Abstract:
The present invention is directed toward Radio Frequency Identification (RFID) devices and related technologies. Specifically, an RFID device is provided that includes a photon receiver. Photon signals are received at the photon receiver and analyzed before the RFID device begins interacting in Radio Frequency (RF) communications, thereby disclosing data stored on the RFID device to other devices.

Description:
[0001]     This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/708,532, filed Aug. 15, 2005, which is herein incorporated by this reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is generally directed to access control systems and radio frequency identification transponders. More specifically, the present invention provides a photon authenticated RFID transponder that is enabled by light emitted by a reading device confirming the authenticity of the reading device.  
       BACKGROUND  
       [0003]     A Radio Frequency (RF) communication interface between a reader and an RF Identification (RFID) device is typically automatically established when the RFID device is brought within an active zone of a reader/interrogator. The active zone of the reader is defined as a three dimensional space where the intensity of RF signals emitted by the reader exceeds a threshold of sensitivity of the RFID device and the intensity of RF signals emitted by the RFID device exceeds a threshold of sensitivity of the reader. When an RFID device is presented to most readers, such an interface is created and the reader and RFID device begin transmitting data back and forth. Typically, the RFID device is asked by the reader to supply some sort of credential data that verifies the authenticity of the RFID device, and its holder, to the reader. Typically, the RFID device assumes any entity that is asking for credential data must need it for the holder of the RFID device to gain access to a particular asset. Essentially, these RFID devices assume any reader is a trusted reader. Criminals have exploited this fact to steal data stored on the RFID device by creating an interface between the RFID device and an illicit reader. The RFID device assumes that the reader is a valid reader and readily transmits credential data to the reader.  
         [0004]     Contactless RFID devices are rapidly displacing other machine-readable card-based technologies as the technology of choice due to their convenience. Unfortunately with this convenience comes a potential compromise to a cardholder&#39;s privacy. This can occur during the time when a card is presented to a reader since the RF signal can be surreptitiously intercepted and the data remotely retrieved from the card without the cardholder&#39;s knowledge. It can also occur while a card is being carried in a person&#39;s wallet or purse. Such attacks may include replay attacks, man-in-the-middle attacks, and other known RFID attacks. Security mechanisms such as mutual authentication, challenge/response, encryption of data, and even the use of secure communication channels attempt to minimize the risk of having data intercepted by an unscrupulous entity, but can never completely eliminate it.  
         [0005]     Additionally, ISO-compliant contactless smart cards adhering to the ISO 14443A, 14443B, and 15693 specifications currently utilize a static unique User ID (UID) that can be read without the use of any security mechanisms. Even though the UID is randomly assigned to a user when the card is issued, there exists the possibility of associating this UID with a particular individual. Once this association is made, then this individual can be surreptitiously tracked by his/her UID using RFID technologies.  
         [0006]     Further complicating the situation, there are proposals to integrate RFID devices into banknotes, credit cards, debit cards, store loyalty cards and other high-value objects in an attempt to prevent fraud. The thought is that a person carrying an object with all of the authentication information must be the true object owner. As more and more objects are equipped with these RFID devices, the chances of having one&#39;s personal information stolen from them increases. High-value objects integrated with RFID devices typically carry extremely sensitive information (e.g. social security numbers, addresses, bank account numbers, ATM pin codes, names, etc.) If this type of information is stolen, the entire identity of the object holder may be compromised. This poses a very serious threat to the general population carrying objects equipped with an RFID device.  
         [0007]     There have been some attempts to mitigate the risks of having ones information stolen from their RFID device. For example, in GB Patent Application No. 2,410,151 to RF Tags Ltd., which is herein incorporated by this reference in its entirety, an RFID device is described that includes an electronic identification circuit coupled to an antenna. The RFID device further includes a photodiode or the like that ensures that the data from the RFID device can only be read when the RFID device is exposed to ambient light. This prevents data from being read from the RFID device when the tag is in a person&#39;s pocket, for example. The assumption is that the person only wants to have the data read when the RFID device is out of the person&#39;s pocket. A drawback to the proposed solution is that the person may have their RFID device out of their pocket and still may not want to have the data read. For example, the person may be carrying the RFID device in a purse that inadvertently exposes the RFID device to light, thereby allowing the data to be potentially read by an unauthorized entity. Essentially the data from the RFID device may be stolen any time the tag is exposed to light. Just because the RFID device is exposed to light does not mean that the holder of the RFID device wishes to have that data read.  
         [0008]     Additionally, a person may be carrying an object that has several applications loaded on it. The person may present that object to a first reader only wanting it to have information related to the first reader accessed (e.g., the first application information). Unfortunately, once exposed to any type of light, the data related to other applications is exposed to potential data harvesters.  
         [0009]     Another drawback to such a solution is that it relies primarily on ambient light to power components of the credential. Thus, the credential may not work unless an adequate amount of light energy is available to the credential. Therefore, the credential would be rendered useless at night and in other dark situations where an illumination source is not present near the reader.  
       SUMMARY  
       [0010]     The present invention is generally directed toward a method, apparatus, and system that utilizes a photon authenticated RFID transponder to substantially prohibit illicit data harvesting. As can be appreciated, an RFID device can be implemented as a part of an ID/access card, smart card, RF tag, cellular phone, Personal Digital Assistant (PDA), and the like.  
         [0011]     In accordance with one embodiment of the present invention, a system is provided that substantially prevents the illegitimate harvesting of data from an RFID device. The data may have degrees of sensitivity. For example, highly sensitive data may include, but is not limited to, bank account numbers, social security numbers, PIN codes, passwords, keys, RFID unique ID, encryption schemes, etc. Less sensitive data may include, but is not limited to, user name, manufacturer ID, job title, and so on. Specifically, the system includes an authorized RFID reader that has a photon source and an RFID device that has a photon receiver. Light is emitted from the RFID device reader to the RFID device. The light received from the RFID device reader typically enables the RFID device. This ensures that the RFID device is only enabled when it is presented to a reader associated with an enabling photon source.  
         [0012]     A photon is a quantum of light, or the smallest possible packet of light at a given wavelength. Photons travel at the speed of light and have mass and momentum dependent upon their frequencies. Thus, light, regardless of its wavelength, comprises photons. Accordingly, “photons” and “light” are used interchangeably herein, as can be appreciated by one of skill in the art. Enabling light can be emitted at various wavelengths including, black light and ultraviolet light (e.g., 10 nm≦λ≦400 nm), visible light (e.g., 400 nm≦λ≦700 nm), infrared light (e.g., 700 mn≦λ≦0.01 cm).  
         [0013]     In further embodiments of the present invention, the RFID device reader may encode the light emitted by its photon source. The encoded light is then received by the RFID device and decoded. Thereafter the RFID device can verify the authenticity of the RFID device reader before it allows data to be read from the RFID device reader. Again, this eliminates the possibility of the RFID device having data read from a potentially unauthorized reader. By having the RFID device verify the authenticity of the reader, the RFID device can be assured that a credible reader is reading its data.  
         [0014]     In accordance with embodiments of the present invention, a method is provided that enables an RFID device to have its data read only when it receives proper photon radiation. The method includes receiving a photon signal at a photon receiver, processing the received signal to determine if the source of the photon signal is authorized to read data from the RFID device. If the source of the photon signal is determined to be authorized, the RFID device sends a signal back to the photon signal source, to initiate an authorization process. If the RFID device cannot determine that the source of the photon signal is authorized to receive data from the tag, then the RFID device does not allow its data to be read.  
         [0015]     This method ensures that only authorized readers have access to the data stored on the RFID device. The presence of any type of light does not simply enable the RFID device. Instead, the RFID device is enabled only when presented with an enabling type of radiation. Enabling radiation may, for example, be dependent upon the characteristics of the radiation (e.g., wavelength, frequency, intensity, etc.), source of radiation, data contained within the radiation, or combinations thereof.  
         [0016]     In accordance with further embodiments of the present invention, an RFID device having a photon-receiving unit is provided. The RFID device is characterized in that it does not freely emit data stored in its memory. The RFID device also has a photon authentication function stored in its memory. The RFID device receives a photon signal at the photon-receiving unit. The signal is sent to a controller of the RFID device. The controller uses the photon authentication function stored on the memory of the RFID device and verifies the identity of the source of the photon signal before it allows anything to read its data.  
         [0017]     In accordance with embodiments of the present invention, the photon authentication function may include a lookup table of authorized readers and the identity of the reader may be sent to the RFID device through the photon signal. The controller may compare the identity of the source of the photon signal with a list of authorized readers in the lookup table to determine if the source of the photon signal is authorized to read data from the RFID device. The photon authentication function may also include a photon analyzer that determines characteristics of the radiation that was received and if those characteristics correspond to valid radiation characteristics. If the characteristics are valid and/or the reader is listed in the lookup table, then it can be assumed that the source of the radiation is an authorized source and the RFID device will allow the source of radiation to read data from its memory.  
         [0018]     In accordance with one embodiment, an RF field generated by a reader generally powers a passive RFID device. Accordingly, a reader may continuously emit an RF field but the RFID device does not transmit data using RF until the photon authentication process is complete. For active RFID devices (i.e., those with a power source), the RFID device may not have to be powered by an external RF field. Thus, the active device may use RF or light to “wake up”, still photon authentication should occur before any data is transmitted between the RFID device and the reader.  
         [0019]     By requiring a photon authentication, known attacks such as the man-in-the-middle attack can be mitigated. This is because photon authentication generally requires a line of sight between a reader and RFID device. Since the man-in-the-middle attack generally relies on the actual RFID device not being within proximity of the reader, the RFID device will not release any useful information to the man-in-the-middle.  
         [0020]     These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a diagram depicting an exemplary system for authenticating RFID devices with authorized readers in accordance with embodiments of the present invention;  
         [0022]      FIG. 2  is a block diagram depicting an exemplary RFID device reader in accordance with embodiments of the present invention;  
         [0023]      FIG. 3  is a block diagram depicting an exemplary RFID device in accordance with embodiments of the present invention;  
         [0024]      FIG. 4  is a flow chart depicting a method initiating an authentication routine from the perspective of a reader in accordance with embodiments of the present invention; and  
         [0025]      FIG. 5  is a flow chart depicting a method of authorizing data to be read from an RFID in accordance with embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0026]     The present invention generally is a radio frequency identification (RFID) device, method, and system for authenticating RFID devices, such as ID/access cards, smart cards, RF tags, and the like. The invention advantageously addresses deficiencies of the prior art and may be utilized within the context of security systems, as well as be equally efficiently utilized in a broad range of other applications using interactive computerized data acquisition techniques, both contactless or requiring a physical contact with a carrier of pre-programmed information (e.g., monitoring moving objects, tracking inventory, verifying credit cards, and the like).  
         [0027]      FIG. 1  depicts an access network  100  used to verify the identity of at least one RFID device. In one embodiment of the present invention, the system  100  comprises a control panel  104 , a hub  108 , a plurality of readers  112   1−n , and a plurality of RFID devices  116   1−k  such that n and k are integers wherein n≧1, k≧1, and typically k is greater than n. The plurality of readers  112   1−n  may include readers  112  of the same type, as well as readers of different types. For example, a subset of the plurality of readers  112   1−n  may be legacy readers (e.g. readers using older transmission protocols). Whereas another subset of the plurality of readers  112   1−n  may be new readers utilizing more secure protocols including the protocols described herein. In the depicted embodiment, the readers  112  are coupled to the control panel  104  via the interconnecting hub  108  through interfaces  120  and  124 . In an alternate embodiment (not shown), the readers  112  may be directly coupled to the respective inputs/outputs of the control panel  104 . Interfaces  120  and  124  between the readers  112 , the hub  108 , and the control panel  104  are generally bi-directional interfaces, which may selectively be implemented in a form of wired, wireless, fiber-optic communication links, or combinations thereof. Even though the interfaces  120  and  124  are depicted as bi-directional interfaces, one skilled in the art can appreciate that the interfaces  120  and  124  may be implemented with unidirectional interfaces that use a unidirectional communication protocol, for example, the Wiegand protocol.  
         [0028]     As can be appreciated by one of skill in the art, the interfaces  120  and  124  may be implemented utilizing buses or other types of connections. For example, the I/O ports may be one or more of a USB port, parallel port, serial port, Small Computer Systems Interface (SCSI) port, modem, Ethernet, and/or an RF interface. The protocols used to communicate between the control panel  104  and the readers  112  may include one or more of the TCP/IP protocol, RS 232, RS 485, Current Loop, Power of Ethernet (POE), Bluetooth, Zigbee, GSM, WiFi, and other communication methods and protocols known in the art.  
         [0029]     Interface  128  represents the communication interface that exists between a reader and an RFID device  116 . Interface  128  may represent an RF communication interface and/or a photon communication interface. As will be described in detail below, generally an RFID device  116  may not establish, and/or transmit any data across, the interface  128  if it cannot verify the authenticity of the reader  112  that is attempting to communicate with it.  
         [0030]     The control panel  104  may be a general-purpose computer adapted for multi-task data processing and suitable for use in a commercial setting. Alternatively, the control panel  104  may be implemented with a host computer and readers  112  can be connected to the host computer via a TCP/IP connection or other type of network connection. A memory of the control panel  104  comprises software program(s) containing a database of records for the system  100 . Alternatively, a database  132  may be separated from the control panel  104  as depicted in  FIG. 1 . The database  132  whether integral to the control panel  104 , separate from the control panel  104 , or both, maintains records associated with the readers  112 , RFID devices  116  and their respective holders or users, algorithm(s) for acquiring, decoding, verifying, and modifying data contained in the readers  112 , algorithm(s) for testing authenticity and validity of the RFID devices  116 , and algorithm(s) for implementing actions based on the results of these tests. Specific configurations of the control panel  104  are determined based on and compliant with computing and interfacing capabilities of the readers  112  and/or the hub  108 .  
         [0031]     As used herein, in reference to an individual or an object associated with an RFID device  116 , the terms a “holder” and a “user” are used interchangeably.  
         [0032]     Referring now to  FIG. 2 , an exemplary reader  112  will be described in accordance with embodiments of the present invention. The reader  112  comprises a controller  204 , an RF send/receive unit  208  including an RF antenna  212  and an RF Modulation/Demodulation Unit (MDU)  216 , a memory  220 , an input/output (I/O) Unit  224  to communicate with the control panel  104  via interface  124  (either directly or through the hub  108 ) and other external devices such as locks, door stripes, door monitor sensors, egress push buttons. The reader  112  may further comprise a photon source  228 , and a power supply  232 . Typically, a reader  112  is associated with a particular asset (i.e., a door protecting access to a secure room, a computer lock protecting sensitive information or computer files, a lock on a safe, a bank account, a credit card, and the like). In one embodiment, upon verification of credential information stored on the RFID device  116 , the reader  112  generates signals facilitating execution of the results of interrogating the RFID device  116  (e.g., engages/disengages a locking mechanism, allows/disallows movement of a monitored article, temporarily disables itself, activates an alarm system, provides access to a computer system, provides access to a particular document, authorize a purchase/withdrawal, and the like). If the credential information is not verified by the reader  112  or is determined to be fraudulent, nothing may happen, the RFID device may be rejected, and/or alarms may be triggered alerting security personnel. Alternatively, the control panel  104  may generate such signals.  
         [0033]     The controller  204  (e.g., microprocessor, application specific integrated circuit (ASIC), or the like) uses bi-directional interfaces to communicate with the MDU  216 , the memory  220 , the I/O Unit  224 , and/or the photon source  228 . In an alternate embodiment (not shown), portions of the MDU  216  may be incorporated in the controller  204 .  
         [0034]     The memory  220  generally comprises software routines facilitating, in operation, pre-determined functionality of the reader  112 . The memory  220  may be implemented using various types of electronic memory generally including at least one array of non-volatile memory cells (e.g., Erasable Programmable Read Only Memory (EPROM) cells or FLASH memory cells, etc.) The memory  220  may also include at least one array of dynamic random access memory (DRAM) cells. The content of the DRAM cells may be pre-programmed and write-protected thereafter, whereas other portions of the memory may selectively be modified or erased. Furthermore, the memory may comprise magnetic and/or optical memory in place of, or in combination with, the electronic memory described above. Typical types of magnetic and/or optical memory include, a hard drive, optical drive, tape drive, floppy disk, and the like.  
         [0035]     In addition to being RFID readers (e.g. readers that verify authenticity of the RFID devices) the readers  112  may have additional functionality. The readers  112  may include a keypad or other user input devices for receipt of additional user known passwords, contact card identification devices, and biometric authentication devices including voice recognition, retina scanners, finger print analyzers, facial feature analyzers, and the like.  
         [0036]     In one embodiment of the present invention, a reader  112  continuously creates an RF field with the RF Antenna  212 . In another embodiment, the RF field may be run through a duty cycle in an attempt to conserve energy. When an RFID device  116  is presented to the reader  112  (e.g., placed within the active zone of the reader  112 ), the controller  204  will detect an increase in power consumption by the RFID device  116 . The controller  204 , in response to detecting the presence of an RFID device  116 , sends a signal to the photon source  228  thereby enabling the photon source  228  to transmit a light message. The light message transmitted by the photon source  228  may have data encoded thereon or may simply be light from one or several parts of the electromagnetic spectrum (e.g., visible light, infrared light, black light, and/or ultraviolet light). The purpose of emitting light from the photon source  228  is so that the RFID device  116  can verify the authenticity of the reader  112  without engaging in RF communications. As can be appreciated, the photon source  228  may also act as a photon receiver if light communications between the reader  112  and the RFID device  116  is desired. The photon source  228  may include one or more photodiodes, light emitting diodes, laser diodes, phototransistors, photocells, modulators/demodulators, multiplexers, organic LEDs, incandescent lights, or any other type of light emitting/receiving devices. For example, in two Intel papers entitled “Introducing Intel&#39;s Advances in Silicon Photonics” published in February 2004 and “Continuous Silicon Laser White Paper” published in February 2005, each of which are herein incorporated by this reference, various silicon devices are discussed that can modulate data onto a continuous laser. Data may also be encoded on a light signal by pulsing the light signal in a determined fashion.  
         [0037]     In accordance with another embodiment of the present invention, rather than waiting until an RFID device  116  is detected to transmit a photon signal, the reader  112  may periodically transmit photon signals from the photon source  228 . Therefore, the reader  112  does not have to continuously transmit an RF signal. By periodically transmitting a photon signal, the reader  112  would only have to wait until it receives an RF signal from an RFID device  116  that received and verified the periodically transmitted photon signal. This may save on power consumption at the reader  112  if doing so requires less power from the power source  232  (e.g. battery, AC/DC converter, or the like) to intermittently send a photon signal rather than continuously sending an RF signal.  
         [0038]     Once RF communications have been initiated, the controller  204  determines what type of credential data is necessary to allow the holder of the RFID device  116  to access the asset that the reader  112  is associated with. The controller  204  makes the determination by accessing the memory  220  where information about the asset and required credentials are stored. The controller  204  then sends a signal to the MDU  216  where the signal is modulated (e.g., by frequency, amplitude, pulse-width, phase, etc.) onto a carrier signal. The modulated signal is then sent to the RF Antenna  212  to be emitted to the RFID device  116  via interface  128 .  
         [0039]     In accordance with embodiments of the present invention, during the RF receiving mode, the RF Antenna  212  receives an RF signal. The signal is then sent to the MDU  216  where it is demodulated and forwarded to the controller  204 . The controller  204  checks the data from the signal against data in the memory  220  to verify the authenticity of the RFID device  116  or sends the signal to the control panel  104  for verification of the same. The controller  204  may generate additional messages to be sent, via an RF signal and/or a photon signal, if it wishes to determine more information about the RFID device  116 . However, if the controller  204  has properly verified (in the event that the control panel  104  did not perform the verification) the authenticity of the RFID device  116 , then a signal is sent to the I/O Unit  224 . The I/O Unit  224  then sends the signal to the control panel  104  to perform a task associated with verifying the authenticity of the RFID device  116 . Alternatively, the reader  112  may facilitate execution of the results directly rather than forwarding these signals on to the control panel  104 .  
         [0040]     In accordance with further embodiments of the present invention, the photon source  228  may be separated from the reader  112 . For example, a reader  112  may use a photon source  228  to generate a photon signal, however, the photon source  228  is not integral to the reader  112 . The photon source  228  and reader  112  may be in wired or wireless communication with each other. By having the photon source  228  separated from the reader  112 , the photon source  228  may be used by more than one reader  112 . The photon source  228  may be a stand-alone device, or may be implemented as a part of another device. Specifically, one reader among a set of readers may comprise a photon source  228 . All of the readers among the set of readers not equipped with a photon source  228  may use the photon source  228  of the one reader among them with a photon source  228  in order to generate a photon signal.  
         [0041]     A stand-alone reader  112  may be utilized to perform the functionality of both the reader  112  and the control panel  104 . This stand-alone reader may include, or have access to, the database that contains data used to determine the authenticity of an RFID device  116  and/or algorithm(s) used to make the determination of authenticity of the RFID device  116 . A determination of authenticity for an RFID device  116  is made at the receiving point rather than having to transmit data across a network from the reader  112  to a control panel  104  in order to make a determination of authenticity. The stand-alone reader is further operable to execute instructions based upon the analysis of the RFID device  116 .  
         [0042]     Referring now to  FIG. 3  and exemplary RFID device  116  will be described in accordance with embodiments of the present invention. In the depicted embodiment, the RFID device  116  includes a controller  304 , an RF send/receive unit  308  comprising an RF Antenna  312  and an MDU  316 , a memory  320 , an RF rectifier  324 , and a light receiver  328 . The RFID device  116  may also include an optional power source  330  if the RFID device requires more power than can be obtained from the RF rectifier  324 .  
         [0043]     The RF signals generated by the reader  112  inherently contain electromagnetic energy. The signals can be sent to the optional RF rectifier  324  and the energy from those signals can be converted into energy to run various components of the RFID device  116 . An optional power source  224  is also available to supply power to any other component of the RFID device  116  depicted or not depicted. Additionally, energy from the light receiver  328  may be rectified and used to power the RFID device. Various schemes used to provide power to the RFID device  116  are further described in the GB Patent Application No. 2,410,151, which is herein incorporated by reference.  
         [0044]     The controller  304  of the RFID device generally includes (e.g., a microprocessor, application specific integrated circuit (ASIC), or the like) using bi-directional interfaces to communicate with the MDIJ  316 , the memory  320 , and/or the photon receiver  328 . In an alternate embodiment (not shown), portions of the MDU  216  may be incorporated in the controller  204 .  
         [0045]     The memory  220  generally comprises software routines facilitating, in operation, pre-determined functionality of the RFID device  116 . The memory  320  of the RFID device  116  generally comprises at least one array of non-volatile memory cells, e.g., Erasable Programmable Read Only Memory (EPROM) cells or Flash Memory Cells, among other types of non-volatile memory cells. The memory  320  may also comprise at least one array of dynamic random access memory (DRAM) cells, in the event that the RFID device  116  includes an optional power source. Therefore a content of at least a portion of the memory  320  may be pre-programmed and write protected thereafter, whereas the content of other portions of the memory  320  may be selectively modified and/or erased by the reader  112 .  
         [0046]     The RFID device  116 , according to embodiments of the present invention, is used as an identification device. The RFID  116  can be implemented as a part of an ID/access card, smart card, RF tag, cellular phone, PDA, and the like. Identification information is preferably loaded into a secure area of the memory  320  where it can be accessed by controller  304  to communicate to readers  112  via interface  128  only after an enabling photon signal has been verified. Information or data loaded on the memory  320  may include credential information of the user of the RFID device  116 , for instance, unique IDs, manufacture IDs, passwords, keys, encryption schemes, transmission protocols, and the like. Additionally, the memory  320  may contain executable functions that are used by the controller  304  to run other components of the RFID device  116 . An example of such an executable function would be a photon authentication function  332 . Of course, the photon authentication function  332  may reside wholly or in part in the controller  304 . To determine if photons received at the photon receiver  328  correspond to an authorized source, the controller  304  may execute the photon authentication function  332 .  
         [0047]     Accessing a lookup table (not shown) in the memory  320  may help the controller  304  to make a verification of authenticity for a given source of light. Alternatively, mathematical/cryptographic authentication techniques may be employed. Further in the alternative, the light may be transmitted for a predetermined amount of time and when the RFID device receives the light for the predetermined amount of time (within a certain threshold of nano-seconds for example), then verification of authenticity for the source of light can be completed.  
         [0048]     In operation, the data contents of the memory  320  are secured and are not transmitted to any other object until enabling light is received at the photon receiver  328 . Specifically, all kinds of data may be maintained in a secured state in memory  320 . Sensitive data may be a part of the data maintained in a secure state in the memory  320 . Highly sensitive data may include, but is not limited to, bank account numbers, social security numbers, PIN codes, passwords, access codes, keys, RFID unique ID, encryption schemes, etc. Less sensitive data may include, but is not limited to, user name, manufacturer ID, job title, and so on. Even non-sensitive data may be maintained in a secured state in memory  320 . Non-sensitive data may include the time of day, type of RFID device, and the like. The photon receiver  328  may also act as a photon transmitter and devices incorporated in the photon receiver  328  may include those noted above in relation to the photon source  228  of the reader  112 . The photon receiver  328  receives a light signal and forwards the signal&#39;s contents to the controller  304 . The controller  304  accesses the photon authentication function  332  in the memory  320  to determine if the source of the light signal is a “trusted” source (e.g., can be verified as authentic based on information in the memory  320 ). Assuming the controller  304  determines that the source of the light is a trusted source, for instance an authorized reader, the controller  304  generates a signal (e.g., RF signal or light signal) to be transmitted.  
         [0049]     The transmitted signal may be transmitted back to the now trusted reader  112  or a reader  112  associated with the photon source  228 . The signal indicates that the RFID device  116  is ready to allow the reader access to the contents of the memory  320 . The transmitted signal may also be transmitted such that any reader  112  within proximity of the RFID device  116  is able to receive the signal.  
         [0050]     In an alternative embodiment, the RFID device  116  may generate light to begin the authentication process with the reader  112 . Then only after the reader  112  has determined that the RFID device  116  is authentic through a photon authentication algorithm, RF signals may be transmitted between the devices.  
         [0051]     In an RF receiving mode, an RF signal is received at the RF antenna  312  and forwarded to the MDU  316 . The MDU  316  demodulates the signal and sends it to the controller  304 . Thereafter, the controller  304  processes the contents of the signal and determines what information from memory  320  should be sent back to the reader  112 . The controller  304  generates a signal including contents from the memory  320  that will allow the reader  112  to verify the identity of the RFID device  116  and potentially the holder of the RFID device  116 . That signal is forwarded to the MDU  316 , where it is modulated according to various methods noted above. The modulated signal is passed on to the RF antenna  312  where it is transmitted to the reader  112  via interface  128 . As can be appreciated, the signal may be transmitted to the reader  112  via a light signal instead of, or in combination with, sending the RF signal.  
         [0052]     In accordance with embodiments of the present invention, the memory  320  may further comprise credential data and authenticating functions. Examples of credential data include, but are not limited to, assets the RFID device  116  has access to, times of allowed access to each asset, and other data that can help the RFID device  116  determine if it is eligible to gain access to a particular asset. The authenticating functions use the credential data to enable the RFID device  116  to make a determination of its own access rights with respect to an asset.  
         [0053]     An RFID device  116  that determines its own access rights and permissions is typically referred to as a smart card. In operation, a “smart” RFID device  116  is presented to a reader  112 . The reader  112  is associated with one or more assets and the reader  112  is the gatekeeper of those assets. The reader  112  contains information about its associated assets and usually time of day information. Upon presentation of the RFID device  116  to the reader  112 , the reader  112  supplies the asset information and time of day information to the RFID device  116 . The RFID device  116  then analyzes the asset information and time of day information using its credential data. The RFID device  116  then makes a determination whether it is allowed to access the given asset (e.g., whether the holder of the RFID device  116  can have access to a room behind a door, a bank account, computer files, etc.) If the RFID device  116  determines that it is allowed access to the particular asset, then it sends a signal back to the reader  112  indicating that validation of the RFID device  116  has been confirmed and access should be granted. Upon confirmation of validation of the RFID device  116 , the reader  112  will unlock the door, access the bank account, permit access to the computer files, or perform the requisite steps to grant access to the holder of the RFID device  116 . If the RFID device  116  determines that it is not allowed access to the particular asset, then it can either do nothing or send a signal back to the reader  112  indicating that validation of the RFID device  116  was not confirmed and access should not be granted. Upon the receipt of this signal, the reader  112  may perform no action, generate a message indicating that access was not granted, sound an alarm, or perform some other sort of action in accordance with denying the holder of the RFID device  116  access to the asset.  
         [0054]     Referring now to  FIG. 4 , a method for sending a light signal to an RFID device  116  in order to gain access to information contained on the RFID device  116  will be described in accordance with embodiments of the present invention. In the depicted embodiment, the method starts by detecting an increase in power consumption at, for example, a reader  112 . Typically, in order for a reader  112  to detect an increase in power consumption, the reader  112  must be continuously emitting an RF signal. Alternatively, the signal may be produced according to a predetermined duty cycle.  
         [0055]     When an RFID device  116  is placed into an active zone of the reader  112 , the reader  112  will be able to detect the increase in power consumption. The reader  112  then emits a message utilizing a photon source  228  whether integral to or separate from the reader  112  (step  408 ). The message may simply be a beam of light emitted at a particular wavelength. However, the message may also be encoded with additional data relating to the identity and access rights of the reader  112 . As can be appreciated, an encoded signal may simply be sent as a series of pulses of light from the photon source  228 , where the pulses correspond to some type of known code. Alternatively, a continuous photon signal may be encoded with data relating to the identity of the reader  112  using, for example, a silicon modulator as noted above.  
         [0056]     In order to facilitate easy reception of the light signal, a platform may be provided in the area where the light signal is being emitted. A holder of the RFID device  116  can then place the RFID device  116  on the platform in order to ensure that the card is placed within the light signal path. Alternatively, the light may be emitted divergently such that an RFID device  116  may receive the light signal anywhere within the active zone of the reader  112  and a holder of the RFID device  116  only needs to position the RFID device  116  somewhere close to the reader  112 . In a preferred embodiment, a line of sight is needed between the RFID device  116  and reader  112 .  
         [0057]     Once the light message has been sent, the reader  112  waits for a response from the RFID device  116  (step  412 ). In step  416 , it is determined if the reader  112  has received a return “OK” signal from the RFID device  116 . Typically the return “OK” will be in the form of an RF signal, but may also be implemented as a light signal. The OK signal is generally an authenticated message from the RFID device  116  to the reader  112 . If the reader  112  has not received a return “OK” signal from the RFID device  116 , then the method returns to step  412  to wait for a response. The reader  112  may also receive a message from the RFID device  116  indicating that the RFID device  116  is processing the data and the reader  112  must stand by. Additionally, the reader  112  may receive a signal from the RFID device  116  indicating that the reader  112  does not have the authority to read information from the memory of RFID device  116 . If this is the case then the method returns to step  412  to wait for a different response or the process may end. If the reader  112  does receive the return “OK” signal from the RFID device  116 , then the reader  112  sends an RF signal to the RFID device requesting data from the RFID device  116  (step  420 ). As noted above, the signal requesting data from the RFID device  116  may also be sent via a light signal from the photon source  228 .  
         [0058]     Once the reader  112  has sent the signal to the RFID device  116  requesting data, the reader  112  waits for a response from the RFID device  116  (step  424 ). In step  428 , it is determined if the reader has received a return signal from the RFID device  116 . Typically, assuming that the reader  112  and RFID device  116  are both valid and following the proper protocol, a return signal will contain the data that was requested by the reader  112 . If the reader  112  does not receive this return signal in step  428 , it returns to step  424  to wait for that signal. However, if the reader  112  does receive the return signal, then the reader  112  begins to verify the authenticity of the RFID device  116  by processing the data from the signal (step  432 ). In step  436 , it is determined if the RFID device  116  is valid. If the RFID device  116  is not valid then the process end at step  444 . However, if the RFID device  116  is determined to be valid, then the reader  112  and/or the control panel  104  allows access to the asset that the reader  112  is associated with (step  440 ). Once access has been allowed to the asset the method ends in step  444 .  
         [0059]     Referring now to  FIG. 5 , a method for validating a source of a light signal will be described in accordance with embodiments of the present invention. Initially, the RFID device  116  receives a light signal at the photon receiver  328  (step  504 ). As noted above, the signal may be encoded with data. In step  508 , it is determined if the signal was encoded. If the signal was encoded, then the signal is decoded in step  512 . The decoding can be done at the controller  304  or at the photon receiver  328 .  
         [0060]     Once the encoded signal has been decoded, the method proceeds to step  516 . If the signal was not encoded, then the method bypasses step  512  and proceeds directly to step  516 . In step  516 , it is determined if the signal&#39;s source is authorized to receive secured data from the memory  320  of the RFID device  116 . As noted above, the controller  304  utilizing the photon authentication function  332  is enabled to make this determination. A signal&#39;s source may be determined valid if it is simply emitting the proper wavelength of light. In a more secure system, the RFID device  116  may require more data from the source, for example its identity, authorization codes, passwords, and the like. If the RFID device  116  cannot authorize the signal&#39;s source then there will be no signal sent by the RFID device  116  (step  520 ). Step  520  may alternatively include sending a message to the signal&#39;s source informing it that source is not authorized to read data from the RFID device  116 . However, if the signal&#39;s source (or a reader  112  associated with the source) is authorized to read data from the RFID device  116 , then an RF signal is generated and emitted from the RFID device  116  (step  524 ). The RFID device  116  may also send a light signal via the photon receiver  328 , which may be adapted to send and receive light signals.  
         [0061]     Once the signal has been sent, the RFID device  116  waits for a response from a reader  112  (step  532 ). In step  532 , it is determined if the RFID device  116  has received the signal requesting data from the RFID device  116 . Typically, the signal requesting data will be sent via an RF signal. If the RFID device  116  has not yet received the signal from the authorized source, then it continues to wait at step  528 . When the RFID device  116  finally receives the signal from the authorized source requesting data, the controller  304  will access the necessary parts of the memory  320  and retrieve data corresponding to the authorized source&#39;s requests. The controller  304  will generate a message containing the retrieved data and transmit it (e.g., send it to the signal&#39;s source) in step  536 . Then when all of the authentication information has been sent that is required, the method ends at step  540 .  
         [0062]     As a default, all of the data stored in the memory  320  is maintained in a secure state until a light signal has been received, and the identity of the source of that light signal (or a device associated with the source of the light signal) has been verified. In an alternative configuration, any reader  112  may freely access selected portions of the memory, whereas more sensitive information (e.g., passwords, keys, social security numbers, etc.) may be maintained in a secure state. Additionally, based on the access authorization, one reader may be allowed access to one subset of the data stored in the memory  320 , and another reader may be allowed access to a different subset of the data stored in the memory  320 . The RFID device  116  can make a determination of how much data a given reader  112  is allowed to read. The determination can be based solely on the identity of the reader  112 , or may simply be based upon the type of light that the reader  112  transmits.  
         [0063]     In accordance with one embodiment of the present invention, various photon authentication techniques may be employed in a device that is separate from a credential or RFID device  116 . For example, the photon authentication mechanism may reside on an electronic holder of RFID devices  116 . The RFID device  116  may be inserted to the holder and the holder can restrict transmission of data on the RFID device  116  based on results of photon authentication.  
         [0064]     The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation.  
         [0065]     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.  
         [0066]     Moreover though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.