Abstract:
An apparatus and method are disclosed for determining authentication frequency (i.e., the length of time between authenticating and re-authenticating a user) and challenge type (e.g., username/password, fingerprint recognition, voice recognition, etc.) based on one or more environmental properties (e.g., ambient noise level, ambient luminosity, temperature, etc.), or one or more physiological properties of a user (e.g., heart rate, blood pressure, etc.), or both. Advantageously, the illustrative embodiment enables authentication frequency and challenge type to be adjusted based on the likelihood of malicious activity, as inferred from these properties. In addition, the illustrative embodiment enables the authentication challenge type to be tailored to particular environmental conditions (e.g., noisy environments, dark environments, etc.).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    moon This application is a divisional of U.S. patent application Ser. No. 12/241,584, filed Sep. 30, 2008, which is a continuation-in-part of U.S. patent application Ser. No. 11/942,670, filed 19 Nov. 2007, now U.S. Pat. No. 8,918,079, issued on Dec. 23, 2014, which are incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to computer security in general, and, more particularly, to authentication. 
       BACKGROUND OF THE INVENTION 
       [0003]    In some instances it is desirable for security reasons to require that the user of a data-processing system (e.g., a wireless telecommunications terminal such as a cellular phone or a smart phone, a personal computer, a server, etc.) be authenticated before the user is permitted to access an application or resource of the data-processing system. Typically a user is presented with an authentication challenge, and the user must supply a valid response to the challenge. Examples of different types of authentication challenges include:
       requiring a user to furnish his or her username and password;   requiring a user to consult an electronic token device or a list of numbers in order to furnish a one-time password;   requiring a user to answer a pre-arranged secret question (e.g., “What is your mother&#39;s maiden name?”, “What was your first telephone number?”, etc.); and   biometrics (e.g., fingerprint recognition, voice recognition, retinal or iris scan, etc.).
 
Furthermore, in some instances the user of wireless telecommunications terminal  110  might be periodically challenged (i.e., the user is periodically re-authenticated) for greater security.
       
 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention enables authentication frequency (i.e., the length of time between authenticating and re-authenticating a user) and challenge type (e.g., username/password, fingerprint recognition, voice recognition, etc.) to be determined based on one or more environmental properties (e.g., ambient noise level, ambient luminosity, temperature, etc.), or one or more physiological properties of a user (e.g., heart rate, blood pressure, etc.), or both. In accordance with the illustrative embodiment, both current and historical environmental and physiological properties can be used in these determinations. 
         [0009]    The present invention is advantageous in that it enables authentication frequency to be increased (i.e., less time between re-authentication challenges, which corresponds to tighter security) and the challenge type to be stronger (i.e., more secure) in situations where it is more likely that a malicious user has gained access to a data-processing system. For example, it might be more likely that a user&#39;s wireless telecommunications terminal (e.g., a cell phone, a personal digital assistant [PDA], etc.) is left behind or stolen in an environment with a lot of ambient noise (the theory being that the environment is a public place with a lot of people around). As another example, the authentication frequency and challenge type for an office worker&#39;s personal computer might be set for a higher level of security when the office is dark. As yet further examples, authentication frequency and challenge type for a wireless telecommunications terminal might be set for a higher level of security when one or more physiological properties of its user differ substantially from their normal prior ranges, or when the physiological properties indicate that the user might be nervous, or when the environment of the terminal at a particular day and time (say, a weekday morning) differs substantially from the norm. 
         [0010]    In addition, the present invention enables the selection of an authentication challenge type that is especially well-suited to a particular situation. For example, a voice recognition challenge might be issued when it is dark, as opposed to a retina scan challenge (because it&#39;s dark), or a fingerprint recognition challenge (as it might be difficult for the user to find the fingerprint sensor in the dark). As another example, a challenge/response via a video display and keyboard might be more appropriate than a voice recognition challenge in a noisy environment. As yet another example, when physiological properties of a user suggest that the user is engaged in vigorous exercise, a speaker-independent challenge/response via a speaker and microphone might be more suitable than a display/keyboard challenge (as it is likely difficult for the user to type via keyboard while exercising) or a voice recognition challenge (as the error rate might be high when a user is breathing heavily). 
         [0011]    The illustrative embodiment comprises: presenting a first authentication challenge at time t 1 ; and presenting a second authentication challenge at time t 2 ; wherein the magnitude of t 2 -t 1  is based on an environmental property at one or more instants in time interval [t 1 , t 2 ]. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  depicts the salient elements of data-processing system  100 , in accordance with the illustrative embodiment of the present invention. 
           [0013]      FIG. 2  depicts the salient elements of environmental sensor array  160 , as shown in  FIG. 1 , in accordance with the illustrative embodiment of the present invention. 
           [0014]      FIG. 3  depicts the salient elements of physiological sensor array  170 , as shown in  FIG. 1 , in accordance with the illustrative embodiment of the present invention. 
           [0015]      FIG. 4  depicts a flowchart of a method for determining re-authentication challenge frequency and type, in accordance with the illustrative embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    For the purposes of the specification and claims, the term “calendrical time” is defined as indicative of one or more of the following:
       (i) a time (e.g., 16:23:58, etc.),   (ii) one or more temporal designations (e.g., Tuesday, November, etc.),   (iii) one or more events (e.g., Thanksgiving, John&#39;s birthday, etc.), and   (iv) a time span (e.g., 8:00 PM to 9:00 PM, etc.).       
 
         [0021]      FIG. 1  depicts the salient elements of data-processing system  100 , in accordance with the illustrative embodiment of the present invention. As shown in  FIG. 1 , data-processing system  100  comprises transceiver  110 , memory  120 , clock  130 , input devices  140 - 1  through  140 -N, where N is a positive integer, output devices  150 - 1  through  150 -M, where M is a positive integer, environmental sensor array  160 , and physiological sensor array  170 , and processor  180 , interconnected as shown. 
         [0022]    Transceiver  110  is capable of receiving external signals (e.g., via a wired network, via a wireless network, etc.) and forwarding information encoded in these signals to processor  180 , and of receiving information from processor  180  and transmitting signals that encode this information (e.g., via a wired network, via a wireless network, etc.), in well-known fashion. 
         [0023]    Memory  120  is capable of storing data, program source code, and executable instructions, as is well-known in the art, and might be any combination of random-access memory (RAM), flash memory, disk drive, etc. In accordance with the illustrative embodiment, memory  120  is capable of storing historical environmental and physiological data. 
         [0024]    Clock  130  is capable of transmitting the current time, date, and day of the week to processor  180 , in well-known fashion. 
         [0025]    Input devices  140 - 1  through  140 -N are capable of receiving input from a user and of forwarding the input to processor  180 , in well-known fashion. Examples of input devices  140 - 1  through  140 -N might include a numeric keypad, an alphanumeric keyboard, a fingerprint sensor, a microphone, a magnetic card reader, and so forth. 
         [0026]    Output devices  150 - 1  through  150 -M are capable of receiving information, including authentication challenges, from processor  180 , and of outputting the information to a user, in well-known fashion. Examples of output devices  150 - 1  through  150 -M might include a video display, a speaker, a vibration mechanism, and so forth. 
         [0027]    Environmental sensor array  160  is capable of receiving information concerning environmental properties, as is described in detail below and with respect to  FIG. 2 , and of forwarding this information to processor  180 , in well-known fashion. 
         [0028]    Physiological sensor array  170  is capable of receiving information concerning a user&#39;s physiological properties, as is described in detail below and with respect to  FIG. 3 , and of forwarding this information to processor  180 , in well-known fashion. 
         [0029]    Processor  180  is a general-purpose processor that is capable of reading data from and writing data into memory  120 , of executing instructions stored in memory  120 , and of executing the tasks described below and with respect to  FIG. 4 . As will be appreciated by those skilled in the art, in some embodiments of the present invention processor  180  might be a special-purpose processor, rather than a general-purpose processor. 
         [0030]      FIG. 2  depicts the salient elements of environmental sensor array  160 , in accordance with the illustrative embodiment of the present invention. Environmental sensor array  160  comprises sound level meter  210 , photometer  220 , thermometer  230 , hygrometer  240 , and barometer  250 . 
         [0031]    Sound level meter  210  measures ambient sound intensity, in well-known fashion, and transmits its measurements to processor  180 . 
         [0032]    Photometer  220  measures ambient light intensity, in well-known fashion, and transmits its measurements to processor  180 . 
         [0033]    Thermometer  230  measures ambient temperature, in well-known fashion, and transmits its measurements to processor  180 . 
         [0034]    Hygrometer  240  measures ambient humidity, in well-known fashion, and transmits its measurements to processor  180 . 
         [0035]    Barometer  250  measures ambient air pressure, in well-known fashion, and transmits its measurements to processor  180 . 
         [0036]      FIG. 3  depicts the salient elements of physiological sensor array  170 , in accordance with the illustrative embodiment of the present invention. An exemplary group of sensors  170 , such as a physiological sensor array, can include heart rate monitor  310 , blood pressure monitor  320 , respiration rate monitor  330 , body temperature monitor  340 , and brain activity monitor  350 . As will be appreciated by those skilled in the art, in some embodiments of the present invention, some or all of the monitors  310 ,  320 ,  330 ,  340 ,  350  might receive input from the user via one or more sensors that are coupled to the user&#39;s body (e.g., via the user&#39;s forehead, via one of the user&#39;s fingers, etc.) and that transmit data to data-processing system  100 , either wirelessly or via a wire. Alternatively, in some other embodiments of the present invention in which data-processing system  100  is a handheld telecommunications terminal, some or all of monitors  210  through  250  might receive input from the user via one or more sensors that are located on the surface of the terminal, and that receive physiological signals from the user when the user is holding the terminal. Moreover, as will be appreciated by those skilled in the art, in some other embodiments of the present invention physiological sensor array might be capable of receiving physiological signals from one or more other persons, either in addition to or instead of the user of data-processing system  100 . 
         [0037]    Heart rate monitor  210  measures a user&#39;s heart rate, in well-known fashion, and transmits its measurements to processor  180 . 
         [0038]    Blood pressure monitor  220  measures a user&#39;s blood pressure, in well-known fashion, and transmits its measurements to processor  180 . 
         [0039]    Respiration rate monitor  230  measures a user&#39;s respiration rate, in well-known fashion, and transmits its measurements to processor  180 . 
         [0040]    Body temperature monitor  240  measures a user&#39;s body temperature, in well-known fashion, and transmits its measurements to processor  180 . 
         [0041]    Brain activity monitor  250  is a device such as an electroencephalograph, an electromyograph, etc. that obtains one or more measurements of a user&#39;s brain activity and transmits its measurements to processor  180 . As will be appreciated by those skilled in the art, in some embodiments of the present invention brain activity monitory  250  might be capable of indicating such conditions as when a user is engaged in deep thought, when a user is engaged in vigorous exercise, when a user is in a stupor, when a user is asleep, and so forth. 
         [0042]    As will be appreciated by those skilled in the art, in some embodiments of the present invention physiological sensor array  170  might comprise other kinds of physiological monitors (e.g., an electrocardiograph, a pulse oximeter, etc.) and/or collect other physiological properties (e.g., heart beat, pulse regularity, skin color, etc.) in addition to, or instead of, those depicted in  FIG. 3  and described above, and it will be clear to those skilled in the art, after reading this disclosure, how to make and use such embodiments of the present invention. 
         [0043]      FIG. 4  depicts a flowchart of a method for determining re-authentication challenge frequency and type, in accordance with the illustrative embodiment of the present invention. In accordance with the illustrative embodiment, the tasks of  FIG. 4  are performed by data-processing system  100 . As will be appreciated by those skilled in the art, however, in some other embodiments of the present invention, one or more tasks of  FIG. 4 , such as the determination of the challenge frequency and type at task  440 , might instead be performed by another entity (e.g., an authentication server, etc.) and the result transmitted to transceiver  110  of data-processing system  100 . 
         [0044]    At task  410 , environmental properties at data-processing system  100  are obtained from sensor array  160 , in well-known fashion. 
         [0045]    At task  420 , physiological properties of the user of data-processing system  100  are obtained from sensor array  170 , in well-known fashion. 
         [0046]    At task  430 , the input capabilities of data-processing system  100  are determined. As will be appreciated by those skilled in the art, in embodiments of the present invention in which task  430  is performed by data-processing system  100  itself, data-processing system  100  merely has to check which of input devices  140 - 1  through  140 -N are currently enabled and functional; while in some other embodiments of the present invention, an authentication server or some other entity might transmit a message to data-processing system  100  that explicitly asks for its input capabilities; while in yet some other embodiments, an authentication server or some other entity might transmit a message to data-processing system  100  that asks for its manufacturer and model (e.g., Apple iPhone , etc.), and then consult a database to determine the input capabilities of data-processing system  100  (under the assumption that all of data-processing system  100 &#39;s capabilities are currently enabled and functional). 
         [0047]    At task  440 , an authentication challenge type T and time A between challenges are determined based on:
       the current environmental properties at data-processing system  100 ,   environmental properties at data-processing system  100  since the last authentication challenge at data-processing system  100 ,   historical environmental properties associated with data-processing system  100 ,   historical environmental properties associated with data-processing system  100  and the current calendrical time,   the current physiological properties of the current user of data-processing system  100 ,   physiological properties of data-processing system  100 &#39;s user since the last authentication challenge at data-processing system  100 ,   historical physiological properties associated with data-processing system  100 ,   historical physiological properties associated with data-processing system  100  and the current calendrical time, and   the input capabilities of data-processing system  100 .       
 
         [0057]    As will be appreciated by those skilled in the art, in some embodiments of the present invention, an authentication challenge type might comprise a plurality of successive challenges, rather than a single challenge, thereby enabling even “stronger” authentication challenges. For example, a challenge type determined at task  440  might be “fingerprint recognition, followed by iris scan.” 
         [0058]    As will further be appreciated by those skilled in the art, for embodiments of the present invention in which task  440  is performed by data-processing system  100 , the current day and time might be obtained from clock  130 , or might be obtained from an external source via transceiver  110 . Moreover, although in the illustrative embodiment historical environmental and physiological property data are stored in memory  120 , in some other embodiments of the present invention these data might be stored in an external database and accessed by data-processing system  100  via transceiver  110 . As will further be appreciated by those skilled in the art, in some embodiments of the present invention the collection, storing, and organization of these historical data might be performed by data-processing system  100  itself, while in some other embodiments of the present invention some other entity might perform these functions. 
         [0059]    As will further be appreciated in the art, in some embodiments of the present invention in which physiological sensor array  170  is capable of receiving signals from one or more other persons in addition to the current user of data-processing system  100 , the physiological properties of these other persons might also be considered in the determination of task  440 . Similarly, in some other embodiments of the present invention in which physiological sensor array  170  is capable of receiving signals from one or more other persons instead of the current user of data-processing system  100 , the physiological properties of at least one of these other persons will be considered in lieu of physiological properties of the current user of data-processing system  100 . 
         [0060]    At task  450 , an authentication challenge of type T is generated, in well-known fashion. 
         [0061]    At task  460 , the authentication challenge generated at task  450  is presented to the user of data-processing system  100  at a time in accordance with A, in well-known fashion. After task  460 , the method of  FIG. 4  terminates. 
         [0062]    It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims.