WO2018147673A1

WO2018147673A1 - Symmetric key-based user authentication method for ensuring anonymity in wireless sensor network environment

Info

Publication number: WO2018147673A1
Application number: PCT/KR2018/001745
Authority: WO
Inventors: 정재욱; 박정환; 전재율
Original assignee: 에스지에이솔루션즈 주식회사
Priority date: 2017-02-09
Filing date: 2018-02-09
Publication date: 2018-08-16
Also published as: KR101721511B1

Abstract

The present invention relates to a symmetric key-based user authentication method performed by a smart card, a user terminal capable of reading and writing the smart card, a plurality of sensors, and a gateway communicating with the sensor. The present invention provides a configuration comprising the steps of: (a) receiving, by the gateway, a user ID and a dynamic password from the user terminal, generating a secret key encrypted with the ID and the dynamic password, and a login verification value composed of the dynamic password and the secret key, and storing the same in the smart card; (b) extracting, by the user terminal, the dynamic password from the input ID and password, decrypting the secret key by using the extracted dynamic password, restoring the login verification value, and verifying the restored login verification value with the login verification value of the smart card; (c) generating, by the user terminal, a dynamic ID, generating a symmetric key with a dynamic ID and a secret key, encrypting the dynamic ID with a symmetric key to generate a first message, and transmitting the dynamic ID and the first message to the gateway; (d) restoring, by the gateway, the symmetric key with the received dynamic ID and the stored secret key, decoding the first message with the restored symmetric key, and verifying the dynamic ID; (e) generating, by the gateway, a second random number, encrypting the second random number with a shared key, generating a session key with the received dynamic ID, the shared key, and the second random number, generating a second verification value with a dynamic ID, a session key, a shared key, and a sensor ID, and transmitting the encrypted second random number, the dynamic ID, and the second verification value to each sensor; (f) decrypting, by each sensor, the second random number with the shared key, extracting and sharing the session key with the received dynamic ID, the shared key, and the decrypted second random number, and extracting and verifying the second verification value with the dynamic ID, the extracted session key, the shared key, and the sensor ID; (g) generating, by each sensor, a third verification value with the shared key, the extracted session key, the received dynamic ID, and the sensor ID, and transmitting the generated third verification value to the gateway; (h) extracting, by the gateway, the third verification value with the shared key, the generated session key, the received dynamic ID, and the sensor ID to compare and verify the extracted third verification value with the transmitted third verification value, and transmitting a second message in which the dynamic ID, the sensor ID, the session key, and a first random number are encrypted with the symmetric key; and (i) decrypting, by the user terminal, the second message with the symmetric key, and verifying the dynamic ID and the first random number. By using only the hash function with a very small amount of computation and the symmetric key-based cryptosystem according to the user authentication method as described above, it is possible to have a very high efficiency in terms of efficiency.

Description

Symmetric Key-based User Authentication Method for Anonymity in Wireless Sensor Networks

The present invention provides a user authentication method suitable for a wireless sensor network environment that is secure against various attack methods, but uses only a hash function and a symmetric key based encryption system with a very small amount of computation. It relates to a user authentication method based on.

Wireless sensor network is a network environment composed of many sensor nodes and gateway nodes that manage them. Currently, wireless sensor networks are widely used in combination with various technologies in various fields such as military facility management, health care service, and smart grid environment.

As the importance of wireless sensor network environment increases, various researches are underway to ensure the confidentiality and integrity of important information of sensors. In particular, research on the design of user authentication protocols has been in the spotlight as a representative method for ensuring the safety of the wireless sensor network environment. The user authentication protocol is a security technology that aims for successful authentication between users by securely accessing the corresponding gateway node and sensor node using their smart card, ID, and password information. However, since the characteristics of sensor nodes that are very limited in terms of energy use must be taken into consideration, user authentication protocols must be designed considering not only safety but also efficiency.

An object of the present invention is to solve the problems described above, to provide a user authentication method suitable for a wireless sensor network environment that is safe for various attack methods, using only a hash function and a symmetric key-based encryption system with a very small amount of calculation, It is to provide a symmetric key based user authentication method that guarantees anonymity in a wireless sensor network environment.

In particular, an object of the present invention is to configure an encryption / decryption using only symmetric key cryptography and XOR operation in consideration of the limited hardware resources of the sensor. To provide a way.

To achieve the above object, the present invention relates to a symmetric key-based user authentication method performed by a smart card, a user terminal capable of reading and writing the smart card, a plurality of sensors, and a gateway communicating with the sensor. The gateway receives the user's ID and dynamic password from the user terminal, generates a secret key encrypted with the ID and the dynamic password, and a login verification value composed of the dynamic password and the secret key to the smart card. Storing; (b) extracting, by the user terminal, a dynamic password from the input ID and password, decrypting the secret key using the extracted dynamic password, restoring the login verification value, and verifying the login verification value of the smart card; (c) the user terminal generates a dynamic ID, generates a symmetric key with the dynamic ID and a secret key, generates a first message by encrypting the dynamic ID with a symmetric key, and transmits the dynamic ID and the first message to the gateway. Doing; (d) restoring, by the gateway, the symmetric key with the received dynamic ID and the stored secret key, and verifying the dynamic ID by decrypting the first message with the restored symmetric key; (e) the gateway generates a second random number, encrypts the second random number with a shared key, generates a received dynamic ID, a shared key, and a session key with the second random number, and generates a dynamic ID, a session key, and a shared key. Generating a second verification value using a sensor ID and transmitting an encrypted second random number, a dynamic ID, and the second verification value to each sensor; (f) Each sensor decrypts the second random number with the shared key, extracts the shared session key with the received dynamic ID, shared key, and decrypted second random number, and shares the dynamic ID, extracted session key, shared key, and sensor ID. Extracting and verifying a second verification value with; (g) generating, by each sensor, a third verification value using a shared key, an extracted session key, a received dynamic ID, and a sensor ID, and transmitting the third verification value to the gateway; (h) The gateway extracts a third verification value using the shared key, the generated session key, the received dynamic ID, and the sensor ID, and verifies it against the transmitted third verification value, and checks the dynamic ID, the sensor ID, and the session key. And transmitting a second message obtained by encrypting a first random number with the symmetric key; And (i) the user terminal decrypting the second message with a symmetric key to verify the dynamic ID and the first random number.

In addition, in the symmetric key-based user authentication method, the dynamic password or dynamic ID is generated by concatenating a random number to the password or ID and hashing the same.

In addition, the present invention is a symmetric key-based user authentication method, in the step (a), characterized in that the secret key is used as a hash value of the secret value previously generated by the gateway.

In addition, the present invention is a symmetric key-based user authentication method, wherein in the step (e), the shared key is used as a hash value by concatenating the sensor ID to a secret value previously shared between the gateway and the sensor. It is characterized by.

In addition, the present invention, in the symmetric key-based user authentication method, in the step (d), (f), (h), (i), the time stamp is received, predetermined by the time stamp After the grace time has elapsed, it is characterized in that the subsequent steps are not performed.

In addition, the present invention is a symmetric key-based user authentication method, in step (c), generating a first random number, including the first random number in the first message, and in step (h), The first random number of the first message is included in the second message and transmitted. In step (i), the first random number of the second message is verified.

The present invention also relates to a computer-readable recording medium having recorded thereon a program for performing a user authentication method based on a symmetric key.

As described above, according to the symmetric key-based user authentication method for guaranteeing anonymity in a wireless sensor network environment according to the present invention, by using only a hash function having a very small amount of computation and a symmetric key-based encryption system, An effect with very high advantages is obtained.

1 is a block diagram of an overall system for practicing the present invention.

2 is a table showing a notation for explaining a symmetric key-based user authentication method of the present invention.

3 is a flowchart illustrating a user registration step of a symmetric key based user authentication method according to an embodiment of the present invention.

4 is a flowchart illustrating the login and verification steps of a symmetric key based user authentication method according to an embodiment of the present invention.

5 is a flowchart illustrating a password change step of a symmetric key based user authentication method according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, specific contents for carrying out the present invention will be described with reference to the drawings.

In addition, in describing this invention, the same code | symbol is attached | subjected and the repeated description is abbreviate | omitted.

First, examples of the configuration of the entire system for implementing the present invention will be described with reference to FIG.

As shown in FIG. 1, the entire system for implementing the present invention includes a smart card 11, a user terminal 10 capable of reading or recording the smart card 11, a gateway 20, and a plurality of sensors. Or a sensor node 30.

The user terminal 10 is a computing terminal used by a user, such as a smartphone, a tablet PC, a PC, a laptop, and the like. In addition, the user terminal 10 may access the smart card 11 to read, record or change the contents recorded in the card.

The smart card 11 is a storage medium having a security function, and is a conventional IC chip, a smart card, or the like.

The gateway 20 is a gateway device that collects data or controls the sensor 30 through a plurality of sensors 30 and wirelessly.

The sensor or sensor node 30 is a sensor for measuring temperature, image, sound, humidity, and the like, and is a device that communicates using a short range communication protocol such as Zigbee, Wi-Fi, or Bluetooth.

That is, in order for the user terminal 10 such as a smartphone to access the sensor 30, the user authentication information is stored in the smart card. When the user terminal 10 passes the authentication of the gateway by the smart card, the user terminal 10 may access the sensor through the gateway.

The notation used for clarity below is summarized as shown in the table of FIG. 2.

Next, various security requirements that can be satisfied in the user authentication method according to the present invention will be described. That is, the security requirements to be considered in the wireless sensor network environment are as follows, and the user authentication method according to the present invention should also satisfy the following security requirements.

(1) User Anonymity: The user's identity must be secure even if the messages sent over the protocol are exposed through eavesdropping attacks, and must be secured against user smart card attacks.

(2) Mutual authentication: Verifies the mutual authentication by performing verification process on all messages exchanged between users, sensor nodes, and gateway nodes participating in the wireless sensor network environment.

(3) Session key distribution: Finally, the session key distribution process is performed through mutual authentication. The user can then use the distributed session key to securely communicate with the gateway and sensor nodes.

(4) Quick detection of incorrectly entered password: The user must enter his ID and password when logging into the wireless sensor network. However, if the legitimacy check process for the password input by the user is not performed at the login stage, it is determined whether or not the correctness of the password is performed after proceeding to the verification stage performed after the login stage. Since this is very inefficient, the login phase must confirm the validity of the password entered by the user.

(5) Efficient password change: The user authentication method generally includes a step of safely changing a user's password. At this time, the user should change the user's password in the smart card itself rather than changing the password through the server.

(6) Safe against spoofing attacks: An attacker has the ability to penetrate the authentication method. A fake attack is an act of deceiving an opponent by acting as if the attacker is a legitimate user.

(7) Safe against offline password attacks: Your password is important information that should not be exposed. Offline password attack is an attack method that infers these user's passwords by total investigation method.

(8) Safe to insider attack: The administrator who manages the gateway node in the user registration stage can use malicious packets sent by the user to grasp the user's personal information. In general, a lot of password information is exposed, and this must be considered in the user authentication method.

Meanwhile, in the present invention, an authentication method is constructed using only a symmetric key-based encryption technique and a hash function operation in consideration of limited hardware resources of a sensor node.

Next, a symmetric key based user authentication method according to an embodiment of the present invention will be described in more detail with reference to FIGS. 3 to 5.

The user authentication method according to the present invention comprises a registration step, a login and verification step (or an authentication step), a password change step, and the like. In addition, the user authentication method according to the present invention satisfies all the security requirements described above.

First, the registration step will be described with reference to FIG. 3.

The registration step is a step in which the user or the user terminal 10 registers the user (or his smart card information) with the gateway or the gateway node 20 using the user's information. 3 shows a registration step, and a detailed execution procedure according to this is as follows.

First, the user terminal 10 selects the ID ID _i and the password PW _i of the user, and generates a random number b (S1). And dynamic passwords

Calculate = h (PW _i ∥b). Where i is the subscript identifying the user.

And to the gateway node 20 <ID _i ,

Send> (S2).

Next, the gateway node 20 calculates the secret key v = h (x _a ), and stores v in the database (S3). And the secret key encrypted by encrypting vN _i = h (ID _i ∥)

)

v, and the login verification value M _i = h (

∥v) and store v in the database. Where x _a is the secret generated by the gateway node.

The gateway node 20 generates a smart card for use by the user and stores the smart card authentication information (N _i , M _i , h (·)) in the smart card and issues it to the user. That is, the issued smart card (N _i , M _i , h (·)) is transmitted to the user terminal 10 (S4).

Next, the user terminal 10 having received the smart card inserts a random number b generated by the user into the smart card 11 (S5). Finally, after the registration phase, the user gets a smart card that stores (N _i , M _i , h (·), b).

Next, a login and verification step (or authentication step) will be described with reference to FIG. 4. As shown in Figure 4, it consists of a login process and a verification process.

First, the login process is explained. The login process is a step performed when the user terminal approaches the wireless sensor network environment.

The user inserts his smart card into the terminal and enters ID _i and PW _i (S11). Smart card

^* = h (PW _i ∥b), v ^* = N _i

h (ID _i ∥

^* ), M _i ^* = h (

After calculating ^* ∥ v ^* ), M _i ^* values and M _i values stored in the smart card are compared with each other (S12). If the two values are the same, the user is proved to have entered the correct password, and if the two values are different, the login phase ends.

Next, the smart card generates a random number first random number R ₁ , the dynamic ID DID _i = h (ID _i ∥ R ₁ ), the symmetric key k = h (DID _i ∥v ^* ∥T ₁ ), Compute the first message A _i = E _k (DID _i ∥R ₁ ∥T ₁ ) (S13).

Finally, the smart card transmits a login request message <DID _i , A _i , T ₁ > to the gateway node (S14).

Next, the verification process will be described. The verification process begins when the gateway receives a login request message from the user. In this step, mutual authentication procedure is performed through verification of messages sent and received, and when all authentication procedures are completed, session key SK is finally shared between sensor node and user. In addition, by using the shared session key SK, the user can securely communicate with the corresponding sensor node in the future.

Next, after receiving the login request message <DID _i , A _i , T ₁ > from the user, the gateway node uses the timestamp T ₁ value to transmit the first message received | T ₁ '-T ₁ | The validity is checked through <ΔT (S21).

In addition, the gateway node calculates the symmetric key k = h (DID _i ∥h (x _a ) ∥T ₁ ) and decrypts the encrypted A _i value D _k (A _i ) = (DID _i , R ₁ , T ₁ } (S22). To validate the login request message, compare the DID _i and T ₁ values obtained from the decryption operation with the values in the received login request message. If the two values are equal to each other, the following procedure is continued, and if the two values are different, the step ends.

Next, the gateway node 20 generates a second random number R ₂ value and L _i = R ₂

h (x _s ∥SID _n ), session key SK = h (DID _i ∥h (x _s ∥SID _n ) ∥R ₂ ∥T ₂ ), 2nd verification value B _i = h (DID _i ∥SK∥h ( x _s ∥ SID _n ) ∥ SID _n ∥ T ₂ ) (S23). L _i is a second random number encrypted with h (x _s ∥ SID _n ).

The gateway node 20 transmits <L _i , DID _i , B _i , and T ₂ > to the sensor node 30 (S24).

Next, the sensor node 30 first checks | T ₂ '-T ₂ | for the received <L _i , DID _i , B _i , T ₂ >. Time stamp verification is performed through <ΔT (S31).

If the verification is done correctly, the sensor node 30 will return R ₂ = L _i

h (x _s ∥SID _n ), SK = h (DID _i ∥h (x _s ∥SID _n ) ∥R ₂ ∥T ₂ ), B _i ^* = h (DID _i ∥SK ∥h (x _s ∥SID _n ) SID _n ∥T ₂ ) is calculated and B _i ^* and B _i are compared with each other to verify the received message <L _i , DID _i , B _i , T ₂ > (S32). If the verification is successful, the sensor node ensures that the gateway node that sent the message is a legitimate gateway node.

Next, the sensor node 30 calculates a third verification value C _i = h (h (x _s ∥SID _n ) ∥SK ∥DID _i ∥SID _n ∥T ₃ ) and gives the gateway node <C _i , T _3. The value is transmitted (S33).

Next, the gateway node 20 transmits | T ₃ '-T ₃ | to the received <C _i , T ₃ >. Time stamp verification is performed by <ΔT (S41).

If the verification is done correctly, calculate C _i ^* = h (h (x _s ∥ SID _n ) ∥ SK ∥ DID _i ∥ SID _n ∥ T ₃ ), compare C _i ^* and C _i with each other and receive the message <C _i , T ₃ > is verified (S42). If the verification is successful, the gateway node ensures that the sensor node that sent the message is a legitimate sensor node.

Next, the gateway node 20 calculates a second message D _i = E _k (DID _i ∥SID _n ∥SK ∥R ₁ ∥T ₄ ) and transmits <D _i , T ₄ > to the user (S43, S44).

Next, the user terminal 10 with respect to the received <D _i , T ₄ > | T ₄ '-T ₄ | The time stamp verification is performed through <ΔT (S51).

After the verification is correctly performed, the decryption operation D _k (D _i ) = {DID _i , SID _n , SK, R ₁ , T ₄ } on the encrypted D _i value is performed (S52). In addition, to verify the validity of the received message <D _i , T ₄ >, the DID _i , R ₁ , T ₄ values obtained through the decoding operation are compared with the DID _i , R ₁ , T ₄ values previously held. .

If all of the comparison values match, the user is convinced that the gateway node sending the message <D _i , T ₄ > is a valid gateway node and the verification step is successfully completed.

Next, the password change step will be described with reference to FIG.

The password change step is for changing a user's password. If the user password is changed, the values in the smart card that are affected by the password should also be changed. In the password change step according to the present invention, since the smart card itself is designed to change the password without a separate communication with the server, it can be said that it is very excellent in terms of efficiency. A detailed description of the password change step follows.

First, the user inserts his smart card into the terminal and enters ID _i , the existing password PW _i ^old , and the new password PW _i ^new (S71).

* Next, smart card

= h (PW _i ^old ∥ b), v ^old = N _i

h (ID _i ∥

), M _i ^old = h (

∥v ^old ) is calculated, and then M _i ^old and M _i stored in the smart card are compared with each other (S72). If the two values are different, the password change step is terminated, and if they are the same, the following procedure is performed.

Next, the smart card is configured with a new password

= h (PW _i ^new ∥ b), N _i ^new = h (ID _i ∥

)

v, M _i ^new = h (

∥ calculate v) (S73).

Finally, the smart card replaces the newly calculated {N _i ^new , M _i ^new } values with the {N _i , M _i } values stored in the existing smart card (S74). After the password change phase, the smart card contains the values (N _i ^new , M _i ^new , h (·), b).

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

Claims

A smart card, a user terminal capable of reading and writing the smart card, a plurality of sensors, and a symmetric key based user authentication method performed by a gateway communicating with the sensor,

The gateway receives the user's ID and dynamic password from the user terminal, generates a secret key encrypted with the ID and the dynamic password, and a login verification value composed of the dynamic password and the secret key to the smart card. Storing;

(b) extracting, by the user terminal, a dynamic password from the input ID and password, decrypting the secret key using the extracted dynamic password, restoring the login verification value, and verifying the login verification value of the smart card;

(c) the user terminal generates a dynamic ID, generates a symmetric key with the dynamic ID and a secret key, generates a first message by encrypting the dynamic ID with a symmetric key, and transmits the dynamic ID and the first message to the gateway. Doing;

(d) restoring, by the gateway, the symmetric key with the received dynamic ID and the stored secret key, and verifying the dynamic ID by decrypting the first message with the restored symmetric key;

(e) the gateway generates a second random number, encrypts the second random number with a shared key, generates a received dynamic ID, a shared key, and a session key with the second random number, and generates a dynamic ID, a session key, and a shared key. Generating a second verification value using a sensor ID and transmitting an encrypted second random number, a dynamic ID, and the second verification value to each sensor;

(f) Each sensor decrypts the second random number with the shared key, extracts and shares the session key with the received dynamic ID, the shared key, and the decrypted second random number, and the dynamic ID, the extracted session key, the shared key, and the sensor ID. Extracting and verifying a second verification value with;

(g) generating, by each sensor, a third verification value using a shared key, an extracted session key, a received dynamic ID, and a sensor ID, and transmitting the third verification value to the gateway;

(h) The gateway extracts a third verification value using the shared key, the generated session key, the received dynamic ID, and the sensor ID, and verifies it against the transmitted third verification value, and checks the dynamic ID, the sensor ID, and the session key. And transmitting a second message obtained by encrypting a first random number with the symmetric key; And,

(i) the user terminal decrypts the second message with a symmetric key to verify the dynamic ID and the first random number.
The method of claim 1,

Dynamic password or dynamic ID is a symmetric key-based user authentication method characterized in that generated by concatenating (hash) concatenation (random number) to the password or ID.
The method of claim 1,

In the step (a), the secret key is a symmetric key-based user authentication method, characterized in that the gateway is used as a hash value of the previously generated secret value.
The method of claim 1,

In the step (e), the shared key is a symmetric key-based user authentication method, characterized in that used as a hash value by concatenating a sensor ID to a secret value previously shared between the gateway and the sensor.
The method of claim 1,

In steps (d), (f), (h), and (i), a timestamp is received, and after a predetermined grace time has elapsed by the timestamp, subsequent steps are not performed. Symmetric key based user authentication.
The method of claim 1,

In step (c), a first random number is generated and transmitted by including the first random number in the first message,

In step (h), the first random number of the first message is included in the second message and transmitted.

In step (i), the user authentication method based on the symmetric key, characterized in that to verify the first random number of the second message.
A computer-readable recording medium recording a program for performing the user authentication method based on any one of claims 1 to 6.