WO2017166054A1

WO2017166054A1 - Quantum homomorphism symmetry searchable encryption method and system

Info

Publication number: WO2017166054A1
Application number: PCT/CN2016/077681
Authority: WO
Inventors: 张鹏; 孙小强; 刘宏伟; 喻建平
Original assignee: 深圳大学
Priority date: 2016-03-29
Filing date: 2016-03-29
Publication date: 2017-10-05

Abstract

The present invention is suitable for data encryption searching. Provided is a quantum homomorphism symmetry searchable encryption method, comprising: A, randomly generating a plurality of private keys; B, encrypting plaintext data according to the private keys and keywords, and then saving same in a cloud server; C, according to ciphertext to be sorted, determining ciphertext corresponding to an identity identifier, and sorting the ciphertext containing the same identity identifier by means of a simplification operation to obtain an index table; D, encrypting search keywords according to reversed offset of the private keys, searching the ciphertext of the same user in the index table according to the encrypted search keywords and the identity identifier, and returning same; and E, decrypting a search result according to the private keys, and obtaining a decryption result. Plaintext information is encrypted by utilizing private keys and keywords, the generated ciphertext is saved in a cloud server, a data user can search ciphertext containing keywords by utilizing the characteristics of a quantum homomorphism encryption algorithm, and any information about the plaintext cannot be revealed without private keys.

Description

Method and system for quantum homomorphic symmetric searchable encryption

Technical field

The invention belongs to the field of cloud computing and information security, and in particular relates to a method and system for quantum homomorphic symmetric searchable encryption.

Background technique

Searchable encryption allows retrieval of ciphertext data without decryption, which ensures the security of data stored on the cloud server and the retrieval of keywords, and is very suitable for solving privacy protection problems in cloud computing. The key used in the encryption and decryption process of the searchable encryption is the same. Considering the need for the user to retrieve the encrypted data uploaded by the user to the server, the research on the symmetric searchable encryption can maximize the computational efficiency. Quantum information has the characteristics of being non-cloning. Any illegal user attempting to spoof ciphertext will be known to legitimate users and has absolute security. The use of quantum homomorphism to construct search encryption can further improve security.

Summary of the invention

The technical problem to be solved by the present invention is to provide a method and system for quantum homomorphic symmetric searchable encryption, which aims to improve the security when a quantum homomorphic construct can be used to retrieve an encryption.

The present invention is implemented in such a way that a quantum homomorphic symmetric searchable encryption method comprises the following steps:

Step A, randomly generating a plurality of private keys; the plurality of private keys may be shared by the data owner and the data user;

Step B: The data owner encrypts the plaintext data according to the private key and the preset keyword, and then stores the generated ciphertext in the cloud server; the ciphertext includes an identifier of the data owner;

Step C: The data owner determines the ciphertext corresponding to the identity identifier in the ciphertext to be collated, and then condenses the ciphertexts having the same identity identifier through the simplification operation, and obtains the index table according to the collation result;

Step D, the data user uses the keyword as a search key, encrypts the search keyword according to the opposite offset of the private key, and then according to the encrypted search keyword and the identity identifier. Find the ciphertext of the same user in the index table, and search the ciphertext as the retrieval result and return;

Step E: The data user decrypts the search result according to the private key to obtain a decrypted result.

Further, in the step B, the private key is represented by K _j , M _j represents the keyword, and the dimensions of the records K _j and M _j are both n, and ρ _cj represents the ciphertext, then:

among them:

i in the matrix Y represents an imaginary unit in the complex number; M _i,j represents the i-th component of the keyword M _j , and θ _i,j represents the i-th component of the private key K _j .

Further, with the opposite offset of the private key indicated by K′ _j , the keyword is used as a search key, the search key is represented by Key _j , and the identity identifier is represented by an ID, _Cj represents the ciphertext, then;

The step D specifically includes:

Step D1: generating an inverse offset K' _j of the private key, encrypting the search key Key _j according to the opposite offset K' _j of the private key, and recording the dimension of K' _j and Key _j The number is n, then:

Where: if Key _i,j =|0>, Encrypt(-K' _j , Key _i,j )=R _y (0)·R _y (-θ′ _i,j ); otherwise, Encrypt(-K′ _j , Key _i,j )=R _y (π/2)·R _y (-θ′ _i,j );

Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; Key _{i, j} represents the ith component of Key _j ; θ′ _{i, j} represents the ith component of K′ _j ;

Step D2: Find the ciphertext of the same user in the index table according to the identity identifier, and then use the quantum homomorphic feature to retrieve the ciphertext found according to the encrypted search keyword, that is,

If K _j = K' _j , then

Keywords Key _j ρ _cj ciphertext ciphertext ρ _cj step D3, D2 retrieval step to find whether the ciphertext includes the search keyword Key _j, if retrieved including a search keyword, then to retrieve the secret The text is used as a search result and returns the search result; that is:

If

It means that the ciphertext containing the keyword Key _j is retrieved.

Ciphertext

return.

Further, in step E, the search result is represented by C _j , and M′ _j represents the decrypted result, and the dimensions of K′ _j and C _j are both n, then:

among them,

Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; M′ _{i, j} represents the ith component of the message M′ _j .

The invention also provides a system for quantum homomorphic symmetric searchable encryption, comprising:

a private key generating unit, configured to randomly generate a plurality of private keys; the plurality of private keys may be shared by the data owner and the data user;

An encryption storage unit, configured to encrypt, by the data owner, the plaintext data according to the private key and the preset keyword, and then store the generated ciphertext in the cloud server; the ciphertext includes the identity of the data owner symbol;

An operation unit for determining, by the data owner, the ciphertext corresponding to the identity identifier in the ciphertext to be collated, and then merging the ciphertexts having the same identity identifier together by the simplification operation, according to the collation result direction chart;

An encryption retrieval unit, configured to: use, by the data user, the keyword as a retrieval key, encrypt the retrieval keyword according to an inverse offset of the private key, and then, according to the encrypted retrieval keyword and the identity identifier Finding the ciphertext of the same user in the index table, and searching the ciphertext as a retrieval result and returning;

The ciphertext decryption unit is configured to decrypt the search result according to the private key by the data user to obtain a decryption result.

Further, in the encrypted storage unit, the private key is represented by K _j , M _j represents the keyword, and the dimensions of the records K _j and M _j are both n, and ρ _cj represents the ciphertext, then:

among them:

The encryption retrieval unit is specifically configured to:

First, generating an inverse offset K' _j of the private key, encrypting the search key Key _j according to the opposite offset K' _j of the private key, and recording the dimension of K' _j and Key _j Both are n, then:

Secondly, the ciphertext of the same user is found in the index table according to the identity identifier, and then the discovered ciphertext is retrieved by using the quantum homomorphic feature according to the encrypted search key, namely:

If K _j = K' _j , then

Finally, whether Search Find ciphertext contains the search key Key _j ciphertext ρ _cj, if retrieved Key _j contain the keyword search key ciphertext ρ _cj, then the ciphertext to retrieve the search result And returning the search result; that is:

If

It means that the ciphertext containing the keyword Key _j is retrieved.

Ciphertext

return.

Further, in the ciphertext decryption unit, the search result is represented by C _j , and M′ _j represents the decryption result, and the dimensions of K′ _j and C _j are both n, then:

among them,

Compared with the prior art, the present invention has the beneficial effects that the present invention encrypts the plaintext information by using the private key and the keyword, stores the encrypted ciphertext in the cloud server, and further utilizes the characteristics of the quantum homomorphic encryption algorithm. The data user can retrieve the ciphertext containing the keyword Key, since the cloud server only has the ciphertext

And encrypted keywords

In the absence of a private key, no information about the plaintext will be revealed, where 0≤j<m; and the method adopted by Song et al. first uses the pseudo-random sequence and the check sequence technique to generate the stream cipher T, and then T and The plaintext M performs an exclusive OR operation to generate the ciphertext C, and the result of the exclusive OR operation of the encrypted keyword W and the ciphertext C is used to determine whether or not there is a ciphertext containing the specified keyword. Due to the symmetric one-time dense quantum homomorphic encryption algorithm, the proposed quantum homomorphic searchable encryption algorithm is more efficient than the scheme proposed by Song et al., and the non-cloning of quantum information can guarantee the absolute security of the scheme.

DRAWINGS

FIG. 1 is a flowchart of a method for quantum homomorphic symmetric searchable encryption provided by an embodiment of the present invention.

2 is a schematic structural diagram of a system for quantum homomorphic symmetric searchable encryption provided by an embodiment of the present invention.

FIG. 3 is a schematic diagram of the use of a system for quantum homomorphic symmetric searchable encryption provided by an embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The quantum homomorphic encryption algorithm has the advantage of directly performing ciphertext operation without decryption, and can ensure the absolute security of the encryption algorithm. definition

The i in the matrix Y represents the imaginary unit in the complex number. Based on the quantum homomorphic encryption algorithm, as shown in FIG. 1 , an efficient method for quantum homomorphic symmetric searchable encryption provided by an embodiment of the present invention includes the following steps:

S1, a plurality of private keys are randomly generated; the plurality of private keys can be shared by the data owner and the data user. In this step, a number of private keys are randomly generated, and the default generated private key is safely and effectively shared by the data owner and the data user.

S2: The data owner encrypts the plaintext data according to the private key and the preset keyword, and then stores the generated ciphertext in the cloud server; the ciphertext includes an identifier of the data owner. The user's identity identifier is equivalent to the user's unique ID number. When the user is generated, it is given a unique identity identifier corresponding to the user. In this step, the data owner uses the private key and The preset keyword encrypts the plaintext data, and the keyword corresponds to the related data, and the encrypted ciphertext is stored in the cloud server, and the data user can directly access the cloud server to obtain the ciphertext in subsequent use. Because in the actual application, the plaintext data often contains a lot of content. In order to facilitate the subsequent retrieval and use of the data user, the data owner generally uses the relevant keywords to the plaintext data according to the commonly used keywords or according to actual needs. To perform encryption, a keyword may correspond to a corresponding plaintext data or a plurality of plaintext data, or multiple keywords may correspond to one or more pieces of plaintext data. The data owner can set the keyword and the corresponding plaintext data according to the actual situation.

S3, the data owner determines, in the ciphertext to be collated, the ciphertext corresponding to the identity identifier, Then, through the simplification operation, the ciphertexts with the same identity identifier are put together, and the index table is obtained according to the collation result. In this step, the mapping operation (Map operation) is performed to enumerate the ciphertext corresponding to the identity identifier, and then the ciphertexts having the same identity identifier are sorted together by a reduction operation, and the result is obtained according to the collation result. direction chart.

In the above steps, the data owner encrypts the plaintext data by using the private key and the keyword, and then stores the generated ciphertext in the cloud server, and generates an index table at the same time. By utilizing the characteristics of the quantum homomorphic encryption algorithm, the data user can easily and quickly retrieve the ciphertext containing the keyword through the index table in subsequent use.

In order to further ensure the security of the ciphertext retrieval in the cloud server, the keyword is used as a search key, and the method further includes:

S4. The data user encrypts the search key according to the reverse offset of the private key, and then searches for the ciphertext of the same user in the index table according to the encrypted search key and the identity identifier. , the ciphertext found is returned as a search result. In this step, the data user encrypts the search key by using the opposite offset of the private key, encrypts the search key, and performs ciphertext search to ensure the security of the information.

S5. The data user decrypts the search result according to the private key to obtain a decrypted result.

Specifically, in step S1, the private key is represented by K _j , and the private key K _j ∈ θ _{i, j} , {0 ≤ _θ _{i, j} < 2π, 0 ≤ i < n, 0 randomly generated. ≤ _j <m}; where n represents the dimension of the private key K _j , m represents the number of private keys K _j , and θ _{i, j} represents the i-th component of the private key K _j .

In step S2, M _j represents the keyword, and the dimensions of the records K _j and M _j are both n, and ρ _cj represents the ciphertext, then:

among them:

In step S3, given a ciphertext to be collated, a map operation is performed to enumerate the ciphertext ρ ^ID corresponding to the identity identifier ^ID , and then the secret having the same identity identifier ID is obtained through a reduction operation. The text ρ ^{ID is} sorted together, and the index table index is built according to the collation result.

Specifically, step S4 includes:

S41, generating an inverse offset K' _j of the private key, encrypting the search key Key _j according to the opposite offset K' _j of the private key, and recording the dimension of K' _j and Key _j Both are n, then:

S42. Search for the ciphertext of the same user in the index table according to the identity identifier, and then use the quantum homomorphic feature to retrieve the ciphertext found according to the encrypted search keyword, that is,

If K _j = K' _j , then

S43, S42 retrieval step to find whether the ciphertext includes the search keyword Key _j ciphertext ρ _cj, if ciphertext to retrieve the keyword Key _j ρ _cj contains search keywords, then retrieved the ciphertext As a result of the search and return the search result; that is:

If

It means that the ciphertext containing the keyword Key _j is retrieved.

Ciphertext

return.

In step S5, the search result is represented by C _j , and M′ _j represents the decrypted result, and the dimensions of K′ _j and C _j are both n:

among them,

As shown in FIG. 2, the present invention also provides a system for quantum homomorphic symmetric searchable encryption, comprising:

a private key generating unit 1 configured to randomly generate a plurality of private keys; the plurality of private keys may be shared by the data owner and the data user;

The encryption storage unit 2 is configured to encrypt, by the data owner, the plaintext data according to the private key and the preset keyword, and then store the generated ciphertext in the cloud server; the ciphertext includes the identity of the data owner. Identifier

The operation collating unit 3 is configured to: in the ciphertext to be collated, the data owner determines the ciphertext corresponding to the identity identifier, and then sorts the ciphertexts having the same identity identifier through the simplification operation, according to the collation result Get the index table;

The encryption retrieval unit 4 is configured to: use the keyword as a retrieval key by the data user, encrypt the retrieval keyword according to the opposite offset of the private key, and then, according to the encrypted retrieval keyword and the identity The identifier finds the ciphertext of the same user in the index table, and uses the found ciphertext as a retrieval result and returns;

The ciphertext decryption unit 5 is configured to decrypt the search result according to the private key by the data user to obtain a decryption result.

Further, in the encryption storage unit 2, the private key is represented by K _j , M _j represents the keyword, and the dimensions of the records K _j and M _j are both n, and ρ _cj represents the ciphertext, then:

among them:

i in the matrix Y represents an imaginary unit in the complex number; M _i,j represents the i-th component of the keyword M _j , and θ _i,j represents the i-th component of the private key K _j . Further, with the opposite offset of the private key indicated by K′ _j , the keyword is used as a search key, the search key is represented by Key _j , and the identity identifier is represented by an ID, _Cj represents the ciphertext, then;

The encryption retrieval unit 4 is specifically used to:

If K _j = K' _j , then

If

It means that the ciphertext containing the keyword Key _j is retrieved.

Ciphertext

return.

Further, in the ciphertext decryption unit 5, the search result is represented by _Cj , and _M'j represents the decryption result, and the dimensions of _K'j and _Cj are both n, then:

among them,

As shown in FIG. 3, it is a specific use example of the present invention:

The data owner encrypts the plaintext data by using the private key and the keyword, stores the encrypted ciphertext in the cloud server, and then builds an index table according to the ciphertext with the identity identifier. The data user encrypts the ciphertext in the cloud server by encrypting with the opposite offset of the private key according to the search keyword. The data user then decrypts the retrieved ciphertext using the private key to obtain plaintext data.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A method for quantum homomorphic symmetric searchable encryption, characterized in that the method comprises the following steps:

Step A, randomly generating a plurality of private keys; the plurality of private keys may be shared by the data owner and the data user;

Step B: The data owner encrypts the plaintext data according to the private key and the preset keyword, and then stores the generated ciphertext in the cloud server; the ciphertext includes an identifier of the data owner;

Step C: The data owner determines the ciphertext corresponding to the identity identifier in the ciphertext to be collated, and then condenses the ciphertexts having the same identity identifier through the simplification operation, and obtains the index table according to the collation result;

Step D, the data user uses the keyword as a search key, encrypts the search keyword according to the opposite offset of the private key, and then according to the encrypted search keyword and the identity identifier. Find the ciphertext of the same user in the index table, and search the ciphertext as the retrieval result and return;

Step E: The data user decrypts the search result according to the private key to obtain a decrypted result.
The method according to claim 1, wherein in the step B, the private key is represented by K j , M j represents the keyword, and the dimensions of K j and M j are both n, ρ Cj represents the ciphertext, then:

among them:
∈ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; M i,j represents the i-th component of the keyword M j , and θ i,j represents the number of the private key K j i components.
The method according to claim 1, characterized in that, to K 'j of the private key shown opposite to the offset to the keyword as a search keyword to the search key Key j represents, to ID represents the identity identifier, and the ciphertext is represented by ρ cj ;

The step D specifically includes:

Step D1: generating an inverse offset K' j of the private key, encrypting the search key Key j according to the opposite offset K' j of the private key, and recording the dimension of K' j and Key j The number is n, then:

Where: if Key i,j =|0>, Encrypt(-K' j , Key i,j )=R y (0)·R y (-θ′ i,j ); otherwise, Encrypt(-K′ j , Key i,j )=R y (π/2)·R y (-θ′ i,j );

Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; Key i, j represents the ith component of Key j ; θ′ i, j represents the ith component of K′ j ;

Step D2: Find the ciphertext of the same user in the index table according to the identity identifier, and then use the quantum homomorphic feature to retrieve the ciphertext found according to the encrypted search keyword, that is,

If K j = K' j , then

Keywords Key j ρ cj ciphertext ciphertext ρ cj step D3, D2 retrieval step to find whether the ciphertext includes the search keyword Key j, if retrieved including a search keyword, then to retrieve the secret The text is used as a search result and returns the search result; that is:

If
It means that the ciphertext containing the keyword Key j is retrieved.
Ciphertext
return.
The method according to claim 1, wherein in step E, said retrieval result is represented by C j , and M' j represents said decryption result, and the dimensions of K' j and C j are both n, then:

among them,
Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; M′ i, j represents the ith component of the message M′ j .
A system of quantum homomorphic symmetric searchable encryption, characterized in that the system comprises:

a private key generating unit, configured to randomly generate a plurality of private keys; the plurality of private keys may be shared by the data owner and the data user;

An encryption storage unit, configured to encrypt, by the data owner, the plaintext data according to the private key and the preset keyword, and then store the generated ciphertext in the cloud server; the ciphertext includes the identity of the data owner symbol;

An operation unit for determining, by the data owner, the ciphertext corresponding to the identity identifier in the ciphertext to be collated, and then merging the ciphertexts having the same identity identifier together by the simplification operation, according to the collation result direction chart;

An encryption retrieval unit, configured to: use, by the data user, the keyword as a retrieval key, encrypt the retrieval keyword according to an inverse offset of the private key, and then, according to the encrypted retrieval keyword and the identity identifier Finding the ciphertext of the same user in the index table, and searching the ciphertext as a retrieval result and returning;

The ciphertext decryption unit is configured to decrypt the search result according to the private key by the data user to obtain a decryption result.
The system according to claim 5, wherein in said encrypted storage unit, said private key is represented by K j , M j represents said keyword, and the dimensions of K j and M j are both n. ρ cj represents the ciphertext, then:

among them:
∈ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; M i,j represents the i-th component of the keyword M j , and θ i,j represents the number of the private key K j i components.
The system as claimed in claim 5, characterized in that, opposite to the offset of the private key K 'j, the keyword in the search key to the search key Key j represents, to ID represents the identity identifier, and the ciphertext is represented by ρ cj ;

The encryption retrieval unit is specifically configured to:

First, generating an inverse offset K' j of the private key, encrypting the search key Key j according to the opposite offset K' j of the private key, and recording the dimension of K' j and Key j Both are n, then:

Where: if Key i,j =|0>, Encrypt(-K' j , Key i,j )=R y (0)·R y (-θ′ i,j ); otherwise, Encrypt(-K′ j , Key i,j )=R y (π/2)·R y (-θ′ i,j );

Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; Key i, j represents the ith component of Key j ; θ′ i, j represents the ith component of K′ j ;

Secondly, the ciphertext of the same user is found in the index table according to the identity identifier, and then the discovered ciphertext is retrieved by using the quantum homomorphic feature according to the encrypted search key, namely:

If K j = K' j , then

Finally, whether Search Find ciphertext contains the search key Key j ciphertext ρ cj, if retrieved Key j contain the keyword search key ciphertext ρ cj, then the ciphertext to retrieve the search result And returning the search result; that is:

If
It means that the ciphertext containing the keyword Key j is retrieved.
Ciphertext
return.
The system according to claim 5, wherein in said ciphertext decryption unit, said retrieval result is represented by Cj , M'j represents said decryption result, and the dimension of K'j and Cj is recorded Both are n, then:

among them,
Where θ ∈ [0, 2π), i in the matrix Y represents an imaginary unit in the complex number; M′ i, j represents the ith component of the message M′ j .