KR102123435B1 - Encryption method for supporting equality query in multi-client environment and apparatus using the same - Google Patents

Abstract

Disclosed are an encryption method and apparatus for supporting an equivalent query for ciphertexts in a multi-client environment. According to one embodiment of the present invention, the method comprises the steps of: obtaining a user encryption key from a key generating device; and generating a ciphertext for an attribute vector based on a label for the attribute vector and the user encryption key.

Description

ENCRYPTION METHOD FOR SUPPORTING EQUALITY QUERY IN MULTI-CLIENT ENVIRONMENT AND APPARATUS USING THE SAME}

Embodiments of the invention relate to encryption technology.

Predicate Encryption (Predicate Encryption) is a secret key encryption technology that enables the equivalent operation between the attribute vector and the attribute of the encrypted message. Conventional predicate-based cryptography has been difficult to compare multiple ciphertexts generated by multiple clients at once. Some multiple predicate-based cryptography supports comparison of multiple ciphertexts generated by multiple clients, but the disadvantage of linear increase in the number of ciphertexts processed by the process of performing a query (or decryption) operation on multiple ciphertexts It was inefficient.

Republic of Korea Patent Registration No. 10-1695361 (January 2017. 11. Announcement)

Embodiments of the present invention are to provide an encryption method supporting an equivalent query in a multi-client environment and an apparatus using the same.

A method according to an embodiment of the present invention is a method performed in a computing device having one or more processors, and a memory storing one or more programs executed by the one or more processors, the user password from the key generating device Obtaining a key; And generating a ciphertext for the attribute vector based on the label for the attribute vector and the user encryption key.

The generating of the ciphertext may include generating a hash value for the label;

Generating a pseudo-random number for each of the one or more attribute values included in the attribute vector; And generating the ciphertext based on the hash value, the pseudo-random number, and the user encryption key.

The ciphertext may include a plurality of ciphertext elements calculated by using a pseudo-random number for each of the one or more attribute values as an index of the hash value.

The user encryption key, the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number)을 만족하고, 상기 의사 난수를 생성하는 단계는, 아래의 수학식 2 및 3(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the step of generating the pseudo-random number includes Equations 2 and 3 below.

[Equation 2]

[Equation 3]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 상기 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값,

는 상기 속성 값

에 대한 의사 난수)을 이용하여 상기 하나 이상의 속성 값 각각에 대한 의사 난수를 생성할 수 있다.(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute value for attribute category j among the one or more attribute values,

Is the attribute value

Pseudo-random number for) to generate a pseudo-random number for each of the one or more attribute values.

The step of generating the ciphertext is Equation 4 below.

[Equation 4]

는 상기 암호문,

은 상기 속성 벡터에 포함된 속성 카테고리의 총 개수, T는 상기 라벨,

는 상기 해시 값)을 이용하여 상기 암호문을 생성할 수 있다.(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

May generate the ciphertext using the hash value).

A method according to an embodiment of the present invention is a method performed in a computing device having one or more processors, and a memory storing one or more programs executed by the one or more processors, for each of a plurality of users Generating a user encryption key and a master secret key; Providing the generated user encryption key to the client devices of each of the plurality of users; Receiving a query vector set including a plurality of query vectors from the query device; Generating a token for the query vector set using the query vector set and the master secret key; And providing the generated token to the query device.

Generating the token may include generating a pseudo-random number for the query vector set; And generating the token using the pseudo-random number and the master secret key.

The user encryption key is the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number))을 만족하고, 상기 의사 난수를 생성하는 단계는, 아래의 수학식 2 및 3(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the step of generating the pseudo-random number includes Equations 2 and 3 below.

[Equation 2]

[Equation 3]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 상기 질의 벡터 집합에 대한 토큰,

는 질의 벡터 i에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값, S_i는 상기 질의 벡터 i에 포함된 하나 이상의 속성 값들 중 와일드 카드(wild card) 속성 값을 제외한 나머지 속성 값들 각각에 대한 속성 카테고리 인덱스들의 집합)을 이용하여 상기 의사 난수를 생성할 수 있다.(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is the token for the vector set of queries,

Is an attribute value for an attribute category j among one or more attribute values included in the query vector i, and S _i is an attribute value for each of the attribute values excluding wild card attribute values among one or more attribute values included in the query vector i. The set of attribute category indices for) may be used to generate the pseudo-random number.

The step of generating the master secret key is Equation 4 below.

[Equation 4]

는 위수가 p인 순환군(cyclic group)

의 원소)를 이용하여 상기 마스터 비밀키를 생성하고, 상기 토큰을 생성하는 단계는, 아래의 수학식 5(At this time, MK is the master secret key, n is the total number of the plurality of users,

Is a cyclic group with p

Step of generating the master secret key using the elements of, and generating the token, Equation 5 below

[Equation 5]

는 상기 질의 벡터 집합에 대한 토큰,

,

및

는 각각

의 원소)를 이용하여 상기 토큰을 생성할 수 있다.(At this time,

Is the token for the vector set of queries,

,

And

Each

The element can be generated using the () element.

A method according to an embodiment of the present invention is a method performed in a computing device having one or more processors, and a memory storing one or more programs executed by the one or more processors, including a plurality of query vectors Generating a vector set of queries to be performed; Obtaining a token for the set of query vectors from a key generator; And an attribute vector set including the plurality of attribute vectors and the query using a ciphertext for each of the plurality of attribute vectors encrypted using different user encryption keys, a label for the plurality of attribute vectors, and the token. And determining whether to establish an equivalent relationship between vector sets.

The ciphertext for each of the plurality of attribute vectors includes a hash value for the label, a first pseudo-random number for each of one or more attribute values included in each of the plurality of attribute vectors, and the user encryption key. The token may be generated using the second pseudo-random number for the query vector set and the master secret key.

The user encryption key is the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number))을 만족하고, 상기 제1 의사 난수는, 아래의 수학식 2(

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the first pseudo-random number is Equation 2 below.

[Equation 2]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 사용자 i의 사용자 암호키를 이용하여 암호화된 속성 벡터

에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값,

는 상기 속성 값

에 대한 제1 의사 난수)을 이용하여 생성되고, 상기 제2 의사 난수는, 아래의 수학식 3(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute vector encrypted using the user's user encryption key.

The attribute value for attribute category j among one or more attribute values included in

Is the attribute value

Is generated using the first pseudo-random number for, the second pseudo-random number, Equation 3 below

[Equation 3]

는 상기 질의 벡터 집합에 대한 토큰,

는 상기 속성 벡터

에 대한 질의 벡터

에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값, S_i는 상기 질의 벡터 i에 포함된 하나 이상의 속성 값 중 와일드 카드(wild card) 속성 값을 제외한 나머지 속성 값들 각각에 대한 속성 카테고리 인덱스들의 집합)을 이용하여 생성되며, 상기

는 아래의 수학식 4(At this time,

Is the token for the vector set of queries,

Is the above attribute vector

Query for vector

Attribute value for attribute category j among one or more attribute values included in, S _i is an attribute category index for each of the other attribute values excluding wild card attribute values among one or more attribute values included in the query vector i Is generated using a set of

Equation 4 below

[Equation 4]

It can be generated using.

The master secret key is Equation 5 below

[Equation 5]

는 위수가 p인 순환군(cyclic group)

의 원소)를 만족하고,(At this time, MK is the master secret key, n is the number of the plurality of users,

Is a cyclic group with p

Element of)

The ciphertext is the following Equation 6

[Equation 6]

는 상기 암호문,

은 상기 속성 벡터에 포함된 속성 카테고리의 총 개수, T는 상기 라벨,

는 상기 해시 값)을 만족하고,(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Satisfies the above hash value),

The token, Equation 7 below

[Equation 7]

는 상기 토큰,

,

및

는 각각

의 원소)을 만족할 수 있다.(At this time,

Is the token,

,

And

Each

Element of).

The determining step, Equation 8 below

[Equation 8]

를 만족하는 겹선형 함수(bilinear map),

,

및

는 위수(order)가 소수 p인 순환군(cyclic group))이 만족되는 경우, 상기 동치 관계가 성립하는 것으로 판단할 수 있다.(At this time, e is

Bilinear map, which satisfies

,

And

When the cyclic group having a small number of p is satisfied, it may be determined that the same relationship is established.

An apparatus according to an embodiment of the present invention, a memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the program comprising: obtaining a user encryption key from a key generating device; And instructions for executing the step of generating a ciphertext for the attribute vector based on the label for the attribute vector and the user encryption key.

The generating of the ciphertext may include generating a hash value for the label; Generating a pseudo-random number for each of the one or more attribute values included in the attribute vector; And the ciphertext based on the hash value, the pseudo-random number, and the user encryption key.

The ciphertext may include a plurality of ciphertext elements calculated by using a pseudo-random number for each of the one or more attribute values as an index of the hash value.

The user encryption key, the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number)을 만족하고, 상기 의사 난수를 생성하는 단계는, 아래의 수학식 2 및 3(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the step of generating the pseudo-random number includes Equations 2 and 3 below.

[Equation 2]

[Equation 3]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 상기 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값,

는 상기 속성 값

에 대한 의사 난수)을 이용하여 상기 하나 이상의 속성 값 각각에 대한 의사 난수를 생성할 수 있다.(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute value for attribute category j among the one or more attribute values,

Is the attribute value

Pseudo-random number for) to generate a pseudo-random number for each of the one or more attribute values.

The step of generating the ciphertext is Equation 4 below.

[Equation 4]

는 상기 암호문,

은 상기 속성 벡터에 포함된 속성 카테고리의 총 개수, T는 상기 라벨,

는 상기 해시 값)을 이용하여 상기 암호문을 생성할 수 있다.(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

May generate the ciphertext using the hash value).

An apparatus according to an embodiment of the present invention, one or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, wherein the programs generate a user encryption key and a master secret key for each of the plurality of users. To do; Providing the generated user encryption key to the client devices of each of the plurality of users; Receiving a query vector set including a plurality of query vectors from the query device; Generating a token for the query vector set using the query vector set and the master secret key; And instructions for executing the step of providing the generated token to the query device.

Generating the token may include generating a pseudo-random number for the query vector set; And generating the token using the pseudo-random number and the master secret key.

The user encryption key is the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number))을 만족하고, 상기 의사 난수를 생성하는 단계는, 아래의 수학식 2 및 3(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the step of generating the pseudo-random number includes Equations 2 and 3 below.

[Equation 2]

[Equation 3]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 상기 질의 벡터 집합에 대한 토큰,

는 질의 벡터 i에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값, S_i는 상기 질의 벡터 i에 포함된 하나 이상의 속성 값들 중 와일드 카드(wild card) 속성 값을 제외한 나머지 속성 값들 각각에 대한 속성 카테고리 인덱스들의 집합)을 이용하여 상기 의사 난수를 생성할 수 있다.(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is the token for the vector set of queries,

Is an attribute value for an attribute category j among one or more attribute values included in the query vector i, and S _i is an attribute value for each of the attribute values excluding wild card attribute values among one or more attribute values included in the query vector i. The set of attribute category indices for) may be used to generate the pseudo-random number.

The step of generating the master secret key is Equation 4 below.

[Equation 4]

는 위수가 p인 순환군(cyclic group)

의 원소)를 이용하여 상기 마스터 비밀키를 생성하고, 상기 토큰을 생성하는 단계는, 아래의 수학식 5(At this time, MK is the master secret key, n is the total number of the plurality of users,

Is a cyclic group with p

Step of generating the master secret key using the elements of, and generating the token, Equation 5 below

[Equation 5]

는 상기 질의 벡터 집합에 대한 토큰,

,

및

는 각각

의 원소)를 이용하여 상기 토큰을 생성할 수 있다.(At this time,

Is the token for the vector set of queries,

,

And

Each

The element can be generated using the () element.

An apparatus according to an embodiment of the present invention, one or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the program comprising: generating a set of query vectors comprising a plurality of query vectors; Obtaining a token for the set of query vectors from a key generator; And an attribute vector set including the plurality of attribute vectors and the query using a ciphertext for each of the plurality of attribute vectors encrypted using different user encryption keys, a label for the plurality of attribute vectors, and the token. It includes instructions for executing a step of determining whether an equivalent relationship between vector sets is established.

The ciphertext for each of the plurality of attribute vectors includes a hash value for the label, a first pseudo-random number for each of the one or more attribute values included in each of the plurality of attribute vectors, and the user encryption key. The token may be generated using the second pseudo-random number for the query vector set and the master secret key.

The user encryption key is the following equation 1

[Equation 1]

는 사용자 인덱스,

는 사용자 i에 대한 사용자 암호키,

는

의 원소,

및

는 각각 임의의 정수, p는 소수(prime number))을 만족하고, 상기 제1 의사 난수는, 아래의 수학식 2(

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number, and the first pseudo-random number is Equation 2 below.

[Equation 2]

는 속성 카테고리 인덱스, PRF()는 의사 랜덤 함수,

는 사용자 i의 사용자 암호키를 이용하여 암호화된 속성 벡터

에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값,

는 상기 속성 값

에 대한 제1 의사 난수)을 이용하여 생성되고, 상기 제2 의사 난수는, 아래의 수학식 3(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute vector encrypted using the user's user encryption key.

The attribute value for attribute category j among one or more attribute values included in

Is the attribute value

Is generated using the first pseudo-random number for, the second pseudo-random number, Equation 3 below

[Equation 3]

는 상기 질의 벡터 집합에 대한 토큰,

는 상기 속성 벡터

에 대한 질의 벡터

에 포함된 하나 이상의 속성 값 중 속성 카테고리 j에 대한 속성 값, S_i는 상기 질의 벡터 i에 포함된 하나 이상의 속성 값 중 와일드 카드(wild card) 속성 값을 제외한 나머지 속성 값들 각각에 대한 속성 카테고리 인덱스들의 집합)을 이용하여 생성되며, 상기

는 아래의 수학식 4(At this time,

Is the token for the vector set of queries,

Is the above attribute vector

Query for vector

Attribute value for attribute category j among one or more attribute values included in, S _i is an attribute category index for each of the other attribute values excluding wild card attribute values among one or more attribute values included in the query vector i Is generated using a set of

Equation 4 below

[Equation 4]

It can be generated using.

The master secret key is Equation 5 below

[Equation 5]

는 위수가 p인 순환군(cyclic group)

의 원소)를 만족하고, 상기 암호문은, 아래의 수학식 6(At this time, MK is the master secret key, n is the number of the plurality of users,

Is a cyclic group with p

Element), and the ciphertext is Equation 6 below.

[Equation 6]

는 상기 암호문,

은 상기 속성 벡터에 포함된 속성 카테고리의 총 개수, T는 상기 라벨,

는 상기 해시 값)을 만족하고, 상기 토큰은, 아래의 수학식 7(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Is the hash value), and the token is represented by Equation 7 below.

[Equation 7]

는 상기 토큰,

,

및

는 각각

의 원소)을 만족할 수 있다.(At this time,

Is the token,

,

And

Each

Element of).

The determining step, Equation 8 below

[Equation 8]

를 만족하는 겹선형 함수(bilinear map),

,

및

는 위수(order)가 소수 p인 순환군(cyclic group))이 만족되는 경우, 상기 동치 관계가 성립하는 것으로 판단할 수 있다.(At this time, e is

Bilinear map, which satisfies

,

And

When the cyclic group having a small number of p is satisfied, it may be determined that the same relationship is established.

According to embodiments of the present invention, it is possible to perform efficient equivalent operation for multiple ciphertexts generated by different clients in a multi-client environment.

1 is a block diagram of an encryption system according to an embodiment of the present invention
Figure 2 is a flow chart for explaining the encryption process according to an embodiment of the present invention
3 is a flowchart for explaining a process of determining whether an equivalent relationship is established between a query vector set and an attribute vector set according to an embodiment of the present invention.
4 is a block diagram illustrating and illustrating a computing environment including a computing device suitable for use in example embodiments.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to aid in a comprehensive understanding of the methods, devices and/or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, when it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the contents throughout this specification. The terminology used in the detailed description is only for describing embodiments of the present invention and should not be limiting. Unless expressly used otherwise, a singular form includes a plural form. In this description, expressions such as “including” or “equipment” are intended to indicate certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and one or more other than described. It should not be interpreted to exclude the presence or likelihood of other characteristics, numbers, steps, actions, elements, parts or combinations thereof.

1 is a block diagram of an encryption system according to an embodiment of the present invention.

Referring to FIG. 1, the encryption system 100 according to an embodiment of the present invention includes a key generating device 110, a plurality of client devices 120-1, 120-2, 120-n, a database 130, and Query device 140.

The key generating device 110 is a device for generating a master secret key, a user encryption key, and public parameters to be used in the encryption system 100, and is operated by a trusted entity, such as a trusted third party, for example. Can be.

Specifically, the key generating device 110 generates a user encryption key for each of a plurality of users participating in the encryption system 100, and a client used by each user to encrypt the user encryption key for each generated user Devices 120-1, 120-2, and 120-n.

In addition, the key generating device 110 generates a master secret key and a public parameter to safely store the master secret key, and the public parameter can be disclosed in the encryption system 100.

Meanwhile, the key generating device 110 may generate a token for a set of query vectors at the request of the query device 140 and provide it to the query device 140.

The client devices 120-1, 120-2, and 120-n are devices used by each user who has issued a user encryption key from the key generation device 110 for generating a ciphertext, and the client devices 120-1, 120 The number of -2, 120-n) may be changed according to embodiments.

Database 130 is for storing the ciphertext generated by each client device (120-1, 120-2, 120-n), each client device (120-1, 120-2, 120-n) and query It may be implemented in one or more servers or cloud environments accessible by the device 140.

The querying device 140 generates tokens for a set of query vectors provided from the key generating device 110 and a plurality of queries generated by the client devices 120-1, 120-2, and 120-n and stored in the database 130. Using the ciphertext for each attribute vector, it is determined whether an equivalence relationship between the attribute vector set including a plurality of attribute vectors and the query vector set is established.

Meanwhile, the encryption technique performed in the encryption system 100 illustrated in FIG. 1 may be composed of the following four algorithms.

Setup algorithm

,

및

를 생성할 수 있다.The setup algorithm receives security parameters 1 ^λ and the total number (n) of users to participate in the encryption system 100, and a cyclic group having a prime number p, respectively.

,

And

Can generate

를 만족하는 겹선형 함수(bilinear map)

,

를 만족하는

의 생성원(generator)

및

를 만족하는

의 생성원

를 생성할 수 있다. Also, the setup algorithm

Bilinear map that satisfies

,

Satisfying

Generator

And

Satisfying

Origin of

Can generate

인 정수)에 대해

를 만족하는

, 임의의 정수

및

를 선택하여 각 사용자에 대한 사용자 암호키

를 생성할 수 있다.After that, the setup algorithm is set to all i (where i is the user index

Phosphorus constants)

Satisfying

, Any integer

And

Select the user encryption key for each user

Can generate

를 만족하는

를 선택하고, 마스터 비밀키

를 생성할 수 있다.Also, the setup algorithm

Satisfying

Select and Master Secret Key

Can generate

Meanwhile, in one embodiment of the present invention, the setup algorithm may be performed by the key generation device 110. In this case, the key generating device 110 may provide the user encryption key EK _i of each user generated by performing the setup algorithm to the client devices 120-1, 120-2, and 120-n of each user.

는 공개할 수 있다. 이때,

는 임의의 문자 열을

로 맵핑시키는 해시 함수(hash function)(즉,

)를 나타낸다.In addition, the key generating device 110 securely stores the master secret key MK, and public parameters

Can be released. At this time,

Is a random string

Hash function to map to (i.e.

).

Encryption algorithm

The encryption algorithm can generate a ciphertext for the attribute vector based on the user encryption key, public parameters, and a label for the attribute vector.

In this case, the attribute vector may include attribute values for each of one or more attribute categories as a vector for representing a specific attribute, such as an attribute for grade data of a specific student or class, an attribute for biometric data of a specific person, for example. have. For example, when the attribute vector is grade class performance data, the attribute category may be, for example, a grade average, a high score, a low score, or the like.

On the other hand, the label for the attribute vector is information that is assigned to the attribute vector according to a preset method in the encryption system 100, and may be, for example, classification information about the attribute vector, information about a viewpoint related to the attribute vector, and the like. It is not necessarily limited to specific information.

As a specific example, when the attribute vector is an attribute vector for genetic data among iris data, fingerprint data, and genetic data of a specific person, a label for the attribute vector may be information indicating that the attribute vector is an attribute vector for genetic data. As another example, when the attribute vector is an attribute vector for the first semester grade data of the first semester grade data and the second semester grade data of a specific class, the label for the attribute vector may be information indicating that the first semester grade data.

(이때,

은 속성 벡터에 포함될 속성 카테고리의 총 개수)에 포함된 각 속성 값

(이때, j는 속성 카테고리의 인덱스로서

인 정수)에 대한 의사 난수(pseudo-random number)를 생성할 수 있다.Meanwhile, the encryption algorithm is an attribute vector to be encrypted.

(At this time,

Is the total number of attribute categories to be included in the attribute vector)

(In this case, j is the index of the attribute category

Can generate a pseudo-random number.

에 포함된 각 속성 값

에 대한 의사 난수

를 생성할 수 있다.Specifically, the encryption algorithm is a property vector using Equation 1 below.

Value of each attribute included in

Pseudo random number for

Can generate

[Equation 1]

는 아래의 수학식 2를 이용하여 산출될 수 있다.In Equation 1, PRF() represents a pseudo-random function,

Can be calculated using Equation 2 below.

[Equation 2]

의 라벨 T에 대한 해시 값 H(T), 의사 난수

및 사용자 암호키 EK_i에 기초하여 속성 벡터

에 대한 암호문을 생성할 수 있다.Then, the encryption algorithm is a property vector

Hash value for label T of H(T), pseudo-random number

And attribute vector based on user encryption key EK _i

You can generate a cipher text for.

에 대한 암호문

를 생성할 수 있다.Specifically, the encryption algorithm is a property vector using Equation 3 below.

Ciphertext for

Can generate

[Equation 3]

Meanwhile, in one embodiment of the present invention, the encryption algorithm may be performed by each of the client devices 120-1, 120-2, and 120-n, which are issued a user encryption key from the key generating device 110.

를 데이터베이스(130)에 저장할 수 있다. 이때, 각 클라이언트 장치(120-1, 120-2, 120-n)는 속성 벡터의 라벨 T 및 사용자의 인덱스 정보 i를 해당 속성 벡터에 대한 암호문

와 함께 데이터베이스(130)에 저장할 수 있다.In this case, each client device (120-1, 120-2, 120-n) is a ciphertext generated by performing an encryption algorithm

Can be stored in the database 130. At this time, each client device (120-1, 120-2, 120-n) the label T of the attribute vector and the index information i of the user is the ciphertext for the attribute vector

With it can be stored in the database 130.

Token generation algorithm

에 대한 토큰을 생성할 수 있다. 이때, 질의 벡터 집합은 암호화 알고리즘을 이용하여 각 클라이언트 장치(120-1, 120-2, 120-n)에 의해 암호화된 속성 벡터들 각각에 대한 질의 벡터

를 포함할 수 있다.Token generation algorithm is a set of query vectors

Can generate tokens for At this time, the query vector set is a query vector for each of the attribute vectors encrypted by each client device 120-1, 120-2, 120-n using an encryption algorithm.

It may include.

에 포함된 각 속성 카테고리의 속성 값

는 속성 벡터

에 포함된 속성 값들 중

와 동일한 인덱스 튜플(tuple) (i, j)를 가지는 속성 값

가 만족하여야 할 값을 의미할 수 있다. At this time, the query vector

Attribute values for each attribute category included in

The property vector

Among the attribute values included in

Property value with the same index tuple (i, j) as

Can mean the value to be satisfied.

에 포함된 속성 값 중 하나 이상은 와일드 카드(wild card) 속성 값을 가질 수 있다. 이때, 와일드 카드 속성 값은 속성 벡터

포함된 속성 값들 중 와일드 카드 속성 값과 동일한 인덱스 튜플을 가지는 속성 값이 어떠한 값을 가지더라도 무관함을 의미할 수 있다.Meanwhile, according to an embodiment, each query vector

At least one of the attribute values included in may have a wild card attribute value. At this time, the wildcard attribute value is the attribute vector

Among attribute values included, it may mean that any attribute value having the same index tuple as the wildcard attribute value has any value.

Meanwhile, the token generation algorithm may generate a token TK _Y for the query vector set Y using the query vector set Y and the master secret key MK.

를 생성할 수 있다. 이때, 토큰 생성 알고리즘은 아래의 수학식 4를 이용하여 의사 난수

를 생성할 수 있다.Specifically, the token generation algorithm is a pseudo-random number for the query vector set Y.

Can generate At this time, the token generation algorithm uses the following equation (4) to generate a pseudo-random number.

Can generate

[Equation 4]

의 속성 값들 중 와일드 카드(wild card) 속성 값을 제외한 나머지 속성 값들 각각에 대한 속성 카테고리 인덱스들을 포함하는 집합을 나타내며,

는 상술한 수학식 2를 이용하여 산출될 수 있다.In Equation 4, S _i is each query vector included in the query vector set Y

A set of attribute category indices for each of the attribute values other than the wild card attribute value among the attribute values of

Can be calculated using Equation 2 above.

및 마스터 비밀키 MK를 이용하여 질의 벡터 집합 Y에 대한 토큰 TK_Y을 생성할 수 있다.After that, the token generation algorithm generates the generated pseudo-random number.

And a token TK _Y for the query vector set Y using the master secret key MK.

Specifically, the token generation algorithm may generate the token TK _Y using Equation 5 below.

[Equation 5]

Meanwhile, in one embodiment of the present invention, the token generation algorithm may be performed by the key generation device 110.

In this case, the key generation device 110 may generate a token TK _Y for the query vector set Y by performing a token generation algorithm when a request is generated for the query vector set Y from the query device 140. In addition, the key generation device 110 may provide the generated token TK _Y to the query device 140.

Query algorithm

에 대한 암호문

, 라벨 T 및 질의 벡터 집합

에 대한 토큰 TK_Y를 이용하여 질의 벡터 집합 Y와 속성 벡터 집합

사이의 동치 관계 성립 여부를 판단할 수 있다.The query algorithm is an attribute vector generated by each client device (120-1, 120-2, 120-n).

Ciphertext for

Set of labels, labels T and quality

Query vector set Y and attribute vector set using token TK _Y for

It is possible to determine whether or not the same relationship is established.

Specifically, when the following equation (6) is satisfied, the query algorithm may determine that an equivalence relationship between the query vector set Y and the attribute vector set X is established.

[Equation 6]

Meanwhile, in one embodiment of the present invention, the query algorithm may be performed by the querying device 140.

In this case, the querying device 110 performs a query algorithm to output 1 when it is determined that an equivalence relationship between the query vector set Y and the attribute vector set X is established, and 0 when it is determined that it is not established. Can print

2 is a flowchart illustrating an encryption process according to an embodiment of the present invention.

In the flowchart shown in FIG. 2, it is assumed that there are three client devices 120-1, 120-2, and 120-3 used by different users in the encryption system 100 for convenience of explanation, but the user and The number of client devices is not necessarily limited to the illustrated example.

, 마스터 비밀키

및 공개 파라미터

를 생성한다(201).Referring to FIG. 2, first, the key generating device 110 performs a setup algorithm, so that each user's user encryption key

, Master secret key

And public parameters

Create (201).

Thereafter, the key generating device 110 provides the user encryption key EK ₁ of the user 1 to the client device 1 120-1 used by the user 1 (202 ).

In addition, the key generating device 110 provides the user encryption key EK ₂ of the user 2 to the client device 2 120-2 used by the user 2 (203).

In addition, the key generating device 110 provides the user encryption key EK ₃ of the user 3 to the client device 3 (120-3) used by the user 3 (204).

에 대한 암호문

을 생성한다(205).On the other hand, the client device 1 (120-1) obtained the user encryption key EK ₁ from the key generation device 110 performs an encryption algorithm to label the attribute vector T

Ciphertext for

Create (205).

을 데이터베이스(130)에 저장한다(206).Thereafter, the client device 1 (120-1) generates the encrypted text

Is stored in the database 130 (206).

에 대한 암호문

을 생성한다(207).In addition, the client device 2 (120-2), which has obtained the user encryption key EK ₂ from the key generation device 110, performs an encryption algorithm to obtain an attribute vector labeled T.

Ciphertext for

Create (207).

을 데이터베이스(130)에 저장한다(208).Thereafter, the client device 2 (120-2) generates the encrypted text

Is stored in the database 130 (208).

에 대한 암호문

을 생성한다(209).In addition, the client device 3 (120-3), which has obtained the user encryption key EK ₃ from the key generation device 110, performs an encryption algorithm to obtain an attribute vector labeled T.

Ciphertext for

Creates (209).

을 데이터베이스(130)에 저장한다(210).Thereafter, the client device 3 (120-3) generates the encrypted text

Is stored in the database 130 (210).

FIG. 3 is a flowchart illustrating a process of determining whether an equality relationship is established between a query vector set and an attribute vector set according to an embodiment of the present invention.

The process illustrated in FIG. 3 may be performed after the encryption process illustrated in FIG. 2.

에 대한 질의 벡터 집합

를 생성한다(301).Referring to FIG. 3, first, the query device 140 sets a set of attribute vectors

Vector set of queries for

Create (301).

Thereafter, the query device 140 requests the key generation device 110 to generate a token for the query vector set Y (302).

를 생성한다(303).Thereafter, the key generation device 110 performs a token generation algorithm to generate a token for the query vector set Y.

Create (303).

Thereafter, the key generating device 110 provides the generated token TK _Y to the query device 140 (304).

,

및

각각에 대한 암호문

,

및

와 토큰 TK_Y를 이용하여 질의 벡터 집합 Y와 속성 벡터 집합 X 사이의 동치 관계 성립 여부를 판단한다(305).Thereafter, the querying device 140 may include an attribute vector included in the attribute vector set X among ciphertexts stored in the database 130.

,

And

Cryptogram for each

,

And

It is determined whether an equivalence relationship between the query vector set Y and the attribute vector set X is established using and TK _Y (305).

이 만족된 경우, 질의 벡터 집합 Y와 속성 벡터 집합 X 사이의 동치 관계가 성립하는 것으로 판단하고, 만족되지 않은 경우, 동치 관계가 성립하지 않는 것으로 판단할 수 있다.At this time, the query device 140

If this is satisfied, it can be determined that an equivalence relationship between the query vector set Y and the attribute vector set X is established, and if not satisfied, it can be determined that the equivalence relationship is not established.

Meanwhile, in the flowcharts illustrated in FIGS. 2 and 3, the process is divided into a plurality of steps, but at least some of the steps are performed by changing the order, combined with other steps, or omitted, or as detailed steps. It may be performed separately, or may be performed by adding one or more steps not shown.

4 is a block diagram illustrating and illustrating a computing environment including a computing device suitable for use in example embodiments. In the illustrated embodiment, each component may have different functions and capabilities in addition to those described below, and may include additional components in addition to those described below.

The illustrated computing environment 10 includes a computing device 12. In one embodiment, computing device 12 may be one or more components included in encryption system 100.

The computing device 12 includes at least one processor 14, a computer readable storage medium 16 and a communication bus 18. The processor 14 can cause the computing device 12 to operate in accordance with the exemplary embodiment mentioned above. For example, processor 14 may execute one or more programs stored on computer readable storage medium 16. The one or more programs may include one or more computer-executable instructions, which, when executed by the processor 14, configure the computing device 12 to perform operations according to an exemplary embodiment. Can be.

Computer readable storage medium 16 is configured to store computer executable instructions or program code, program data and/or other suitable types of information. The program 20 stored on the computer readable storage medium 16 includes a set of instructions executable by the processor 14. In one embodiment, the computer readable storage medium 16 is a memory (volatile memory such as random access memory, non-volatile memory, or a suitable combination thereof), one or more magnetic disk storage devices, optical disk storage devices, flash Memory devices, other types of storage media that can be accessed by the computing device 12 and store desired information, or suitable combinations thereof.

The communication bus 18 interconnects various other components of the computing device 12, including a processor 14 and a computer readable storage medium 16.

Computing device 12 may also include one or more I/O interfaces 22 and one or more network communication interfaces 26 that provide an interface for one or more I/O devices 24. The input/output interface 22 and the network communication interface 26 are connected to the communication bus 18. The input/output device 24 may be connected to other components of the computing device 12 through the input/output interface 22. Exemplary input/output devices 24 include pointing devices (such as a mouse or trackpad), keyboards, touch input devices (such as touch pads or touch screens), voice or sound input devices, various types of sensor devices, and/or imaging devices. Input devices and/or output devices such as display devices, printers, speakers, and/or network cards. The exemplary input/output device 24 is a component constituting the computing device 12 and may be included inside the computing device 12 or may be connected to the computing device 12 as a separate device distinct from the computing device 12. It might be.

Although the present invention has been described in detail through exemplary embodiments above, those skilled in the art to which the present invention pertains are capable of various modifications within the limits of the embodiments described above without departing from the scope of the present invention. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims to be described later, but also by the claims and equivalents.

10: computing environment
12: computing device
14: processor
16: computer readable storage media
18: Communication bus
20: Program
22: I/O interface
24: I/O device
26: network communication interface
100: encryption system
110: key generation device
120-1, 120-2, 120-3, 120-n: client device
130: database
140: query device

Claims (28)

One or more processors, and
A method performed in a computing device having a memory that stores one or more programs executed by the one or more processors,
Obtaining a user encryption key from the key generating device; And
Generating a ciphertext for the attribute vector based on the label for the attribute vector and the user encryption key,
The step of generating the ciphertext,
Generating a hash value for the label;
Generating a pseudo-random number for each of the one or more attribute values included in the attribute vector; And
Generating the ciphertext based on the hash value, the pseudo-random number, and the user encryption key,
The ciphertext includes a plurality of ciphertext elements calculated by using a pseudo-random number for each of the one or more attribute values as an index of the hash value.
delete delete The method according to claim 1,
The user encryption key, the following equation 1
[Equation 1]

(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p is a prime number
Satisfied,
The step of generating the pseudo-random number may include Equations 2 and 3 below.
[Equation 2]

[Equation 3]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute value for attribute category j among the one or more attribute values,

Is the attribute value

Pseudo-random number for)
A method for generating a pseudo-random number for each of the one or more attribute values.
The method according to claim 4,
The step of generating the ciphertext is Equation 4 below.
[Equation 4]

(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Is the hash value above)
Method for generating the ciphertext using.
One or more processors, and
A method performed in a computing device having a memory that stores one or more programs executed by the one or more processors,
Generating a user encryption key and a master secret key for each of the plurality of users;
Providing the generated user encryption key to the client devices of each of the plurality of users;
Receiving a query vector set including a plurality of query vectors from the query device;
Generating a token for the query vector set using the query vector set and the master secret key; And
And providing the generated token to the querying device.
The method according to claim 6,
The step of generating the token,
Generating a pseudo-random number for the query vector set; And
And generating the token using the pseudo-random number and the master secret key.
The method according to claim 7,
The user encryption key is the following equation 1
[Equation 1]

(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Each satisfy an arbitrary integer, p is a prime number,
The step of generating the pseudo-random number may include Equations 2 and 3 below.
[Equation 2]

[Equation 3]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is a pseudo-random number for the vector set of queries,

The vector of the query

Of one or more attribute values included in the attribute value for attribute category j, S _i is the query vector

A set of attribute category indices for each of the attribute values other than the wild card attribute value among one or more attribute values included in)
Method for generating the pseudo-random number using the method.
The method according to claim 8,
The step of generating the master secret key is Equation 4 below.
[Equation 4]

(At this time, MK is the master secret key, n is the total number of the plurality of users,

Is a cyclic group with p

Element of)
To generate the master secret key,
The step of generating the token, Equation 5 below
[Equation 5]

(At this time,

Is the token for the vector set of queries,

,

And

Each

Element of)
How to generate the token using the method.
One or more processors, and
A method performed in a computing device having a memory that stores one or more programs executed by the one or more processors,
Generating a query vector set including a plurality of query vectors;
Obtaining a token for the set of query vectors from a key generator; And
A ciphertext for each of the plurality of attribute vectors encrypted using different user encryption keys, a label for the plurality of attribute vectors, and the token, and the attribute vector set and the query vector including the plurality of attribute vectors And determining whether an equality relationship between the sets is established.
The method according to claim 10,
The ciphertext for each of the plurality of attribute vectors includes a hash value for the label, a first pseudo-random number for each of one or more attribute values included in each of the plurality of attribute vectors, and the user encryption key. Is created using
The token is generated using a second pseudo-random number and a master secret key for the query vector set.
The method according to claim 11,
The user encryption key is the following equation 1
[Equation 1]

(

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p is a prime number
Satisfied,
The first pseudo-random number is Equation 2 below.
[Equation 2]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute vector encrypted using the user's user encryption key.

The attribute value for attribute category j among one or more attribute values included in

Is the attribute value

First pseudo-random number for)
Is created using,
The second pseudo-random number is Equation 3 below.
[Equation 3]

(At this time,

Is a second pseudo-random number for the vector set of queries,

Is the above attribute vector

Query for vector

Of one or more attribute values included in the attribute value for attribute category j, S _i is the query vector

It is generated using a set of attribute category indices for each of the attribute values other than the wild card attribute value among the one or more attribute values included in,
remind

Equation 4 below
[Equation 4]

Method created using.
The method according to claim 12,
The master secret key is Equation 5 below
[Equation 5]

(At this time, MK is the master secret key, n is the number of the plurality of users,

Is a cyclic group with p

Element of)
Satisfied,
The ciphertext is the following Equation 6
[Equation 6]

(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Is the hash value above)
Satisfied,
The token, Equation 7 below
[Equation 7]

(At this time,

Is the token,

,

And

Each

Element of)
How to satisfy, how.
The method according to claim 13,
The determining step, Equation 8 below
[Equation 8]

(At this time, e is

Bilinear map, which satisfies

,

And

Is a cyclic group with a prime p
If it is satisfied, it is determined that the same relationship is established.
One or more processors;
Memory; And
A device comprising one or more programs,
The one or more programs are stored in the memory and configured to be executed by the one or more processors,
The above program,
Obtaining a user encryption key from the key generating device; And
And instructions for executing a step of generating a ciphertext for the attribute vector based on the label for the attribute vector and the user encryption key,
The step of generating the ciphertext,
Generating a hash value for the label;
Generating a pseudo-random number for each of the one or more attribute values included in the attribute vector; And
Generating the ciphertext based on the hash value, the pseudo-random number, and the user encryption key,
And the ciphertext includes a plurality of ciphertext elements calculated by using a pseudo-random number for each of the one or more attribute values as an index of the hash value.
delete delete The method according to claim 15,
The user encryption key, the following equation 1
[Equation 1]

(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Is an arbitrary integer, p satisfies a prime number,
The step of generating the pseudo-random number may include Equations 2 and 3 below.
[Equation 2]

[Equation 3]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute value for attribute category j among the one or more attribute values,

Is the attribute value

Pseudo-random number for)
And generating a pseudo-random number for each of the one or more attribute values.
The method according to claim 18,
The step of generating the ciphertext is Equation 4 below.
[Equation 4]

(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Is the hash value above)
Device for generating the ciphertext using.
One or more processors;
Memory; And
A device comprising one or more programs,
The one or more programs are stored in the memory and configured to be executed by the one or more processors,
The above program,
Generating a user encryption key and a master secret key for each of the plurality of users;
Providing the generated user encryption key to the client devices of each of the plurality of users;
Receiving a query vector set including a plurality of query vectors from the query device;
Generating a token for the query vector set using the query vector set and the master secret key; And
And instructions for executing the step of providing the generated token to the querying device.
The method according to claim 20,
The step of generating the token,
Generating a pseudo-random number for the query vector set; And
And generating the token using the pseudo-random number and the master secret key.
The method of claim 21,
The user encryption key is the following equation 1
[Equation 1]

(At this time,

User index,

Is the user encryption key for user i,

The

Element of,

And

Each satisfy an arbitrary integer, p is a prime number,
The step of generating the pseudo-random number may include Equations 2 and 3 below.
[Equation 2]

[Equation 3]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is a pseudo-random number for the vector set of queries,

The vector of the query

Of one or more attribute values included in the attribute value for attribute category j, S _i is the query vector

A set of attribute category indices for each of the attribute values other than the wild card attribute value among one or more attribute values included in)
Using the device, to generate the pseudo-random number.
The method according to claim 22,
The step of generating the master secret key is Equation 4 below.
[Equation 4]

(At this time, MK is the master secret key, n is the total number of the plurality of users,

Is a cyclic group with p

Element of)
To generate the master secret key,
The step of generating the token, Equation 5 below
[Equation 5]

(At this time,

Is the token for the vector set of queries,

,

And

Each

Element of)
Using the device to generate the token.
One or more processors;
Memory; And
A device comprising one or more programs,
The one or more programs are stored in the memory and configured to be executed by the one or more processors,
The above program,
Generating a query vector set including a plurality of query vectors;
Obtaining a token for the set of query vectors from a key generator; And
A ciphertext for each of the plurality of attribute vectors encrypted using different user encryption keys, a label for the plurality of attribute vectors, and the token, and the attribute vector set and the query vector including the plurality of attribute vectors And instructions for executing a step of determining whether an equivalent relationship between sets is established.
The method according to claim 24,
The ciphertext for each of the plurality of attribute vectors includes a hash value for the label, a first pseudo-random number for each of one or more attribute values included in each of the plurality of attribute vectors, and the user encryption key. Is created using
The token is generated using a second pseudo-random number and a master secret key for the query vector set.
The method according to claim 25,
The user encryption key is the following equation 1
[Equation 1]

(

User index,

Is the user encryption key for user i,

The

Element of,

And

Each satisfy an arbitrary integer, p is a prime number,
The first pseudo-random number is Equation 2 below.
[Equation 2]

(At this time,

Is the attribute category index, PRF() is a pseudo-random function,

Is an attribute vector encrypted using the user's user encryption key.

The attribute value for attribute category j among one or more attribute values included in

Is the attribute value

First pseudo-random number for)
Is created using,
The second pseudo-random number is Equation 3 below.
[Equation 3]

(At this time,

Is a second pseudo-random number for the vector set of queries,

Is the above attribute vector

Query for vector

Of one or more attribute values included in the attribute value for attribute category j, S _i is the query vector

It is generated using a set of attribute category indices for each of the attribute values other than the wild card attribute value among the one or more attribute values included in,
remind

Equation 4 below
[Equation 4]

Device created using.
The method according to claim 26,
The master secret key is Equation 5 below
[Equation 5]

(At this time, MK is the master secret key, n is the number of the plurality of users,

Is a cyclic group with p

Element of)
Satisfied,
The ciphertext is the following Equation 6
[Equation 6]

(At this time,

Is the ciphertext,

Is the total number of attribute categories included in the attribute vector, T is the label,

Is the hash value above)
Satisfied,
The token, Equation 7 below
[Equation 7]

(At this time,

Is the token,

,

And

Each

Element of)
Device that satisfies.
The method according to claim 27,
The determining step, Equation 8 below
[Equation 8]

(At this time, e is

Bilinear map, which satisfies

,

And

Is a cyclic group with a prime p
If it is satisfied, the device determines that the same relationship is established.

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