CN104283667A - A data transmission method, device and system - Google Patents

Abstract

The present invention discloses a data transmission method, device and system, wherein the data transmission method for a node includes: using a first key to encrypt a request for communication between a node and a private key generator, generating a first ciphertext, and first The key is the symmetric key pre-distributed by the key distribution center for the node; send the first ciphertext to the key distribution center; receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain this The second session key and the third ciphertext; forward the third ciphertext to the private key generator; receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, Obtain public parameters and private keys. In the present invention, the node uses the key distribution center to communicate with the private key generator by using different symmetric keys to distribute the one-time secret session key to the node, which effectively avoids the node counterfeiting attack, and at the same time ensures that the private key server distributes the public parameters and the security of the node's private key.

Description

A data transmission method, device and system

technical field

The present invention relates to the security field of the Internet of Things, in particular to a data transmission method, device and system.

Background technique

The Internet of things (The Internet of things) is to connect items with the Internet through radio frequency identification and other information sensing devices to realize intelligent identification and management. The core and foundation of the Internet of Things is still the Internet, which is an extended and expanded network based on the Internet. Its client end extends and extends to any item and item for information exchange and communication. The Internet of Things is mainly composed of a large number of wireless sensor nodes, wireless sensor networks and the Internet. Both the sensor nodes and the sensor network itself have certain resource limitations, which will directly affect the security mechanism of the Internet of Things.

In all security solutions, authenticated encryption technology is the basis of all security technologies, through authenticated encryption can meet the sensor network authentication, confidentiality, non-repudiation, integrity and other security requirements. Authentication and encryption are the most important modules in the security mechanism of wireless sensor networks. At present, wireless sensor network key management schemes and protocols can be divided into symmetric key management schemes and asymmetric key management schemes.

For the asymmetric key management scheme, due to the particularity of sensor nodes such as poor computing power, low storage capacity, and limited energy, the simple asymmetric key method is not suitable for deployment on sensor nodes.

Examples of symmetric key management schemes include E-G scheme and q-composite.

The E-G program consists of 3 phases. The first phase is the key pre-distribution phase. Before deployment, the deployment server first generates a large key pool with a total of P keys and key identifiers. Each node randomly selects k (k<<P) different keys from the key pool. This random pre-allocation The method enables any two nodes to have a shared key with a certain probability. The second stage is the shared key discovery stage. After random deployment, if two adjacent nodes have a shared key, randomly select one of them as the pairing key of both parties; otherwise, enter the third stage. The third stage is the key path establishment stage. The node establishes a key path between the two parties after going through several hops with other neighbor nodes with shared keys.

In the q-composite scheme, the node pre-randomly selects m different keys from the key pool with the total number of keys |S|. After deployment, two adjacent nodes need to share at least q keys to directly establish a pairing key . If the number of shared keys is t(t>=q), the pairing key K=hash(k1||k2||..kz) can be established using a one-way hash function (the key serial number is agreed in advance).

In the key pre-distribution scheme based on the symmetric key system, the concept of identity-based encryption (IBE) is also proposed. IBE can use the identity information of the message recipient as the public key to encrypt the message. Compared with traditional public key encryption, IBE does not require certificate management, which greatly simplifies the implementation of secure communication.

Compared with asymmetric key management methods, the biggest advantage of symmetric keys is that the amount of calculation is small. But its obvious disadvantage is that there must be a key pre-distribution process, that is, the symmetric key is stored in the node in advance, which is not flexible enough for adding and replacing nodes. The disadvantage of using the symmetric key system in the WSN of the Internet of Things is that the ability to resist man-in-the-middle attacks is very limited, it does not support identity authentication of neighbor nodes, and it cannot resist impersonation attacks. With the increase of captured nodes, more key information will be exposed.

Contents of the invention

In order to solve the above-mentioned defects in the prior art, the present invention proposes a data transmission method, device and system, which can adapt to the particularity of wireless sensor nodes, and the algorithm is simple to implement, thereby improving the security and security of the Internet of Things collection data transmission. transmission efficiency.

One aspect of the present invention provides a data transmission method for a node, comprising the following steps:

Using the first key to encrypt a request for communication between the node and the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center;

Send the first ciphertext to the key distribution center;

Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext is: The key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key;

forwarding said third ciphertext to a private key generator;

Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key to obtain the public parameters and the private key.

In the data transmission method for nodes proposed in the embodiment of the present invention, nodes use different symmetric keys distributed by the key distribution center to communicate with the private key generator to communicate with the private key generator, effectively avoiding the node Counterfeiting attacks, while ensuring the security of private key servers distributing public parameters and node private keys.

The embodiment of the present invention also proposes a data transmission method for the key distribution center, including the following steps:

Assign different symmetric keys to each node and private key generator in advance;

receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys;

When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator;

Use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext;

Using the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext;

Send the second ciphertext to the node.

In the data transmission method for the key distribution center proposed in the embodiment of the present invention, the key distribution center uses different symmetric keys to distribute one-time-encrypted session keys for nodes and private key generators, effectively avoiding node counterfeiting attacks, while ensuring the security of the private key generator PKG to distribute public parameters and node private keys.

The embodiment of the present invention also proposes a data transmission method for a private key generator, comprising the following steps:

Receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; A symmetric key assigned by the key generator;

Using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate the fourth ciphertext;

Send the fourth ciphertext to the node.

In the data transmission method for the private key generator proposed by the embodiment of the present invention, the private key generator uses the different pre-allocated symmetric keys to distribute the one-time secret session key to the nodes through the key distribution center, and Nodes communicate, effectively avoiding node counterfeiting attacks, and at the same time ensuring the security of private key servers distributing public parameters and node private keys.

As a preference of the above technical solution, the method for generating the pre-generated public parameters and the private key of the node includes:

Select domain elements a,b∈F _p to satisfy the elliptic curve equation E:y ² ≡x ³ +ax+b(mod p), where Δ=4a ³ +27b ² ≠0(mod p);

Calculate E(F _p ) point set according to p and a, b value and elliptic curve equation E;

Select the base point G in the E(F _p ) point set, and use the elliptic curve addition rule and the point doubling rule to solve the order of G point;

Generate a random number s as the master key of the system, and calculate the public parameters and the private key of the node according to the order and s of the G point.

An embodiment of the present invention proposes a node, including:

Generate a first ciphertext module, used to use the first key to encrypt the request of the node to communicate with the private key generator, and generate the first ciphertext; wherein, the first key is the key distribution center for the node in advance the assigned symmetric key;

A first sending module, configured to send the first ciphertext to the key distribution center;

The first receiving module is used to receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key and the third ciphertext between the node and the private key generator; wherein, the The third ciphertext is: the key distribution center uses the symmetric key pre-allocated to the private key generator to encrypt and generate the session key;

A second sending module, configured to forward the third ciphertext to the private key generator;

The second receiving module is configured to receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key.

The embodiment of the present invention proposes a key distribution center, including:

An allocation module, which is used to pre-allocate different symmetric keys for each node and private key generator;

A third receiving module, configured to receive the first ciphertext sent by the node, and decrypt the first ciphertext using the first key assigned to the node among the symmetric keys;

Generate a session key module, used to generate random parameters as the current session key between the node and the private key generator when the first ciphertext is that the node requests to communicate with the private key generator;

Generate a third ciphertext module, which is used to encrypt the current session key using the second key assigned to the private key generator in the symmetric key to generate a third ciphertext;

Generate a second ciphertext module, which is used to encrypt the current session key using the first key and the third ciphertext to generate the second ciphertext;

A third sending module, configured to send the second ciphertext to the node.

The embodiment of the present invention proposes a private key generator, including:

The fourth receiving module is used to receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; wherein the second key is The symmetric key pre-assigned by the key distribution center to the private key generator;

Generate a fourth ciphertext module, which is used to encrypt the pre-generated public parameters and the private key of the node using the session key to generate the fourth ciphertext;

A fourth sending module, configured to send the fourth ciphertext to the node.

As a preference of the above technical solution, the device also includes:

The generation module is used to select domain elements a,b∈F _p , satisfying the elliptic curve equation E:y ² ≡x ³ +ax+b(mod p), where, Δ=4a ³ +27b ² ≠0(mod p) ; Calculate E(F _p ) point set according to p and a, b value and elliptic curve equation E; select base point G in E(F _p ) point set, use elliptic curve addition rule and doubling point rule to solve the order of G point; generate The random number s is used as the master key of the system, and the public parameters and the private key of the node are calculated according to the order and s of the G point.

The present invention also proposes a data transmission system, including a node, a key distribution center and a private key generator, wherein the node is used for:

Using the first key to encrypt a request for communication between the node and the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center;

Send the first ciphertext to the key distribution center;

Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext is: The key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key;

forwarding said third ciphertext to a private key generator;

Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key;

The key distribution center is used for:

Assign different symmetric keys to each node and private key generator in advance;

receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys;

When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator;

Use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext;

Using the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext;

sending the second ciphertext to the node;

The private key generator is used to:

receiving and using the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtaining the current session key with the node; A symmetric key assigned to the private key generator;

Using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate the fourth ciphertext;

Send the fourth ciphertext to the node.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

FIG. 1 is a flowchart of a data transmission method for a node proposed in an embodiment of the present invention;

Fig. 2 is a flow chart of a data transmission method for a key distribution center proposed by an embodiment of the present invention;

Fig. 3 is a flow chart of a data transmission method for a private key generator proposed by an embodiment of the present invention;

Fig. 4 is the flow chart of the method that private key generator PKG generates public parameter and the private key of node in the embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a node proposed in an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a key distribution center proposed by an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of a private key generator proposed by an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

As shown in Figure 1, a data transmission method for a node proposed by an embodiment of the present invention includes the following steps:

Step S101: use the first key to encrypt the request of the node to communicate with the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center;

Step S102: sending the first ciphertext to the key distribution center;

Step S103: Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext The text is: the key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key;

Step S104: forwarding the third ciphertext to the private key generator;

Step S105: Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key.

In the data transmission method for nodes proposed in the embodiment of the present invention, nodes use different symmetric keys distributed by the key distribution center to communicate with the private key generator to communicate with the private key generator, effectively avoiding the node Counterfeiting attacks, while ensuring the security of private key servers distributing public parameters and node private keys.

As shown in Figure 2, a data transmission method for a key distribution center proposed by an embodiment of the present invention includes the following steps:

Step S201: assign different symmetric keys to each node and private key generator in advance;

Step S202: receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys;

Step S203: When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator;

Step S204: using the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext;

Step S205: use the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext;

Step S206: Send the second ciphertext to the node.

In the data transmission method for the key distribution center proposed in the embodiment of the present invention, the key distribution center uses different symmetric keys to distribute one-time-encrypted session keys for nodes and private key generators, effectively avoiding node counterfeiting attacks, while ensuring the security of the private key generator PKG to distribute public parameters and node private keys.

As shown in Figure 3, a data transmission method for a private key generator proposed by an embodiment of the present invention includes the following steps:

Step S301: Receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; wherein, the second key is the key distribution center A pre-assigned symmetric key for the private key generator;

Step S302: using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate a fourth ciphertext;

Step S303: Send the fourth ciphertext to the node.

In the data transmission method for the private key generator proposed by the embodiment of the present invention, the private key generator uses the different pre-allocated symmetric keys to distribute the one-time secret session key to the nodes through the key distribution center, and Nodes communicate, effectively avoiding node counterfeiting attacks, and at the same time ensuring the security of private key servers distributing public parameters and node private keys.

Among them, the private key generator PKG can use the scheme shown in Figure 4 when generating public parameters and private keys of nodes:

Choose a finite field of prime numbers F _p , and then choose an elliptic curve E on F _p so that its order is a large prime number n, or the product of a large prime number n and another small integer. Then select a point G of order n to generate system parameters T=(p,a,b,G,P _pub ,q,h,H1,H2). This parameter variable is a public system parameter. The specific process is as follows:

Step S401: select domain elements a, b∈F _p to satisfy the equation E:y ² ≡x ³ +ax+b(mod p), where Δ=4a ³ +27b ² ≠0(mod p).

Step S402: Calculate the corresponding E(F _p ) point set according to the selected p, a, b values and the elliptic curve E. The specific process is as follows:

Assuming that the value of x is in the set {0, 1, 2, ..., p-1}, bring it into the elliptic curve equation E, and solve y=d(modp), the solution process is a quadratic residual solution process. A quadratic residue is defined as a congruence of the form y ² ≡d(mod p), where p>1. If the congruence has a solution, then d is called a quadratic residue modulo p; if the congruence has no solution, then d is called a quadratic non-residue modulo p. Use Euler's discriminant to judge whether there is a solution: if p is an odd prime number and p cannot divide d, then:

The necessary and sufficient condition for d to be a quadratic residue modulo p is: d ^(p-1)/2 =1(mod p)

The necessary and sufficient condition for d to be a quadratic non-subordinate remainder modulo p is: d ^(p-1)/2 =-1(mod p);

For a prime number p=3mod4, the square root of the quadratic residue d is: ±d ^(p+1)/4 mod p;

Step S403: After obtaining the point set solution, select the base point G=(x _g , y _g ) on the curve E(F _p ), and use the elliptic curve addition rule and the point doubling rule to solve the order of point G. The solution process is as follows:

Addition rule: P(x ₁ ,y ₁ )+Q(x ₂ ,y ₂ )=S(x ₃ ,y ₃ ), where:

x ₃ =λ ² -x ₁ -x ₂

y ₃ =λ(x ₁ -x ₃ )-y ₁

$\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}$

Doubling rule: P(x ₁ ,y ₁ )+P(x ₁ ,y ₁ )=2P(x ₁ ,y ₁ )=S(x ₃ ,y ₃ ), where:

x ₃ =λ ² -2x ₁

y ₃ =λ(x ₁ -x ₃ )-y ₁

$\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}$

a is the coefficient of the first-order term in the elliptic curve equation. In solving, x ₃ , y ₃ , and λ all take mod p. Calculate 2G, 3G...nG=0 (point at infinity), and n is the order of the G point. At the same time, the parameters satisfy the following constraints: h=E(F _p )/q, E(F _p )≠p, p ^B ≠1(mod q), where, 1≤B<20, h≤4, p, q also Should satisfy p=2mod3 and p=6q-1.

Step S404: Generate a random number *, s is the master key of the system, and calculate P _pub =s*G (using the doubling point rule); for any given string ID∈{0,1}*, select Hash hash function H ₁ :{ 0,1} ^* →G ₁ ^* , this Hash function maps the user’s identity ID to an element in G1; H ₂ :G ₁ →{0,1} ⁿ , this Hash function determines that M (plaintext space) is { 0,1} ⁿ , the purpose is to convert the character mark into a discrete value, which is convenient for encryption and decryption algorithm processing; map the mark ID _id corresponding to mark management to the point P _id on the elliptic curve E(F _p ), and generate the corresponding Private key PID _id =s*P _id . In addition, verification can also be performed according to the identification information sent by each node, and then corresponding private key records of each node are generated in the PKG.

Step S405: Publish system parameters T=(p, a, b, G, P _pub , q, h, H1, H2).

The method of solving the G-point order by the elliptic curve addition rule and the doubling rule proposed in the embodiment of the present invention increases the difficulty of deciphering the key generated by the IBE algorithm.

Below, the embodiment of the present invention will be described in conjunction with nodes, key distribution center (KDC) and private key generator (PKG):

1. System initialization:

System initialization is mainly used to realize KDC's authentication of sensor nodes and PKG, generation of PKG public parameters and node private key.

1. Sensor nodes and PKG are registered on KDC

1) The key distribution center KDC is certified by an authority.

2) When sensor nodes register, KDC assigns different symmetric keys to each sensor node, and KDC knows the key of each sensor node. Each sensor node can use this key to communicate securely with the KDC;

For example, the symmetric key between KDC and sensor node A is K _A-KDC ; the symmetric key between KDC and private key generator PKG is K _PKG-KDC ; the ID of KDC storage node, the ID of PGK and the corresponding symmetric key K _{A -KDC} , K _PKG-KDC .

3) KDC sends the authenticated node ID information to PKG through K _PKG-KDC encryption, and PKG stores the node ID information in the database after decryption.

2. For the generation of PKG public parameters and node private keys, the process can refer to the above, and will not be repeated here.

2. Distribution of session keys between sensor nodes and PKG:

1. When sensor node A wants to communicate with PKG and transmit the public parameters of IBE and the private key of A generated by PKG, A has K _A-KDC , ID; KDC has K _A-KDC and K _PKG-KDC ; PKG It has K _PKG-KDC , the public parameters of IBE and the private key of A generated by PKG.

2. A uses K _A-KDC to encrypt the request information to communicate with PKG, and sends it to KDC through K _{A-KDC (A, PKG)} .

3. After receiving the request, KDC uses the stored K _A-KDC to decrypt, knowing that A wants to communicate with PKG. The KDC generates a random parameter R1, and uses R1 as the session key for the communication between A and PKG.

4. KDC encrypts with the known symmetric key of A and PKG, and sends K _A-KDC (R1, K _PKG-KDC (A, R1)) to A.

5. After receiving the ciphertext sent by the KDC, A decrypts it with K _A-KDC to obtain the current session key R1 and K _PKG-KDC (A, R1). A sends K _PKG-KDC (A, R1) to PKG.

6. After receiving the ciphertext, PKG uses K _PKG-KDC to decrypt and obtain R1.

3. PKG public parameters, distribution of private keys and encryption and decryption of collected information:

1. The PKG encrypts the public parameters and A's private key generated by the PKG with the session key R1 and sends them to the sensor node A.

2. Sensor node A uses the IBE algorithm and the obtained public parameters, uses the ID of the sink node as the public key, encrypts the collected information, and transmits the ciphertext to the sink node hop by hop.

3. The sink node uses the private key obtained from PGK to decrypt and obtain the original text.

The data scheme proposed by the embodiment of the present invention first authenticates and registers in the KDC through the sensor nodes and PKG, and the KDC uses different symmetric keys to distribute one-time secret session keys to the nodes, effectively preventing counterfeiting; considering the special characteristics of the sensor nodes The identity-based encryption algorithm IBE is adopted. The public key is the identity ID of the other party. The generated key is only owned by the node itself. When a node is cracked, it does not involve the security of other nodes and does not affect the security of the entire network. , has nothing to do with the scale of the network, which ensures the robustness of the network, and solves the G-point order through the addition rule and the doubling rule, which improves the security of the algorithm, thus ensuring the privacy, security and reliability of information .

Through the data transmission method proposed by the embodiment of the present invention, the security and transmission efficiency of the data transmission collected by the Internet of Things are improved, and reliable support is provided for the security guarantee of the data transmission of the Internet of Things.

Correspondingly, the embodiment of the present invention also proposes a node, as shown in FIG. 5 , including:

Generate a first ciphertext module 501, used to use the first key to encrypt the request of the node to communicate with the private key generator, and generate the first ciphertext; wherein, the first key is the key distribution center for the Symmetric keys assigned by nodes;

A first sending module 502, configured to send the first ciphertext to the key distribution center;

The first receiving module 503 is configured to receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key and the third ciphertext between the node and the private key generator; wherein, The third ciphertext is: the key distribution center uses the symmetric key pre-allocated to the private key generator to encrypt and generate the session key;

The second sending module 504 is configured to forward the third ciphertext to the private key generator;

The second receiving module 505 is configured to receive and use the current session key to decrypt the fourth ciphertext encrypted by the current session key sent by the private key generator, to obtain the public parameters and the private key.

As shown in Figure 6, the embodiment of the present invention also proposes a key distribution center, including:

An allocation module 601, configured to pre-allocate different symmetric keys for each node and private key generator;

The third receiving module 602 is configured to receive the first ciphertext sent by the node, and decrypt the first ciphertext using the first key assigned to the node among the symmetric keys;

Generate a session key module 603, configured to generate random parameters as the current session key between the node and the private key generator when the first ciphertext is that the node requests to communicate with the private key generator;

Generate a third ciphertext module 604, configured to use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext;

Generating a second ciphertext module 605, configured to use the first key to encrypt the current session key and the third ciphertext to generate a second ciphertext;

A third sending module 606, configured to send the second ciphertext to the node.

As shown in Figure 7, the embodiment of the present invention also proposes a private key generator, including:

The fourth receiving module 701 is configured to receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; wherein the second key The symmetric key pre-assigned to the private key generator by the key distribution center;

Generate a fourth ciphertext module 702, configured to use the current session key to encrypt the pre-generated public parameters and the private key of the node to generate a fourth ciphertext;

A fourth sending module 703, configured to send the fourth ciphertext to the node.

The private key generator also includes:

The generation module is used to select an elliptic curve on the finite field of prime numbers, and make its order be a large prime number n, or the product of a large prime number n and another small integer; select a base point on the elliptic curve, and calculate the order n of the base point , to generate the public parameters and the private key of the node.

The embodiment of the present invention also proposes a data transmission system, including a node, a key distribution center, and a private key generator, wherein the node is used for:

Using the first key to encrypt a request for communication between the node and the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center;

Send the first ciphertext to the key distribution center;

Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext is: The key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key;

forwarding said third ciphertext to a private key generator;

Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key;

The key distribution center is used for:

Assign different symmetric keys to each node and private key generator in advance;

receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys;

When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator;

Use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext;

Using the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext;

sending the second ciphertext to the node;

The private key generator is used to:

receiving and using the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtaining the current session key with the node; A symmetric key assigned to the private key generator;

Using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate the fourth ciphertext;

Send the fourth ciphertext to the node.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and combinations of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a Means for realizing the functions specified in one or more steps of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart flow or flows and/or block diagram block or blocks.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (9)

1. A data transmission method for a node, comprising the following steps: Using the first key to encrypt a request for communication between the node and the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center; Send the first ciphertext to the key distribution center; Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext is: The key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key; forwarding said third ciphertext to a private key generator; Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key to obtain the public parameters and the private key. 2. A data transmission method for a key distribution center, comprising the following steps: Assign different symmetric keys to each node and private key generator in advance; receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys; When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator; Use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext; Using the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext; Send the second ciphertext to the node. 3. A data transmission method for a private key generator, comprising the following steps: Receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; A symmetric key assigned by the key generator; Using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate the fourth ciphertext; Send the fourth ciphertext to the node. 4. The method according to claim 3, wherein the method for generating the pre-generated public parameters and the private key of the node comprises: Select domain elements a,b∈F _p to satisfy the elliptic curve equation E:y ² ≡x ³ +ax+b(mod p), where Δ=4a ³ +27b ² ≠0(mod p); Calculate E(F _p ) point set according to p and a, b value and elliptic curve equation E; Select the base point G in the E(F _p ) point set, and use the elliptic curve addition rule and the point doubling rule to solve the order of G point; Generate a random number s as the master key of the system, and calculate the public parameters and the private key of the node according to the order and s of the G point. 5. A node, characterized in that, comprising: Generate a first ciphertext module, used to use the first key to encrypt the request of the node to communicate with the private key generator, and generate the first ciphertext; wherein, the first key is the key distribution center for the node in advance the assigned symmetric key; A first sending module, configured to send the first ciphertext to the key distribution center; The first receiving module is used to receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key and the third ciphertext between the node and the private key generator; wherein, the The third ciphertext is: the key distribution center uses the symmetric key pre-allocated to the private key generator to encrypt and generate the session key; A second sending module, configured to forward the third ciphertext to the private key generator; The second receiving module is configured to receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key. 6. A key distribution center, characterized in that it comprises: An allocation module, which is used to pre-allocate different symmetric keys for each node and private key generator; A third receiving module, configured to receive the first ciphertext sent by the node, and decrypt the first ciphertext using the first key assigned to the node among the symmetric keys; Generate a session key module, used to generate random parameters as the current session key between the node and the private key generator when the first ciphertext is that the node requests to communicate with the private key generator; Generate a third ciphertext module, which is used to encrypt the current session key using the second key assigned to the private key generator in the symmetric key to generate a third ciphertext; Generate a second ciphertext module, which is used to encrypt the current session key using the first key and the third ciphertext to generate the second ciphertext; A third sending module, configured to send the second ciphertext to the node. 7. A private key generator, characterized in that, comprising: The fourth receiving module is used to receive and use the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtain the current session key with the node; wherein the second key is The symmetric key pre-assigned by the key distribution center to the private key generator; Generate a fourth ciphertext module, which is used to encrypt the pre-generated public parameters and the private key of the node using the session key to generate the fourth ciphertext; A fourth sending module, configured to send the fourth ciphertext to the node. 8. The private key generator according to claim 7, wherein the private key generator further comprises: The generating module is used to select domain elements a, b∈F _p , satisfying the elliptic curve equation E:y ² ≡x ³ +ax+b(modp), where Δ=4a ³ +27b ² ≠0(mod p); Calculate the E(F _p ) point set according to p, a, b value and the elliptic curve equation E; select the base point G in the E(F _p ) point set, use the elliptic curve addition rule and the point doubling rule to solve the order of G point; generate random The number s is used as the master key of the system, and the public parameters and the private key of the node are calculated according to the order of point G and s. 9. A data transmission system, characterized in that it includes a node, a key distribution center and a private key generator, wherein the node is used for: Using the first key to encrypt a request for communication between the node and the private key generator, and generate a first ciphertext; wherein, the first key is a symmetric key previously assigned to the node by the key distribution center; Send the first ciphertext to the key distribution center; Receive and use the first key to decrypt the second ciphertext returned by the key distribution center, and obtain the current session key between the node and the private key generator and the third ciphertext; wherein, the third ciphertext is: The key distribution center uses the symmetric key pre-assigned to the private key generator to encrypt and generate the session key; forwarding said third ciphertext to a private key generator; Receive and use the current session key to decrypt the fourth ciphertext sent by the private key generator and encrypted with the current session key, to obtain the public parameters and the private key; The key distribution center is used for: Assign different symmetric keys to each node and private key generator in advance; receiving the first ciphertext sent by the node, and decrypting the first ciphertext using the first key assigned to the node among the symmetric keys; When the first ciphertext is that the node requests to communicate with the private key generator, generate a random parameter as the current session key between the node and the private key generator; Use the second key assigned to the private key generator in the symmetric key to encrypt the current session key to generate a third ciphertext; Using the first key to encrypt the current session key and the third ciphertext to generate the second ciphertext; sending the second ciphertext to the node; The private key generator is used to: receiving and using the second key to decrypt the third ciphertext generated by the key distribution center forwarded by the node, and obtaining the current session key with the node; A symmetric key assigned to the private key generator; Using the current session key to encrypt the pre-generated public parameters and the private key of the node to generate the fourth ciphertext; Send the fourth ciphertext to the node.