CN108400871B - In conjunction with the searching ciphertext system and method for identity and the support proxy re-encryption of attribute - Google Patents

In conjunction with the searching ciphertext system and method for identity and the support proxy re-encryption of attribute Download PDF

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CN108400871B
CN108400871B CN201810071831.6A CN201810071831A CN108400871B CN 108400871 B CN108400871 B CN 108400871B CN 201810071831 A CN201810071831 A CN 201810071831A CN 108400871 B CN108400871 B CN 108400871B
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encryption
ciphertext
keyword
authorized user
key
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CN108400871A (en
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陈燕俐
朱敏惠
胡媛媛
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Nanjing Post and Telecommunication University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/30—Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy
    • H04L9/3066—Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy involving algebraic varieties, e.g. elliptic or hyper-elliptic curves
    • H04L9/3073—Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy involving algebraic varieties, e.g. elliptic or hyper-elliptic curves involving pairings, e.g. identity based encryption [IBE], bilinear mappings or bilinear pairings, e.g. Weil or Tate pairing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/60—Protecting data
    • G06F21/62—Protecting access to data via a platform, e.g. using keys or access control rules
    • G06F21/6218—Protecting access to data via a platform, e.g. using keys or access control rules to a system of files or objects, e.g. local or distributed file system or database
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/04—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks
    • H04L63/0428—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks wherein the data content is protected, e.g. by encrypting or encapsulating the payload
    • H04L63/0485—Networking architectures for enhanced packet encryption processing, e.g. offloading of IPsec packet processing or efficient security association look-up

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Abstract

The invention discloses the searching ciphertext system and method for a kind of combination identity and the support proxy re-encryption of attribute, this method realizes the shared of safe and efficient one-to-many user's search permission under cloud environment.Identity-based before can search for encryption and Proxy Signature Scheme is by the proxy re-encryption of identity-based and can search for encipherment scheme and combine, be accomplished that the agency of one-to-one search permission.And the program is Identity based encryption method used in the encryption of initial ciphertext, it is used in the re-encryption stage and is based on the linear privacy sharing matrix access structure of LSSS, searching ciphertext permission grant can be given to the other users for meeting access structure, therefore scheme can support the shared of more fine-grained user's search permission, and computational efficiency with higher.It is submitted to Cloud Server after the re-encryption threshold generation stage blinds user key using random value, ensure that the confidentiality and safety of user key.

Description

In conjunction with the searching ciphertext system and method for identity and the support proxy re-encryption of attribute
Technical field
The present invention relates to the searching ciphertext system and methods of a kind of combination identity and the support proxy re-encryption of attribute, belong to Field of cloud computer technology.
Background technique
Cloud computing technology is the important technology in social informatization development process, and cloud storage technology is based on cloud computing technology The novel memory technology of the one kind set up.Cloud storage technology provides a user storage service by modes such as pay-for-uses, A large amount of local resource is saved for user.Into after big data era, more and more users' selection saves the data in cloud End.Although cloud storage brings so more benefits, many safety problems are also brought, because data upload to cloud and just shell Take data owner by force to directly control private data, and as (such as hacker does not have by cloud service provider and illegal user The user of access authority) it can attempt to attempt to obtain the privacy information that data are included by access data, this is resulted in The leakage of data information and privacy of user.In order to alleviate these problems guarantee data confidentiality, more and more companies and People user's selection encrypts data, and data are stored in cloud server with ciphertext form.But when user needs to seek When looking for the associated documents comprising some keyword, it will encounter the difficulty for carrying out search operation in the how beyond the clouds ciphertext of server Topic.But in today of network fast development, information explosion, people need quick search to desired information.It can be seen that such as What rapidly and efficiently find data interested to user, be essential function under cloud computing environment.
Then it can search for encryption (Searchable Encryption, SE) to be suggested, it realizes the retrieval to ciphertext. In it can search for encryption, data owner can be used SE mechanism and encrypt to keyword, and encryption data is uploaded to cloud clothes It is engaged in device.When user, which wants search, includes the file of special key words, corresponding thresholding will be generated with own private key, and The threshold value is uploaded in Cloud Server.Cloud Server responds the request of user by a verification algorithm.If Keyword in user's thresholding is consistent with the keyword in keyword ciphertext, and explanation is proved to be successful, and Cloud Server can will be corresponding Ciphertext returns to user, and user, which only needs that ciphertext is decrypted with the private key of oneself, can obtain desired file.It can search for The appearance of encryption both ensure that the safety of data, also realize document retrieval function in the case where not being related to and decrypting ciphertext, A large amount of local computing space is saved for user, especially suitable for cloud computing environment.The existing scheme that can search for mainly has public affairs Key can search for encryption, identity-based can search for encryption, based on attribute can search for encrypting.2004, Boneh et al. was mentioned for the first time Having gone out middle public key can search for encrypting, but because needing many and diverse CA to manage in public key encryption method, and researcher considers will Identity based encryption, which applies to, can search in encryption.2005, Abdalla et al. was put forward for the first time searching for identity-based The concept of Suo Jiami (IBEKS), thereafter again there are many IBEKS scheme be suggested.2013, Kulvaibhavh et al. construction It can search for the scheme of encryption based on CP-ABE, program data owner utilizes access structure cryptography key word, when user wants When carrying out cipher text searching, key is generated according to self attributes, keyword to be retrieved is encrypted and generates keyword thresholding, thresholding is passed Pass server.Server first judges whether user key attribute meets the access structure of ciphertext, could be into when attribute meets The verifying of row keyword, only attribute and keyword are simultaneously in matched situation, and server is just by the ciphertext comprising the search thresholding Return to user.Wherein, ABE refers to the encryption based on attribute, and the encipherment scheme based on attribute is divided into two kinds, the base of key strategy In encryption attribute (Key-Policy ABE, KP-ABE) and Ciphertext policy based on encryption attribute (Ciphertext-Policy ABE,CP-ABE).In KP-ABE, key is with access strategy correlation, and for ciphertext with property set correlation, encipherer is only data choosing Descriptive attribute is selected, cannot determine that who can decrypt ciphertext, can only believe cipher key distribution person；Attribute is used to describe in CP-ABE The private key of user, access strategy can be used to determine accessible encryption data in encipherer, but encipherer is not aware that specifically Whose accessible ciphertext.So the deployment way of CP-ABE is more nearly with traditional access control model, can be good at fitting For, to the protection of sensitive data, while the control more flexible to access strategy may be implemented in cloud computing environment.
However, IBEKS scheme having some limitations property in data sharing, for example when authorized user is not online, can not will search Suo Quanli entrusts to the demand of other users.One effective method is exactly to introduce proxy re-encryption (Proxy Re- Encryption, PRE) technology, a half online believable agency is set, the conversion of ciphertext is completed instead of authorized person, and Proxy server cannot learn any information relevant to plaintext, to have effectively achieved the shared of search right.But it is single The IBEKS of pure support proxy re-encryption can only realize that one-to-one agency, i.e. a user once can only be by search permission generations It manages to a user, and search permission cannot once be acted on behalf of to multiple users.
Summary of the invention
In order to overcome can search in encipherment scheme of identity-based in cloud computing environment, search permission cannot be effectively realized Multi-user authorizes problem, and the present invention provides searching ciphertext system and the side of the support proxy re-encryption of a kind of combination identity and attribute Method.The system the initial stage use identity-based can search for encryption method, used and be based in the re-encryption stage The access structure encrypted cipher text of LSSS, realizes one-to-many agency, improves system effectiveness.The present invention is by identity and category Property combine, the initial ciphertext stage using identity the re-encryption stage use attribute, realize a user once will search Delegation gives the function of multiple users, the problem above very good solution.
The present invention uses following technical scheme to solve above-mentioned technical problem:
On the one hand, the present invention provides a kind of searching ciphertext system of the support proxy re-encryption of combination identity and attribute, packet It is raw to include initialization module, the private key generation module of identity-based, the private key generation module based on attribute, initial keyword ciphertext Mould is generated at module, initial threshold generation module, initial searching ciphertext module, re-encrypted private key generation module, re-encryption ciphertext Block, re-encryption threshold generation module, re-encryption searching ciphertext module；
Initialization module: system public key and system master key are generated by authorization center, and system public key is disclosed, system master Key is saved by authorization center；
The private key generation module of identity-based: according to the identity id ∈ { 0,1 } of authorized user*Authorized user is generated for closing The private key of key search words；
Private key generation module based on attribute: authorized user is generated for key according to the attribute set of authorized user The private key of search words；
Initial keyword ciphertext generation module: data owner adds keyword using the identity id of authorized user It is close, generate initial keyword ciphertext；
Initial threshold generation module: the private key and keyword to be searched that authorized user possesses according to it generate initial Threshold value；
Initial searching ciphertext module: when the keyword to be searched in the initial threshold value that authorized user generates and initially Keyword ciphertext in keyword it is equal when, carry out searching ciphertext, otherwise retrieval failure；
Re-encrypted private key generation module: authorized user generates according to the private key of oneself and the access structure of authorized user Re-encrypted private key is then passed to proxy server；
Re-encryption ciphertext generation module: the re-encrypted private key that proxy server is provided according to authorized user is come at the beginning of re-encrypted The keyword ciphertext of beginning generates re-encryption ciphertext；
Re-encryption threshold generation module: authorized user generates according to its own private key and keyword to be searched to be added again Close threshold value；
Re-encryption searching ciphertext module: when the attribute in the re-encryption threshold value of authorized user meets in re-encryption ciphertext Access structure and threshold value in keyword to be searched and re-encryption ciphertext in keyword it is equal when, carry out re-encryption Searching ciphertext, otherwise retrieval failure.
As further technical solution of the present invention, the initial key word encrypting module uses identity-based Encryption Algorithm；The re-encryption ciphertext generation module uses the encryption attribute CP-ABE algorithm based on Ciphertext policy.
It is first right that random value is used as further technical solution of the present invention, in the re-encryption threshold generation module Private key carries out blinding processing, then is uploaded to Cloud Server.
As further technical solution of the present invention, the re-encryption ciphertext generation module uses proxy re-encryption skill Art.
As further technical solution of the present invention, the access structure of authorized user is based on the linear privacy sharing of LSSS Matrix access structure.
On the other hand, the present invention also provides the searching ciphertext sides of a kind of combination identity and the support proxy re-encryption of attribute Method includes the following steps:
Step 1: input security parameter λ generates system public key and system master key by authorization center, and system public key gp is public It opens, and system master key msk is saved by authorization center:
Msk=(a, α)
Wherein, e is a multilinear pairing { e:Gi×Gj→Gi+j| i, j >=1 }, giIt is prime number p rank cyclic group GiOn life Cheng Yuan；H1、H2、H3It is safe hash function, H1:{0,1}*→G0, H2:{0,1}*→G0, H3:{0,1}*→G0；A, α are The group of integers Z of p rankpOn random integers；
Step 2: input system public key gp, system master key msk and authorized user identities id are generated by authorization center and are authorized User is used for the private key sk of key searchid:
skid=H1(id)α
Step 3: input system public key gp, system master key msk and the attribute set S of authorized user, by authorization center Generate the private key sk that authorized user is used for key searchS:
skS=(K, L, { Kx}x∈S)
Wherein, random value t ∈ Zp,For any one attribute x in attribute set S, there is Kx =H (x)t；
Step 4: input system public key gp, keyword w and authorized user identities id, it is close that data owner executes initial key word Literary generating algorithm generates initial keyword ciphertext CT:
CT=(C1,C2)
Wherein, r is random value,
Step 5: authorized user's input system public key gp, authorized user's private key skidAt the beginning of keyword w ' generation to be searched The threshold T of beginningw:
Tw=H2(w′)·skid；
Step 6: if authorized user's search permission licenses to other users, thening follow the steps 7, otherwise input system public key Gp, initial keyword ciphertext CT and initial threshold Tw, Cloud Server retrieved, and detailed process is as follows:
Judge initial threshold TwIn keyword w ' to be searched whether with the pass in initial keyword ciphertext CT Key word w is equal, and keyword match success, Cloud Server success search key file are represented if equal, and output 1 indicates inspection Suo Chenggong；Otherwise judgment value 0 is exported, indicates retrieval failure；
Step 7: input system public key gp, authorized user private key skidWith the access structure (M, ρ) of authorized user, by Authorized user generates re-encrypted private key rkid→(M,ρ), it is then sent to proxy server:
rkid→(M,ρ)=(V1,V2,A,R1)
Wherein, M is the linear matrix of l × n, and ρ is that every a line of matrix is mapped to user property one single mapping function, One group of random value is selected to constitute random vectorHave for M from the 1st row to l rowMi It is the corresponding vector of the i-th row of matrix M, chooses random value δ ∈ { 0,1 }*, calculate ForHaveR1=H2(δ)· skid；
Step 8: input system public key gp, initial keyword ciphertext CT and re-encrypted private key rkid→(M,ρ), agency service Re-encryption ciphertext CT ' is calculated in device:
CT '=(C '1,C′2,V1,V2,A)
Wherein, C '1=C1, C '2=C2/e(C1,R1)；
Step 9: authorized user's input system public key gp, authorized user's private key skSIt is raw with keyword w ' to be searched At re-encryption threshold T 'w:
T′w=(T '1,T′2,T′x)
Wherein, random value β ∈ Zp,T′x =Kx·H3(x)β=H3(x)(t+β)；
Step 10: when Cloud Server receives the keyword search request of authorized user, input system public key gp, adding again Close threshold T 'wWith re-encryption ciphertext CT ', execute re-encryption searching ciphertext by Cloud Server: Cloud Server first judges re-encryption Whether the attribute in threshold value meets the access structure in re-encryption ciphertext, and failure is retrieved if being unsatisfactory for, and otherwise judges weight again Whether the keyword in encrypted cipher text and the keyword in re-encryption threshold value are consistent, and judgment value 1 is exported if consistent, indicate clothes Business device success search key file；Otherwise judgment value 0 is exported, indicates retrieval failure.
As further technical solution of the present invention, initial threshold T is judged in step 6wIn key to be searched Whether word w ' is equal with the keyword w in initial keyword ciphertext CT, as verifying e (C1,Tw)=C2It is whether true.
As further technical solution of the present invention, the keyword and re-encryption door in re-encryption ciphertext are judged in step 10 Whether the keyword in limit value is consistent, as verifying equation e (C '2,V2)=e (C '1, Q) it is whether true, whereinωiFor one group of constant vector, { ωi∈Zp}i∈I。
The invention adopts the above technical scheme compared with prior art, has following technical effect that
1. the present invention uses Identity based encryption method to keyword encryption in the initial stage, key generates, is crucial All fairly simple during word encryption and threshold generation, computing cost is smaller；
2. one Identity based encryption ciphertext is switched to another and is based on attribute present invention introduces proxy re-encryption technology Ciphertext, realize the function that search permission is entrusted to multiple users when authorized user is not online, support more fine granularity User's search permission shared, the encrypting and decrypting pressure of authorized user when alleviating traditional Authority sharing, and agency service Device cannot obtain any information about keyword ciphertext, to ensure that the secure access of data and share；
3. the present invention can search for encipherment scheme using CP-ABE in the re-encryption stage, using LSSS access structure to ciphertext It is encrypted, LSSS access strategy can be realized the fine granularity description to user property, and data owner is facilitated to weigh file access Control, meet practical application, in thresholding calculating process, first the private key of user blinded, prevents private key in server Leakage, protect the privacy of user；
4. the present invention effectively by identity-based can search for encryption, based on attribute can search for encryption and proxy re-encryption Technological incorporation, the advantages of making full use of three, the committee of search permission when effectively solving that authorized user is not online in practical application Under the premise of support problem, the flexible control to visitor's permission not only ensure that, but also realize the secure access to data and share, Computing cost is reduced, system effectiveness is improved.
Detailed description of the invention
Fig. 1 is flow chart of the method for the present invention.
Fig. 2 is the specific implementation flow chart of ciphertext re-encryption algorithm of the present invention.
Fig. 3 is system model figure of the present invention in cloud computing environment.
Specific embodiment
Technical solution of the present invention is described in further detail with reference to the accompanying drawing:
The present invention for existing identity-based can search for encryption method cannot achieve search permission it is effective share ask Proxy re-encryption is introduced into can search in encryption of identity-based by topic.And in view of in practical application donor need by Search permission gives the case where multiple users, has used the encryption method based on attribute in the re-encryption stage, has proposed a kind of by body The cipher text retrieval method for the support proxy re-encryption that part and attribute combine.When authorized user is not online, can pass through agency will Search permission safely and efficiently shares to other users, and then improves the treatment effeciency of system.
The searching ciphertext system that the support proxy re-encryption of identity and attribute is combined in a kind of cloud computing of the present invention includes just Beginningization module, the private key generation module of identity-based, the private key generation module based on attribute, initial keyword ciphertext generate mould Block, initial threshold generation module, initial searching ciphertext module, re-encrypted private key generation module, re-encryption ciphertext generation module, again Encrypt threshold generation module, re-encryption searching ciphertext module.
Initialization module: system public key and system master key are generated by authorization center, and system public key is disclosed, system master Key is saved by authorization center；
The private key generation module of identity-based: according to the identity id ∈ { 0,1 } of authorized user*Authorized user is generated for closing The private key of key search words；
Private key generation module based on attribute: authorized user is generated for key according to the attribute set of authorized user The private key of search words；
Initial keyword ciphertext generation module: data owner adds keyword using the identity id of authorized user It is close, generate initial keyword ciphertext；
Initial threshold generation module: the private key and keyword to be searched that authorized user possesses according to it generate initial Threshold value；
Initial searching ciphertext module: the keyword to be searched in the initial threshold value that authorized user generates It when equal with the keyword in initial keyword ciphertext, could search for successfully, otherwise search failure；
Re-encrypted private key generation module: authorized user generates according to the private key of oneself and the access structure of authorized user Re-encrypted private key, it is then passed to proxy server；
Re-encryption ciphertext generation module: the re-encrypted private key that proxy server is provided according to authorized user is come at the beginning of re-encrypted The keyword ciphertext of beginning generates re-encryption ciphertext；
Re-encryption threshold generation module: authorized user generates according to its own private key and keyword to be searched to be added again Close threshold value；
Re-encryption searching ciphertext module: it is close to meet re-encryption and if only if the attribute in authorized user's re-encryption threshold value When the keyword in the keyword to be searched and re-encryption ciphertext in access structure and thresholding limit in text is equal, can just it search Suo Chenggong, otherwise search failure.
The initial key word encrypting module uses Identity based encryption algorithm；The re-encryption ciphertext is raw Encryption attribute (the Ciphertext-Policy Attribute-Based based on Ciphertext policy is used at module Encryption, CP-ABE) algorithm, private key is related to property set in the algorithm, and ciphertext is related to access structure, it is easier to realize Owner controls the permission of visitor；Using LSSS access structure, it can be realized and visitor's attribute fine granularity is described, spirit Access authority is controlled livingly.
Random value is used in the re-encryption threshold generation module first private key is carried out to blind processing, then be uploaded to cloud Server ensure that the safety of private key so that private key is invisible for incredible server, ensure that re-encryption is close The safety of text.
It in two retrieval modules is matched to keyword, operation is not decrypted, because of data There is corresponding relationship between ciphertext and keyword ciphertext, so when user search is to corresponding keyword ciphertext, it just can be by corresponding data Ciphertext submits to user, in this way can safety protection data ciphertext, and search operaqtion only is carried out to keyword ciphertext, improved Effectiveness of retrieval.
Proxy re-encryption technology has been used in the re-encryption module；Proxy re-encryption technology is exactly to turn to ciphertext A kind of encryption technology changed, wherein Cloud Server plays the function of proxy server, and script can be directed to the pass of donor by it Key word ciphertext is converted into the ciphertext for licensee, and in the process, proxy server is for the text of data corresponding to ciphertext Part is known nothing in plain text, can guarantee the safety of data file well.
The proxy re-encryption technology is single-hop, unidirectional；According to the conversion times of ciphertext in proxy re-encryption, agency Re-encryption scheme can be divided into single-hop and multi-hop, and single-hop refers to that proxy re-encryption scheme can only allow ciphertext primary by conversion, A proxy re-encryption can only be carried out；Multi-hop refers to that ciphertext can be multiple by conversion；Again according to the conversion direction of ciphertext, Dai Lichong Encryption can be divided into it is two-way and unidirectional, it is two-way to refer to that the A ciphertext that decrypted can be both converted into the ciphertext that B can be decrypted by agency, The B ciphertext that can be decrypted can be converted into the ciphertext that A can be decrypted again；Unidirectionally referring to only allows the ciphertext that can decrypt A to be converted into B The ciphertext that can be decrypted.
Below with an example come to the support proxy re-encryption for combining identity and attribute in the cloud computing in the present invention Cipher text retrieval method is specifically illustrated.
As shown in Figures 1 to 3, the present invention provides the searching ciphertexts of a kind of combination identity and the support proxy re-encryption of attribute Method, this method comprises the following steps:
Step 1: input security parameter λ generates system public key and system master key by authorization center, and system public key is public It opens, and system master key is saved by authorization center, it is specific to determine that method includes the following:
Wherein, gp represents system public key, and e is a multilinear pairing { e:Gi×Gj→Gi+j| i, j >=1 }, giIt is prime number p Rank cyclic group GiOn generation member.H1, H2, H3It is safe hash function, H1:{0,1}*→G0, H2:{0,1}*→G0, H3: {0,1}*→G0。
Msk=(a, α) formula 2
Wherein, msk is system master key, and a, α are the group of integers Z of p rankpOn random integers.
After initialization module is finished, two private key generation modules of step 2 and step 3 are continued to execute；
Step 2: input system public key gp, system master key msk and authorized user identities id are generated by authorization center and are authorized User is used for the private key sk of key searchid, it is used for initial threshold generation module and re-encrypted private key generation module:
skid=H1(id)αFormula 3
Step 3: input system public key gp, system master key msk and the attribute set S of authorized user, by authorization center Generate the private key sk that authorized user is used for key searchS, it is used for re-encryption threshold generation module.
skS=(K, L, { Kx}x∈S) formula 4
Wherein, skSRepresent the private key of licensee, K, L, KxAll it is the component part of private key, selects a random value t ∈ Zp, then calculateFor any one attribute x in property set S, there is Kx=H (x)t。
Before data file is uploaded Cloud Server by user, in order to which the safety and privacy of data must be first to data files It is uploaded again with after keyword encryption, executes step 4；
Step 4: input system public key gp, keyword w and authorized user identities id, it is close that data owner executes initial key word Literary generating algorithm, generates initial keyword ciphertext CT, and specific ciphering process includes the following:
CT=(C1,C2) formula 5
Wherein, CT represents ciphertext, C1And C2It is the component part of ciphertext, randomly chooses random value r, When user wants search key, threshold generation module is gone to, is executed Step 5；
Step 5: authorized user's input system public key gp, authorized user's private key skidAt the beginning of keyword w ' generation to be found The threshold T of beginningw, specific calculating process includes the following:
Tw=H2(w′)·skidFormula 6
Wherein, TwInitial threshold is represented, user can be uploaded in Cloud Server after generating, and Cloud Server receives use When the threshold value submitted when the retrieval at family, searching ciphertext module is gone to, executes step 6；
Step 6: if search permission is licensed to other users by authorized user, thening follow the steps 7, otherwise input system public key Gp, initial keyword ciphertext CT and initial threshold Tw, Cloud Server retrieved, and detailed process is as follows:
Judge whether keyword w ' to be searched equal with the keyword w in initial keyword ciphertext, i.e. verifying e (C1,Tw)=C2It is whether true.Verification process is as follows:
If formula 7 is set up, keyword match success, Cloud Server success search key file, output 1, generation are represented Table is retrieved successfully；Otherwise judgment value 0 is exported, indicates retrieval failure.
If wanting search permission licensing to other users when authorized user is not online, goes to re-encrypted private key and generate mould Block executes step 7；
Step 7: input system public key gp, authorized user private key skidWith the access structure (M, ρ) of licensee.Access In structure (M, ρ), M is the linear matrix of l × n, and ρ is a single mapping function, every a line of matrix can be mapped to user Attribute.
Re-encrypted private key rk is generated by authorized userid→(M,ρ), it is then sent to proxy server, detailed process is as follows:
rkid→(M,ρ)=(V1,V2,A,R1) formula 8
Wherein, rkid→(M,ρ)Represent re-encrypted private key, V1,V2,A,R1It is the component part of re-encrypted private key；Select one group Random value constitutes random vectorHave for access matrix from the 1st row to l rowIts Middle MiIt is the corresponding vector of the i-th row of matrix M.It is generated according to access structure ForHaveFinally according to the private key of donor Generate R1=H2(δ)·skid。
When proxy server receives the re-encrypted private key of authorized person's offer, re-encryption ciphertext generation module is gone to, Proxy server executes step 8；
Step 8: input system public key gp, initial keyword ciphertext CT and re-encrypted private key rkid→(M,ρ), agency service Re-encryption ciphertext is calculated in device, and detailed process is as follows:
CT '=(C '1,C′2,V1,V2, A) and formula 9
Wherein, CT ' represents re-encryption ciphertext, C '1,C′2,V1,V2, A is the component part of re-encryption ciphertext, wherein C '1= C1, C '2=C2/e(C1,R1), V1,V2, A is to be transmitted through to come from re-encrypted private key.
C′2Calculating it is as follows:
When licensee wants search key, re-encryption threshold generation module is gone to, executes step 9；
Step 9: authorized user's input system public key gp, authorized user's private key skSIt is raw with keyword w ' to be found At re-encryption threshold value, specific calculating process includes the following:
T′w=(T '1,T′2,T′x) formula 11
Wherein, T 'wRepresent re-encryption threshold value, T '1,T′2,T′xIt is the component part of re-encryption threshold value, selects first One random value β ∈ Zp, calculateThen it is carried out using private key of the random value to licensee It blinds,
When Cloud Server receives the keyword search request of authorized user, re-encryption searching ciphertext module is gone to, is held Row step 10；
Step 10: when Cloud Server receives the keyword search request of authorized user, input system public key gp, being awarded Weigh the thresholding T ' of peoplewWith re-encryption ciphertext CT ', re-encryption searching ciphertext is executed by Cloud Server, detailed process includes the following:
Firstly, according to the thresholding of licensee and re-encryption cryptogram computationWherein the calculating process of Q is as follows:
Finally, it is verified that equation e (C '2,V2)=e (C '1, Q) it is whether true.
I.e.If W=w ', i.e., when the keyword in re-encryption ciphertext is consistent with the keyword in licensee's thresholding, formula 13 is set up, output judgement Value 1, representative server success search key file.Otherwise judgment value 0 is exported, indicates retrieval failure.
The searching ciphertext system and method for a kind of combination identity disclosed by the invention and the support proxy re-encryption of attribute, should Method realizes the shared of safe and efficient one-to-many user's search permission under cloud environment.Identity-based before is searched Suo Jiami and Proxy Signature Scheme are by the proxy re-encryption of identity-based and to can search for encipherment scheme and combine, and are accomplished that one-to-one Search permission agency.And the program is Identity based encryption method used in the encryption of initial ciphertext, again plus The close stage, which uses, is based on the linear privacy sharing matrix access structure of LSSS, can tie searching ciphertext permission grant to access is met The other users of structure, therefore scheme can support the shared of more fine-grained user's search permission, and calculating with higher Efficiency.It is submitted to Cloud Server after the re-encryption threshold generation stage blinds user key using random value, ensure that user is close The confidentiality and safety of key.
It is in summary only the preferred embodiments of the invention, it is noted that for the ordinary skill people of the art Member, without departing from the inventive concept of the premise, can also make several improvements and modifications, these improvements and modifications also should be regarded as In protection scope of the present invention.

Claims (8)

1. combining the searching ciphertext system of the support proxy re-encryption of identity and attribute, which is characterized in that including initialization module, The private key generation module of identity-based, the private key generation module based on attribute, initial keyword ciphertext generation module, initial gate Limit generation module, initial searching ciphertext module, re-encrypted private key generation module, re-encryption ciphertext generation module, re-encryption thresholding Generation module, re-encryption searching ciphertext module；
Initialization module: system public key and system master key are generated by authorization center, and system public key is disclosed, system master key It is saved by authorization center；
The private key generation module of identity-based: according to the identity id ∈ { 0,1 } of authorized user*It generates authorized user and is used for keyword The private key of retrieval；
Private key generation module based on attribute: authorized user is generated according to the attribute set of authorized user and is examined for keyword The private key of rope；
Initial keyword ciphertext generation module: data owner encrypts keyword using the identity id of authorized user, raw At initial keyword ciphertext；
Initial threshold generation module: the private key and keyword to be searched that authorized user possesses according to it generate initial thresholding Value；
Initial searching ciphertext module: when in the initial threshold value that authorized user generates keyword to be searched and initial pass When keyword in key word ciphertext is equal, searching ciphertext is carried out, otherwise retrieval failure；
Re-encrypted private key generation module: authorized user generates and adds again according to the private key of oneself and the access structure of authorized user Key is then passed to proxy server；
Re-encryption ciphertext generation module: proxy server is according to the re-encrypted private key that authorized user provides initial come re-encrypted Keyword ciphertext generates re-encryption ciphertext；
Re-encryption threshold generation module: authorized user generates re-encryption door according to its own private key and keyword to be searched Limit value；
Re-encryption searching ciphertext module: when the attribute in the re-encryption threshold value of authorized user meets the visit in re-encryption ciphertext When asking that keyword in the keyword to be searched and re-encryption ciphertext in structure and threshold value is equal, re-encryption ciphertext is carried out Retrieval, otherwise retrieval failure.
2. the searching ciphertext system of combination identity according to claim 1 and the support proxy re-encryption of attribute, feature It is, the initial key word encrypting module uses Identity based encryption algorithm；The re-encryption ciphertext generates Module uses the encryption attribute CP-ABE algorithm based on Ciphertext policy.
3. the searching ciphertext system of combination identity according to claim 1 and the support proxy re-encryption of attribute, feature It is, random value is used in the re-encryption threshold generation module, first private key is carried out to blind processing, then is uploaded to cloud clothes Business device.
4. the searching ciphertext system of combination identity according to claim 1 and the support proxy re-encryption of attribute, feature It is, the re-encryption ciphertext generation module uses proxy re-encryption technology.
5. the searching ciphertext system of combination identity according to claim 1 and the support proxy re-encryption of attribute, feature It is, the access structure of authorized user is based on the linear privacy sharing matrix access structure of LSSS.
6. combining the cipher text retrieval method of the support proxy re-encryption of identity and attribute, which comprises the steps of:
Step 1: input security parameter λ generates system public key and system master key by authorization center, system public key gp is disclosed, And system master key msk is saved by authorization center:
Msk=(a, α)
Wherein, e is a multilinear pairing { e:Gi×Gj→Gi+j| i, j >=1 }, giIt is prime number p rank cyclic group GiOn generation member； H1、H2、H3It is safe hash function, H1:{0,1}*→G0, H2:{0,1}*→G0, H3:{0,1}*→G0；A, α are p ranks Group of integers ZpOn random integers；
Step 2: input system public key gp, system master key msk and authorized user identities id generate authorized user by authorization center Private key sk for key searchid:
skid=H1(id)α
Step 3: input system public key gp, system master key msk and the attribute set S of authorized user are generated by authorization center Authorized user is used for the private key sk of key searchS:
skS=(K, L, { Kx}x∈S)
Wherein, random value t ∈ Zp,For any one attribute x in attribute set S, there is Kx=H (x)t；
Step 4: input system public key gp, keyword w and authorized user identities id, it is raw that data owner executes initial key word ciphertext At algorithm, initial keyword ciphertext CT is generated:
CT=(C1,C2)
Wherein, r is random value,
Step 5: authorized user's input system public key gp, authorized user's private key skidIt is initial with keyword w ' generation to be searched Threshold Tw:
Tw=H2(w′)·skid；
Step 6: if authorized user's search permission licenses to other users, then follow the steps 7, otherwise input system public key gp, just The keyword ciphertext CT of beginning and initial threshold Tw, Cloud Server retrieved, and detailed process is as follows:
Judge initial threshold TwIn keyword w ' to be searched whether with the keyword w in initial keyword ciphertext CT It is equal, represented if equal keyword match success, Cloud Server success search key file, output 1, indicate retrieval at Function；Otherwise judgment value 0 is exported, indicates retrieval failure；
Step 7: input system public key gp, authorized user private key skidWith the access structure (M, ρ) of authorized user, by authorizing User generates re-encrypted private key rkid→(M,ρ), it is then sent to proxy server:
rkid→(M,ρ)=(V1,V2,A,R1)
Wherein, M is the linear matrix of l × n, and ρ is that every a line of matrix is mapped to user property one single mapping function, selection One group of random value constitutes random vectorHave for M from the 1st row to l rowMiIt is square The corresponding vector of battle array the i-th row of M, calculatesForHaveR1=H2(δ)·skid；
Step 8: input system public key gp, initial keyword ciphertext CT and re-encrypted private key rkid→(M,ρ), proxy server calculating Obtain re-encryption ciphertext CT ':
CT '=(C '1,C′2,V1,V2,A)
Wherein, C '1=C1, C '2=C2/e(C1,R1)；
Step 9: authorized user's input system public key gp, authorized user's private key skSAdd again with keyword w ' generation to be searched Close threshold T 'w:
T′w=(T '1,T′2,T′x)
Wherein, random value β ∈ Zp,T′x= Kx·H3(x)β=H3(x)(t+β)；
Step 10: when Cloud Server receives the keyword search request of authorized user, input system public key gp, re-encryption door Limit value T 'wWith re-encryption ciphertext CT ', execute re-encryption searching ciphertext by Cloud Server: Cloud Server first judges re-encryption thresholding Whether the attribute in value meets the access structure in re-encryption ciphertext, and failure is retrieved if being unsatisfactory for, otherwise judges re-encryption again Whether the keyword in ciphertext and the keyword in re-encryption threshold value are consistent, and judgment value 1 is exported if consistent, indicate server Success search key file；Otherwise judgment value 0 is exported, indicates retrieval failure.
7. the cipher text retrieval method of combination identity according to claim 6 and the support proxy re-encryption of attribute, feature It is, initial threshold T is judged in step 6wIn keyword w ' to be searched whether in initial keyword ciphertext CT Keyword w it is equal, as verifying e (C1,Tw)=C2It is whether true.
8. the cipher text retrieval method of combination identity according to claim 6 and the support proxy re-encryption of attribute, feature It is judge whether the keyword in the keyword in re-encryption ciphertext and the threshold value of re-encryption is consistent in step 10, as Verify equation e (C '2,V2)=e (C '1, Q) it is whether true, wherein
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