CN102916957A - Safe, reliable and low-cost RFID mutual authentication method - Google Patents

Abstract

The invention discloses a safe, reliable and low-cost RFID mutual authentication method, which belongs to the field of wireless network communication technology. The method provided by the invention is an RFID mutual authentication protocol based on a linear feedback shift register, a physical unclonable function and mapping array technology. The method comprises the following steps: performing key authentication after completion of repeated information interaction between a reader and a tag, so as to ensure that only legal reader and tag can realize data reading, and then completing mutual authentication between the RFID tag and the reader. The method is characterized in that the linear shift register is adopted to generate pseudorandom numbers so as to effectively reduce gate circuit numbers; the physical unclonable function is adopted to disguise tag ID information so as to avoid core information leakage; and the mapping array technology is adopted to protect the tag position privacy. The method provided by the invention not only can protect the privacy data of the tags from being stolen by illegal users, but also can effectively defense internal/external malicious system attack by users.

Description

A kind of safe and reliable, RFID mutual authentication method cheaply

Technical field

The present invention relates to the identity identifying technology field, particularly a kind of safe and reliable, RFID mutual authentication method cheaply belongs to the wireless network communication technique field.

Background technology

RFID(Radio Frequency Identification) be a kind of non-contact automatic identification technology, it is automatically identified destination object and obtains related data information by radiofrequency signal.Rfid interrogator sends the radiofrequency signal of certain frequency by transmitting antenna, when the RFID label entered the transmitting antenna working region, label was crossed its built-in transmitting antenna with self information exchange such as coding grade and sent; System's reception antenna receives the carrier signal of sending from label, is sent to read write line through the antenna adjustments device, and read write line carries out the demodulation code to the signal that receives, and then delivers to background data base and carries out relevant treatment; Background data base is judged the legitimacy of this card according to logical operation, make corresponding processing and control for different settings, sends the action of command signal control actuator.Because the high speed legibility now has been widely used in the fields such as logistics, market and parking lot, brings great convenience to the human lives.

The structure of RFID automatic recognition system mainly comprises RFID label, rfid interrogator and background data base as shown in Figure 1.Adopt the mode of wired connection to communicate between rfid interrogator and the background data base, adopt wireless radio-frequency to communicate between RFID label and the rfid interrogator.The RFID label is by inner memory chip stores data.

Communication between RFID label and the rfid interrogator provides flexibility for the system data collection, but meanwhile, data are also leaked cruelly in public, become a large potential safety hazard.Obviously, do not have reliable Information Security Mechanism, just can't effectively protect the data message in the RFID label.If the information in the label is stolen even the malice change, bring the loss that to estimate may for the lawful owner of label.In addition, do not have the RFID label of authentic communication security mechanism, also exist easily and leaks some sensitive informations to contiguous read write line, easily disturbed, the easy potential safety hazard such as tracked.If the fail safe of rfid system can not be fully guaranteed, the personal information in the rfid system, trade secret and military secret all may be stolen by the people or be utilized by the lawless person, and this will have a strong impact on economic security, military security and national security.

At present, the fail safe of rfid system has become the key factor of its extensive use of restriction.Simultaneously, the RFID label itself has the shortcoming of oneself, and for example: storage capacity is limited, and computing capability is limited, and battery-powered time is limited, and these deficiencies are all limiting the design of RFID safety authentication protocol.Therefore, design is efficient, safety, safety authentication protocol cheaply, has become the in the world main development direction of RFID technology.

At present, existing safety authentication protocol mainly contains Hash chain agreement, Hash-Lock agreement, randomized Hash-Lock agreement and LCAP agreement etc.

Wherein, Hash chain agreement is a kind of unilateral authentication agreement, and its shortcoming is: 1. only realized the authentication of rfid interrogator to label, do not realized that the RFID label is to the authentication of read write line; 2. background data base will carry out repeatedly computing in once authenticating, and amount of calculation is quite large.Hash-Lock agreement, randomized Hash-Lock agreement and LCAP agreement are bidirectional identification protocols, and its shortcoming is: 1. the Hash-Lock agreement does not have dynamic I D update mechanism, and key and ID expressly transmit, and this has all seriously influenced Security of the system.2. randomized Hash-Lock agreement does not have forward security, and does not resist the position and follow the tracks of attack.3. the LCAP agreement easily causes the problems such as data between database and the RFID label are asynchronous, therefore subjects to asynchronous attacks.

Summary of the invention

The objective of the invention is the deficiency that exists in order to overcome the existing safety authentication protocol that is applied in the RFID automatic recognition system, propose a kind of safe and reliable, RFID mutual authentication method cheaply, realize that the RFID label is with the two-way authentication of read write line.

The objective of the invention is to be achieved through the following technical solutions.

A kind of safe and reliable, RFID mutual authentication method cheaply, carry out safety certification when being used between RFID automatic recognition system RFID label and the rfid interrogator radio communication, described RFID automatic recognition system comprises RFID label, rfid interrogator and background data base, and it comprises:

(1) embedding linear feedback shift register and physics can not be cloned function (Physical Unclonable Function, PUF) in the RFID label; Wherein, the function of linear feedback shift register is to generate pseudo random number; The function that physics can not be cloned function is to generate and the unique identity code of the Id(of RFID label) corresponding camouflage Id, avoid the plaintext transmission of RFID label Id and key.Embed random number generator and the linear feedback shift register identical with the RFID label in background data base, wherein, the function of random number generator is to generate any random number; The function of the linear feedback shift register in the background data base also is to generate pseudo random number.

(2) the RFID automatic recognition system is carried out initialization, specific as follows:

In each RFID label, be written into four-tuple { Id, a Key _CUR, P _CUR(Id), Array[m], wherein, Id represents unique identity code of RFID label; Key _CURRepresent the key of current sessions, its initial value is any random number; P _CUR(Id) represent the current camouflage Id of RFID label, can not clone function by physics and generate, initial value is for can not clone the end value that function obtains to label Id Applied Physics; Array[m] be an array that length is m, it is positive integer that the initial value of this array element is 0, m, m 〉=64.

In background data base, be written into five-tuple { ID, a KEY _CUR, P _CUR(ID), KEY _PRE, P _PRE(ID) }.Wherein, unique identity code of the current communication of ID representative RFID label; KEY _CURRepresent the current sessions key of current communication RFID label, its initial value is identical with the initial session key of current communication RFID label; P _CUR(ID) the current camouflage ID of the current communication of representative RFID label, initial value is identical with the initial camouflage Id of current communication RFID label; KEY _PRERepresent the last time session key of current communication RFID label, its initial value is empty; P _PRE(ID) the last time camouflage ID of the current communication of representative RFID label, its initial value is empty.

(3) proof procedure between RFID label and the rfid interrogator is specially:

Step 1: random number generator generates a random number (representing with R) in the background data base, and this random number R is sent to rfid interrogator, and rfid interrogator is to extraneous RFID label broadcasting random number R and communication request.

Step 2: after the RFID label is received random number R and communication request from read write line, calculate the value of temporary variable Temp by formula (1); Then check Array[Temp] whether be 1; If Array[Temp]=1, then send refuse information to rfid interrogator, finish current sessions; Otherwise, will Send to rfid interrogator, and Array[Temp be set]=1; Wherein,

The expression XOR, L () expression acts on parameter in the bracket with the linear shift register function.

Temp=L(R)%m （1）

Wherein, Temp is a temporary variable; % is the complementation symbol.

Step 3:RFID read write line judges whether this message is refuse information, if refuse information then finishes current sessions after receiving the message of RFID label transmission.If not refuse information, then this message is considered as

Current sessions key K ey according to the current communication of formula (2) reduction RFID label _CURThen, in background data base, search and Key _CURThe KEY that value equates _CURValue if find, then extracts and this KEY _CURCorresponding ID and P _CUR(ID), and calculate temporary variable Temp ' according to formula (3), then Temp ' is sent to the RFID label; If do not find, then in database, search and Key _CURThe KEY that value equates _PREValue if find, extracts and this KEY _PRECorresponding ID and P _PRE(ID), and calculate temporary variable Temp ' according to publicity (4), Temp ' is sent to the RFID label; Otherwise, finish current sessions.

${\mathrm{Key}}_{\mathrm{CUR}}=(({\mathrm{Key}}_{\mathrm{CUR}}\⊕L\left(R\right))\⊕L\left(R\right))---\left(2\right)$

${\mathrm{Temp}}^{\′}=(L\left(R\right)\⊕\mathrm{ID})\⊕P_{\mathrm{CUR}}\left(\mathrm{ID}\right)---\left(3\right)$

Wherein, Temp ' is a temporary variable.

${\mathrm{Temp}}^{\′}=(L\left(R\right)\⊕\mathrm{ID})\⊕P_{\mathrm{PRE}}\left(\mathrm{ID}\right)---\left(4\right)$

After step 4:RFID label receives Temp ' value, calculate temporary variable Temp by formula (5) ", " compare with Temp ' then with Temp, if equate, assert that then rfid interrogator is legal, the RFID label calculates temporary variable Temp1 according to formula (6), and with Temp1,

With

Send to rfid interrogator, wherein, P (Key _CUR) represent that physics can not be cloned function acts on Key _CUR, P (P _CUR(Id)) representing that just physics can not be cloned function acts on P _CUR(Id); If unequal, send refuse information to rfid interrogator, finish current sessions.

${\mathrm{Temp}}^{\′\′}=(L\left(R\right)\⊕\mathrm{Id})\⊕P_{\mathrm{CUR}}\left(\mathrm{Id}\right)---\left(5\right)$

Wherein, Temp " is a temporary variable.

$\mathrm{<figure-callout\; id="1"\; label="Temp"\; filenames="HDA00002256529700012.png"\; state="\{\{state\}\}">Temp</figure-callout>}1=P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\&CirclePlus;L\left(\mathrm{Id}\right)---\left(6\right)$

Wherein, Temp1 is a temporary variable.

Step 5: judge whether the message that rfid interrogator receives is refuse information, if so, end session then; Otherwise, calculate Temp2 by formula (7); Temp2 and Temp1 are compared, if Temp2 and Temp1 are unequal, assert that then the RFID label is illegal, finish current sessions.Otherwise, assert that the RFID label is legal, upgrade background data base; Renewal to background data base is divided into 2 kinds of situations processing:

Situation 1: as in the step 3, at KEY _CURIn find and Key _CURThe value that equates is then upgraded KEY _PREAnd P _PRE(ID), make KEY _PRE=KEY _CUR, P _PRE(ID)=P _CUR(ID), then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

Situation 2: as in the step 3, at KEY _PREIn find and Key _CURThe value that equates then keeps KEY _PREAnd P _PRE(ID) constant, then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

$\mathrm{<figure-callout\; id="2"\; label="Temp"\; filenames="HDA00002256529700012.png"\; state="\{\{state\}\}">Temp</figure-callout>}2=P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\&CirclePlus;L\left(\mathrm{ID}\right)---\left(7\right)$

Wherein, Temp2 is a temporary variable.

$P\left({\mathrm{KEY}}_{\mathrm{CUR}}\right)=(L\left(P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\right)\&CirclePlus;P\left({\mathrm{Key}}_{\mathrm{CUR}}\right))\&CirclePlus;L\left(P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\right)---\left(8\right)$

$P\left(P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\right)=(L\left(P\left({\mathrm{Key}}_{\mathrm{CUR}}\right)\right)\&CirclePlus;P\left(P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\right))\&CirclePlus;L\left(P\left({\mathrm{KEY}}_{\mathrm{CUR}}\right)\right)---\left(9\right)$

Step 6:RFID read write line sends and is updated successfully message and KEY _CURGive the RFID label.

Step 7:RFID label receives updating message, with Key _CURValue be updated to P (Key _CUR), with P _CUR(Id) value is updated to P (P _CUR(Id)); Then array Array[m in the label resets] in each element value be 0, finish the RFID tag update, by checking.

By the operation of above-mentioned steps, finish the proof procedure between RFID label and the rfid interrogator, can carry out subsequent communications by RFID label and the rfid interrogator of verifying.

Beneficial effect

That the present invention proposes is a kind of safe and reliable, the RFID mutual authentication method is compared with existing RFID authentication method cheaply, has following advantage:

1. has dynamic I D update mechanism.RFID label and database whenever are successfully completed after the session, and camouflage ID and key all once upgrade, and can avoid the replay attack of malice.

2. avoid the plaintext of data to transmit, strengthened Security of the system.The present invention has used physics can not clone function.The correlation properties of the integrated circuit of this functional dependence generate random number, and ID pretends to label, and any method all can't clone identical label and copy the purpose that generates random number to reach.

3. has forward security.The present invention has used linear feedback shift register.Linear feedback shift register is good pseudorandom number generator, and after seed number of input, the numeral of generation has good randomness; Simultaneously, the circuit cost of linear feedback shift register is very low, for 128 key, only need 268 gate circuits, therefore, it is suitable for cheaply in the RFID label, can prevent that also the assailant from according to current the transmission of data, extrapolating historical data, therefore have forward security

4. resist the position and follow the tracks of attack.The present invention has adopted mapping array technology, this kind technology can record this and take turns all random numbers that read write line adopts in the communication, because in same the wheel, database adopts the probability of same random number extremely little, so the communication that the random number that label only accepts not to be used is brought.Therefore, this kind technology can effectively be resisted the position tracking of outer bound pair label.

Description of drawings

Fig. 1 is the structural representation of RFID automatic recognition system in the prior art;

Fig. 2 is RFID label in the specific embodiment of the invention and the proof procedure schematic diagram between the rfid interrogator.

Embodiment

Below in conjunction with the accompanying drawing embodiment that develops simultaneously, describe the present invention.

A kind of safe and reliable, RFID mutual authentication method cheaply, carry out safety certification when being used between RFID automatic recognition system RFID label and the rfid interrogator radio communication, described RFID automatic recognition system comprises RFID label, rfid interrogator and background data base, and it comprises:

(1) embedding linear feedback shift register and physics can not be cloned function (Physical Unclonable Function, PUF) in the RFID label; Wherein, the function of linear feedback shift register is to generate pseudo random number; The function that physics can not be cloned function is to generate the camouflage Id corresponding with the Id of RFID label, avoids the plaintext transmission of RFID label Id and key.Embed random number generator and the linear feedback shift register identical with the RFID label in background data base, wherein, the function of random number generator is to generate any random number; The function of the linear feedback shift register in the background data base also is to generate pseudo random number.

(2) the RFID automatic recognition system is carried out initialization, specific as follows:

In each RFID label, be written into four-tuple { Id, a Key _CUR, P _CUR(Id), Array[m], wherein, Id represents unique identity code of RFID label; Key _CURRepresent the key of current sessions, its initial value is any random number, and it is the binary number of 64 of length that this random number is set; P _CUR(Id) represent the current camouflage Id of RFID label, can not clone function by physics and generate, initial value is for can not clone the end value that function obtains to label Id Applied Physics, and the length of this numerical value also is 64 binary number; Array[m] be an array that length is m, the initial value of this array element is 0, m=64.

In background data base, be written into five-tuple { ID, a KEY _CUR, P _CUR(ID), KEY _PRE, P _PRE(ID) }.Wherein, unique identity code of the current communication of ID representative RFID label; KEY _CURRepresent the current sessions key of current communication RFID label, its initial value is identical with the initial session key of current communication RFID label; P _CUR(ID) the current camouflage ID of the current communication of representative RFID label, initial value is identical with the initial camouflage Id of current communication RFID label; KEY _PRERepresent the last time session key of current communication RFID label, its initial value is empty; P _PRE(ID) the last time camouflage ID of the current communication of representative RFID label, its initial value is empty.

(3) the proof procedure schematic diagram between RFID label and the rfid interrogator as shown in Figure 2, concrete proof procedure is:

Step 1: random number generator generates a random number R in the background data base, and this random number R is sent to rfid interrogator, and rfid interrogator is to extraneous RFID label broadcasting random number R and communication request.

Step 2: after the RFID label is received random number R and communication request from read write line, calculate the value of temporary variable Temp by formula (1); Then check Array[Temp] whether be 1; If Array[Temp]=1, then send refuse information to rfid interrogator, finish current sessions; Otherwise, will Send to rfid interrogator, and Array[Temp be set]=1.For example: when m=64, L (R)=1010101010, then Temp=(101010) ₂=(42) ₁₀, check Array[42] whether be 1; Wherein, () ₂The expression binary numeral, () ₁₀Expression decimal system numerical value.

Step 3:RFID read write line judges whether this message is refuse information, if refuse information then finishes current sessions after receiving the message of RFID label transmission.If not refuse information, then this message is considered as

Current sessions key K ey according to the current communication of formula (2) reduction RFID label _CURThen, in background data base, search and Key _CURThe KEY that value equates _CURValue if find, then extracts and this KEY _CURCorresponding ID and P _CUR(ID), and calculate temporary variable Temp ' according to formula (3), then Temp ' is sent to the RFID label; If do not find, then in database, search and Key _CURThe KEY that value equates _PREValue if find, extracts and this KEY _PRECorresponding ID and P _PRE(ID), and calculate temporary variable Temp ' according to publicity (4), Temp ' is sent to the RFID label; Otherwise, finish current sessions.

After step 4:RFID label receives Temp ' value, calculate temporary variable Temp by formula (5) ", " compare with Temp ' then with Temp, if equate, assert that then rfid interrogator is legal, the RFID label calculates temporary variable Temp1 according to formula (6), and with Temp1,

With Send to rfid interrogator, wherein, P (Key _CUR) represent that physics can not be cloned function acts on Key _CUR, P (P _CUR(Id)) representing that just physics can not be cloned function acts on P _CUR(Id); If unequal, send refuse information to rfid interrogator, finish current sessions.

Step 5: judge whether the message that rfid interrogator receives is refuse information, if so, end session then; Otherwise, calculate Temp2 by formula (7); Temp2 and Temp1 are compared, if Temp2 and Temp1 are unequal, assert that then the RFID label is illegal, finish current sessions.Otherwise, assert that the RFID label is legal, upgrade background data base; Renewal to background data base is divided into 2 kinds of situations processing:

Situation 1: as in the step 3, at KEY _CURIn find and Key _CURThe value that equates is then upgraded KEY _PREAnd P _PRE(ID), make KEY _PRE=KEY _CUR, P _PRE(ID)=P _CUR(ID); Then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

Situation 2: as in the step 3, at KEY _PREIn find and Key _CURThe value that equates then keeps KEY _PREAnd P _PRE(ID) constant, then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

Step 6:RFID read write line sends and is updated successfully message and KEY _CURGive the RFID label.

Step 7:RFID label receives updating message, with Key _CURValue be updated to P (Key _CUR), with P _CUR(Id) value is updated to P (P _CUR(Id)); Then array Array[m in the label resets] in each element value be 0, finish the RFID tag update, by checking.

By the operation of above-mentioned steps, finish the proof procedure between RFID label and the rfid interrogator, can carry out subsequent communications by RFID label and the rfid interrogator of verifying.

Above-described specific descriptions; purpose, technical scheme and beneficial effect to invention further describe; institute is understood that; the above only is specific embodiments of the invention; be used for explaining the present invention, the protection range that is not intended to limit the present invention, within the spirit and principles in the present invention all; any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (1)

1. safe and reliable, RFID mutual authentication method cheaply carries out safety certification when being used between RFID automatic recognition system RFID label and the rfid interrogator radio communication; Described RFID automatic recognition system comprises RFID label, rfid interrogator and background data base; Described RFID mutual authentication method is characterized in that: comprising:

(1) embedding linear feedback shift register and physics can not be cloned function in the RFID label; Wherein, the function of linear feedback shift register is to generate pseudo random number; The function that physics can not be cloned function is to generate the camouflage Id corresponding with unique identity code Id of RFID label, avoids the plaintext transmission of RFID label Id and key; Embed random number generator and the linear feedback shift register identical with the RFID label in background data base, wherein, the function of random number generator is to generate any random number; The function of the linear feedback shift register in the background data base also is to generate pseudo random number;

(2) the RFID automatic recognition system is carried out initialization, specific as follows:

In each RFID label, be written into four-tuple { Id, a Key _CUR, P _CUR(Id), Array[m], wherein, Id represents unique identity code of RFID label; Key _CURRepresent the key of current sessions, its initial value is any random number; P _CUR(Id) represent the current camouflage Id of RFID label, can not clone function by physics and generate, initial value is for can not clone the end value that function obtains to label Id Applied Physics; Array[m] be an array that length is m, it is positive integer that the initial value of this array element is 0, m, m 〉=64;

In background data base, be written into five-tuple { ID, a KEY _CUR, P _CUR(ID), KEY _PRE, P _PRE(ID) }; Wherein, unique identity code of the current communication of ID representative RFID label; KEY _CURRepresent the current sessions key of current communication RFID label, its initial value is identical with the initial session key of current communication RFID label; P _CUR(ID) the current camouflage ID of the current communication of representative RFID label, initial value is identical with the initial camouflage Id of current communication RFID label; KEY _PRERepresent the last time session key of current communication RFID label, its initial value is empty; P _PRE(ID) the last time camouflage ID of the current communication of representative RFID label, its initial value is empty;

(3) proof procedure between RFID label and the rfid interrogator is specially:

Step 1: random number generator generates a random number R in the background data base, and this random number R is sent to rfid interrogator, and rfid interrogator is to extraneous RFID label broadcasting random number R and communication request;

Step 2: after the RFID label is received random number R and communication request from read write line, calculate the value of temporary variable Temp by formula (1); Then check Array[Temp] whether be 1; If Array[Temp]=1, then send refuse information to rfid interrogator, finish current sessions; Otherwise, will

Send to rfid interrogator, and Array[Temp be set]=1; Wherein,

The expression XOR, L () expression acts on parameter in the bracket with the linear shift register function;

Temp=L(R)%m （1）

Wherein, Temp is a temporary variable; % is the complementation symbol;

Step 3:RFID read write line judges whether this message is refuse information, if refuse information then finishes current sessions after receiving the message of RFID label transmission; If not refuse information, then this message is considered as

Current sessions key K ey according to the current communication of formula (2) reduction RFID label _CURThen, in background data base, search and Key _CURThe KEY that value equates _CURValue if find, then extracts and this KEY _CURCorresponding ID and P _CUR(ID), and calculate temporary variable Temp ' according to formula (3), then Temp ' is sent to the RFID label; If do not find, then in database, search and Key _CURThe KEY that value equates _PREValue if find, extracts and this KEY _PRECorresponding ID and P _PRE(ID), and calculate temporary variable Temp ' according to publicity (4), Temp ' is sent to the RFID label; Otherwise, finish current sessions;

${\mathrm{Key}}_{\mathrm{CUR}}=(({\mathrm{Key}}_{\mathrm{CUR}}\&CirclePlus;L\left(R\right))\&CirclePlus;L\left(R\right))---\left(2\right)$

${\mathrm{Temp}}^{\&prime;}=(L\left(R\right)\&CirclePlus;\mathrm{ID})\&CirclePlus;P_{\mathrm{CUR}}\left(\mathrm{ID}\right)---\left(3\right)$

Wherein, Temp ' is a temporary variable;

${\mathrm{Temp}}^{\&prime;}=(L\left(R\right)\&CirclePlus;\mathrm{ID})\&CirclePlus;P_{\mathrm{PRE}}\left(\mathrm{ID}\right)---\left(4\right)$

After step 4:RFID label receives Temp ' value, calculate temporary variable Temp by formula (5) ", " compare with Temp ' then with Temp, if equate, assert that then rfid interrogator is legal, the RFID label calculates temporary variable Temp1 according to formula (6), and with Temp1,

With

Send to rfid interrogator, wherein, P (Key _CUR) represent that physics can not be cloned function acts on Key _CUR, P (P _CUR(Id)) representing that just physics can not be cloned function acts on P _CUR(Id); If unequal, send refuse information to rfid interrogator, finish current sessions;

${\mathrm{Temp}}^{\&prime;\&prime;}=(L\left(R\right)\&CirclePlus;\mathrm{Id})\&CirclePlus;P_{\mathrm{CUR}}\left(\mathrm{Id}\right)---\left(5\right)$

Wherein, Temp " is a temporary variable;

$\mathrm{Temp}1=P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\&CirclePlus;L\left(\mathrm{Id}\right)---\left(6\right)$

Wherein, Temp1 is a temporary variable;

Step 5: judge whether the message that rfid interrogator receives is refuse information, if so, end session then; Otherwise, calculate Temp2 by formula (7); Temp2 and Temp1 are compared, if Temp2 and Temp1 are unequal, assert that then the RFID label is illegal, finish current sessions; Otherwise, assert that the RFID label is legal, upgrade background data base; Renewal to background data base is divided into 2 kinds of situations processing:

Situation 1: as in the step 3, at KEY _CURIn find and Key _CURThe value that equates is then upgraded KEY _PREAnd P _PRE(ID), make KEY _PRE=KEY _CUR, P _PRE(ID)=P _CUR(ID), then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

Situation 2: as in the step 3, at KEY _PREIn find and Key _CURThe value that equates then keeps KEY _PREAnd P _PRE(ID) constant, then recover P (KEY by formula (8) and formula (9) _CUR) and P (P _CUR(ID)), with KEY _CURValue be updated to P (KEY _CUR), with P _CUR(ID) value is updated to P (P _CUR(ID));

$\mathrm{Temp}2=P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\&CirclePlus;L\left(\mathrm{ID}\right)---\left(7\right)$

Wherein, Temp2 is a temporary variable;

$P\left({\mathrm{KEY}}_{\mathrm{CUR}}\right)=(L\left(P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\right)\&CirclePlus;P\left({\mathrm{Key}}_{\mathrm{CUR}}\right))\&CirclePlus;L\left(P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\right)---\left(8\right)$

$P\left(P_{\mathrm{CUR}}\left(\mathrm{ID}\right)\right)=(L\left(P\left({\mathrm{Key}}_{\mathrm{CUR}}\right)\right)\&CirclePlus;P\left(P_{\mathrm{CUR}}\left(\mathrm{Id}\right)\right))\&CirclePlus;L\left(P\left({\mathrm{KEY}}_{\mathrm{CUR}}\right)\right)---\left(9\right)$

Step 6:RFID read write line sends and is updated successfully message and KEY _CURGive the RFID label;

Step 7:RFID label receives updating message, with Key _CURValue be updated to P (Key _CUR), with P _CUR(Id) value is updated to P (P _CUR(Id)); Then array Array[m in the label resets] in each element value be 0, finish the RFID tag update, by checking;

By the operation of above-mentioned steps, finish the proof procedure between RFID label and the rfid interrogator, can carry out subsequent communications by RFID label and the rfid interrogator of verifying.

Images