CN101931535A - An Adaptive Data Encryption and Authentication Method Without Authentication Center - Google Patents

Abstract

The invention discloses an adaptive data encryption and authentication method without an authentication center, comprising the steps of: (1) determining system parameters; (2) registering both sending and receiving parties of information; Perform data encryption and authentication protection operations; (4) The receiver interprets and verifies the received data message. Step (3) By calculating key parameters, calculating signature parameters, outputting an electronic signature equal to zero when only performing data encryption on plaintext messages, outputting an encrypted ciphertext equal to plaintext messages when only performing electronic signatures, and calculating electronic signatures when both are performed simultaneously , Encrypt the combination of plaintext message and electronic signature, combine ciphertext, signature parameters and electronic signature, form and send data message to achieve. The method can self-adaptively carry out data encryption and content integrity authentication on the plaintext message, and can avoid the problems caused by using the authentication center and multiple functional components in the existing method.

Description

An Adaptive Data Encryption and Authentication Method Without Authentication Center

technical field

The invention belongs to data protection technology in the fields of e-commerce, e-government, information security and the like, and in particular relates to an adaptive data encryption and authentication method without an authentication center.

Background technique

In various fields related to information such as e-commerce system, e-government system, information security system, network communication system, etc., data encryption technology and electronic signature technology are two extremely basic data protection technologies. Among them, data encryption technology protects the confidentiality of data. It converts data into meaningless ciphertext through encryption keys and data encryption algorithms to prevent data from being accessed by unauthorized persons. The electronic signature technology authenticates the integrity and source of the data, completely simulating the function of a handwritten signature in real life, and has the capabilities of identity authentication, source identification, non-repudiation, and anti-counterfeiting, ensuring the authenticity of data messages, Security, reliability and legality, so it is of great significance to ensure the normal operation of information systems. In many countries, including our country, electronic signatures have been legally recognized.

With the promotion and application of technologies such as data encryption and electronic signature, in practical applications, people often encounter the following three operations:

(i) Only encrypt and protect data;

(ii) electronically sign data only;

(iii) Perform encryption protection and electronic signature operations on data at the same time.

In the existing application system, in order to meet the application requirements of these three situations, it is usually necessary to prepare multiple independent functional components such as encryption protection and electronic signature, which respectively meet the above three different requirements, but increases the application system The consumed space resources cannot meet the application requirements in time and space resource-constrained environments such as embedded environments, mobile communications, and wireless communications.

In addition, in the actual operation process of the above three cases, due to the use of technologies such as electronic signature, key distribution and data encryption, it is strongly dependent on a trusted third-party organization as the certification center, in the electronic signature, key distribution and data encryption. In the authentication process of data encryption, the verifier and the authentication center need to complete the relevant authentication through real-time interaction, which brings a large calculation burden, communication burden, and data expansion, which not only greatly increases the workload of the system, but also reduces the system. Work efficiency cannot meet the needs of practical applications, which seriously limits the promotion and application of related technologies.

The relevant terms used in the present invention are described as follows:

According to the definition of my country's "Electronic Signature Law", the so-called electronic signature refers to the data contained in electronic form in the data message and attached to identify the identity of the signatory and indicate that the signatory approves the content. Data messages refer to information generated, sent, received or stored by electronic, optical, electromagnetic or similar means.

The certification center refers to an electronic certification service agency established in accordance with Article 17 of the "Electronic Signature Law" that is recognized by all parties and is a credible third party that provides relevant electronic certification services. The electronic signature certificate stipulated in Article 21 of the Law.

The key distribution center refers to the organization used to cooperate with users to generate user public keys and identity certification documents.

Contents of the invention

The purpose of the present invention is to provide an adaptive data encryption and authentication method that does not require an authentication center. Under the premise of meeting the various application requirements of electronic signature and data encryption, without increasing the space resources consumed by the application system, it can meet the requirements of embedded environment, mobile communication, Application requirements in time and space resource-constrained environments such as wireless communication, and in the process of implementing data encryption and authentication, there is no need to rely on a trusted third-party organization as the authentication center, and there is no need for the verifier and the authentication center to complete relevant authentication through real-time interaction , reduce the calculation burden, communication burden and data expansion, reduce the workload of the system, and improve the work efficiency of the system.

In order to achieve the above object, the present invention provides a kind of self-adaptive data encryption and authentication method without authentication center, comprises the following steps: (1) determine system parameter: select large integer p, elliptic curve E (GF (p)): y ² =x ³ +ax+b(mod p) is a safe elliptic curve defined on the finite field GF(p), randomly select a base point G on the elliptic curve E, set n=#E(GF(p) ) is the order of the elliptic curve E, q is a large prime factor of n, the private key of the key distribution center is SK _SA , where SK _SA is a random positive integer less than q-1, then the public key of the key distribution center is PK _SA = SK _SA × G; (2) Registration of information sending and receiving parties: users of both information sending and receiving parties respectively execute the user registration agreement, interact with the key distribution center, and obtain their respective private keys and public keys; Carry out data encryption and authentication protection operations to the receiver's plaintext message, wherein the step (3) is specifically: (31) the sender randomly selects a positive integer k less than the number q-1, and according to the receiver's public key, receiving (32) The sender calculates the signature parameters according to the positive integer k and the base point G; (33) If the data encryption operation is only performed on the plaintext message, the output The electronic signature equal to zero; if only the electronic signature authentication protection operation is performed on the plaintext message, then the encrypted ciphertext equal to the plaintext message is directly output; if not only the data encryption operation is performed on the plaintext message, but also the electronic signature authentication protection operation is performed on the plaintext message, then The sender uses the hash digest algorithm Hash to calculate the electronic signature, conducts electronic signature authentication and protection operations on the plaintext message, and uses the hash digest algorithm and data encryption algorithm to encrypt the combination of the plaintext message and the electronic signature; (34) the sender will The ciphertext, signature parameters and electronic signature are combined to form a data message, and the data message is sent to the receiver.

In one embodiment of the present invention, the method further includes the step of: (4) the receiver performs an interpretation and verification operation on the received data message, specifically: (41) the receiver according to its own private key, and the receiver (42) If the ciphertext in the received data message is equal to the plaintext message, then directly output the plaintext message equal to the ciphertext; if the received data message The electronic signature in is equal to zero, or the receiver only needs to perform the message decryption operation, and then directly output the plaintext message; otherwise, the receiver uses the hash digest algorithm and data decryption algorithm according to the key parameters to decrypt the encrypted data in the received data message. text, get the plaintext message and original signature, and extract the original signature from the plaintext message and electronic signature; (43) If the original signature is different from the electronic signature in the received data message, it means that the decrypted plaintext is invalid; otherwise, The receiver checks whether the signature parameters and electronic signature in the received data message are consistent with the plaintext message obtained by decrypting the data message. If they are consistent, it means that the received data message is valid and accepted; otherwise, it means that the received data message The message is invalid and rejected directly.

In another embodiment of the present invention, the step (2) in which the information sender obtains its _own private key and public key is specifically as follows: (21) The sender randomly selects a positive integer k a smaller than q-1 , calculate the registration parameters according to the positive integer k _a and the base point G, and send the registration parameters to the key distribution center; (22) After receiving the registration parameters submitted by the sender himself, the key distribution center randomly selects one less than q-1 A positive integer k0, calculate the sender’s public key according to the positive integer k0, registration parameters and base point G; (23) The key distribution center assigns the sender’s public key according to the sender’s public key, the sender’s personal identity information, and the key distribution center (24) The key distribution center generates the sender’s identity certificate based on its own private key, the sender’s identity certificate, positive integer k, and The large prime factor q uses the hash digest algorithm to calculate the verification parameters, and the verification parameters and the sender's identity certificate form the key parameters, and send the key parameters to the sender; (25) the sender receives the key parameters from the key distribution center After sending the key parameters, check whether the key parameters are sent by the key distribution center and have not been tampered with during the transmission process; (26) when the verification result is that the key parameters are sent by the key distribution center, but , the sender requires the key distribution center to resend the key parameters; (27) When the verification result is that the key parameters are sent by the key distribution center and have not been tampered with during transmission, the sender, according to the received key parameters, Calculate its own private key, wherein the information receiver obtains its own private key and public key through the same steps as the information sender obtains its own private key and public key.

Compared with the prior art, the self-adaptive data encryption and authentication method of the present invention, which does not require an authentication center, is based on the difficulty of solving the elliptic curve discrete logarithm problem on a finite field. Without the need of a trusted certification center, the functions of data encryption and content integrity authentication of the plaintext message m can be completed by only using the above step S3, and can be based on the system's electronic signature, data encryption, and simultaneous execution of "electronic signature + data encryption", etc. Adaptively provide different functions for various application requirements. On the one hand, the original multiple independent functional components can be used to realize different application requirements with one encrypted signature component, which does not increase the space resources consumed by the application system and satisfies the requirement of embedding application requirements in environments with limited time and space resources such as mobile communication, wireless communication, etc., and on the other hand, it does not need the help of a third-party trusted certification center, which avoids the calculation burden and communication burden brought by the existing method of using the certification center and data expansion, this method reduces the workload of the system, improves the work efficiency of the system, is simple to operate, runs efficiently, can resist various known attack schemes, has high security, and can ensure the confidentiality of data messages , authenticity, security, reliability and legality, and can be widely used in various software and hardware environments such as computers, communication networks, smart cards, and mobile phones, as well as e-commerce systems, e-government systems, information security systems, network communication systems, etc. field, has a good application prospect.

The present invention will become clearer through the following description in conjunction with the accompanying drawings, which are used to explain the embodiments of the present invention.

Description of drawings

FIG. 1 is a flow chart of the self-adaptive data encryption and authentication method without an authentication center in the present invention.

FIG. 2 is a flow chart of data encryption and authentication protection operations in the adaptive data encryption and authentication method shown in FIG. 1 without an authentication center.

Detailed ways

Embodiments of the present invention will now be described with reference to the drawings, in which like reference numerals represent like elements.

In this embodiment, the adaptive data encryption and authentication method without an authentication center includes the following steps:

Step S1, determine the system parameters: select a large integer p, the elliptic curve E(GF(p)): y ² =x ³ +ax+b(modp) is a safe elliptic curve defined on the finite field GF(p) , randomly select a base point G on the elliptic curve E, let n=#E(GF(p)) be the order of the elliptic curve E, q be a large prime factor of n, and the private key of the key distribution center SA is SK _SA , where SK _SA is a random positive integer less than q-1, then the public key PK _SA of the key distribution center = SK _SA × G;

Step S2, the sending and receiving parties of the information, that is, the information sender A and the information receiver B, respectively execute the user registration protocol, interact with the key distribution center SA, and obtain their own private key SK _A , public key PK _A and private key SK _B , public key PK _B ;

Step S3, the sender A performs data encryption and authentication protection operations on the plaintext message m to be sent to the receiver B, specifically:

Step S31, the sender A randomly selects a positive integer k less than the number q-1, according to the public key PK _B of the receiver B, the identity certification document ID _B of the receiver B, and the public key PK SA of the key distribution center _SA Calculating the key parameter K, wherein the calculation formula of the key parameter K is K=k×Hash(ID _B )×PK _SA +k×PK _B ;

Step S32, the sender A calculates the signature parameter R according to the positive integer k and the base point G, where the calculation formula of the signature parameter R is R=k×G;

Step S33, if the data encryption operation is only performed on the plaintext message m, then output the electronic signature s=0; if only the electronic signature authentication protection operation is performed on the plaintext message m, then directly output the encrypted ciphertext c=m; if not only the plaintext message m m performs data encryption operations, and performs electronic signature authentication and protection operations on plaintext message m, then sender A uses the hash digest algorithm Hash() agreed in advance by the system to perform electronic signature authentication and protection operations on plaintext message m, and calculates electronic signature s, The calculation formula of the electronic signature s is s=(Hash(m, R)×R×SK _A +k)mod q, and the hash digest algorithm Hash() and the data encryption algorithm Enc() agreed by the system in advance are used to process the plaintext message The combination (m, s) of m and electronic signature s performs an encryption operation to calculate the encrypted ciphertext c. The calculation formula of the encrypted ciphertext c is c=Enc(Hash(K), (m, s)), as shown in the figure below;

Step S34, the sender A combines the ciphertext c, the signature parameter R and the electronic signature s to form a data message M=(c, R, s), and sends the data message M=(c, R, s) to recipient B.

It can be seen from the above technical solution that the self-adaptive data encryption and authentication method in this embodiment without the need for an authentication center is based on the difficulty of solving the elliptic curve discrete logarithm problem over a finite field, and by organically combining the identity of the sender and the identity of the receiver, Without the need of a trusted certification center, the functions of data encryption and content integrity authentication of the plaintext message m can be completed by only using the above step S3, and can be based on the system's electronic signature, data encryption, and simultaneous execution of "electronic signature + data encryption", etc. Adaptively provide different functions for various application requirements. On the one hand, the original multiple independent functional components can be used to realize different application requirements with one encrypted signature component, which does not increase the space resources consumed by the application system and satisfies the requirement of embedding application requirements in environments with limited time and space resources such as mobile communication, wireless communication, etc., and on the other hand, it does not need the help of a third-party trusted certification center, which avoids the calculation burden and communication burden brought by the existing method of using the certification center and data expansion, this method reduces the workload of the system, improves the work efficiency of the system, is simple to operate, runs efficiently, can resist various known attack schemes, has high security, and can ensure the confidentiality of data messages , authenticity, security, reliability and legality, and can be widely used in various software and hardware environments such as computers, communication networks, smart cards, and mobile phones, as well as e-commerce systems, e-government systems, information security systems, network communication systems, etc. field, has a good application prospect.

The method also includes the steps of:

Step S4, after receiving the data message M=(c, R, s), the receiver B interprets and verifies the data message M=(c, R, s), specifically:

Step S41, the recipient B calculates the key parameter K' according to its own private key SK _B and the signature parameter R in the received data message M=(c, R, s), where the key parameter K' The calculation formula is: K'=SK _B ×R;

Step S42, if the ciphertext c in the received data message M=(c, R, s) is equal to the plaintext message m, that is, the user A has only performed the electronic signature authentication protection operation, then directly output the plaintext message m=c, End; if the electronic signature s in the received data message M=(c, R, s) is equal to 0, that is, the user A has only performed the data encryption protection operation, or the receiver B only needs to perform the message decryption operation, then directly Output plaintext message m, end; otherwise (that is, the user performs electronic signature authentication protection operation and data encryption protection operation at the same time), receiver B uses the hash digest algorithm Hash() and data decryption algorithm agreed in advance by the system according to the key parameter K' Dec(), decrypt the ciphertext c in the received data message M=(c, R, s), and obtain the plaintext message m and the original signature s', wherein the decryption formula of the ciphertext c is: (m, s' ) = Dec(Hash(K'), c);

Step S43, if the original signature s' is different from the electronic signature s in the received data message M=(c, R, s), it means that the plaintext obtained by decryption is invalid, and the operation is terminated and terminated; otherwise, receiver B checks Whether the signature parameter R and the electronic signature s in the data message M=(c, R, s) are consistent with the plaintext message m obtained by decrypting the data message M=(c, R, s), the specific inspection formula is: s× G=Hash(m, R)×Hash(ID _A )×R×PK _SA +Hash(m, R)×R×PK _A +R, if they are consistent (that is, the equation is established), it means that the received data message If M=(c, R, s) is valid, it is accepted; if it is inconsistent (that is, the equation is not established), it means that the received data message M=(c, R, s) is invalid, and it is rejected directly.

It can be seen from the above that step S4 cooperates with step S3 to interpret and verify the data message. During the verification, it can also adaptively provide different functional interpretation and verification work according to the received message, without third-party trusted certification Center for help.

In this embodiment, the steps for the information sender A to obtain its own private key SK _A and public key PK _A in the step S2 are as follows:

Step S21, the sender A randomly selects a positive integer k _a smaller than q-1, calculates the registration parameter K A according to the positive integer k _a and the base point G, and sends the registration parameter _{K A to} the key distribution center SA, where the registration parameter The calculation formula of K _A is: K _A =k _a ×G,;

Step S22, after receiving the registration parameter K _A submitted by the sender A, the key distribution center SA randomly selects a positive integer k0 less than q-1, and calculates the sender A according to the positive integer k0, the registration parameter K _A and the base point G public key PK _A , where the calculation formula of the public key PK _A is: PK _A =k×G+K _A ;

Step S23, the key distribution center SA according to the sender A's public key PK _A , the personal identity information id _A submitted by the sender A, the sender A's identification document serial number sn _A assigned by the key distribution center SA, and the password The self-identification information ID _SA of the key distribution center SA (the self-identification information ID _SA is information used to identify the key distribution center SA according to the X.509 standard, such as the name, number, and validity period of the key distribution center SA), Generate sender A’s identity certification document ID _A , that is, ID _A = (PK _A , id _A , sn _A , ID _SA ), wherein the generation method is to combine the public key PK _A , personal identity information id _A. The serial number sn of the identity certificate document and the identification information ID _SA are spliced together;

Step S24, the key distribution center _SA uses the hash abstract algorithm Hash() agreed in _advance by the system to calculate and verify the Parameter s _a , the key parameter (ID _A , s _a ) is composed of the verification parameter s _a and the ID _A of the sender A, and the key parameter (ID _A , s _a ) is sent to the sender A, where the verification The calculation formula of parameter s _a is: s _a =(Hash(ID _A )×k+SK _SA )mod q;

Step S25, after the sender A receives the key parameter (ID _A , s _a ) sent by the key distribution center SA, it checks whether the key parameter (ID _A , s _a ) is sent by the key distribution center SA and is being transmitted The process has not been tampered with (that is, the authenticity and integrity of the authentication key parameters (ID _A , s _a )), where the verification process is to extract its own public key PK _A and verification parameters from the key parameters (ID _A , s _a ) s _a , and according to the public key PK _SA of the key distribution center SA, verify whether the equation s _a ×G=Hash(ID _A )×(PK _A -K _A )+PK _SA is valid, where "extraction" is the step S23 combined splicing method to achieve segmentation;

Step S26, when the verification result is that the key parameter (ID _A , s _a ) is sent by the key distribution center SA, but the transmission process is tampered (that is, the equation does not hold), the sender A requires the key distribution center SA to resend keyparam(ID _A , s _a );

Step S27, when the verification result is that the key parameter (ID _A , s _a ) is sent by the key distribution center SA, and the transmission process has not been tampered with (that is, the equation is established), the sender A according to the received key parameter (ID _A , s _a ), calculate its own private key SK _A , where the formula for calculating the private key SK _A is: SK _A =s _a +Hash(ID _A )×k _a ;

Wherein, the information receiver B obtains its own private key SK _B and public key PK _B through the same steps as the information sender A obtains its own private key SK _A and public key _PKA .

The following examples illustrate several parameters of this embodiment, and verify that this embodiment can realize data encryption and authentication functions without an adaptive data encryption and authentication method of an authentication center.

In step S1, a 192-bit large prime number p is randomly selected, and the elliptic curve E(GF(p)): y ² =x ³ +ax+b(modp) is a secure ellipse defined on the finite field GF(p) The curve, on which the base point randomly selected is G=(x, y), the order of the elliptic curve E is n=#E(GF(p)), and q is a large prime factor of n. in,

p =

6277101735386680763835789423207666416083908700390324961279

a=

592616546630905635115220920655548752905575269097021663719

b=

4804233895280899388319973107961190048453702796229268188014

n =

165186887773333704311468142720121385129365739211127201127

q=

165186887773333704311468142720121385129365739211127201127

x =

767497456867608967492675205059054232203172713727662547906

y=

773339505718536040565224929606618157393578012863049959916

In steps S2, S3, and S4, the system agrees to use the SHA-256 algorithm as the agreed hash digest algorithm Hash(), and the AES-256 algorithm as the data encryption algorithms Enc() and Dec().

The present invention has been described above in conjunction with the best embodiments, but the present invention is not limited to the above-disclosed embodiments, but should cover various modifications and equivalent combinations made according to the essence of the present invention.

Claims (3)

1. A self-adaptive data encryption and authentication method without an authentication center comprises the following steps:

(1) determining system parameters: selecting the large integer p, elliptic curve E (gf (p)): y is²＝x³+ ax + b (modp) is a secure elliptic curve defined in the finite field gf (p), a base point G is randomly selected from the elliptic curve E, n ═ E (gf (p)) is the order of the elliptic curve E, q is a large prime factor of n, and the private key of the key distribution center is SK_SAWhere SK_SAIs a random positive integer less than q-1, the public key of the key distribution center is PK_SA＝SK_SA×G；

(2) Registration of both information transmitting and receiving parties: the users of the information transceiver and the user registration protocol are respectively executed, and interact with the key distribution center to obtain respective private key and public key;

(3) the sender carries out data encryption and authentication protection operation on a plaintext message to be sent to a receiver, wherein the step (3) is specifically as follows:

(31) a sender randomly selects a positive integer k less than the number q-1, and key parameters are calculated according to a public key of a receiver, an identification document of the receiver and a public key of a key distribution center;

(32) the sender calculates a signature parameter according to the positive integer k and the base point G;

(33) if only the data encryption operation is carried out on the plaintext message, outputting an electronic signature equal to zero; if only the electronic signature authentication protection operation is carried out on the plaintext message, directly outputting an encrypted ciphertext equal to the plaintext message; if not only the data encryption operation is carried out on the plaintext message, but also the electronic signature authentication protection operation is carried out on the plaintext message, the sender adopts a Hash digest algorithm Hash to calculate the electronic signature, carries out the electronic signature authentication protection operation on the plaintext message, and adopts the Hash digest algorithm and the data encryption algorithm to carry out the encryption operation on the combination of the plaintext message and the electronic signature;

(34) the sender combines the ciphertext, the signature parameters and the electronic signature together to form a data message, and the data message is sent to the receiver.

2. The authentication-centric-free adaptive data encryption and authentication method according to claim 1, further comprising the steps of:

(4) the receiver performs reading and verifying operations on the received data message, specifically:

(41) the receiver calculates the key parameter according to the private key of the receiver and the signature parameter in the received data message;

(42) if the ciphertext in the received data message is equal to the plaintext message, directly outputting the plaintext message equal to the ciphertext; if the electronic signature in the received data message is equal to zero or the receiver only needs to perform message decryption operation, the plaintext message is directly output; otherwise, the receiver decrypts the ciphertext in the received data message by adopting a hash digest algorithm and a data decryption algorithm according to the key parameter to obtain a plaintext message and an original signature, and separates the original signature from the plaintext message and the electronic signature;

(43) if the original signature is different from the electronic signature in the received data message, the plaintext obtained by decryption is invalid; otherwise, the receiver checks whether the signature parameter and the electronic signature in the received data message are consistent with the plaintext message obtained by decrypting the data message, if so, the received data message is valid and is accepted; otherwise, the received data message is invalid and is directly rejected.

3. The adaptive data encryption and authentication method without an authentication center as claimed in claim 1, wherein the step of the information sender obtaining its own private key and public key in the step (2) is specifically:

(21) the sender randomly selects a positive integer k less than q-1_aAccording to a positive integer k_aThe base point G calculates the registration parameters and sends the registration parameters to the key distribution center;

(22) after receiving the registration parameters submitted by the sender, the key distribution center randomly selects a positive integer k0 smaller than q-1, and calculates the public key of the sender according to the positive integer k0, the registration parameters and the base point G;

(23) the key distribution center generates an identification document of the sender according to the public key of the sender, the personal identification information of the sender, the identification document serial number of the sender distributed by the key distribution center and the self identification information of the key distribution center;

(24) the key distribution center calculates verification parameters by adopting a hash digest algorithm according to a private key of the key distribution center, an identity certificate of a sender, a positive integer k and a large prime factor q, the verification parameters and the identity certificate of the sender form key parameters, and the key parameters are sent to the sender;

(25) after receiving the key parameters sent by the key distribution center, the sender checks whether the key parameters are sent by the key distribution center and are not tampered in the transmission process;

(26) when the verification result is that the key parameter is sent by the key distribution center, but the key parameter is tampered in the transmission process, the sender requires the key distribution center to resend the key parameter;

(27) when the verification result is that the key parameter is sent by the key distribution center and is not tampered in the transmission process, the sender calculates the own private key according to the received key parameter,

the information receiver obtains the private key and the public key of the information receiver through the same steps as the steps of obtaining the private key and the public key of the information receiver by the information sender.

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