Abstract:
A system with methods and apparatus for authenticating measurements that resist human errors and attempts to render or present fraudulent measurements. A system according to the present teachings obtains a measurement and substantially contemporaneously determines a set of one or more space/time parameters for the measurement. The system includes methods and apparatus for generating a certificate in response to the measurement and the space/time parameters such that the certificate enables a determination of whether a set of alleged data is the measurement obtained according to the space/time parameters.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The present invention pertains to the field of measurements. More particularly, this invention relates to measurement authentication.  
           [0003]    2. Art Background  
           [0004]    It is often desirable in a variety of applications to authenticate the fact that a particular measurement occurred at a specific location and/or at a specific time. Such space/time authentication may have important legal ramifications or other consequences with respect to the measurement. For example, it may be desirable to prove that a photograph was taken at a particular time and at a particular location when used by police, insurers, and others. Other examples include measurements of pollution violations, verifying movement of dangerous material, measurements critical to establishing intellection property rights, etc.  
           [0005]    Prior techniques for authenticating the fact that a particular measurement occurred at a specific location and/or at a specific time typically rely on statements made by individuals involved in the measurement. Unfortunately, such techniques are commonly vulnerable to human errors such as mistakes in determining a location or properly obtaining time or failures in human memory as well as fraudulent statements.  
         SUMMARY OF THE INVENTION  
         [0006]    A system is disclosed with methods and apparatus for authenticating measurements that resist human errors and attempts to render or present fraudulent measurements. A system according to the present teachings obtains a measurement and substantially contemporaneously determines a set of one or more space/time parameters for the measurement. The system includes methods and apparatus for generating a certificate in response to the measurement and the space/time parameters such that the certificate enables a determination of whether a set of alleged data is the measurement obtained according to the space/time parameters.  
           [0007]    Other features and advantages of the present invention will be apparent from the detailed description that follows.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The present invention is described with respect to particular exemplary embodiments thereof and reference is accordingly made to the drawings in which:  
         [0009]    [0009]FIG. 1 shows a method for authenticating a measurement according to the present teachings;  
         [0010]    [0010]FIG. 2 shows a system for authenticating a measurement according to one embodiment of the present teachings;  
         [0011]    [0011]FIG. 3 shows a system for authenticating a measurement according to another embodiment of the present teachings.  
     
    
     DETAILED DESCRIPTION  
       [0012]    [0012]FIG. 1 shows a method for authenticating a measurement according to the present teachings. At step  100 , the measurement is obtained and substantially contemporaneously a set of one or more space/time parameters for the measurement is determined. The space/time parameters may include a location at which the measurement was obtained or a time stamp which indicates a time at which the measurement was obtained or a combination of location and time stamp.  
         [0013]    Examples of measurements are numerous and include photographs or other light measurements, temperature measurements, pressure measurements, chemical measurements, measurements rendered by motion sensors or electrical signal sensors, to name a few examples. The measurement obtained at step  100  is represented in the form of digital data. The measurement at step  100  may be obtained by a device having the appropriate hardware/software for rendering a measurement as appropriate.  
         [0014]    A location obtained at step  100  indicates the geographic location at which the measurement of step  100  is obtained. A location determined at step  100  in one embodiment is a latitude and a longitude which is represented in the form of digital data. A time stamp obtained at step  100  may include data and time according to a standard and is represented in the form of digital data.  
         [0015]    At step  110 , a certificate is generated in response to the measurement and the space/time parameters from step  100 . The certificate generated at step  110  enables a determination of whether a set of alleged data corresponds to the measurement and the space/time parameters.  
         [0016]    The certificate may be generated at step  110  using well known techniques including encryption. For example, a cryptographic signature may be applied to the measurement and the space/time parameters obtained at step  100  thereby yielding a digitally signed certificate. Thereafter, the digitally signed certificate may be used to determine whether a set of alleged data is authentic, i.e. that it matches the measurement and the space/time parameters obtained at step  100 . The cryptographic signature may be a public-private key system.  
         [0017]    For example, the measurement obtained at step  100  may be a digital data value M 0  and the space/time parameters obtained at step  100  may yield a digital data value P 0  which may include a location and/or a time stamp. The certificate yielded by step  110  may be a digital data value C 0 . An individual or organization may hold the certificate C 0  as proof that the measurement M 0  was obtained at a location and/or a time given by P 0 . If that individual or organization wishes to prove the authenticity of a set of data A 0  which is alleged to be the measurement M 0  obtained at the space/time parameters P 0 , that individual or organization may present the alleged data A 0  along with the certificate C 0  to an authenticating entity. The authenticating entity decrypts C 0  using an appropriate key which reveals M 0  and P 0  from C 0 . The alleged data A 0  may then be compared to M 0  and a match indicates that A 0  is the measurement obtained at the location and/or time specified by P 0 .  
         [0018]    [0018]FIG. 2 shows a system  30  for authenticating a measurement according to one embodiment of the present teachings. The system  30  includes a measurement device  10  that generates a measurement  22 . The measurement device  10  in this embodiment includes a transceiver  24  that enables communication via a wireless telephone infrastructure  14 .  
         [0019]    The measurement device  10  obtains the measurement  22  and substantially contemporaneously with obtaining the measurement  22  it transfers the measurement  22  to an authentication entity  12  in a message  20  via the wireless telephone infrastructure  14 . The authentication entity  12  obtains the measurement  22  from the message  20  and determines a location of the measurement device  10 .  
         [0020]    In one embodiment, the authentication entity  12  determines the location of the measurement device  10  by querying the wireless telephone infrastructure  14 . The wireless telephone infrastructure  14  may determine the location of the measurement device  10  using cell site identifiers, triangulation or other techniques.  
         [0021]    The authentication entity  12  then generates a certificate in response to the measurement  22  and the location obtained from the wireless telephone infrastructure  14 . The authentication entity  12  may also generate a time stamp using its own real-time clock when the measurement  22  is received and incorporate the time stamp into the certificate.  
         [0022]    It is preferable that a relatively short time span be allowed to pass between generation of the measurement  22  in the measurement device  10  and the receipt of the message  20  by the authentication entity  12 . This would hinder attempts to falsify a measurement location by obtaining the measurement  22  at one location and then moving to another location and initiating the phone call that carries the message  20  to the authentication entity  12 . This would also hinder attempts to falsify measurement times.  
         [0023]    For example, the measurement device  10  may undergo a certification process which ensures that it is not capable of storing the measurement  22  for long periods of time and/or that it can only obtain a measurement during a telephone call to the authentication entity  12 . The measurement device  10  in such an embodiment initiates a wireless phone call and then generates the measurement  22  and transmits it on the fly to the authentication entity  12  during the wireless phone call.  
         [0024]    In another example, the measurement device  10  may be implemented with a tamper resistant real-time clock that generates a time-stamp at or near the time when the measurement  22  is generated. The time-stamp is sent to the authentication agency  12  in the message  20  and the authentication entity  12  compares the time-stamp to the time of receipt of the message  20  to determine whether an unreasonable delay has occurred.  
         [0025]    The measurement device  10  may include a GPS receiver that generates a location when the measurement  22  is obtained and transfer the location to the authentication entity  12  in the message  20 . The GPS receiver may be tamper resistant to hinder falsified data. In addition, the authentication entity  12  may verify the location contained in the message  20  by querying the wireless telephone infrastructure  14  for the location of the measurement device  10  once the message  20  is received.  
         [0026]    The measurement device  10  may be a digital camera, a temperature sensor, a pressure sensor, a chemical sensor, a motion sensor, an electrical signal sensor, or any other type of device capable of rendering a digital measurement. The measurement device  10  may have the transceiver  24  built in or attached with an appropriate possibly tamper resistant interface.  
         [0027]    The authentication entity  12  may be an organization or device or combination that provides a measurement authentication service using the present techniques. The authentication entity  12  may be a partially or fully automated system including the computational resources used to apply digital encryption and decryption as needed to generate certificates and to use certificates to authenticate alleged data. The authentication entity that generates the certificate need not be the same entity that authenticates alleged data.  
         [0028]    [0028]FIG. 3 shows a system  70  for authenticating a measurement according to another embodiment of the present teachings. The system  70  includes a measurement device  50  that generates a measurement  82 . The measurement device  50  in this embodiment includes a real-time clock  56 , a global positioning system (GPS) receiver  52 , and a communication subsystem  54 . The communication subsystem  54  enables communication via a network  60 .  
         [0029]    The measurement device  50  obtains the measurement  82  and substantially contemporaneously with obtaining the measurement  82  it obtains a time stamp  84  from the real-time clock  56  and a location  86  from the GPS receiver  52 . The measurement device  50  may undergo a certification to ensure its real-time clock  56  and GPS receiver  52  are tamper resistant in the sense that these elements may not be easily manipulated to create a substantially delay between the time-stamp  84  and the location  86  and the sampling of the measurement  82 .  
         [0030]    The measurement device  50  transfers the time-stamp  84  and the location  86  and the measurement  82  to the authentication entity  12  in a message  80  via the network  60 . The authentication entity  12  then generates a certificate in response to the measurement  82  and the location  86  and the time stamp  84  as discussed above.  
         [0031]    The network  60  may support Internet protocols and the message  80  may be transferred to the authentication entity using web protocols. For example, the communication subsystem  52  may include the functionality for acting as a web client to a web server in the authentication entity  12 .  
         [0032]    The measurement device  50  may be a digital camera, a temperature sensor, a pressure sensor, a chemical sensor, a motion sensor, an electrical signal sensor, or any other type of device capable of rendering a digital measurement. The measurement device  50  may have the real-time clock  56  and the GPS receiver  52  and the communication subsystem  54  each built in or attached with an appropriate, possibly tamper resistant, interface or any combination thereof.  
         [0033]    The foregoing detailed description of the present invention is provided for the purposes of illustration and is not intended to be exhaustive or to limit the invention to the precise embodiment disclosed. Accordingly, the scope of the present invention is defined by the appended claims.