Patent Application
20080001725
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.
Methods, systems, and apparatuses for preventing unwanted read access to data stored in tags are described. The present specification discloses one or more embodiments that incorporate the features of the invention. The disclosed embodiment(s) merely exemplify the invention. The scope of the invention is not limited to the disclosed embodiment(s). The invention is defined by the claims appended hereto.
References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
Furthermore, it should be understood that spatial descriptions (e.g., “above,” “below,” “up,” “left,” “right,” “down,” “top,” “bottom,” “vertical,” “horizontal,” etc.) used herein are for purposes of illustration only, and that practical implementations of the structures described herein can be spatially arranged in any orientation or manner. Likewise, particular bit values of “0” or “1” (and representative voltage values) are used in illustrative examples provided herein to represent data for purposes of illustration only. Data described herein can be represented by either bit value (and by alternative voltage values), and embodiments described herein can be configured to operate on either bit value (and any representative voltage value), as would be understood by persons skilled in the relevant art(s).
Before describing embodiments of the present invention in detail, it is helpful to describe an example RFID communications environment in which the invention may be implemented.
Environment 100 includes any number of one or more readers 104. For example, environment 100 includes a first reader 104a and a second reader 104b. Readers 104a and/or 104b may be requested by an external application to address the population of tags 120. Alternatively, reader 104a and/or reader 104b may have internal logic that initiates communication, or may have a trigger mechanism that an operator of a reader 104 uses to initiate communication. Readers 104a and 104b may also communicate with each other in a reader network.
As shown in
Various types of tags 102 may be present in tag population 120 that transmit one or more response signals 112 to an interrogating reader 104, including by alternatively reflecting and absorbing portions of signal 110 according to a time-based pattern or frequency. This technique for alternatively absorbing and reflecting signal 110 is referred to herein as backscatter modulation. Readers 104a and 104b receive and obtain data from response signals 112, such as an identification number of the responding tag 102. In the embodiments described herein, a reader may be capable of communicating with tags 102 according to any suitable communication protocol, including Class 0, Class 1, EPC Gen 2, other binary traversal protocols and slotted aloha protocols, any other protocols mentioned elsewhere herein, and future communication protocols.
Baseband processor 212 and network interface 216 are optionally present in reader 104. Baseband processor 212 may be present in reader 104, or may be located remote from reader 104. For example, in an embodiment, network interface 216 may be present in reader 104, to communicate between transceiver portion 220 and a remote server that includes baseband processor 212. When baseband processor 212 is present in reader 104, network interface 216 may be optionally present to communicate between baseband processor 212 and a remote server. In another embodiment, network interface 216 is not present in reader 104.
In an embodiment, reader 104 includes network interface 216 to interface reader 104 with a communications network 218. As shown in
Reader 104 has at least one antenna 202 for communicating with tags 102 and/or other readers 104. Antenna(s) 202 may be any type of reader antenna known to persons skilled in the relevant art(s), including a vertical, dipole, loop, Yagi-Uda, slot, or patch antenna type. For description of an example antenna suitable for reader 104, refer to U.S. Ser. No. 11/265,143, filed Nov. 3, 2005, titled “Low Return Loss Rugged RFID Antenna,” now pending, which is incorporated by reference herein in its entirety.
Transceiver 220 receives a tag response via antenna 202. Transceiver 220 outputs a decoded data signal 214 generated from the tag response. Network interface 216 is used to transmit decoded data signal 214 received from transceiver portion 220 (optionally through baseband processor 212) to a remote server coupled to communications network 218. Baseband processor 212 optionally processes the data of decoded data signal 214 prior to being sent over communications network 218.
In embodiments, network interface 216 enables a wired and/or wireless connection with communications network 218. For example, network interface 216 may enable a wireless local area network (WLAN) link (including a IEEE 802.11 WLAN standard link), a BLUETOOTH link, and/or other types of wireless communication links. Communications network 218 may be a local area network (LAN), a wide area network (WAN) (e.g., the Internet), and/or a personal area network (PAN).
In embodiments, a variety of mechanisms may be used to initiate an interrogation request by reader 104. For example, an interrogation request may be initiated by a remote computer system/server that communicates with reader 104 over communications network 218. Alternatively, reader 104 may include a finger-trigger mechanism, a keyboard, a graphical user interface (GUI), and/or a voice activated mechanism with which a user of reader 104 may interact to initiate an interrogation by reader 104.
In the example of
Modulator/encoder 208 receives interrogation request 210, and is coupled to an input of RF front-end 204. Modulator/encoder 208 encodes interrogation request 210 into a signal format, modulates the encoded signal, and outputs the modulated encoded interrogation signal to RF front-end 204. For example, pulse-interval encoding (PIE) may be used in a Gen 2 embodiment. Furthermore, double sideband amplitude shift keying (DSB-ASK), single sideband amplitude shift keying (SSB-ASK), or phase-reversal amplitude shift keying (PR-ASK) modulation schemes may be used in a Gen 2 embodiment. Note that in an embodiment, baseband processor 212 may alternatively perform the encoding function of modulator/encoder 208.
RF front-end 204 may include one or more antenna matching elements, amplifiers, filters, an echo-cancellation unit, a down-converter, and/or an up-converter. RF front-end 204 receives a modulated encoded interrogation signal from modulator/encoder 208, up-converts (if necessary) the interrogation signal, and transmits the interrogation signal to antenna 202 to be radiated. Furthermore, RF front-end 204 receives a tag response signal through antenna 202 and down-converts (if necessary) the response signal to a frequency range amenable to further signal processing.
Demodulator/decoder 206 is coupled to an output of RF front-end 204, receiving a modulated tag response signal from RF front-end 204. In an EPC Gen 2 protocol environment, for example, the received modulated tag response signal may have been modulated according to amplitude shift keying (ASK) or phase shift keying (PSK) modulation techniques. Demodulator/decoder 206 demodulates the tag response signal. For example, the tag response signal may include backscattered data formatted according to FM0 or Miller encoding formats in an EPC Gen 2 embodiment. Demodulator/decoder 206 outputs decoded data signal 214. Note that in an embodiment, baseband processor 212 may alternatively perform the decoding function of demodulator/decoder 206.
The configuration of transceiver 220 shown in
The present invention is applicable to any type of RFID tag.
IC 306 controls operation of tag 102, and transmits signals to, and receives signals from RFID readers using antenna 304. In the example embodiment of
Memory 308 is typically a non-volatile memory, but can alternatively be a volatile memory, such as a DRAM. Memory 308 stores data, including an identification number 318. Identification number 318 typically is a unique identifier (at least in a local environment) for tag 102. For instance, when tag 102 is interrogated by a reader (e.g., receives interrogation signal 110 shown in
Demodulator 314 is coupled to antenna 304 by antenna signal 328. Demodulator 314 demodulates a radio frequency communication signal (e.g., interrogation signal 110) on antenna signal 328 received from a reader by antenna 304. Control logic 310 receives demodulated data of the radio frequency communication signal from demodulator 314 on input signal 322. Control logic 310 controls the operation of RFID tag 102, based on internal logic, the information received from demodulator 314, and the contents of memory 308. For example, control logic 310 accesses memory 308 via a bus 320 to determine whether tag 102 is to transmit a logical “1” or a logical “0” (of identification number 318) in response to a reader interrogation. Control logic 310 outputs data to be transmitted to a reader (e.g., response signal 112) onto an output signal 324. Control logic 310 may include software, firmware, and/or hardware, or any combination thereof. For example, control logic 310 may include digital circuitry, such as logic gates, and may be configured as a state machine in an embodiment.
Modulator 316 is coupled to antenna 304 by antenna signal 328, and receives output signal 324 from control logic 310. Modulator 316 modulates data of output signal 324 (e.g., one or more bits of identification number 318) onto a radio frequency signal (e.g., a carrier signal transmitted by reader 104) received via antenna 304. The modulated radio frequency signal is response signal 112, which is received by reader 104. In an embodiment, modulator 316 includes a switch, such as a single pole, single throw (SPST) switch. The switch changes the return loss of antenna 304. The return loss may be changed in any of a variety of ways. For example, the RF voltage at antenna 304 when the switch is in an “on” state may be set lower than the RF voltage at antenna 304 when the switch is in an “off” state by a predetermined percentage (e.g., 30 percent). This may be accomplished by any of a variety of methods known to persons skilled in the relevant art(s).
Charge pump 312 is coupled to antenna 304 by antenna signal 328. Charge pump 312 receives a radio frequency communication signal (e.g., a carrier signal transmitted by reader 104) from antenna 304, and generates a direct current (DC) voltage level that is output on a tag power signal 326. Tag power signal 326 is used to power circuits of IC die 306, including control logic 320.
In an embodiment, charge pump 312 rectifies the radio frequency communication signal of antenna signal 328 to create a voltage level. Furthermore, charge pump 312 increases the created voltage level to a level sufficient to power circuits of IC die 306. Charge pump 312 may also include a regulator to stabilize the voltage of tag power signal 326. Charge pump 312 may be configured in any suitable way known to persons skilled in the relevant art(s). For description of an example charge pump applicable to tag 102, refer to U.S. Pat. No. 6,734,797, titled “Identification Tag Utilizing Charge Pumps for Voltage Supply Generation and Data Recovery,” which is incorporated by reference herein in its entirety. Alternative circuits for generating power in a tag are also applicable to embodiments of the present invention. Further description of charge pump 312 is provided below.
It will be recognized by persons skilled in the relevant art(s) that tag 102 may include any number of modulators, demodulators, charge pumps, and antennas. Tag 102 may additionally include further elements, including an impedance matching network and/or other circuitry. Embodiments of the present invention may be implemented in tag 102, and in other types of tags. Furthermore, although tag 102 is shown in
Memory 308 may have a variety of logical structures.
First memory bank 402 may be referred to as “reserved memory” or “memory bank 00.” Memory bank 402 stores kill and access passwords. The access password is a 32-bit value stored in memory addresses 20hex to 3Fhex. A default (unprogrammed) value for the access password is zero. Tags with a nonzero access password require a reader to issue the access password before transitioning to a secured state. A tag that does not implement an access password operates as though it had a zero-valued access password that is permanently read/write locked.
Second memory bank 404 may be referred to as “EPC memory” or “memory bank 01.”
Third memory bank 406 may be referred to as “TID memory” or “memory bank 10.” Memory bank 406 stores an 8-bit ISO/IEC 15963 allocation class identifier (111000102 for EPCglobal) at memory locations 00hex to 07hex. Memory bank 406 further includes sufficient identifying information above 07hex for a reader to uniquely identify the custom commands and/or optional features that a tag supports.
Fourth memory bank 408 may be referred to as “user memory” or “memory bank 11.” Memory bank 408 stores user-specific data. The organization of memory bank 408 is user-defined.
Further description of memory banks 402-408 in a Gen 2-type tag can be found in “EPC™ Radio-Frequency Identity Protocols, Class-1 Generation-2 UHF RFID, Protocol for Communications at 860 MHz-960 MHz,” Version 1.0.9, EPCglobal, Inc., copyright 2004, dated Jan. 1, 2005, pages 1-94 (see section 6.3.2.1, pages 35 and 36), which is incorporated by reference herein in its entirety.
Embodiments described herein are applicable to all forms of tags, including tag “inlays” and “labels.” A “tag inlay” or “inlay” is defined as an assembled RFID device that generally includes an integrated circuit chip (and/or other electronic circuit) and antenna formed on a substrate, and is configured to respond to interrogations. A “tag label” or “label” is generally defined as an inlay that has been attached to a pressure sensitive adhesive (PSA) construction, or has been laminated, and cut and stacked for application. A “tag” is generally defined as a tag inlay that has been attached to another surface, or between surfaces, such as paper, cardboard, etc., for attachment to an object to be tracked, such as an article of clothing, etc.
Example embodiments of the present invention are described in further detail below. Such embodiments may be implemented in the environments, readers, and tags described above, and/or in alternative environments and alternative RFID devices. For example, embodiments of the present invention may be implemented with regard to pharmaceutical, defense, border control (e.g., passports), and other applications.
The example embodiments described herein are provided for illustrative purposes, and are not limiting. The examples described herein may be adapted to any type of tag and reader. Further structural and operational embodiments, including modifications/alterations, will become apparent to persons skilled in the relevant art(s) from the teachings herein.
Methods, systems, and apparatuses for preventing unauthorized reading of identifying data stored in tags are described. Embodiments of the present invention may be implemented in a wide variety of types of tags, including Class 0, Class 1, and Gen 2type tags.
In an example embodiment, an RFID tag is configured to be singulated without reading a portion or all of the tag identifying information stored on the tag. The tag is “read locked” (temporarily or permanently), not allowing an identification of the tag to be made but still allowing a system to recognize that the tag is in the RF field. Thus, such an embodiment addresses privacy and security concerns in applications such as an EAS (Electronic Article Surveillance) application.
In an example Gen 2 embodiment, an RFID tag is rendered unreadable by receipt of a custom read lock command and a passcode, which read lock the tag. This “read lock” state of the tag may be permanent or temporary. For example, in a temporary read lock condition, subsequent receipt of the custom read lock command and passcode allows the tag to be read for identifying information. The tag transitions from the temporary read lock condition back to a readable state.
In an embodiment, a state machine of the tag is configured to implement the read lock functionality, which is initiated by receipt of the read lock command. Thus, the tag state machine may include a “read lock” state, for example. The command may include a bit sequence custom to the tag. This unique custom command (and passcode) is issued by a reader.
The tag is not killed during a read lock. Currently, an RFID system must kill a tag in order to render the unique identification number of the tag inoperable (unreadable), which also completely disables the tag. Thus, after being killed, the tag is no longer detectable. In contrast, the read lock feature allows the tag to be detected but not uniquely identified. Thus, in an embodiment, the read lock feature enables the unique identification number of a tag to be unreadable, while the presence of the tag can still be detected, such as by reading non-identification-related data of the tag.
In an embodiment, the tag may be singulated by the reader during read lock, but the tag does not transmit its identification number (e.g., EPC bits in a Gen 2 embodiment). By singulating the tag, but without obtaining the identification number of the tag, the reader merely determines that a tag is in the RF field of the reader, without being able to identify the tag (and the item with which the tag is associated). For example, this may prevent a rouge reader from being able to identify a tag, and therefore the item/object associated with the tag, thereby providing a measure of security.
For example,
Reader logic 602 may include hardware, software, firmware, or any combination thereof to perform its functions. Reader logic 602 may be configured to be triggered to perform this function by an operator of reader 600, by a computer system coupled to reader 600, and/or in other manners, including any of the ways described elsewhere herein.
Refer to “EPC™ Radio-Frequency Identity Protocols, Class-1 Generation-2 UHF RFID, Protocol for Communications at 860 MHz-960 MHz,” Version 1.0.9, EPCglobal, Inc., copyright 2004, dated Jan. 1, 2005, pages 1-94 (hereinafter “Gen 2 Specification”) (see section 6.3.2.4, pages 39-41), for description of example tag states for a Gen 2 embodiment for tag 700.
As shown in
As shown in
Non-identifying bit pattern 708 may be any bit pattern used by a tag to respond to a reader to indicate the presence of the tag, without identifying the tag. Non-identifying bit pattern 708 may be a permanent bit pattern or may be periodically changed (e.g., regenerated). For example, non-identifying bit pattern 708 may be generated by a random number generator of tag 700. In a Gen 2 embodiment, non-identifying bit pattern 708 may be the RN16 value transmitted by a tag in response to a Query or other type command. Thus, in an embodiment, non-identifying bit pattern 708 may be transmitted by tag 700 to indicate the present of tag 700 (i.e., to singulate tag 700), but does not uniquely identify tag 700.
Identifying bit pattern 710 may be any bit pattern used by a tag to uniquely identify the tag (and to identify the item/object with which the tag is associated) to an entity, such as a reader. For example, in a Gen 2 embodiment, identifying bit pattern 710 may be any suitable portion or all of the CRC code, the PC bits, and/or the EPC code stored in EPC memory (memory bank 404 shown in
Passcode 712 is a passcode for tag 700 used to enable read lock of tag 700. For example, as described above, tag read lock logic 706 is configured to process a received read lock command 604 and passcode 606 received from reader 600.
In an embodiment, tag 700 does not acknowledge to reader 600 that tag 700 successfully transitioned to read lock state, or that tag 700 did not transition to read lock state, such as if tag read lock logic 706 determined that passcode 606 did not match passcode 712. In another embodiment, tag 700 transmits a response signal 802 to reader 600. If tag 700 successfully transitioned to read lock state, response signal 802 may include any indication of this, including transmitting non-identifying bit pattern 708 (e.g., RN16 in a Gen 2 embodiment) and/or other non-identifying bit pattern (e.g, a “1” bit/bits to indicate success). If tag 700 did not successfully transitioned to read lock state, response signal 802 may include any indication of this, including transmitting non-identifying bit pattern 708 (e.g., RN16 in a Gen 2 embodiment) and/or other non-identifying bit pattern (e.g, a “0” bit/bits to indicate failure).
In an example Gen 2 embodiment, passcode 712 may be the 32-bit access password in reserved memory (memory bank 402), or other previously defined passcode stored in a tag. Alternatively, passcode 712 may be a passcode present specifically for read locking.
As further shown in
As still further shown in
As described above, the read lock state for tag 700 may be permanent or temporary. For example, in a permanent read lock embodiment, when lock flag 714 is present and is set, it cannot be reset to transition tag 700 out of read lock (e.g., in a non-volatile memory of tag 700). Thus, in such a permanent state, the presence of tag 700 can be determined (e.g., non-identifying bit pattern 708 can be read from tag 700), but tag 700 cannot be uniquely identified (e.g., identifying bit pattern 710 cannot be read from tag 700).
In a temporary read lock embodiment, when tag 700 is in a read lock state, reader 600 may communicate with tag 700 to transition tag 700 to a non-read lock state. In an embodiment, reader 600 can cause tag 700 to toggle between read lock and non-read lock states. For example,
In an embodiment, tag 700 does not acknowledge to reader 600 that tag 700 successfully transitioned to non-read lock state, or that tag 700 did not transition to non-read lock state, such as if tag read lock logic 706 determined that passcode 606 did not match passcode 712. In another embodiment, tag 700 transmits a response signal 1002 to reader 600. If tag 700 successfully transitioned to non-read lock state, response signal 1002 may include any indication of this, including transmitting non-identifying bit pattern 708 (e.g., RN16 in a Gen 2 embodiment), other non-identifying bit pattern (e.g, a “1” bit/bits to indicate success), and/or may transmit identifying bit pattern 710. If tag 700 did not successfully transitioned to a non-read lock state, response signal 1002 may include any indication of this, including transmitting non-identifying bit pattern 708 (e.g., RN16 in a Gen 2 embodiment) and/or other non-identifying bit pattern (e.g, a “0” bit/bits to indicate failure).
Note that, as described above, a read lock state for tag 700 disables tag 700 from transmitting identifying information. In various embodiments, a variety of information stored in tag 700 may be disabled from being transmitted while in a read lock state. For example, any portion of, all of, or combination of the following data elements may be disabled from transmission in tag 700 when in a read lock state in a Gen 2 embodiment: EPC memory (memory bank 404), including first memory portion 502 (CRC checksum), second memory portion 504 (PC bits), and/or third memory portion 506 (EPC code); TID memory 406, such as the identifier; user memory (memory bank 408), such as any information stored in user memory that could uniquely identify the tag and/or an item/object with which the tag is associated. In one embodiment, a single read lock command may be used by reader 600 to lock memory in tag 700 from being read for identifying information. In another embodiment, a plurality of different read lock commands may be transmitted by reader 600, that each lock a particular predetermined portion of memory. In still another embodiment, a read command includes a memory parameter configured by reader 600 that designates which portion of memory of tag 700 is to be read locked by the command.
In an embodiment, reader 600 communicates with a secure database 1100 using a communications module (e.g., network interface 216 or other communications interface) (in a wired or wireless fashion), as shown in
Flowchart 1200 begins with step 1202. In step 1202, a non-identifying bit pattern, an identifying bit pattern, and a first passcode are stored. For example, the non-identifying bit pattern, identifying bit pattern, and first passcode are non-identifying bit pattern 708, identifying bit pattern 710, passcode 712 stored in tag 700.
In step 1204, a read lock command is received. For example, the read lock command is read lock command 604 received from reader 600, as shown in
In step 1206, it is determined whether a second passcode associated with the read lock command matches the first passcode. For example, the second passcode is passcode 604, transmitted with (or after) read lock command 604.
In step 1208, read access to the identifying bit pattern is disabled if it is determined that the second passcode matches the first passcode. For example, read access to identifying bit pattern 710 is disabled by tag read lock logic 706 if it determines that passcode 606 does not match passcode 712.
Steps 1210, 1212, and 1214 are optional steps that may occur in a non-permanent read lock embodiment. In step 1210, a second read lock command is received. For example, a second read lock command 604 is received from reader 600.
In step 1212, it is determined whether a third passcode associated with the second read lock command matches the first passcode. For example, the third passcode is passcode 604, transmitted with (or after) read lock command 604 as shown in
In step 1214, read access to the identifying bit pattern is enabled if the third passcode matches the first passcode. For example, read access to identifying bit pattern 710 is enabled by tag read lock logic 706 if it determines that passcode 606 matches passcode 712.
Flowchart 1300 begins with step 1302. In step 1302, a read lock command and associated passcode are generated. For example, the read lock command and associated passcode are read lock command 604 and passcode 606 generated (e.g., formatted) by reader logic 602, as shown in
In step 1304, a radio frequency (RF) signal is modulated with the read lock command and associated passcode. For example, modulator 208 shown in
In step 1306, the modulated RF signal is transmitted. For example, the RF signal modulated with read lock command 604 is transmitted as shown in
Steps 1308, 1310, and 1312 are optional steps that may occur in a non-permanent read lock embodiment. In step 1308, a second read lock command and associated passcode are generated. For example, the second read lock command and associated passcode are read lock command 604 and passcode 606 generated (e.g., formatted) by reader logic 602, as shown in
In step 1310, the RF signal is modulated with the second read lock command and associated passcode. For example, modulator 208 shown in
In step 1312, the second modulated RF signal is transmitted. For example, the RF signal modulated with read lock command 604 is transmitted as shown in
In this document, the terms “computer program medium” and “computer usable medium” are used to generally refer to media such as a removable storage unit, a hard disk installed in hard disk drive, and signals (i.e., electronic, electromagnetic, optical, or other types of signals capable of being received by a communications interface). These computer program products are means for providing software to a computer system. The invention, in an embodiment, is directed to such computer program products.
In an embodiment where aspects of the present invention are implemented using software, the software may be stored in a computer program product and loaded into a computer system using a removable storage drive, hard drive, or communications interface. The control logic (software), when executed by a processor, causes the processor to perform the functions of the invention as described herein.
According to an example embodiment, a reader may execute computer-readable instructions to communicate with a tag to transition the tag into and out of a read lock state. Furthermore, in an embodiment, the reader may execute computer-readable instructions to communicate with a secure database, as described above.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
The present application claims the benefit of U.S. Appl. No. 60/816,865, filed Jun. 28, 2006, which is incorporated by reference herein in its entirety. The following pending application of common assignee is related to the present application, has the same filing date as the present application, and is herein incorporated by reference in its entirety: “Using Read Lock Capability For Secure RFID Authentication,” Atty. Dkt. No. 2319.0900001, U.S. Appl. No. TBA.
| Number | Date | Country | |
|---|---|---|---|
| 60816865 | Jun 2006 | US |
