if the user fails to perform the geometric pattern. Accordingly, even if the compare circuit  150  determines that the input (e.g., fingerprint) and security information do match, the compare circuit  150  may still issue the flag signal because of the user&#39;s failure to perform the geometric pattern. 
         [0021]    In such a scenario, the computer system  150  recognizes that while the user may be legitimate, the user&#39;s failure to perform the geometric pattern may be an indication that the user is experiencing duress or force to access the computer system  100 , as described for the method of  FIG. 4 . In some applications, it may be desirable to grant a limited access to the user to give the false impression that access to the computer system  100  is granted as usual. As used herein, “limited access” is any access that provides a user or intruder access that is less than complete access to the computer system  100 . However, concurrently with the limited access, a silent security alert may be issued to security personnel, without allowing the user or intruder to know. Using the silent security alert mode silent alert minimizes risk to the user under duress. 
         [0022]    Any of the structural components of the computer system  100 , e.g., the process circuit  120  and compare circuit  150 , may be implemented using commonly known hardware, such as one or more digital circuits, to perform the authentication functions of the computer system  100 . Alternatively, the functions of such structural components may be implemented using a dedicated signal processor, such as a digital signal processor (DSP) that is programmed with instructions to perform the authentication functions of the computer system  100 . 
         [0023]      FIG. 2  is a perspective view of a peripheral device  200  that may be used with the invention. The peripheral device  200  may comprise a mouse that communicates signals with the computer system  100  (see  FIG. 1 ) via a cable  230 , or via a wireless link (not shown in this figure) such as a radio frequency (RF) or infrared (IR) link. In one embodiment, the user interface  110  (see  FIG. 1 ) may comprise the peripheral device  200  through which a user may send user security information (e.g., a user ID, password, fingerprint scan, and a specified pattern) to the computer system  100  to obtain access thereto. 
         [0024]    As shown in  FIG. 2 , the peripheral device  200  comprises one or more buttons  210 ,  212 ,  214 , and  216 , which, when pressed by the user, send various signals that are recognized by the computer system  100 . As described above, in addition to a password and fingerprint scan, the computer system  100  may be configured to require the user to enter a pattern comprising a unique sequence of button pressings to authenticate the user. Accordingly, concurrently with or shortly after the fingerprint scan, the user may press one or more of the buttons  210 - 216  to generate a unique sequence of signals before the computer system  100  may grant access. For example, the sequence of signals may be generated by pressing the button sequence  214 ,  212 ,  216 , and  212 . In response to the user security information, the computer system  100  determines if the user may be granted access as described above. 
         [0025]    The peripheral device  200  may optionally comprise a trackball (not shown in this figure) that allows the user to manipulate the position of a pointer on a visual display, such as a display monitor, in response and proportionally to the motion of the trackball on a surface, such as a pad. The characteristics and operation of such a trackball are well known in the art. The peripheral device  200  may also comprise one or more optical scanner windows  220 ,  222 ,  224 , and  226 . If the authentication process requires a fingerprint scan, one or more of the scanner windows  220 - 226  may scan the fingerprint of the user and form an electronic image of the fingerprint. The peripheral device  200  sends the electronic image to the computer system  100  for authenticating the user as described above. The characteristics and operation of the optical scanner windows  220 - 226  are well known in the art. 
         [0026]    As noted above, in addition to entering a password and fingerprint scan, the computer system  100  may be configured to require the user to enter a unique geometric pattern via the peripheral device  200  to authenticate the user. Accordingly, concurrently with or shortly after the fingerprint scan, the user may move the peripheral device  200  on a flat surface in a predetermined geometric pattern to generate the unique geometric pattern, as outlined by the trackball of the peripheral device  200 .  FIGS. 3A, 3B, 3C, and 3D  illustrate exemplary patterns that are recognized by the computer system  100 . As shown in  FIG. 3A , the user may move the peripheral device  200  to generate a triangle  310  in a specified direction on the flat surface. The peripheral device  200  sends the generated pattern in a form of electrical signals to the computer system  100  for authentication. As described above, if the computer system  100  determines that the generated pattern matches a pattern stored in the memory  140  (see  FIG. 1 ), the computer system  100  grants the access. If, on the other hand, the computer system  100  determines that the generated pattern does not match a stored pattern, the computer system  100  may deny access or, if configured to do so, lock up the computer system  100  and generate a security alert to the responsible authorities. 
         [0027]      FIG. 3B  shows another exemplary pattern in a form of a rectangle  320  that may be generated by the user via the peripheral device  200 .  FIG. 3C  shows another exemplary pattern in a form of a straight line  330  that may be generated by the user via the peripheral device  200 . Finally,  FIG. 3D  shows still another exemplary pattern in a form of a circle  340  that may be generated by the user in a clockwise direction via the peripheral device  200 . 
         [0028]      FIG. 4  is a flowchart describing one embodiment of the method of authenticating a user in accordance with the invention. The method of the invention commences at block  400  when the computer system  100  ( FIG. 1 ) is first powered up. At block  410 , the user enters the user&#39;s security information such as a user identification, password, and/or fingerprint scan, pursuant to system access instructions. At a decision block  416 , the computer system  100  determines whether the entered security information matches corresponding information in the memory  140 . If the security information does not match, the method proceeds to block  470  where the computer system  100  denies access to the user. If, on the other hand, the security information matches corresponding information in the memory  140 , the method proceeds to block  420 . 
         [0029]    In this embodiment, the computer system  100  is configured to recognize the implicit input that the user enters concurrently with, or within a predetermined duration of, entering the security information. As noted above, the implicit input may be a geometric pattern that the user generates via the user interface  110 . Accordingly, at block  420 , the computer system  100  waits and searches for a predetermined pattern signal from the user interface  110 . The pattern signal may be in analog or digital form that represents the pattern that the user generates, e.g., the circle  340 . At a decision block  424 , the computer system  100  determines if a pattern signal is received from the user interface  110  within the predetermined duration. If a pattern signal is not received or found, the method proceeds to block  436 . If, on the other hand, a pattern signal is received from the user interface  110 , the method proceeds to a decision block  428 , where the computer system  100  determines whether the pattern signal matches a corresponding pattern signal stored in memory  140 . If the entered pattern signal matches the stored pattern signal, the method proceeds to block  460  where the computer system  100  grants the user&#39;s request for access. If, on the other hand, the entered signal pattern does not match the stored pattern signal, the method proceeds to the decision block  436 . 
         [0030]    As indicated above, the computer system  100  may be configured to operate in an alert mode if desired by the system administrator. The alert mode represents a mode of operation wherein the computer system  100  responds to an access request using an authentication process that is more stringent than when operating in a non-alert (“normal”) mode. For instance, upon receiving instructions to heighten security measures (e.g., in response to an overt threat or intelligence information), the system administrator may configure the computer system  100  to operate in the alert mode. Alternatively, the system administrator may configure the computer system  100  to operate in the alert mode based on any desired criteria, such as geographic location of the computer system  100 , content or sensitivity of stored information, and/or other factors. In the alert mode, the computer system  100  alerts security personnel if it is determined that there is a possibility of a security breach. Accordingly, at block  436 , the computer system  100  determines if the alert mode is activated. If the alert mode is not activated, the method proceeds to block  470 , where the computer system  100  denies the user&#39;s request to access the computer system  100 . If, on the other hand, the alert mode is activated, the method proceeds to block  440 . Thus, in the event of an absent or incorrect pattern signal, the computer system  100  avoids issuing unwarranted security alerts when operating in the normal mode. However, if it is operating in the alert mode, the computer system  100  applies a stringent authentication process and issues security alerts in the event of an absent or incorrect pattern signal. 
         [0031]    As noted above, the computer system  100  may represent at least a portion of a computer network that is accessible via multiple user terminals, including security and supervisory personnel terminals. Accordingly, if the alert mode is activated, then at block  440  the computer system  100  is configured to issue an alert signal to a predetermined destination, e.g., a security terminal that is accessible by security personnel. The alert signal may be a text message indicating that a potential security breach or unauthorized attempt to access the network has occurred at a particular location, e.g., electronic or physical address of the computer system  100 . At block  446 , the computer system  100  determines whether the silent alert mode is activated. As noted above, the silent alert mode allows a limited access to a user that is potentially under the influence of duress or force. Hence, the system administrator may selectively activate or deactivate the silent alert mode based on any desired criteria, such as the level of safety necessary for users at a particular location. 
         [0032]    Accordingly, if the silent alert mode is not activated, the method proceeds to block  470  where the computer system  100  denies the user access to the computer system  100 . If, on the other hand, the silent alert mode is activated, the method proceeds to block  450  where the computer system  100  downgrades or limits the scope of access for the user who entered the security information. As noted above, limited access is any access that provides a user or intruder access that is less than complete access to the computer system  100 . For example, the limited access may allow the user to read or view only a particular list of files that do not contain sensitive information. The limited access may also include preventing the user from printing or copying any files that are stored in the computer system  100 . After downgrading the scope of access for the user, the method proceeds to block  460  where the computer system  100  provides the user with limited access to the computer system  100 . As noted above, while the computer system  100  grants the user with the limited access, the computer system issues the alert signal to security personnel without notifying the user or intruder that any such signal was issued. The method terminates at block  490  after either granting the user&#39;s request at block  460  or denying the user&#39;s request at block  470  to access the computer system  100 . 
         [0033]    In view of the foregoing, it will be appreciated that the invention overcomes the long-standing need for a method and system for correctly authenticating a user despite the presence of duress and force by a computer hacker. The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiment is to be considered in all respects only illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather by the foregoing description. All changes that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.