CN114938274A - Hierarchical key management and data security distribution method and system - Google Patents
Hierarchical key management and data security distribution method and system Download PDFInfo
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- 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
- H04L63/045—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 wherein the sending and receiving network entities apply hybrid encryption, i.e. combination of symmetric and asymmetric encryption
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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
- H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
- H04L9/0643—Hash functions, e.g. MD5, SHA, HMAC or f9 MAC
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0819—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s)
- H04L9/0822—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) using key encryption key
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0819—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s)
- H04L9/0825—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0819—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s)
- H04L9/083—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
- H04L9/0833—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] involving conference or group key
- H04L9/0836—Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] involving conference or group key using tree structure or hierarchical structure
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0861—Generation of secret information including derivation or calculation of cryptographic keys or passwords
- H04L9/0866—Generation of secret information including derivation or calculation of cryptographic keys or passwords involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0861—Generation of secret information including derivation or calculation of cryptographic keys or passwords
- H04L9/0869—Generation of secret information including derivation or calculation of cryptographic keys or passwords involving random numbers or seeds
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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
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0861—Generation of secret information including derivation or calculation of cryptographic keys or passwords
- H04L9/0872—Generation of secret information including derivation or calculation of cryptographic keys or passwords using geo-location information, e.g. location data, time, relative position or proximity to other entities
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Abstract
The invention discloses a hierarchical key management and data secure distribution method and a system, comprising the following steps: generating a public and private key pair for each user; the user key is sent along with the searchable encrypted key. Distributing a user key for each user in the key distribution and storage stage; encrypting and storing the user identification and the user key on a server; generating a trapdoor according to the identification of the authorized user in a data distribution stage for searching; the server returns a corresponding authorized user key; generating a session key and distributing data by using an authorized user key; after receiving the data, the user decrypts the data by using the user key of the user to obtain the session key, so as to obtain the real data. The invention utilizes the key encryption data of different levels to combine with the ciphertext searchable technology, reduces the length of the ciphertext, reduces the consumption of bandwidth, protects the safety of the user key, reduces the calculation expense of a data center and improves the efficiency.
Description
Technical Field
The invention relates to the technical field of information security, in particular to a hierarchical key management and data security distribution method and system.
Background
With the development of the internet and the arrival of the big data era, the security of data is becoming an increasingly important research content in real life. In some large enterprises or organizations, the operation and reputation of the enterprise may be seriously affected in case of data leakage or some other security problem. Cryptography, as an underlying tool for securing data, is widely used, such as various encryption protocols and signature protocols. In practical applications, it is often the case that data is distributed from one data center to a plurality of users. The former method generally encrypts data with a private key held by its user and then sends the data to the user for each user receiving the data. However, the length of the ciphertext in this approach may appear to grow linearly as the number of users increases. The method not only improves the calculation cost of the data center, but also increases the bandwidth consumption and reduces the operating efficiency of the scheme. How to design an efficient and safe data distribution method under the condition of protecting data security is an urgent problem to be solved.
In addition, in data centers, storage and management of user keys also face some security issues. Generally, the data center may store the user identification and the key in a table. However, in the case of plaintext storage, once the data center is hacked or Bugs occur, the user identity and the secret key are once leaked, which may seriously affect the transmission security of data. A straightforward solution is to store the table encrypted and decrypt the encrypted table when some user key is needed for data encryption. However, this method is not suitable in practical environment, the data center needs to decrypt the whole table every time data is encrypted, the calculation overhead is large, and the operation efficiency of the scheme is low.
Therefore, a need exists in the art for a hierarchical key management and data security distribution method and system that can efficiently and securely store and manage a user's key.
Disclosure of Invention
In view of this, the invention designs an efficient and secure scheme for user key management and data secure distribution in combination with searchable encryption technology.
In order to achieve the purpose, the invention adopts the following technical scheme:
a hierarchical key management and data security distribution method comprises a key storage and distribution step and a data distribution step:
the key storage and distribution step comprises:
a tree-type user organization structure is constructed, wherein one node in the tree corresponds to one user identifier
Representing the ith user identifier of the jth layer as the user identifier
Generating corresponding user keys
Public and private key pair
Pre-stored user identification
Encrypting data with corresponding user key
In the server, the user key encrypts data
And with a secret key K 1 User identification of
With a cableReferral, user key encrypted data
Comprising a secret key K 2 Encrypting data after the user key set;
using public keys
Encrypting and transmitting the user key set to the user sides of all users; the user key set comprises the user key of the current user
And the user keys of all ancestor nodes thereof, the user using the corresponding private key
Decrypting to complete the distribution of the user key;
the data distribution step comprises:
using a secret key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Using a secret key K 2 Decrypting user key encrypted data
Obtaining keys of authorized users
And encrypting the data M by using a session key SK, and transmitting the data M to a user side of an authorized user, wherein the session key SK is encrypted by using an authorized user key.
Preferably, the user key
The generating step comprises: generating a random number of lambda bit length for each user
And a time stamp T x (ii) a Calculating a user key for each user
Where H represents a hash function and | represents the concatenation of two strings.
Preferably, the pre-stored user identifier
Encrypting data with corresponding user key
The steps in the server include:
using a secret key K 2 Encrypting the user key:
generating an index table I with size n and initializing to null, selecting a secret key K 1 The index table is populated as follows:
sending S ═ I, c to the server for storage, wherein
Preferably, the key K 1 And a secret key K 2 For symmetric keys, use is made of a key K 1 For user identification
The algorithm of the encryption is, and utilizes the secret key K 2 The algorithms for encrypting the user key are all symmetric encryption algorithms.
Preferably, the public and private key pair
Are distributed directly to the user end through a secure channel.
Preferably, the key storage and distribution step further comprises: using public keys
And user identification
Generating a lookup table T, and storing the lookup table T in a server in a plaintext form: using each user identity
Inquiring a server lookup table T to obtain a corresponding user identifier
Of (2) a public key
Preferably, the user end of all users receives the public key
After encrypting the user key set, using the private key
And decrypting the key to obtain the user key set.
Preferably, the utilization key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Comprises the following steps:
using a secret key K 1 Generating a corresponding authorized user trapdoor as follows:
e＝(e(1),...,e(i),...,e(w))
＝(f(K 1 ,ID(1)),...f(K 1 ,ID(i)),...,f(K 1 ,ID(w)))
wherein, f (K) 1 ID (i) is a secret key K 1 The pseudo-random permutation of (a), the set of identities of authorized users UT { ID (1),.. ID (i),. ID (w) }, w being the number of authorized users, ID (i) representing the user identity of an authorized user;
the server searches according to the trapdoors in the following way:
if I [ e (I) ] ≠ T, the server returns the corresponding c (I).
Preferably, the method further comprises the data decryption step of the user side:
after receiving the distributed data, the authorized user side decrypts by using the held user key set to obtain a session key SK;
the encrypted message is decrypted using the session key SK to obtain the original data M.
The invention also provides a hierarchical key management and data security distribution system according to the hierarchical key management and data security distribution method, which comprises a key generation center, a distribution center, a server and a user side; wherein the content of the first and second substances,
the key generation center is used for generating a user key corresponding to a tree-type user organization structure
Public and private key pair
Secret key K 1 And a secret key K 2 ；
The server is used for storing the user identification
Encrypting data with corresponding user key
The distribution center is used for executing the key distribution and data distribution steps, encrypting and transmitting the user key set to the user sides of all users and encrypting and transmitting the data M to the user sides of authorized users.
Preferably, the server is further configured to store the public key in clear text
And user identification
A look-up table T is generated to enable the distribution center to utilize the authorized user identification
Inquiring a look-up table T of a server to obtain a corresponding user identifier
Of (2) a public key
Through the technical scheme, compared with the prior art, the invention has the beneficial effects that:
the invention designs a hierarchical key system, and uses a tree structure to divide users with different hierarchies at a user side. Different keys are distributed according to the hierarchy of each user, and each key is related to user identification, time stamp and random number. Such a hierarchical key hierarchy may enable data distribution to a given set of users based on the same user key.
The invention designs an efficient and safe key storage system. The invention utilizes a searchable encryption technology to encrypt and store the user identification and the user key on the server. When data distribution is performed, the distribution center can search for the user key in a ciphertext state. The method not only protects the security of the user key, but also can reduce the calculation expense of the data center.
The invention designs a hierarchical level data distribution system based on a hierarchical key system, the data distribution center utilizes keys of different levels to encrypt data, and utilizes less ciphertext to distribute to realize the receiving and decryption of the same data by users of different levels, thereby reducing the length of the ciphertext, effectively avoiding the problem that the length of the ciphertext can be increased along with the increase of the number of the users, reducing the consumption of bandwidth and improving the efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts;
fig. 1 is a flowchart of a hierarchical key management and data security distribution according to an embodiment of the present invention;
FIG. 2 is a diagram of a user key hierarchy provided by an embodiment of the present invention;
fig. 3 is a flowchart of a user key distribution and storage provided in an embodiment of the present invention;
fig. 4 is a comparison diagram of the server S table encryption to the S' table provided in the embodiment of the present invention;
fig. 5 is a flowchart of data distribution and decryption according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a first aspect of the present invention discloses a hierarchical key management and data secure distribution method, including a key storage and distribution step and a data distribution step:
the key storage and distribution step comprises:
a tree-type user organization structure is constructed, wherein one node in the tree corresponds to one user identifier
Representing the ith user identifier of the jth layer as the user identifier
Generating a corresponding user key
Public and private key pair
Pre-stored user identification
Encrypting data with corresponding user key
In the server, the user key encrypts data
And with a secret key K 1 By usingUser identification
Having an indexed relationship, user keys encrypt data
Comprising a secret key K 2 Encrypting data after the user key set;
using public keys
The user key set is encrypted and transmitted to the user sides of all the users, and the user key set comprises the user keys of the current users
And the user keys of all ancestor nodes, the corresponding users using their own private keys
Decrypting to complete the distribution of the user key set;
the data distribution step comprises:
using a secret key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Using a secret key K 2 Decrypting user key encrypted data
The key of the authorized user is obtained,
and encrypting the data M by using a session key SK, and transmitting the data M to a user side of an authorized user, wherein the session key SK is encrypted by using an authorized user key.
The present embodiment mainly comprises 7 main processes: in the system initialization stage, a key generation center generates a pair of public and private keys for each user; the key generation center sends the user key and the searchable encryption key to the distribution center. In the key distribution and storage phase; thirdly, the distribution center distributes the user key for each user; and fourthly, the distribution center encrypts and stores the user identification and the user secret key on the server. In the data distribution phase; generating a trapdoor by the distribution center according to the identification of the authorized user for searching; sixthly, the server returns the corresponding encrypted user key, and the distribution center decrypts the encrypted user key; the distribution center generates a session key and distributes data using the user key. After receiving the data, the user decrypts the data by using the private key of the user to obtain a session key, and then obtains real data.
The organizational structure of the user can be represented by a tree structure according to different practical applications. Different nodes represent different meanings. For example, the root node of a tree represents the global headquarters of a company and the leaf nodes represent each employee in the enterprise. Other intermediate nodes may represent some regional headquarters or some departments within the enterprise. Referring to fig. 2, this embodiment sets a unique id for each node in the tree
The key generation center will be for each node in the tree
Will generate a corresponding user key
Wherein j ∈ [1, d ]],i∈[1,t j ],t j Representing the number of users in the j-th level and d representing the user hierarchy. For each user node
It not only possesses user key held by itself
But also has the keys held by all of its ancestor nodes. For one user node
In other words, it holds a set of keys of
Wherein
Is the user key of its ancestor node.
For example, if the data distribution center encrypts data with the key of the root user, all user nodes on the tree generated by the root node can be decrypted. If the data distribution center is encrypted by the key of a certain leaf node user, only the leaf node user can decrypt the data, and if the data distribution center is encrypted by the user keys of non-leaf nodes and non-root nodes, the node user and all child node users below the node can decrypt the data.
In one embodiment, the user key
The generating step comprises: generating a random number of lambda bit length for each user
And a time stamp T x (ii) a Calculating a user key for each user
Where H represents a hash function and | represents the concatenation of two strings.
The pre-generated key in the method of the embodiment includes:
given a security parameter lambda, a key generation center(KGC) generating two symmetric keys K for a distribution center 1 And K 2 The two keys are used by the distribution center to encrypt and store the user identification and the user key.
Based on a given security parameter lambda, the key generation center is centered for each user
Generate a pair of public and private keys as
Each pair of public and private keys may be distributed by the key generation center to the respective users over a secure channel. The public and private keys are mainly used for encrypting and transmitting user keys, a distribution center in the data center stores a table T for recording user identification and public keys of users, and the data center can store the table T on a server in a plaintext form because the table T only contains the public keys of the users.
Based on a given security parameter lambda, the key generation center is centered for each user
A corresponding user key is generated.
The key generation center firstly generates a random number with a lambda bit length for each user
And a time stamp T x Then the key generation center calculates the key of each user
Where H represents a hash function and | represents the concatenation of two strings. The user key is used for encrypting the session key at the time of data distribution later. The distribution center generates and stores a table S for recording the user id and the user key, and since the table S contains the user key, the data center should store the table S in the form of ciphertext on the server.
In one embodiment, see FIG. 4, the descriptionPre-stored user identification
Encrypting data with corresponding user key
The steps in the server include:
for each user key
Distribution center using key generation center generated K 2 Encrypting it:
secc herein stands for any symmetric encryption algorithm, such as AES, DES, etc.
Generating an index table I with the size of n, initializing the index table I to be null, and selecting a key K with the key 1 The index table is populated as follows:
sending S ═ I, c to the server for storage, wherein
In one embodiment, the key K 1 And a secret key K 2 For symmetric keys, use is made of a key K 1 To user identification
The algorithm of the encryption is, and utilizes the secret key K 2 The algorithms for encrypting the user key are all symmetric encryption algorithms.
In one embodiment, a public-private key pair
Is directed through a secure channelAnd distributing to the user terminal.
In one embodiment, the key storage and distribution step further comprises: using public keys
And user identification
Generating a lookup table T and storing the lookup table T in a server in a plaintext form; using each user identity
Inquiring a server lookup table T to obtain a corresponding user identifier
Of (2)
The specific implementation process is as follows:
distribution center in data center for each user
Distributing the corresponding user key is as follows:
the distribution center obtains corresponding users according to the query table T of the server
Of (2) a public key
Distribution center for encryption
And each will be
Sending the data to corresponding users, and decrypting by the users by using the private keys of the users to obtain a key set
PEnc and PDec herein represent any public key based encryption and decryption algorithm, such as RSA.
Each user end receives the public key
After encrypting the user key set, using the private key
And decrypting the key to obtain the user key set.
In one embodiment, the utilization key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Comprises the following steps:
using a secret key K 1 Generating a corresponding authorized user trapdoor as follows:
e＝(e(1),...,e(i),...,e(w))
＝(f(K 1 ,ID(1)),...f(K 1 ,ID(i)),...,f(K 1 ,ID(w)))
wherein, f (K) 1 ID (i) is a secret key K 1 The pseudo-random permutation of (a), the set of identities of authorized users UT ═ { ID (1),.. ID (i),. ID.),. ID, (w) }, w being the number of authorized users, ID (i) representing the user identities of the authorized users;
the server searches according to the trapdoors in the following way:
if I [ e (I) ] ≠ T, the server returns the corresponding c (I).
The specific implementation steps of data distribution are as follows:
in the dataThe central distribution first determines the set of authorized users, i.e. which users can decrypt the corresponding broadcast message. First, the distribution center selects an identification set UT ═ ID (1),. ID (i),. ID (w), for the corresponding authorized user, according to the actual situation. w is the number of authorized users and id (i) represents the identity of a user. Thereafter, the data center utilizes the key K 1 Generating a corresponding authorized user trapdoor as follows:
e＝(e(1),...,e(i),...,e(w))＝(f(K 1 ,ID(1)),...f(K 1 ,ID(i)),...,f(K 1 ,ID(w)))。
the distribution center sends the searched trapdoor e to the server, and the server searches according to the trapdoor in the following mode:
if I [ e (I)]≠ t, the server returns the corresponding c (i). The distribution center then uses the key K it owns 2 And c (i) is decrypted to obtain the corresponding K (i). All user keys k (i) together form a set:
BK＝{K(1),..,K(i),...,K(w)}。
when creating the table S, f (K) is used 1 ID (i) is used as an index in a table, a key corresponding to the user ID (i) can be found through the index, and when the trapdoor is constructed, if the input ID (i) does not belong to any one of the previously stored IDs, the server searches f (K) 1 ID (i)) will return ^ t because f (K) 1 ID (i)) this index is not present at all in the table. Correspondingly, if the input ID (i) belongs to a previously stored ID, the server can find the corresponding key ciphertext according to the index, and return to c (i).
For a piece of data M, the distribution center first generates a temporary session key SK to encrypt the data M to obtain EM ═ SEnc (SK, M). The distribution center then encrypts the session SK key with the key k (i) of the authorized user to obtain esk (i) SEnc (k (i), SK).
Finally, the distribution center distributes { (ESK (1),.., ESK (i),.., ESK (w), EM } out.
In one embodiment, referring to fig. 5, the method further includes the data decryption step at the user end:
the authorized user end utilizes the held user key set after receiving the distributed data
Decrypting one of K (i) and K (i) to obtain a session key SK ═ SDec (K (i) and EKS (i));
the encrypted message is decrypted using the session key SK to obtain the original data M SDec (SK, EM).
The invention also discloses a hierarchical key management and data security distribution system of the hierarchical key management and data security distribution method provided by the first aspect, which mainly comprises two kinds of entities: the data center comprises a key generation center, a distribution center and a server; wherein, the first and the second end of the pipe are connected with each other,
the key generation center is used for generating a user key corresponding to the tree-type user organization structure
Public and private key pair
Secret key K 1 And a secret key K 2 ；
The server is used for storing the user identification
Encrypting data with corresponding user key
The distribution center is used for executing the key distribution and data distribution steps, encrypting and transmitting the user key set to the user sides of all users and encrypting and transmitting the data M to the user sides of authorized users.
In one embodiment, the server is further configured to store the public key in clear text
And use ofUser identification
A look-up table T is generated to enable the distribution center to utilize the authorized user identification
Inquiring a look-up table T of a server to obtain a corresponding user identifier
Of (2)
At the user end, the invention designs a user organization structure with hierarchy. The user organization architecture can be divided into several layers according to actual conditions. For example, for a large enterprise, the enterprise may be divided into a global headquarters, a regional headquarters, a department, an employee, and so on. In the present invention, the key generation center needs to generate a key for each user in each layer. Specifically, for a user of the first layer, the key generated for it is
Generate a key of
For its d-th (last) layer user, the generated key is
Where d represents the number of user organization layers, t j Representing the number of users at layer j. In addition, the user at each layer can obtain not only the key belonging to the user, but also the key owned by the parent node of the user. For example, for the first user in three layers, the key he has is
For a piece of data M, when the data M is subjected to data distribution, the data MThe distribution center in the center needs to generate a session key SK and a key to select some authorized users. The session key is used to encrypt the message M and the user key is used to encrypt the session key SK. The corresponding decryptable authorized user is different according to the different selected user key. For example, if used
To encrypt the session key SK, then represent possession
All users of this key (from all children nodes below this node) can decrypt it, if used
The session key SK is encrypted by the key, and then only the possession of
One user (leaf node) can decrypt the session key. In some other applications, there may be more levels of users, and the above-described method may be used to generate keys for each level of users
Where j represents the jth level and i represents the ith user of a certain level.
On the data center side, a key generation center of the data center is responsible for generating a corresponding user key for each user
The key generation center firstly generates a random number with a lambda bit length for each user
And a system time based timestamp T x . According to the corresponding random number
And a time stamp T x The key generation center can calculate a corresponding private key for each user
Where H represents a hash function and | represents the concatenation of two strings. At the time of key distribution, the distribution center distributes the user key to each user separately. The distribution center then identifies each user
With corresponding keys
Stored as one record in table S. Thereafter, the distribution center stores the table S in the data server using searchable encryption. When the distribution center needs to encrypt and distribute data, firstly, a searchable encryption technology is used for searching the identification of the corresponding authorized user on the encryption table S' of the storage server, and a key corresponding to the identification of the corresponding user is returned. This user key is then decrypted and returned to the distribution center. At each data distribution, the distribution center generates a temporary session key SK for encrypting the data M. The session keys are then separately encrypted using the user keys of the authorized users.
Before data distribution begins, communication is required between the distribution center and the user. The distribution center distributes the user key set to each user. Each user has a public and private key pair
The distribution center can use the public key of the user to set the secret key for the public key of the user
The encryption is transmitted to the user. The user utilizes the private key to decrypt and obtain
The above detailed description is made on the hierarchical key management and data security distribution method and system provided by the present invention, and a specific example is applied in this embodiment to explain the principle and the implementation of the present invention, and the description of the above embodiment is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined in this embodiment may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A hierarchical key management and data security distribution method is characterized by comprising the following steps of key storage and distribution and data distribution:
the key storage and distribution step comprises:
a tree-type user organization structure is constructed, wherein one node in the tree corresponds to one user identifier
The ith user identifier of the jth layer is represented as a user identifier
Generating corresponding user keys
Public and private key pair
Pre-stored user identification
Encrypting data with corresponding user key
In the server, the user key encrypts data
And with a secret key K 1 User identification of
Having an indexed relationship, user keys encrypt data
Comprising a secret key K 2 Encrypting the data after the user key;
using public keys
Encrypting and transmitting the user key set to the user sides of all users; the user key set comprises the user key of the current user
And the user keys of all ancestor nodes thereof, the user using the corresponding private key
Carrying out decryption;
the data distribution step comprises:
using a secret key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Using a secret key K 2 Decrypting user key encrypted data
Obtaining keys of authorized users
And encrypting the data M by using a session key SK, and transmitting the data M to a user side of an authorized user, wherein the session key SK is encrypted by using an authorized user key.
2. The hierarchical key management and data security distribution method according to claim 1, wherein the user key is used for managing the user key
The generating step comprises: generating a random number of lambda bit length for each user
And a time stamp T x (ii) a Calculating a user key for each user
Wherein H represents a hash functionAnd | represents the concatenation of two strings.
3. The hierarchical key management and data security distribution method according to claim 1, wherein the pre-stored subscriber identity
Encrypting data with corresponding user key
The steps in the server include:
using a secret key K 2 Encrypting the user key:
generating an index table I with size n and initializing to null, selecting a secret key K 1 The index table is populated as follows:
sending S ═ I, c to the server for storage, wherein
4. The hierarchical key management and data security distribution method of claim 1, wherein the key K is 1 And a secret key K 2 For symmetric keys, use is made of a key K 1 To user identification
Algorithm for encryption, and use of a secret key K 2 The algorithms for encrypting the user key are all symmetric encryption algorithms.
5. The hierarchical key management and data security distribution method according to claim 1, wherein the key storage and distribution step further comprises: using public keys
And user identification
Generating a lookup table T and storing the lookup table T in a server in a plaintext form; using each user identity
Inquiring a server lookup table T to obtain a corresponding user identifier
Of (2) a public key
All users' clients are receiving the public key
After encrypting the user key set, using the private key
And decrypting the key to obtain the user key set.
6. The hierarchical key management and data security distribution method according to claim 3, wherein the utilization key K 1 Generating respective authorized user identifications
Trapdoors searching for the same user identification in a server
Corresponding user key encrypted data
Comprises the following steps:
using a secret key K 1 Generating a corresponding authorized user trapdoor as follows:
e＝(e(1)，...，e(i)，,e(w))
＝(f(K l ，/D(1))，...f(K l ，/D(i)),f(K i ,ID(w)))
wherein, f (K) 1 ID (i) is a secret key K 1 The pseudo-random permutation of (a), the set of identities UT of authorized users being (ID (1), w being the number of authorized users, ID (i) representing the user identities of authorized users;
the server searches according to the trapdoors in the following mode:
if I [ e (I) ] ≠ T, the server returns the corresponding c (I).
7. The hierarchical key management and data security distribution method according to claim 1, further comprising a data decryption step at a user side:
after receiving the distributed data, the authorized user side decrypts the data by using the held user key set to obtain a session key SK;
the encrypted message is decrypted using the session key SK to obtain the original data M.
8. The hierarchical key management and data security distribution method of claim 5, wherein the public-private key pair
Are distributed directly to the user end through a secure channel.
9. A hierarchical key management and data security distribution system of the hierarchical key management and data security distribution method according to any one of claims 1 to 8, comprising a key generation center, a distribution center, a server and a user side; wherein the content of the first and second substances,
the key generation center is used for generating a user key corresponding to the tree-type user organization structure
Public and private key pair
Secret key K 1 And a secret key K 2 ；
The server is used for storing the user identification
Encrypting data with corresponding user key
The distribution center is used for executing the key distribution and data distribution steps, encrypting and transmitting the user key set to the user sides of all users and encrypting and transmitting the data M to the user sides of authorized users.
10. The hierarchical key management and secure data distribution system according to claim 9, wherein the server is further configured to store the public key in the clear
And user identification
So that the distribution center utilizes the authorized subscriber identification
Inquiring a look-up table T of a server to obtain a corresponding user identifier
Of (2) a public key
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| CN114978774A (en) * | 2022-07-28 | 2022-08-30 | 四川九洲空管科技有限责任公司 | Multi-level key management method based on nested protection structure |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114978774A (en) * | 2022-07-28 | 2022-08-30 | 四川九洲空管科技有限责任公司 | Multi-level key management method based on nested protection structure |
| CN114978774B (en) * | 2022-07-28 | 2022-10-04 | 四川九洲空管科技有限责任公司 | Multi-level key management method based on nested protection structure |
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