KR100605138B1 - Authorization method in radio frequency identification system - Google Patents

Abstract

The present invention is an RFID system comprising at least one tag, at least one reader, and at least one back-end database, wherein the reader broadcasts the tags together with the random number R _R generated by the reader. [Step 1: Challenge process], the tag is a concatenation of the random number R _R and the unique authentication information ID of the tag and input to a specific one-way function H ₁ , generated from the output value of the one-way function H ₁ (ID ∥ _{R R} ) and the tag A random number R _T is transmitted to the leader in response to the reader's query [Step 2: Response process], and the leader backs up the random number R _R and H ₁ (ID ∥ _{R R} ) received from the tag, and the random number R _T. Send back to the end database (process 3), the back-end database concatenates all stored IDs with the random number R _R and inputs to the one-way function H ₁ , outputting this one-way function H ₁ (ID∥R _R) and compares the output value H ₁ (ID∥R _R) of the one-way function received from the reader, the output value that matches the one-way output value H _{1 (R} ID∥R function) received from the reader ₁ H (ID∥ R _R ), if present, authenticates the ID as the ID of the tag (step 4), connects the ID and the random number R _T generated by the tag, and inputs it to one-way function H ₁ and another one-way function H ₂ . Send one H ₂ (ID∥R _T ) to the reader (step 5), and the reader sends the output value H ₂ (ID∥R _T ) of the one-way function received from the back-end database (DB) to the tag ( Step 6), the tag connects its ID and R _T generated in the authentication process (session) and inputs it to the one-way function H ₂ , and the output value of the one-way function H ₂ (ID∥R _T ) and received from the reader by comparing an output value H ₂ (ID∥R _T) of the one-way function, when an output value of a one-way function H ₂ (ID∥R _T) match the back-end data Authentication (process 7) device to provide an authentication method in an RFID system, characterized in that.

Description

Authentication method in RFID system

1 is a view schematically showing the configuration of an RFID system.

2 is a diagram schematically illustrating an authentication method according to the related art 1 (Hash-Lock Technique).

3 is a diagram illustrating an authentication method according to the related art 2 (an improved hash lock technique).

4 is a diagram illustrating an authentication method according to the related art 3 (hash-chain method).

5 is a diagram illustrating an authentication method according to the related art 4 (hash-based ID transformation technique).

FIG. 6 is a diagram illustrating a basic embodiment of the RFID authentication method proposed by the present invention, and illustrates a process of secure authentication using a one-way function and a random number.

FIG. 7 is a diagram illustrating Modification Example 1 of the embodiment of FIG. 6, which schematically illustrates an authentication method of adding different values promised to input values of a one-way function so that the tag may include only one one-way function.

FIG. 8 is a diagram illustrating Modification Example 2, which illustrates an authentication method in which an input value of a one-way function is asymmetric such that a tag may include only one one-way function.

FIG. 9 is a diagram illustrating Modification Example 3, which illustrates an authentication method for generating random numbers using an existing one-way function without using a separate random number generator.

FIG. 10 is a diagram showing Modification Example 4, which shows an authentication method using a random number generator for a time (the number of counters in a tag), T = R _R + 1, and the like as a random number.

FIG. 11 is a diagram showing Modification Example 5 showing an authentication method in which Modification Example 2 and Modification Example 3 were integrated.

[Description of Parameters Used in the Present Invention]

Tag: RFID tag. The subscript T or t represents the tag.

Reader: RFID reader. Subscript R or r represents leader.

DB: Back-end database or tag authentication server

Query: Query. Request a response from the tag.

ID: Tag's unique secret authentication information. ID _k means ID of _k th tag.

H or G: one-way function. Different one-way functions are represented by h _j or g _j where j is a natural number. That is, H ₁ , H ₂ or G ₁ or G ₂ are different one-way functions.

One-way function H or G is a function that satisfies the following conditions.

-Finding information M from one-way function value H (M) should be computationally impossible.

Given an information M and a unidirectional function value H (M), it must be computationally impossible to find an information M´ different from M where H (M´) = H (M).

-Finding different information M and M 'where H (M) = H (M´) (without information M and one-way function value H (M)) should not be computationally impossible.

R _R : Random number generated by the reader for each authentication process (session) and sent to the tag.

R _T : Random number generated by tag.

R _T ⁱ is the random number generated by the tag in the i th authentication process (session).

∥: concatenate function. Ex) If A = 0100, B = 1100, A || B = 01001100

→: Transfer. Ex) A → B means transmitting information from A to B.

: 배타적논리합(XOR 또는, Exclusive OR). 각 비트(자릿수)끼리 비교하여 동일하면 0, 서로 다르면 1. 예) A=0011, B=0101이라면 A

B =0110.

Exclusive logical sum (XOR or Exclusive OR). If each bit (digit) is the same, it is 0 if it is the same and if it is different 1. Ex) A if A = 0011 and B = 0101, A

B = 0110.

: 비교(Comparison). 기호 양변의 두 값이 동일한 값인지 아닌지를 판별함.

: Comparison. Determines whether two values on both sides of a symbol are equal.

s: Secret information. s _{t, i} means secret information in the i th authentication process (session) of tag t.

a: Answer. a _{t, i} means the response value to the reader in the i th authentication process (session) of tag t.

TID: A number representing the last authentication process (session) performed recently.

LST: A number representing the last successful authentication process (session) performed recently.

author title Placement Volume Page Publish date S. A. Weis, S. E. Sarma, R. L. Rivest, D. W. Engels Security and Privacy Aspects of Low-Cost Radio Frequency Identification Systems Proc. of Security in Pervasive Computing 2003 LNCS 2802 pp.201 -212 2004 S. E. Sarma, S. A. Weis, D. W. Engels RFID Systems and Security and Privacy Implications Proc. of CHES 2002 LNCS 2523 pp.454 -469 2003 S. E. Sarma, S. A. Weis, D. W. Engels RFID systems, security & privacy implications White Paper MIT-AUTOID-WH-014 - - 2002 S. A. Weis Security an Privacy in Radio-Frequency Identification Devices MIT MS - - 2003.5 A. Juels, R. Pappu Squealing Euros: Privacy protection in RFID-enabled banknotes Proc. of Financial Cryptography'03 LNCS 2742 pp.103 -121 2003 A. Juels, R. L. Rivest, M Szydlo The Blocker Tag: Selective Blocking of RFID Tags for consumer Privacy Proc. of 10th ACM Conference on Computer and Communications Security - pp.103 -111 2003 M. Ohkubo, K. Suzuki, S. Kinoshita Hash-Chain Based Forward-Secure Privacy Protection Scheme for Low-Cost RFID Proc. of SCIS 2004 - pp.719 -724 2004 D. Henrici, P. Muller, Hash-based Enhancement of Location Privacy for Radio-Frequency Identification Devices using Varying Identifiers Varying Proc. of the Second IEEE PERCOMW'04 - pp.149 -153  2004 S. E. Sarma, S. A. Weis, D. W. Engels Radio-Frequency Identification: Secure Risks and Challenges RSA Laboratories Cryptobytes, vol. 6, no. One pp2-9. 2003

The present invention is based on the Challenge-Response method, uses a random number, and since the authentication information of the tag is hidden using a one-way function, the RFID ID system is secured against retransmission attacks and spoofing attacks. It relates to an authentication method.

In general, RFID (Radio Frequency Identification) system is an automatic recognition technology using a radio frequency is a system that can read or record the information of the object without physical contact. Recently, as the automatic recognition technology to reduce the logistics and distribution costs has been attracting attention, active investment and research on the RFID system has been made, and the existing barcode method is used once on average until the end of the life of the product. In contrast, when RFID systems are applied to logistics and distribution processes, many companies are interested in RFID systems because they can provide continuous services using information in tags as well as the advantages of automatic recognition.

As shown in FIG. 1, an RFID system generally consists of a tag, a reader, and a back-end database.

First, referring to FIG. 1A, a tag denoted by ● is an RFID system that transmits identification information such as an object, an animal, a person, etc. in response to a reader's request, also called a transponder. The tag consists of a coupling element for wireless communication and a microchip that performs operations and stores information. The tag comprises an active tag and a passive tag according to a method of receiving power. Classify as

Meanwhile, a reader, also called a transceiver, is connected to a plurality of antennas and may receive identification information transmitted by the tag T. When the tag is passive, the reader transmits power by transmitting an RF signal (Radio Frequency Signal) to the tag T, and transmits the information received from the tag to the back-end database. The reader can read or record the tag's information.

In addition, a back-end database (DB) stores information collected by the reader, and collectively refers to a server, middleware, or database that performs a complex operation in place of a tag or a reader with low computing power. In this case, since the information for identifying the tag is stored, the reader determines the authenticity of the information collected from the tag.

Meanwhile, in FIG. 1B, the omnidirectional region of the reader and the posterior region of the tag are shown. The forward range is an area in which the reader can transmit an RF signal to the tag, and the backward range is a tag. This is the area that can transmit its own information about the leader's request. The posterior region is smaller than the omnidirectional region because the tag's transmission capability is relatively low compared to that of the reader. For example, for an RFID system using a frequency of 915 MHz, the passive tag has a backspace area of about 3 meters radius, but the omnidirectional area of the reader reaches a radius of 100 meters. Therefore, when the reader and the tag are separated by more than 3m, the reader may not recognize even if the tag receiving the reader's frequency transmits its information to the reader.

On the other hand, the authentication method in such an RFID system should be made in consideration of two aspects of safety and efficiency. In particular, RFID's automatic recognition feature can expose sensitive information to an attacker (or eavesdropper) located in an insecure channel between the reader and the tag without the user's knowledge, and could compromise the user's privacy. There is. Therefore, in order to prevent the leakage of sensitive information and to protect the privacy of users in automated billing systems, access control systems, and logistics systems using RFID, it should not be possible to track or impersonate a tag other than the legitimate participants of the system. In addition, since many tags must be authenticated in an RFID system, a large number of distributed databases and servers must be used to perform such authentication at high speed regardless of a location and time. Therefore, the RFID authentication method should be constructed to be applicable to the ubiquitous environment in which these distributed databases and servers exist.

Hereinafter, an authentication method and a problem thereof according to the prior art will be described schematically. Figure 2 shows an authentication method according to the prior art 1 (hash lock method). In the figure, numerals 1 to 6 represent the order of the authentication process.

In the hash-locking scheme proposed by S. A. Weis et al, the metaID is used to prevent the exposure of the real ID, but since the metaID is fixed, the attacker can track the tag and is vulnerable to a retransmission attack. If an attacker receives a metaID from a tag by pretending to be a valid reader, and obtains a key from the reader by pretending to be a tag using this metaID, the attacker can retrieve the ID from the tag by pretending to be a reader again. Eventually, the attacker acquires all metaIDs, keys, and IDs, enabling a spoofing attack that perfectly impersonates a legitimate tag.

Figure 3 shows an authentication method according to the prior art 2 (an improved hash-lock technique). Numbers 1 to 5 indicate the order of the authentication process.

The extended hash-lock scheme proposed by improving the hash-lock scheme proposed by SA Weis uses a method in which a tag generates a random number R and transmits a different response from the database to the reader for each authentication process (session). However, since ID _k (k is a natural number), which is a unique secret authentication information, is transmitted through an insecure channel, location tracking is still possible, and the attacker can answer the reader's query with a random number R and a one-way function H (ID _k). If you eavesdrop on || R), it is also vulnerable to replay attacks because it can be perfectly impersonated with legitimate tags. Also, if an attacker obtains R, H (ID _k || R) from a tag by pretending to be a legitimate reader, the attacker sends the previously obtained R, H (ID _k || R) in response to the leader's query. Can be disguised as a legitimate tag.

4 shows an authentication method according to the prior art 3 (hash-chain technique). Numbers 1 to 4 indicate the order of the authentication process.

The hash-chain technique using two different hash functions (one-way functions) H and G proposed by M. Ohkubo, K. Suzuki, and S. Kinoshita always responds differently to the reader's query, so the attacker responds to the tag a. Even if we know _{t, i} (subscript t is a specific tag, i is the number of sessions), we don't know which tag responded, and we know that it's the same tag for different responses. none. However _{, the} hash-chain technique is vulnerable to retransmission attacks and spoofing attacks because an attacker can impersonate a valid tag if it retransmits a _{t, i} . In addition, the hash-chain technique has an excessive computational burden because the back-end database must perform a hash function operation on all the tags i to authenticate the tag, and the price of the tag because the tag must have two different hash functions This rises.

5 shows an authentication method according to the prior art 4 [hash-based ID modification scheme]. Numbers 1 to 5 indicate the order of the authentication process.

ID), △TID를 획득하고, 정당한 태그가 다음 인증 세션을 수행하기 전에 이 정보들을 리더의 질의에 대한 응답으로 이용하면 공격자는 정당한 태그로 인증받을 수 있다. 그리고 공격자가 정당한 리더로 가장하여 H(ID), H(TID

ID), △TID를 획득하고, 과정 5에서 전송되는 정보를 태그에게 전송하지 않으면, 태그는 과정 5에서의 정보가 유실되었다고 여겨 ID를 변형하지 않는다. 이 경우, 공격자가 여러 개의 리더를 곳곳에 설치해두고 있다면 태그가 정당한 리더와 인증 세션을 수행하여 H(ID)가 갱신되기 전까지 H(ID)를 통해 태그의 위치를 추적할 수 있다. 또한 해쉬 기반 ID 변형 기법은 ID가 인증 세션마다 바뀌므로 변형되는 ID를 저장하고 있는 유일한 데이터베이스가 존재해야만 한다. 그러나, 데이터베이스가 하나만 존재하는 경우 수많은 태그를 인증하기 위해서는 데이터베이스가 매우 많은 연산을 수행해야하며, 다양한 서비스 제공에 어려움이 생기게 된 다. The hash-based ID transformation technique proposed by D. Henrici and P. Muller is a technique for changing the ID, which is authentication information of a tag, in every authentication process (session), similar to the hash-chain technique. The ID of the tag is updated by the random number R in each session, and the TID and LST are updated, so it is safe from attacker's retransmission attack. However, an attacker can pretend to be a legitimate leader and use H (ID), H (TID

ID), ΔTID, and using this information in response to the leader's query before the legitimate tag performs the next authentication session, the attacker can authenticate with the legitimate tag. And attacker impersonates a legitimate leader, H (ID), H (TID

ID), DELTA TID is acquired, and the tag does not modify the ID in view of the information lost in step 5 unless the information transmitted in step 5 is transmitted to the tag. In this case, if an attacker has several readers installed in various places, the tag can perform an authentication session with a valid reader to track the position of the tag through H (ID) until the H (ID) is updated. In addition, because hash-based ID transformations change IDs for each authentication session, there must be a unique database that stores IDs that are transformed. However, if there is only one database, the database has to perform a lot of operations to authenticate a large number of tags, and it becomes difficult to provide various services.

The present invention has been made to improve the authentication method according to the prior art as described above, because it uses a random number based on the Challenge-Response method is safe against retransmission attack and spoofing attack, the authentication information of the tag uses a one-way function It is hidden so that the location of the tag cannot be tracked except the legitimate participants, and since there is no need to synchronize the authentication information of the tag, the purpose is to provide an authentication method in the RFID system that can be suitably used in a distributed database environment. It is done.

Hereinafter, the present invention will be described in detail with reference to the drawings.

(Example)

An embodiment of an authentication method according to the present invention will be described with reference to FIG.

(Course 1: Leader)

The reader broadcasts the tags together with the query and the random number R _R generated by the reader.

Reader → Tags: Query, R _R

(Course 2: tags)

The tag associates the random number R _R with the unique authentication information ID of the tag and inputs it to a specific one-way function H ₁ , and outputs the output value H ₁ (ID ∥ _{R R} ) of the one-way function and the random number R _T generated from the tag to the query of the reader. The response is sent to the reader. Response process.

Tag → Reader: H ₁ (ID∥R _R ), R _T

(Course 3: Leader)

The reader transmits the random number R _R , H ₁ (ID ∥ _{R R} ) and the random number R _T received from the tag to the back-end database (DB).

Reader → Back-End Database: H ₁ (ID∥R _R ), R _R , R _T

(Course 4: Back-End Database)

All IDs stored in the back-end database are concatenated with the random number R _R received from the reader and input into the one-way function H ₁ . Then, the output value H ₁ (ID ∥ _{R R} ) of the one-way function is compared with the output value H ₁ (ID ∥ _{R R} ) of the one-way function received from the reader to determine whether it matches. At this time, if the output values match, the tag authentication is successful, and if the output values do not match, the tag authentication is determined to fail.

리더로부터 수 신한 H1(ID｜R_R)Back-End Database (DB): H ₁ calculated from DB (ID | R _R )

H1 (ID | R _R ) received from leader

(Course 5: back-end database)

If there is an output value H ₁ (ID∥R _R ) of the one-way function that matches H ₁ (ID∥R _R ) received from the reader, the ID is authenticated as the ID of the tag, and this ID and the random number generated by the tag R _T is connected and the output value H ₂ (ID∥R _T ) of the one-way function generated by inputting to the one-way function H ₂ different from the one-way function H ₁ is transmitted to the reader.

Back-end Database → Reader: H ₂ (ID∥R _T )

(Course 6: Leader)

The reader sends the output value H ₂ (ID∥R _T ) received from the back-end database (DB) to the tag.

Readers → Tags: H ₂ (ID∥R _T )

(Course 7: tags)

Tag is concatenated to R _T generated by the own ID and the authentication session and input to the one-way function H _2, and the output value of the one-way function H ₂ the output value received from the (ID∥R _T) and H ₂ reader (ID∥R _T ). In this case, if the output values match, the back-end database is authenticated. If the output values do not match, the authentication of the back-end database is determined to be a failure.

리더로부터 수신한 H₂(ID∥R_T)Tag: H ₂ calculated from tag (ID∥R _T )

H ₂ (ID∥R _T ) received from reader

(Variation)

The number of gates that make up the low-cost tag IC chip is 7.5-15 Kgates. Among them, the number of gates available for implementing the encryption technology is 2.5-5 Kgates. The tag has two different one-way functions with different shapes, The gate of the tag is too short to generate a random number R _T using the random number generator. Therefore, the authentication method proposed by the present invention may have the following modifications.

① One-way functions H ₁ and H ₂ are the same (when only one one-way function is used instead of two different one-way functions).

(Modification 1)

By adding different promised values to the input values of one-way functions (padding), using the same one-way function has the same effect as using different one-way functions. For example, in the embodiment according to FIG. 6, the output value H ₁ (ID || R _R ) of the one-way function from the tag is replaced with H (00 || ID || R _R ), and from the back-end database DB. The output of one-way function of H ₂ (ID || R _T ) is replaced by H (11 || ID || R _T ). The padding values 00 and 11 can be changed according to the protocol between the tag, reader and back-end database.

A modification 1 will be described with reference to FIG. 7.

(Course 1: Leader)

The reader broadcasts the tags together with the query and the random number R _R generated by the reader.

Reader → Tags: Query, R _R

(Course 2: tags)

The tag associates the padding value 00 with the tag's unique authentication information ID and the random number R _R , inputs it to the one-way function H, and outputs the output value H (00 || ID || R _R ) and the random number R _T generated from the tag. Sent to the reader in response to the leader's query. Response process.

Tag → Reader: H (00 || ID || R _R ), R _T

(Course 3: Leader)

The reader sends the random number R _R , the output value H (00 || ID || R _R ) received from the tag, and the random number R _T to the back-end database (DB).

Reader → Back-End Database: H (00 || ID || R _R ), R _R , R _T

(Course 4: Back-End Database)

All IDs stored in the back-end database are concatenated with the received random numbers R _R and entered in the one-way function H, respectively. The output value H (00 || ID || R _R ) of the one-way function is compared with the output value H (00 || ID || R _R ) of the one-way function received from the reader to determine whether the output value is identical. At this time, if the output values match, the tag authentication is successful. If the output values do not match, the tag authentication is determined to fail.

리더로부터 수신한 H(00||ID||R_R)Back-End Database (DB): H calculated from DB (00 || ID || R _R )

H (00 || ID || R _R ) received from the reader

(Course 5: back-end database)

If there is an output value H (00 || ID || R _R ) that matches the output value H (00 || ID || R _R ) received from the reader, the corresponding ID is authenticated as the ID of the tag, and the pre-qualified padding value 11 and the random number R _T generated by the ID and the tag are concatenated, and the output value H (11 || ID || R _T ) of the one-way function generated by inputting to the one-way function H is transmitted to the reader.

Back-end Database → Reader: H (11 || ID || R _T )

(Course 6: Leader)

The reader sends the H (11 || ID || R _T ) received from the back-end database to the tag.

Reader → Tag: H (11 || ID || R _T )

(Course 7: tags)

The tag associates the padding value 11 with its own ID and R _T created in the authentication session and inputs it to the one-way function H. The output value H (11 || ID || R _T ) of the one-way function and the output value H received from the reader. Compare (11 || ID || R _T ). In this case, if the output values match, the back-end database is authenticated. If the output values do not match, authentication of the back-end database is determined to fail.

리더로부터 수신한 H(11||ID||R_T)Tags: H calculated from tags (11 || ID || R _T )

H (11 || ID || R _T ) received from reader

(Modification 2)

By asymmetrical input values of the one-way function, the output value of the one-way function transmitted from the tag side and the output value of the one-way function transmitted from the back-end database side can be distinguished. For example, in the embodiment according to FIG. 6, H ₁ (ID || R _R ) is replaced with H (ID || R _R || R _T ) and H ₂ (ID || R _T ) is H (ID || R _T )

Variation 2 will be described with reference to FIG. 8.

(Course 1: Leader)

The reader broadcasts the Query together with a random number R _R. [Challenge process].

Reader → Tags: Query, R _R

(Course 2: tags)

The tag associates a unique authentication information ID with the random number R _R and a self-generated random number R _T , inputs it to the one-way function H, and outputs the output value H (ID || R _R || R _T ) and the random number generated from the tag. R _T is sent to the reader in response to the reader's query. Response process.

Tag → Reader: H (ID || R _R || R _T ), R _T

(Course 3: Leader)

The reader sends the output value H (ID || R _R || R _T ), the random number R _R, and the random number R _T of the one-way function received from the tag to the back-end database (DB).

Reader → Back-End Database: H (ID || R _R || R _T ), R _R , R _T

(Course 4: Back-End Database)

All IDs stored in the back-end database are concatenated with the received random numbers R _R and R _T , respectively, and entered in the one-way function H, respectively. The output value H (ID || R _R || R _T ) of the one-way function is compared with the output value H (ID || R _R || R _T ) of the one-way function received from the reader to determine whether they match. At this time, if the output values match, the tag authentication is successful. If the output values do not match, the tag authentication is determined to fail.

리더로부터 수신한 H(ID||R_R||R_T)Back-End Database (DB): H calculated from DB (ID || R _R || R _T )

H received from reader (ID || R _R || R _T )

(Course 5: back-end database)

If there is an output value H (ID || R _R || R _T ) that matches the output value H (ID || R _R || R _T ) of the one-way function received from the reader, the corresponding ID is authenticated as the ID of the tag. The ID and the random number R _T generated by the tag are concatenated, and the output value H (ID || R _T ) of the one-way function generated by inputting to the one-way function H is transmitted to the reader.

Back-end Database → Reader: H (ID || R _T )

(Course 6: Leader)

The reader sends the H (ID || R _T ) received from the back-end database (DB) to the tag.

Reader → Tag: H (ID || R _T )

(Course 7: tags)

The tag associates its ID with R _T created in the authentication process (session) and inputs it to the one-way function H. The output value H (ID || R _T ) of the one-way function and the output value H (ID ||) received from the reader. R _T ) is compared. In this case, if the output values match, the back-end database is authenticated. If the output values do not match, authentication of the back-end database is determined to fail.

리더로부터 수신한 H(ID||R_T)Tag: H calculated from tag (ID || R _T )

H (ID || R _T ) received from reader

② When generating random number R _T without using separate random number generator.

(Modification 3)

Instead of a separate random number generator, the key is stored in the tag when the tag is produced so that the random number can be generated using the one-way function already built in. The tag associates the stored key with the random number R _T ^i-1 (i is a natural number) generated from the tag in the previous authentication process (session) and the random number R _R received from the reader, and enters the new random number R _T by entering the one-way function H. Create ⁱ When the first tag is produced, R _T ⁰ is set to H (key). That is, in the implementation according to FIG. 6, before the process 2, the tag generates a random number R _T ⁱ = H (key∥R _T ^i-1 ∥R _R ) (where R _T ⁰ = H (key)) to generate a random number. use.

A modification 3 will be described with reference to FIG. 9.

(Course 1: Leader)

The reader broadcasts the Query together with a random number R _R. [Challenge process].

Reader → Tags: Query, R _R

(Course 2: tags)

The tag is a concatenation of a unique secret authentication ID of the tag and the random number R _R , inputted into the one-way function H ₁ , and the output value H ₁ (ID || R _R ) and the random number R _T ⁱ , generated from the tag. That is, H (key || R _T ^i-1 || R _R ) is transmitted to the reader in response to the reader's query. Response process.

Tag → Reader: H ₁ (ID || R _R ), R _T ⁱ

(Course 3: Leader)

The reader sends the random number R _R and the output value H ₁ (ID || R _R ) of the one-way function received from the tag and the random number R _T ⁱ to the back-end database (DB).

Reader → Back-End Database: H ₁ (ID || R _R ), R _R , R _T ⁱ

(Course 4: Back-End Database)

All IDs stored in the back-end database are concatenated with R _R, and each is entered in one-way function H ₁ . The output value H ₁ (ID || R _R ) of the one-way function is compared with the output value H ₁ (ID || R _R ) of the one-way function received from the reader. At this time, if the output values match, the tag authentication is successful. If the output values do not match, the tag authentication is determined to fail.

리더로부터 수신한 H₁(ID||R_R)Back-End Database (DB): H ₁ calculated from DB (ID || R _R )

H ₁ received from reader (ID || R _R )

(Course 5: back-end database)

If there is a calculated H ₁ (ID∥R _R ) that matches the output value H ₁ (ID∥R _R ) of the one-way function received from the reader, the corresponding ID is authenticated as the ID of the tag. The random number R _T ⁱ is concatenated, and the H ₂ (ID∥R _T ⁱ ) generated by inputting the one-way function H ₁ and the other one-way function H ₂ is transmitted to the reader.

Back-end Database → Reader: H ₂ (ID∥R _T ⁱ )

(Course 6: Leader)

The reader sends to the tag H ₂ (ID∥R _T ⁱ ) received from the back-end database (DB).

Readers → Tags: H ₂ (ID∥R _T ⁱ )

(Course 7: tags)

Tag is concatenated to R _T ⁱ generated by the own ID and the authentication and session type, and the one-way function H _2, the output value of the one-way function H ₂ (ID∥R _T ⁱ⁾ and the output value of a one-way function received from the reader H ₂ Compare (ID∥R _T ⁱ ). At this time, if the output value matches the output value of the one-way function received from the reader, the back-end database is authenticated. If the output value does not match, the authentication of the back-end database is determined to fail.

리더로부터 수신한 H₂(ID∥R_T ⁱ)Tag: H ₂ calculated from tag (ID∥R _T ⁱ )

H ₂ (ID∥R _T ⁱ ) received from reader

Here, if authentication of the back-end database succeeds or fails, the random number R _T ^i-1 is updated to R _T ⁱ and the authentication process ends.

(Modification 4)

A simple way for a tag not to use a separate random number generator is to use the number of counters (or the current time in the tag or T = R _R + n) as the random number R _T. The time at which a tag is requested or responded to a response, the number of counters inside the tag, or R _R + n at the time of a specific response request are available as R _T because they are random. Here, n added to or subtracted from R _R may vary depending on the implementation method. For example, n may be ± 1, 2.

A modification 4 will be described with reference to FIG. 10.

(Course 1: Leader)

The reader broadcasts the Query together with a random number R _R. [Challenge process].

Reader → Tags: Query, R _R

(Course 2: tags)

The tag associates the authentication information ID with the random number R _R , inputs it to the one-way function H ₁ , and outputs the one-way function value H ₁ (ID || R _R ) and the number of counters generated by the tag (or the current time in the tag). Or, send T = R _R + n (n = ± 1,2 ..) to reader in response to leader's query. Response process.

Tag → Reader: H ₁ (ID || R _R ), T

(Course 3: Leader)

The reader reads the random number R _R and the output value H ₁ (ID || R _R ) of the function received from the tag and the number T of the counter of the tag (or the current time in the tag or T = R _R + n (n = ± 1,2. Send.)) To the back-end database (DB).

Reader → Back-End Database: H ₁ (ID || R _R ), R _R , T

(Course 4: Back-End Database)

All IDs stored in the back-end database are concatenated with R _R and entered in the one-way function H ₁ . The output value H ₁ (ID || R _R ) of the one-way function is compared with the output value H ₁ (ID || R _R ) of the one-way function received from the reader. At this time, if the output values match, the tag authentication is successful, and if the output values do not match, the tag authentication is determined to fail.

리더로부터 수신한 H₁(ID||R_R)Back-End Database (DB): H ₁ calculated from DB (ID || R _R )

H ₁ received from reader (ID || R _R )

(Course 5: back-end database)

Back to match the H ₁ (ID∥R _R) received from the reader - if the H ₁ (ID∥R _R) calculated from the end database exists, the authentication ID to the ID of the tag, and the tag ID of the H ₂ (ID generated by concatenating the number of counters (or current time in the tag or T = R _R + n (n = ± 1,2 ..)) T and inputting to one-way function H ₁ and another one-way function H ₂ ∥T) to the reader.

Back-end Database → Reader: H ₂ (ID∥T)

(Course 6: Leader)

The reader sends H ₂ (ID ∥T) received from the back-end database (DB) to the tag.

Readers → Tags: H ₂ (ID∥T)

(Course 7: tags)

Tag is concatenated to T generated by the own ID and the authentication and session type, and the one-way function H _2, and compares the H ₂ (ID∥T) received from the one-way function output value H ₂ (ID∥T) and the leader of the . At this time, if the output value matches the input value received from the reader, the back-end database is authenticated. If the output value does not match, the authentication of the back-end database is determined to be a failure.

리더로부터 수신한 H₂(ID∥T)Tag: H ₂ calculated from tag (ID∥T)

H ₂ (ID∥T) received from reader

③ When the one-way functions H ₁ and H ₂ are the same and generate a random number R _T without using a separate random number generator.

Instead of a separate random number generator, the key is stored in the tag when the tag is produced so that the random number can be generated using the one-way function already built in. Tags are then concatenated to one R _R received from the stored key and a tag is generated random number in a previous authentication session R _T ^{i-1 (i} is a natural number) and a reader, enter the one wherein the function generates a new random number R _T ^i. When the first tag is produced, R _T ⁰ is set to H (key). That is, in the embodiment according to FIG. 6, before the process 2, the tag generates R _T ⁱ = H (key∥R _T ^i-1 ∥R _R ) (where R _T ⁰ = H (key)) and uses it as a random number. do.

(Modification 5)

A modification 5 will be described with reference to FIG. 11.

(Course 1: Leader)

The reader broadcasts the tags together with the query and the random number R _R generated by the reader.

Reader → Tags: Query, R _R

(Course 2: tags)

The tag is a unique authentication information ID and the random number R _R and the random number R _T ⁱ generated from the tag, That is, H (key || R _T ^i-1 || R _R ) is concatenated, input into a specific one-way function H, and the output value H (ID || R _R || R _T ⁱ ) and the random number R generated from the tag. Send _T ⁱ to the reader in response to the reader's query. Response process.

Tag → Reader: H (ID || R _R || R _T ⁱ ), R _T ⁱ

(Course 3: Leader)

The reader sends the random number R _R and the output value H (ID || R _R || R _T ⁱ ) of the one-way function received from the tag and the random number R _T ⁱ to the back-end database (DB).

Reader → Back-End Database: H (ID || R _R || R _T ⁱ ), R _R , R _T ⁱ

(Course 4: Back-End Database)

Concatenate all IDs stored in the back-end database with random numbers R _R and random numbers R _T ⁱ , and enter each one-way function H. The output value H (ID || R _R || R _T ⁱ ) of the one-way function is compared with the output value H (ID || R _R || R _T ⁱ ) of the one-way function received from the reader to determine whether they match. At this time, if the output values match, the tag authentication is successful, and if the output values do not match, the tag authentication is determined to fail.

리더로부터 수신한 H(ID||R_R||R_T ⁱ)Back-End Database (DB): H calculated from DB (ID || R _R || R _T ⁱ )

H received from reader (ID || R _R || R _T ⁱ )

(Course 5: back-end database)

A one-way function of the output value received from the reader H (ID || R _R R _T || ⁱ⁾ and matches the output value of the computed one-way function H (ID || R _R R _T || ⁱ⁾ if the presence of the ID Is authenticated with the ID of the tag, the ID and the random number R _T ⁱ generated by the tag are concatenated, and the output value H (ID || R _T ⁱ ) of the one-way function generated by inputting to the one-way function H is transmitted to the reader.

Back-end Database → Reader: H (ID || R _T ⁱ )

(Course 6: Leader)

The reader sends to the tag an H (ID ∥ R _T ⁱ ) received from the back-end database (DB).

Readers → Tags: H (ID∥R _T ⁱ )

(Course 7: tags)

The tag associates its ID with the R _T ⁱ created in the authentication session and enters it into the one-way function H. The tag compares the output value of the one-way function with the H (ID ∥ R _T ⁱ ) received from the reader. At this time, if the output value matches the input value received from the reader, the back-end database is authenticated. If the output value does not match, the authentication of the back-end database is determined to be a failure.

리더로부터 수신한 H(ID∥R_T ⁱ)Tag: H (ID∥R _T ⁱ ) calculated from tag

H (ID∥R _T ⁱ ) received from reader

Here, if authentication of the back-end database succeeds or fails, the random number R _T ^i-1 is updated to R _T ⁱ and the authentication process ends.

  Already, IT developed countries such as the US, Europe, and Japan see RFID as a key field to lead the growth of the next generation IT industry, and have invested heavily in related technologies and research and development for many years. As a result, these countries are currently growing at 20-30% annually. However, security threats such as user privacy breaches and information leakage that can result from the use of RFID can be a barrier to this growth. In the situation where RFID developers and security companies have not yet been interested in the development of technology that can safely use RFID, the present invention can preoccupy the future RFID authentication technology field by providing a secure RFID authentication method, and the spread of RFID It may contribute to the activation.

Claims (14)

In an RFID system comprising at least one tag, at least one reader and at least one back-end database, The reader broadcasts the tags and the random number R _R generated by the reader to the tags [Step 1: Challenge Step], The tag associates the random number R _R with a unique authentication information ID of a tag and inputs it to a specific one-way function H ₁ , and outputs the output value H ₁ (ID ∥ _{R R} ) of the one-way function and the random number R _T generated from the tag. To the leader in response to the [process 2: response process], The reader transmits the random number R _R and H ₁ (ID ∥ _{R R} ) received from the tag and the random number R _T to a back-end database (DB) (step 3), The back-end database associates all stored IDs with the random number R _R and inputs them to the one-way function H ₁ , respectively. The output value of this one-way function H ₁ (ID ∥ _{R R} ) and the output value of the one-way function received from the reader. Compare H ₁ (ID∥R _R), if the output value H ₁ (ID∥R _R) of the one-way function that matches the one-way output value H ₁ (ID∥R _R) of the function is received from the reader is present, the Authenticate the ID with the ID of the tag (step 4), Transmits the ID tag is concatenated with sikimyeo the random number R _T generated, H ₂ (ID∥R _T) is generated by input to the other one-way function H ₂ and the one-way function H ₁ to the reader, and (process 5), The reader transmits the output value H ₂ (ID∥R _T ) of the one-way function received from the back-end database (DB) to the tag (step 6). The tags are concatenated to R _T generated by the own ID and the authentication process (the session) and input to the one-way function H _2, and the output value of the one-way function H ₂ output of the one-way function received from (ID∥R _T) and leaders compared to H ₂ (ID∥R _T), the output value of the one-way function H ₂ (ID∥R _T) when the back-match-authentication method of the RFID system, characterized in that (process 7), authenticating the end database . The method of claim 1 wherein in step 400 - if the output value of the one-way function H ₁ from the receiving-end database, a one-way function output value H ₁ (ID∥R _R) and the leader of the calculation in (ID∥R _R) do not match, The tag authentication is determined to be a failure and the authentication process is terminated. If the output value H ₂ (ID∥R _T ) of the one-way function calculated in the tag in step 7 does not match the output value H ₂ (ID∥R _T ) of the one-way function received from the reader, authentication of the back-end database fails. The authentication method in the RFID system, characterized in that the determination process is terminated. In an RFID system comprising at least one tag, at least one reader and at least one back-end database, The reader broadcasts the tag and the random number R _R generated by the reader to the tags [Challenge process: process 1], The tag associates the padding value 00 with the unique ID information of the tag and the random number R _R , inputs it to the one-way function H, and generates the output value H (00 || ID || R _R ) of the one-way function and the tag. The random number R _T is transmitted to the leader in response to the leader's query [Response process: process 2], The reader transmits the random number R _R and the output value H (00 || ID || R _R ) of the one-way function received from the tag and the random number R _T to the back-end database (process 3), The back-end database concatenates all stored IDs with the received random numbers R _R and inputs them to the one-way function H, respectively, and outputs the one-way function value H (00 || ID || R _R ) and the one-way function received from the reader. the output value H (ID || 00 || R _R) by comparison, a one-way function output that matches the one-way output value H (ID || 00 || R _R) of the function is received from the reader H (ID || 00 the If R _R ) exists, it is authenticated with the ID of the tag (step 4), Concatenate the padding value 11 and the random number R _T generated by the ID and tag, and transmit the output value H (11 || ID || R _T ) of the one-way function generated by inputting to the one-way function H to the reader (step 5). The reader sends the output value H (11 || ID || R _T ) of the one-way function received from the back-end database DB to the tag (step 6). The tag associates the padding value 11 with its ID and the R _T generated in the authentication process (session) and inputs it to the one-way function H. From the output value H (11 || ID || R _T ) of the one-way function and the reader, An authentication method in an RFID system, characterized by comparing the output value H (11 || ID || R _T ) of the received one-way function and authenticating the back-end database (step 7) if the output values match. The output value H (00 || ID || R _R ) of the one-way function calculated in the back-end database in step 4 and the output value H (00 || ID || _R ) of the one-way function received from the reader. _{If R} ) does not match, the tag authentication is determined to be failed and the authentication process is terminated. If the output value H (11 || ID || R _R ) of the one-way function calculated in the tag in step 7 does not match the output value H (11 || ID || R _R ) of the one-way function received from the reader, the back-end The authentication method of the RFID system, characterized in that the authentication of the database is determined to fail and terminates the authentication process. In an RFID system comprising at least one tag, at least one reader and at least one back-end database, The reader broadcasts the tag and the random number R _R generated by the reader to the tags [Challenge process: process 1], The tag associates a unique authentication information ID with the random number R _R and a self-generated random number R _T , and inputs it to one-way function H, and outputs the one-way function value H (ID || R _R || R _T ) and the tag. Sends the random number R _T created in the reader to the reader in response to the reader's query. The reader transmits the output value H (ID || R _R || R _T ), the random number R _R, and the random number R _T of the one-way function received from the tag to the back-end database (step 3), The back-end database from each input, and an output value of a one-way function H (ID || || R _R R _T) and the reader each one-way function H and concatenated with the random number R and _R R _T receives all the stored ID Compare the output value H (ID || R _R || R _T ) of the received one-way function (step 4), The output value of a one-way function is received from the reader H (ID || || R _R R _T) and the output value of the one-way function matches H (ID || || R _R R _T) of the ID tag if the presence ID Authenticate with the ID and the tag, and concatenate the random number R _T generated by this ID and the tag, and transmit the output value H (ID || R _T ) of the one-way function generated by inputting to the one-way function H (step 5), The reader sends the output value H (ID || R _T ) of the one-way function received from the back-end database (DB) to the tag (step 6). The tag associates its ID with the random number R _T generated during the authentication process and inputs it to the one-way function H. The output value H (ID || R _T ) of the one-way function and the output value H (ID || R) received from the reader. _T ), and if the output values match, authenticating the back-end database (step 7). The method according to claim 5, wherein the output value H (ID || R _R || R _T ) of the one-way function calculated in the back-end database in step 4 and the output value H (ID || R _R | If R _T ) does not match, tag authentication If the output value H (ID || R _T ) of the one-way function calculated in the tag in step 7 does not match the output value H (ID || R _T ) of the one-way function received from the reader, authentication of the back-end database fails. The authentication method in the RFID system, characterized in that to terminate the authentication process. It has at least one tag, at least one reader, and at least one back-end database, and the tag stores a key in the tag when the tag is produced to generate a random number using a built-in one-way function. The tag is a concatenation of the stored key and the random number R _T ^i-1 (i is a natural number) generated from the tag in the previous authentication process (session) and the random number R _R received from the reader. _In an RFID system that generates _T ⁱ and sets R _T ⁰ = H (key) when the tag is produced, The reader broadcasts a random number R _R together with the Query to the reader [Challenge Process: Process 1], The tag associates a unique secret authentication information ID with the random number R _R , inputs it to a one-way function H ₁ , and outputs the output value H ₁ (ID || R _R ) and the random number R _T ⁱ = generated from the tag. Send H (key || R _T ^i-1 || R _R ) to the reader in response to the leader's query [Response process: Step 2], The reader sends the random number R _R and the output value H ₁ (ID || R _R ) and the random number R _T ⁱ of the one-way function received from the tag to the back-end database (step 3), The back-end database associates all stored IDs with R _R , respectively, and inputs them into one-way function H ₁ , and outputs one-way function H ₁ (ID || R _R ) and one-way function H received from the reader. ₁ (ID || R _R ) is compared, and if there is a calculated H ₁ (ID∥R _R ) that matches the output value H ₁ (ID∥R _R ) of the one-way function received from the reader, the corresponding ID of the tag Authenticate by ID (Course 4), Concatenate the random number R _T ⁱ generated by this ID and the tag, input one-way function H ₁ and the other one-way function H ₂ , and transmit the generated H ₂ (ID∥R _T ⁱ ) to the reader (step 5), The reader sends the output value H ₂ (ID ∥R _T ⁱ ) of the one-way function received from the back-end database (DB) to the tag (step 6). The tag concatenates its ID and the random number R _T ⁱ generated in the authentication session and inputs it to the one-way function H ₂ , and the output value of the one-way function H ₂ (ID ∥ R _T ⁱ ) and the one-way function received from the reader. If the output value of the one-way function matches the output value of the one-way function received from the reader by comparing the output value H ₂ (ID∥R _T ⁱ ), the back-end database is authenticated, and the random number R _T ^i-1 is R _T ^i. The authentication method in the RFID system, characterized by updating to (process 7). 8. The method of claim 7, wherein the output value H ₁ (ID || R _R ) of the one-way function calculated in the back-end database in step 4 coincides with the output value H ₁ (ID || R _R ) of the one-way function received from the reader. If not, the tag authentication will be judged as failed and the authentication process will be terminated. If the output value H ₂ (ID∥R _T ⁱ ) of the one-way function calculated in the tag in step 7 does not match the output value H ₂ (ID∥R _T ⁱ ) of the one-way function received from the reader, authentication of the back-end database is performed. The authentication method in the RFID system, characterized in that the failure is determined to terminate the authentication process, and to update the random number R _T ^i-1 to R _T ⁱ . At least one tag and at least one reader and at least one back-end database, wherein the tag is the number of counters (or the current time in the tag or T = R _R + n (n = ± 1,2 In an RFID system which generates ..)) as a random number R _T , where n is ± 1,2 .. The reader broadcasts the tag and the random number R _R generated by the reader to the tags [Challenge process: process 1], The tag associates the authentication information ID with the random number R _R , inputs it to the one-way function H ₁ , and outputs the one-way function value H ₁ (ID || R _R ) and the number of counters generated from the tag (or the current number in the tag. Transmit time or T = R _R + n (n = ± 1,2 ..) to leader in response to leader's query [Response Process: Process 2], The reader transmits the random number R _R and the output value H ₁ (ID || R _R ) of the one-way function received from the tag and the number T of the counters of the tag to the back-end database DB (process 3). remind The back-end database and concatenating all the ID stored in each of R and _R, respectively, input to the one-way function H _1, and an output value of a one-way function H ₁ (ID || R _R) the output value of a one-way function is received from the reader ₁ H Compare (ID || R _R ) and tag the ID if H ₁ (ID∥R _R ) is calculated in the back-end database that matches H ₁ (ID∥R _R ) received from the reader. Authenticate with the ID of (course 4), Generate this by concatenating this ID and the counter number of the tag (or the current time in the tag or T = R _R + n (n = ± 1,2 ..)) T and inputting it to one-way function H ₁ and another one-way function H ₂ . Send one H ₂ (ID∥T) to the reader (step 5), The reader sends H ₂ (ID ∥T) received from the back-end database (DB) to the tag (step 6), The tag T generated by the connecting and the own ID and the authentication session and input to the one-way function H _2, and the output value of a one-way function received from the output value of the one-way function H ₂ (ID∥T) and H ₂ reader (ID∥ Comparing T), and authenticating the back-end database if the output value matches the input value received from the reader. 10. The method of claim 9, wherein if the output value H ₁ (ID ∥ _{R R} ) of the one-way function calculated in the back-end database in step 4 does not match the output value H ₁ (ID ∥ _{R R} ) of the one-way function received from the reader, The tag authentication is determined to be a failure and the authentication process is terminated. If the output value H ₂ (ID ∥T) of the one-way function calculated in the tag in step 7 does not match the output value H ₂ (ID ∥T) of the one-way function received from the reader, the authentication of the back-end database is determined to fail. An authentication method in an RFID system, characterized in that the authentication process is terminated. It has at least one tag, at least one reader, and at least one back-end database, and the tag stores a key in the tag when the tag is produced to generate a random number using a built-in one-way function. and, the tag after concatenating the random number R _R received from the stored key and the previous authentication process (the session), a tag is generated random number in the R _T ^i-1 (i is a natural number) and a reader to input the one-way function, the new random number R _T ^In an RFID system that generates ⁱ and sets R _T ⁰ = H (key) when the tag is produced, The reader broadcasts the tag and the random number R _R generated by the reader to the tags [Challenge process: process 1], The tag associates a unique authentication information ID with the random number R _R and the random number R _T ⁱ = H (key || R _T ^i-1 || R _R ) generated from the tag, and inputs the one-way function H. The output value H (ID || R _R || R _T ⁱ ) of the one-way function and the random number R _T ⁱ generated from the tag are transmitted to the reader in response to the reader's query [Response Process: Process 2], The reader transmits the random number R _R and the output value H (ID || R _R || R _T ⁱ ) of the one-way function received from the tag and the random number R _T ⁱ to the back-end database (Process 3), The back-end database is concatenated with all stored IDs and random numbers R _R and random numbers R _T ⁱ , respectively, and inputs to one-way function H, and the output value of this one-way function H (ID || R _R || R _T ⁱ ) and Comparing the output value H (ID || R _R || R _T ⁱ ) of the one-way function received from the reader, the calculated H (ID matching the H (ID || R _R || R _T ⁱ ) received from the reader || R _R || R _T ⁱ ), if present, authenticates it with the ID of the tag (step 4), Concatenate the random number R _T ⁱ generated by this ID and the tag, input the generated one-way function H to H (ID || R _T ⁱ ) to the reader (step 5), The reader transmits the output value H (ID∥R _T ⁱ ) of the one-way function received from the back-end database DB to the tag (step 6), The tag connects its ID and R _T ⁱ generated in the authentication process (session) and inputs it to the one-way function H, and compares the output value of the one-way function with the received H (ID∥R _T ⁱ ) from the reader, If the output value matches the input value received from the reader, the authentication method in the RFID system is characterized by authenticating the back-end database and updating the random number R _T ^i-1 to R _T ⁱ (step 7). . 12. The method of claim 11, wherein the process 100-4 - han output value H of the one-way function computed in end database (ID || R _R R _T || ⁱ⁾ the output value H (ID of the one-way function is received from the reader R || _R If || R _T ⁱ ) does not match, the tag authentication is determined to be unsuccessful and the authentication process ends. If the output value H (ID∥R _T ⁱ ) of the one-way function calculated in the tag in step 7 does not match the output value H ₂ (ID∥R _T ⁱ ) of the one-way function received from the reader, authentication of the back-end database fails. And the authentication process is terminated, and the random number R _T ^i-1 is updated to R _T ⁱ . In an RFID system comprising at least one tag, at least one reader and at least one back-end database, The reader broadcasts the tag and the random number R _R generated by the reader to the tags [Challenge process: process 1], The tag associates the unique authentication information ID with the random number R _R , inputs it to the one-way function H, and transmits the output value H (ID || R _R ) of the one-way function to the reader in response to the reader's query. Response process: course 2], The reader transmits the output value H (ID || R _R ) and random number R _R of the one-way function received from the tag to the back-end database (Process 3), The back-end database concatenates random numbers R _R , which have received all stored IDs, and inputs them to one-way function H, respectively, and outputs one-way function value H (ID || R _R ) and one-way function value H received from the reader. (ID || R _R ), if the output value is matched, the corresponding ID is authenticated with the ID of the tag (process 4), and the authentication process in the RFID system, characterized in that the end of the authentication process. The method of claim 13, wherein the output value H (ID || R _R ) of the one-way function calculated in the back-end database in step 4 does not match the output value H (ID || R _R ) of the one-way function received from the reader. The authentication method in the RFID system, characterized in that the tag authentication is determined to fail and terminates the authentication process.

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