WO2021090975A1

WO2021090975A1 - Method for generating temporary anonymous certificate

Info

Publication number: WO2021090975A1
Application number: PCT/KR2019/014955
Authority: WO
Inventors: 문기봉; 강준구; 한하원
Original assignee: 한국스마트인증 주식회사
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2021-05-14

Abstract

A preprocessing method for generating a temporary anonymous certificate according to the present invention: generates, by a user terminal, a public key and a private key; generates, by the user terminal, a first validity verification value by digitally signing an ID of a work program module via the private key; generates, by the user terminal, a first encryption value by encrypting the ID of the work program module and the first validity verification value via the public key of a certificate authority; transmits, by the user terminal, a first account ID and the first encryption value to an account module; generates, by the account module, a second encryption value that is a value obtained by homogeneously encrypting a second account ID; generates, by the account module, a second validity verification value by digitally signing the first encryption value; generates, by the account module, a permission value including the first encryption value and the second validity verification value; generates, by the account module, a third validity verification value by digitally signing the second encryption value and the permission value; and transmits, by the account module, the second encryption value, the permission value, and the third validity verification value to the user terminal.

Description

How to generate a temporary anonymous certificate

The present invention relates to a method of generating a temporary anonymous certificate to ensure that the result of the user's work is not forged while ensuring the anonymity of the user in an activity or work where anonymity is to be guaranteed online.

With the development of online, many activities and tasks that were done offline are moving to online. For example, online activities and tasks are increasing, such as making financial transactions online, purchasing products, or expressing intentions such as electronic voting.

Normal online activities or tasks often require measures to verify the identity of the user and prevent non-repudiation. For example, in online financial transactions, it is necessary to check whether the user is a legitimate user, and to prevent users from denying the details of online financial transactions in the future. For these measures, digital certificates have been introduced and used for online transactions, activities, and work. The representative one is the public certificate, which contains the user's private key and public key, so that the details of transactions, activities, and operations transmitted online can be encrypted and transmitted to the other party, and the related details have not been forged. It enables an electronic signature that the other party can prove.

However, there are cases where the identity of the user should not be exposed in online activities or tasks. As a representative example, in the case where anonymity is required, such as electronic voting, which is performed online, the voter's identity is exposed when a certificate according to the prior art is introduced to prove that the voting result has not been forged. It was difficult to apply because of the limitations of

An object of the present invention is to provide a method of generating a temporary anonymous certificate that can guarantee anonymity while certifying the integrity of the result of an activity or work performed online.

The pre-processing method for generating a temporary anonymous certificate according to the present invention is performed in an environment including a block chain including an account module and a work program module, a user terminal, and a certification authority server (CA).

The pre-processing method includes: a first step of generating, by a user terminal, a public key and a private key; A second step of generating, by a user terminal, a first validation value (Sign_1) by digitally signing an ID (V_ID) of a work program module with the secret key; A third step of generating, by the user terminal, the first encryption value E_1 by encrypting the ID of the work program module and the first validation value with a CA Public Key of the certification authority; A fourth step of transmitting, by the user terminal, a first account ID (A_ID) and a first encryption value (E_1) to an account module; A fifth step of generating, by the account module, a second encryption value (E_2), which is a value obtained by homogeneously encrypting the second account ID (AA_ID); A sixth step of generating, by the account module, a second validation value (Sign_2) by electronically signing the first encryption value (E_1); A seventh step of generating, by the account module, a permission value including a first encryption value E_1 and a second validation value Sign_2; An eighth step of generating, by the account module, a third validation value (Sign_3) by electronically signing the second encryption value (E_2) and the permission value; The account module includes a ninth step of transmitting the second encryption value E_2, the permission value, and the third validity verification value Sign_3 to the user terminal.

The second encryption value may be a value calculated by performing a one-way function operation on a value obtained by homomorphic encryption of the first identification ID, the random value generated by the account module, and the random value generated by the user terminal.

The method of storing the work result performed by the user terminal in the work program module after the pre-processing method is performed, the work program module, the ID of the work program module, a public key, a second encryption value (E_2), A step 1-1 of receiving the permission value and the third validity verification value (Sign_3) from the user terminal; A second step of verifying, by the work program module, the second encryption value E_2 and the permission value; A step 3-1 of generating, by the work program module, an ID of a temporary anonymous certificate; A step 4-1 of transmitting, by the work program module, the ID of the temporary anonymous certificate, the work program module ID, the permission value, and the public key to the certification authority server; A step 5-1 of the certification authority server verifying the permission value with the certificate of the account module; A step 6-1 of decoding the authorization value, by the certification authority server, to obtain an ID of the work program module (V_ID) and a first validation value (Sign_1); A step 7-1 of generating, by the certification authority server, a temporary anonymous certificate; Step 8-1, wherein the work program module receives the temporary anonymous certificate from the certification authority server; A 9-1 step of generating, by the work program module, a third encryption value (E_3), which is a value obtained by homogeneously encrypting the job identification ID; Step 10-1, wherein the work program module calculates the random value calculated by the third encryption value E_3 and the first formula as the fourth encryption value E_4 obtained by homomorphic encryption of the tag value. Wow; A step 11-1 of transmitting, by the work program module, a third encryption value (E_3), a fourth encryption value (E_4), and a temporary anonymous certificate to the user terminal; A step 12-1 of decrypting, by the user terminal, the third encryption value E_3 and the fourth encryption value E_4 to obtain a job identification ID and a tag value; A step 13-1 of digitally signing, by the user terminal, a job identification ID, a tag value, and a job result with a secret key of a temporary anonymous certificate to generate a fourth validation value (Sign_4); The work program module includes a work program module ID (V_ID), a work identification ID (Ballot Stamp), a tag value, a work result (voting), a fourth validation value (Sign_4), and an ID of a temporary anonymous certificate. , Step 14-1 of receiving a temporary anonymous certificate from the user terminal; The work program module includes step 15-1 of verifying the fourth validation value Sign_4 and the tag value and storing the work result if successful, and not storing the work result otherwise.

The third encryption value may be a value calculated by performing a one-way function operation on the second encryption value E_2 and the work program module ID.

If the integrity of the online activity or work result is verified and stored using a temporary anonymous certificate as in the present invention, it is impossible to store the forged work result in the work program module.

1 is a flow chart of a pre-processing process for issuing a temporary anonymous certificate.

Fig. 2 is a flow chart of a modified embodiment of Fig. 1;

3 is a flowchart of issuing a temporary anonymous certificate and storing a result of the operation.

Fig. 4 is a block diagram of an electronic computing device embodying the present invention.

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

Encryption/decryption may be applied to the information (data) transmission/reception process performed in this specification as needed, and expressions describing the information (data) transmission process in this specification and claims are all encrypted/ It should be interpreted as including the case of decryption. In this specification, expressions in the form of "transmitted from A to B (transmitted)" or "received from A by B" include those transmitted (transmitted) or received with another medium in the middle, and directly from A to B It does not just express what is transmitted (delivered) or received. In the description of the present invention, the order of each step is to be understood without limitation, unless the preceding step must be performed logically and temporally prior to the subsequent step. That is, except for the above exceptional cases, even if a process described as a subsequent step is performed prior to a process described as a preceding step, the essence of the invention is not affected, and the scope of rights should be defined regardless of the order of the steps. And in the present specification, "A or B" is defined to mean not only selectively indicating any one of A and B, but also including both A and B. In addition, in the present specification, the term "comprising" has the meaning of encompassing a further including other elements in addition to the elements listed as including.

In this specification, the term "module" refers to a logical combination of general-purpose hardware and software that performs the function.

In the present specification, only essential components necessary for the description of the present invention are described, and components not related to the essence of the present invention are not mentioned. In addition, it should not be interpreted as an exclusive meaning including only the mentioned components, but should be interpreted as a non-exclusive meaning that may exclude certain non-essential components or include other components.

The present invention is performed by an electronic computing device such as a computer capable of electronic calculation, and the mathematical calculation and calculation of each step of the present invention described below are suitable for the known coding method and/or the present invention to perform the corresponding calculation or calculation. It can be implemented as a computer operation by a coding designed in a way.

The implementation of the present invention can be performed by various electronic computing devices. An example of an electronic computing device that performs each step of the present invention is shown in FIG. 4. As shown in FIG. 4, the electronic processing unit 1309 includes a processor (e.g., a central processing unit (CPU) 1310), a memory 1320, a wired or wireless communication unit 1330, and at least one input unit. 1340, and at least one output unit 1350, but the included components are not limited to the listed components. It should be understood that the structure shown in FIG. 13 is provided simplified for illustration purposes only. The structure of the electronic computing device 1309 may be changed in an appropriate manner by a person skilled in the art according to the claims to be described later. In addition, each component of the electronic computing device 109 may also be changed in an appropriate manner by a person skilled in the art according to the claims to be described later. Therefore, the structure of the apparatus shown in FIG. 4 is merely exemplary and should not be construed as limiting the scope of the present invention.

The processor 1300 may control the operation of the electronic computing device 1309. In more detail, the processor 1310 may be operated to control and interact with various components installed in the electronic computing device 1309 as shown in FIG. 4. For example, the memory 1320 may store program instructions or data executed by the processor 1300. The process (step) described herein may be stored in the memory 1320 in the form of program instructions for execution of the processor 1300. The communication unit 1330 may allow the electronic computing device 1309 to transmit data to at least one external device or receive data from at least one external device through a communication network. The input unit 1340 may enable the electronic computing device 1309 to receive various types of inputs such as audio/video input, user input, and data input. For this purpose, the input unit 1340 is, for example, at least one camera 1342 (that is, "image acquisition unity"), a touch panel 1344, and a microphone (not shown) in order to accept various types of input. ), a sensor 1346, a keyboard, a mouse, and at least one button or switch (not shown). The term "image acquisition unit" as used herein may refer to the camera 1342, but is not limited thereto. The output unit 1350 may display information on the display screen 1352 so that the user can see it. The display screen 1352 may be configured to accept at least one input, such as a user tapping or pressing the screen 1352 through a variety of known mechanisms. The output unit 1350 may further include a light source 1354. The electronic computing device 1309 is shown as a single device, but may also consist of multiple separate devices that can be connected and interact with each other while in use.

In the present specification, the term "value" is defined in a broad sense including not only scalar values, but also vectors, matrices, tensors, and polynomials.

In the present specification, HE(**) refers to a value obtained by isomorphically encoding a value in parentheses.

In this specification, the terms "electronic signature value" or "electronic signature" are used for convenience of explanation, but any value (validity verification value) that can determine whether information is forged or altered can be used as a validity verification value. In addition, it should be understood that any method other than the usual electronic signature can be used to generate the validation value.

The method according to the present invention is performed in an environment including a user terminal 10, an account module 20, a work program module 30, and a certification authority server 40. The certification authority server 40 is used to obtain a temporary anonymous certificate required when performing an operation online. The account module 20 and the work program module 30 may be components included in the blockchain.

1 is a flowchart of a pre-processing method for issuing a temporary anonymous certificate (TAC) according to the present invention. The temporary anonymous certificate according to the present invention is defined as a digital certificate that is valid only once or within a predetermined number or time for a job that requires verification of the result of a job by means of a certificate, and cannot identify information related to the user's identity.

The user terminal 10 generates a temporary anonymous certificate and a public key and a private key to be used (step 100). The user terminal 10 digitally signs the work program module ID (V_ID) with the generated secret key to generate a first digital signature value (Sign_1) (step 101).

The user terminal 10 generates a first encryption value E_1 by encrypting the work program module ID and the first digital signature value Sign_1 with the public key of the certification authority server (step 102).

The user terminal 10 transmits a first identification ID (A_ID) and a first encryption value (E_1) uniquely assigned to each user in the account module to the account module 20 to request a second identification ID (AA_ID). Do (step 103).

The account module 20 generates a second encryption value E_2, which is an isomorphic encryption value HE(AA_ID) of the second identification ID AA_ID (step 109). The second encryption value E_2 = HE(AA_ID) may be calculated by performing a one-way function operation on a value including the first identification ID A_ID. In order to ensure the randomness of the second identification ID (AA_ID), the above value may include a random value and/or an isomorphic encryption value of a random value.

The second encryption value E_2 may be calculated to have the following relationship, for example.

HE(AA_ID) = Hash[A_ID, Ra, HE(Re)] = HE[Hash(A_ID, Ra, Re)]

Re is a random value generated by the user terminal, and Ra may be a random value generated by the account module.

The account module 20 digitally signs the first encryption value E_1 to generate a second digital signature value Sign_2 (step 110).

The account module 20 generates a permission value in step 111. The permission value includes a first encryption value E_1 and a second digital signature value Sign_2.

The account module 20 generates a third digital signature value Sign_3 by performing an electronic signature on the second encryption value E_2 and the permission value (step 112).

The account module 20 transmits the second encryption value E_2, the permission value, and the third digital signature value Sign_3 to the user terminal 10 (step 113).

FIG. 2 shows a pre-processing process in the case where the user terminal 10 does not have the homomorphic encryption value HE(Re) of the random value Re.

In step 103, in order to receive a request for a second identification ID (AA_ID) from the user terminal 10 and generate the isomorphic encryption value (HE(AA_ID) of the second identification ID, the HE(Re) value as described above. If this is necessary, but if it does not have the value, it requests the user terminal 10 to reset the random value Re (step 104).

The user terminal 10 generates a random value Re and performs homomorphic encryption on the random value (step 105).

The user terminal 10 transmits the isomorphic encryption value HE(Re) of a random value to the account module 20 (step 106), and the account module 20 generates another random value Ra (step 107).

Subsequently, the account module stores the first identification ID (A_ID), the random value (Ra), and the isomorphic encryption value (HE(Re)) of the random value received from the user terminal (step 108), and The second encryption value E_2 is generated through the same relationship (step 109). The subsequent process is the same as steps 110 to 113 of FIG. 1.

After the process of FIG. 1 or 2 is completed, a method of verifying and storing the integrity of the work result when the user performs a predetermined work online will be described with reference to FIG. 3. Working online can be, for example, an electronic voting where anonymity must be guaranteed.

Prior to the process of FIG. 3, it is assumed that an anonymous communication channel is opened between the user terminal 10 and the work program module 30.

The user terminal 10 first transmits a work program module ID (V_ID) to the work program module 30, a public key of a certificate, a second encryption value (E_2), a permission value, and a third digital signature value (Sign_3). By transmitting the job identification ID (BallotStamp) to request the homomorphic encryption value (HE (BallotStamp)) (step 300).

The work program module 30 verifies the second encryption value E_2 and the permission value (step 301), and if the verification is successful, generates a temporary anonymous certificate ID (TAC_ID) (step 302).

The work program module 30 transmits the temporary anonymous certificate ID, the work program module ID (V_ID), the permission value, and the public key of the TAC to the certification authority server 40 to request a temporary anonymous certificate (step 303). ).

The certification authority server 40 verifies the permission value with the certificate of the account module (step 304).

The certification authority server 40 decodes the permission value to obtain a work program module ID (V_ID) and a first digital signature value (Sign_1) (step 305).

The certification authority server 40 verifies the work program module ID (V_ID) (step 306).

The verification of the work program module ID (V_ID) is performed by comparing the V_ID received in step 303 with the V_ID obtained through decoding the permission value in step 305, and whether they are the same.

If verification of the work program module ID (V_ID) is successful, the certification authority server 40 generates a certificate (step 307), and transmits the generated certificate (TAC) to the work program module 40 (step 308).

The job program module 30 generates a third encryption value (E_3) that is set to a value obtained by homomorphic encryption of the job identification ID (BallotStamp), and calculates a random value and a third encryption value (E_3) by a first equation. One value is generated as the fourth encrypted value E_4, which is an isomorphic encrypted value of the tag value (tag) (step 309).

The third encryption value E_3 may be calculated by performing a one-way function operation on a value including the second encryption value E_2, and isomorphic encryption of a random value and/or a random value to the value to ensure randomness. May contain values. For example, the third encryption value may be calculated by the following relationship.

E_3 = HE(BallotStamp) = Hash[HE(AA_ID), V_ID] = HE[Hash(AA_ID, V_ID)]

The first equation may be, for example, an equation that multiplies the first random value r1 and the third encryption value E_3 and then adds the second random value r2.

Then the following relationship is established.

r1*E_3+r2 = HE(r1*BallotStamp+r2) = HE(tag) = E_4

The first equation may include an XOR operation. In that case, the following relationship is established.

XOR(r1, E_3) = HE(XOR(r1, BallotStamp)

The work program module 30 stores a temporary anonymous certificate ID (TAC_ID) and a random value used to generate the third encryption value E_3 (step 310).

The work program module 30 transmits the third encryption value E_3, the fourth encryption value E_4, and the temporary anonymous certificate TAC to the user terminal 10 (step 312).

The user terminal 10 decrypts the third and fourth encryption values E_3 and E_4 to obtain and store a job identification ID (BallotStamp) and a tag value (steps 313 and 314).

The user terminal 10 digitally signs a job identification ID (BallotStamp), a tag value, and a job result (for example, a voting result) using a secret key of a temporary anonymous certificate (TAC) to obtain a fourth digital signature value. (Sign_4) is generated (step 315).

The user terminal 10 includes a work program module ID (V_ID), a work identification ID (BallotStamp), a tag value, a work result, a fourth digital signature value (Sign_4), a temporary anonymous certificate ID (TAC_ID), and , Transmits a temporary anonymous certificate (TAC) to the work program module 30 (step 316).

The job program module 30 verifies the tag value received in step 317 and the fourth digital signature value (Sign_4), and if successful, a job identification ID (BallotStamp), a tag value, a job result, and a random value. And, the fourth digital signature value (Sign_4) and a temporary anonymous certificate are stored, otherwise, the storage of the work result is rejected.

If the tag value received in step 316 is the same as the value calculated by the first equation for the random value and the third encryption value E_3, it is determined that the verification has been successful, otherwise it is determined that the verification has failed.

If the integrity of the online activity or work result is verified and stored using a temporary anonymous certificate as in the present invention, it is impossible to store the forged work result in the work program module. In order for the work program module 30 to falsify the work result, it is necessary to receive a permission value and a third digital signature value (Sign_3) from the account module 20, so that the work program module 30 has an effect that it is impossible to forge the work result. have.

Although the present invention has been described with reference to the accompanying drawings, the scope of the present invention is determined by the claims to be described later and should not be construed as being limited to the above-described embodiments and/or drawings. And it should be clearly understood that the improvements, changes and modifications of the invention described in the claims, which are obvious to those skilled in the art, are included in the scope of the present invention.

Claims

In the preprocessing method for generating a temporary anonymous certificate of a user in an environment including a block chain including an account module and a work program module, a user terminal, and a certification authority server (CA),

A first step of the user terminal generating a public key and a private key,

A second step of generating, by the user terminal, a first validation value (Sign_1) by digitally signing the ID (V_ID) of the work program module with the secret key,

A third step of generating, by the user terminal, the first encryption value E_1 by encrypting the ID of the work program module and the first validation value with the CA Public Key of the certification authority;

A fourth step in which the user terminal transmits the first account ID (A_ID) and the first encryption value (E_1) to the account module,

A fifth step of generating, by the account module, a second encryption value (E_2), which is a value obtained by homogeneously encrypting the second account ID (AA_ID);

A sixth step of generating, by the account module, a second validation value (Sign_2) by electronically signing the first encryption value (E_1),

A seventh step of generating, by the account module, a permission value including a first encryption value E_1 and a second validation value Sign_2, and

An eighth step of generating, by the account module, a third validation value (Sign_3) by electronically signing the second encryption value (E_2) and the permission value;

The account module comprises a ninth step of transmitting a second encryption value (E_2), a permission value, and a third validation value (Sign_3) to the user terminal,

Pre-processing method for generating temporary anonymous certificates.
The method according to claim 1,

The second encryption value is a value calculated by performing a one-way function operation on a homomorphic encryption value of the first identification ID, the random value generated by the account module, and the random value generated by the user terminal,

Pre-processing method for generating temporary anonymous certificates.
In a method of storing a work result performed by a user terminal in a work program module after the pre-processing method of claim 1 or 2 is performed,

Step 1-1 of the work program module receiving the ID of the work program module, the public key, the second encryption value (E_2), the permission value, and the third validation value (Sign_3) from the user terminal; ,

The work program module, step 2-1 of verifying the second encryption value (E_2) and the permission value,

Step 3-1 of the work program module generating the ID of the temporary anonymous certificate,

Step 4-1, in which the work program module transmits the ID of the temporary anonymous certificate, the work program module ID, the permission value, and the public key to the certification authority server,

Step 5-1, in which the certification authority server verifies the permission value with the certificate of the account module,

Step 6-1 of the certification authority server decrypting the permission value to obtain the ID of the work program module (V_ID) and the first validation value (Sign_1),

Step 7-1, in which the certification authority server generates a temporary anonymous certificate,

Step 8-1 in which the work program module receives the temporary anonymous certificate from the certification authority server,

Step 9-1, wherein the work program module generates a third encrypted value (E_3), which is a value obtained by homogeneously encrypting the work identification ID;

Step 10-1, wherein the work program module calculates the random value calculated by the third encryption value E_3 and the first formula as the fourth encryption value E_4 obtained by homomorphic encryption of the tag value. Wow,

Step 11-1 of the work program module transmitting a third encryption value (E_3), a fourth encryption value (E_4), and a temporary anonymous certificate to the user terminal;

Step 12-1 of the user terminal decrypting the third encryption value E_3 and the fourth encryption value E_4 to obtain a job identification ID and a tag value,

Step 13-1 in which the user terminal digitally signs a job identification ID, a tag value, and a job result with a secret key of a temporary anonymous certificate to generate a fourth validation value (Sign_4);

The work program module includes a work program module ID (V_ID), a work identification ID (Ballot Stamp), a tag value, a work result (voting), a fourth validation value (Sign_4), and an ID of a temporary anonymous certificate. Step 14-1 of receiving a temporary anonymous certificate from the user terminal,

The work program module includes step 15-1 of verifying the fourth validation value (Sign_4) and the tag value, and storing the work result if successful, and not storing the work result otherwise,

How to save work results.
The method of claim 3,

The third encryption value is a value calculated by performing a one-way function operation on the second encryption value E_2 and the work program module ID,

How to save work results.