Secure communication method and apparatus based on multiple blind signatures

Abstract

The present invention belongs to the technical field of information communications. Disclosed are a secure communication method and apparatus based on multiple blind signatures. The technical problem to be solved by the present invention is how to organically combine digital envelope technology and digital signature technology, and the technical solution used involves: S1, an initialization stage; S2, a key generation stage; S3, a blinding stage; S4, a signature stage; S5, an unblinding and sending stage; and S6, a receiving stage. Compared with the prior art, by means of an organic combination of multiple blind signatures and digital envelopes, the present invention improves the security, credibility, unforgeability, non-replicability and non-repudiation during an information communication process on the basis of ensuring communication efficiency, and meets secure communication requirements in scenarios such as digital cash and e-commerce.

Description

A secure communication method and device based on multiple blind signatures Technical Field

[0001] The present invention relates to the field of information communication, and specifically provides a secure communication method and device based on multiple blind signatures. Background Art

[0002] With the continuous acceleration of the digital transformation of the economy, especially the rapid popularization and application of new technologies such as 5G, artificial intelligence, and the Internet of Things, information communication is becoming more frequent, and the application of digital envelope technology is becoming more and more common.

[0003] Digital envelopes use symmetric cryptographic algorithms to rapidly encrypt large amounts of data, and employ asymmetric key algorithms to ensure the secure transmission of symmetric keys. This addresses the security issues inherent in symmetric key distribution and the slow speed of public key encryption, improving security, scalability, and efficiency. However, because digital envelopes utilize public key encryption, malicious users can destroy data while unable to decrypt it, thus compromising data integrity and non-repudiation. Digital signatures utilize private key encryption technology, offering trustworthy, unforgeable, uncopyable, and non-repudiation properties. They protect data integrity, verify its origin, and enable secure data communication between network entities.

[0004] In addition, in certain information communication scenarios, such as inter-bank transfers in digital cash and multi-party settlements in e-commerce, the sender of information usually needs to obtain multi-party signatures before sending the information for reasons of anonymity and security, and does not want the signatory to obtain the specific content of the information to be sent.

[0005] However, a single blind signature or multi-signature technology can hardly meet this requirement, and traditional multi-signature technology usually relies on secure channels for key distribution, which greatly increases the communication overhead of the entire signing process and causes many inconveniences in practical applications.

[0006] Therefore, how to organically combine digital envelope and digital signature technology to improve the security, credibility, non-forgeability, non-replicability and non-repudiation of information communication while ensuring communication efficiency is an urgent problem to be solved by technical personnel in this field.

[0007] Summary of the Invention

[0008] The present invention aims to address the above-mentioned deficiencies in the prior art and provides a highly practical secure communication method based on multiple blind signatures.

[0009] A further technical task of the present invention is to provide a secure communication device based on multiple blind signatures that is rationally designed, safe and applicable.

[0010] The technical solution adopted by the present invention to solve its technical problem is:

[0011] A secure communication method based on multiple blind signatures has the following steps:

[0012] S1, initialization phase;

[0013] The key generation center KGC generates a pair of RSA public and private keys (e, d) according to the RSA algorithm, discloses two cryptographic hash functions H0 and H1, and the identity information of each signatory, and the information receiver generates a pair of RSA public and private keys (u, v) according to the RSA algorithm;

[0014] S2, key generation phase;

[0015] Each signatory generates its own random secret value, encrypts it, and sends it to the Key Generation Center (KGC). The KGC aggregates the secret value and collaborates with each signatory to generate their own private key.

[0016] S3, blinding stage;

[0017] The sender of the information, i.e. the signature requester, randomly selects a blinding factor a and uses it to blind the plaintext information to obtain bm1, which is then sent to the key generation center KGC.

[0018] S4, signing stage;

[0019] The key generation center KGC uses the private key d to sign bm1 and broadcasts the signature result bm2 to each signatory. Each signatory uses the aggregate secret value and their own identity private key to sign bm2 individually. The information sender collects the individual signature results of the signatories and performs an aggregate signature.

[0020] S5, unblinding and sending stage;

[0021] The sender of the information unblinds the blind signature result to obtain the signature result of the plaintext information, encrypts the plaintext information with a randomly generated symmetric key, encrypts the symmetric key with the public key u, and forms a digital envelope with the two encrypted results and the signature, which is sent to the recipient of the information;

[0022] S6, receiving stage;

[0023] The information recipient first processes the digital envelope and then the digital signature to obtain valid plaintext information.

[0024] Furthermore, in step S1, it further includes:

[0025] S101. The key generation center KGC randomly selects two large prime numbers p1 and q1, and calculates the RSA modulus n = p1·q1 and the Euler function

[0026] S102, the key generation center KGC selects a random number e, Meet e and Coprime, calculate d so that Public key (e,n) is made public, and private key (d,p1,q1) is kept secret; S103, select two strong anti-collision cryptographic hash functions H0: {0,1} * →Z n * , H1:{0,1} * →{0,1} l , l≤log2n, open H0, H1;

[0027] S104, Public Signing Party P i Identity Num i , i = 1, 2, ..., k, a total of k signing parties;

[0028] S105. The information receiver R0 randomly selects two large prime numbers p2 and q2, and calculates the RSA modulus w = p2·q2, and the Euler function

[0029] S106, information receiver R o Choose a random number u, Satisfy u and Coprime, calculate v, so that The public key (u, w) is made public, and the private key (v, p2, q2) is kept secret.

[0030] Furthermore, in step S2, it further includes:

[0031] S201, Signing Party P i , i=1,2,……,k, select a random number x i ∈Z n , as their respective secret values, calculate x i The inverse element x i -1 , for x i Encrypt to get y i , and y i Send to the key generation center KGC;

[0032] S202, the key generation center KGC to P i Identity information and P i The secret value y i Encrypt to get sgn i , i=1,2,……,k, and aggregate the secret values ​​of all signatories to obtain Y, and convert (sgn i,Y) sent to the signing party P i ;

[0033] S203, Signing Party P i ,i=1,2,……,k,after receiving (sgn i ,Y), then sgn i Calculate the value based on Num i Identity private key ppk i .

[0034] Furthermore, in step S3, it further includes:

[0035] The information sender, that is, the signature requester P0, uses the blinding factor a∈Z n * , calculate the information msg to obtain bm1, and send bm1 to the key generation center KGC.

[0036] Furthermore, in step S4, it further includes:

[0037] S401. The key generation center KGC performs a private key signature on the blinded information bm1 to obtain bm2, and sends bm2 to each signatory.

[0038] S402, Signing Party P i Using ppk i Sign bm2 to get z i , and z i Sent to the information sender P0;

[0039] S403, the information sender P0 aggregates all signatures z i , i=1,2,……,k, and get the blind signature result Z.

[0040] Furthermore, in step S5, it further includes:

[0041] S501: The message sender P0 unblinds the blind signature result Z and obtains F, where (F, Y) is the signature of the message msg.

[0042] S502. The information sender P0 randomly generates a symmetric key sk, and uses a symmetric encryption algorithm to symmetrically encrypt the information msg to obtain Sym. It then uses the public key u to encrypt sk to obtain the public key ciphertext ssk. (Sym, ssk, F, Y) constitutes a digital envelope and sends it to the information receiver R0.

[0043] Furthermore, in step S6, it further includes:

[0044] S601. The message receiver R0 uses the private key v to decrypt ssk to obtain the symmetric key sk, and uses sk to decrypt Sym to obtain the message msg.

[0045] S602: Based on the public information and the signature (F, Y), verify the validity of the information.

[0046] A secure communication device based on multiple blind signatures, comprising: at least one memory and at least one processor;

[0047] The at least one memory is configured to store a machine-readable program;

[0048] The at least one processor is configured to call the machine-readable program to execute a secure communication method based on multiple blind signatures.

[0049] Compared with the prior art, the secure communication method and device based on multiple blind signatures of the present invention have the following outstanding beneficial effects:

[0050] The present invention can improve the reliability of signatures by introducing multiple signatories while ensuring the confidentiality of the information to be signed for each signatory, reducing the risk of leakage of the information to be signed during multi-party transmission, and meeting the anonymity and security requirements in scenarios such as digital cash and e-commerce.

[0051] By combining the signature result with the symmetrically encrypted information to be sent and the asymmetrically encrypted random symmetric key to form a digital envelope for information communication, the dependence of private key distribution on the secure channel in the private key encryption process is overcome, and the problem of long encryption time in the public key encryption process is solved, thus achieving high efficiency, credibility, non-forgeability, non-replicability and non-repudiation in the process of information security communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] FIG1 is a flow chart of a secure communication method based on multiple blind signatures;

[0054] Figure 2 is a schematic diagram of the information sending process in a secure communication method based on multiple blind signatures;

[0055] FIG3 is a schematic diagram of the information receiving process in a secure communication method based on multiple blind signatures. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solutions of the present invention, the present invention will be further described in detail below in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0057] A best embodiment is given below:

[0058] As shown in Figures 1 to 3, a secure communication method based on multiple blind signatures in this embodiment has the following steps:

[0059] S1, initialization phase;

[0060] The key generation center KGC generates a pair of RSA public and private keys (e, d) according to the RSA algorithm, discloses two cryptographic hash functions H0 and H1, and the identity information of each signatory, and the information receiver generates a pair of RSA public and private keys (u, v) according to the RSA algorithm;

[0061] The specific steps are:

[0062] S101. The key generation center KGC randomly selects two large prime numbers p1 and q1, and calculates the RSA modulus n = p1·q1 and the Euler function

[0063] S102, the key generation center KGC selects a random number e, Meet e and Coprime, calculate d so that Public key (e,n) is made public, and private key (d,p1,q1) is kept secret;

[0064] S103, select two strong anti-collision cryptographic hash functions H0: {0,1} * →Z n * , H1:{0,1} * →{0,1} l , l≤log2n, open H0, H1;

[0065] S104, Public Signing Party P i Identity Num i , i = 1, 2, ..., k, a total of k signing parties;

[0066] S105. The information receiver R0 randomly selects two large prime numbers p2 and q2, and calculates the RSA modulus w = p2·q2, and the Euler function

[0067] S106, information receiver R o Choose a random number u, Satisfy u and Coprime, calculate v, so that The public key (u, w) is made public, and the private key (v, p2, q2) is kept secret.

[0068] S2, key generation phase;

[0069] Each signatory generates its own random secret value, encrypts it, and sends it to the Key Generation Center (KGC). The KGC aggregates the secret value and collaborates with each signatory to generate their own private key.

[0070] The specific steps are:

[0071] S201, Signing Party P i , i=1,2,……,k, select a random number x i ∈Z n , as their respective secret values, calculate x i The inverse element x i -1 , calculate y i =x i e (mod n), and y i Send to the key generation center KGC;

[0072] S202, the key generation center KGC calculates sgn i =(y i ·H0(Num i )) d (mod n) and (sgn i ,Y) sent to the signing party P i ;

[0073] S203, Signing Party P i ,i=1,2,……,k,receive(sgn i ,Y), calculate the identity private key ppk respectively i =x i -1 ·sgn i (mod n). The signer can use the RSA public key and identity identifier to verify the identity private key, effectively avoiding malicious key generation center (KGC) attacks.

[0074] S3, blinding stage;

[0075] The sender of the information, i.e. the signature requester, randomly selects a blinding factor a and uses it to blind the plaintext information to obtain bm1, which is then sent to the key generation center KGC.

[0076] The specific steps are:

[0077] The information sender P0 uses the blinding factor Calculate the information msg to get bm1=a e H0(msg)(mod n) and bm1 are sent to the key generation center KGC, ensuring that each signatory cannot obtain the specific content of the signed information during the multi-signature process.

[0078] S4, signing stage;

[0079] The key generation center KGC uses the private key d to sign bm1 and broadcasts the signature result bm2 to each signatory. Each signatory uses the aggregate secret value and their own identity private key to sign bm2 individually. The information sender collects the individual signature results of the signatories and performs an aggregate signature.

[0080] The specific steps are:

[0081] S401. The key generation center KGC performs a private key signature bm2=bm1 on the blinded information bm1. d (mod n), and send bm2 to each signing party;

[0082] S402, Signing Party P i Using ppk i Sign bm2 to get z i =bm2·ppk i ·x i H1(Y) (mod n), and z i Send to the signature requester P0;

[0083] S403, the information sender P0 aggregates all signatures z i , i=1,2,……,k, get the blind signature result

[0084] S5, unblinding and sending stage;

[0085] The sender of the information unblinds the blind signature result to obtain the signature result of the plaintext information, encrypts the plaintext information with a randomly generated symmetric key, encrypts the symmetric key with the public key u, and forms a digital envelope with the two encrypted results and the signature, which is sent to the recipient of the information;

[0086] The specific steps are:

[0087] S501. The information sender P0 unblinds the blind signature result Z and calculates F=Z·a -k (mod n), (F, Y) is the signature of the message msg;

[0088] S502, the information sender P0 randomly generates a symmetric key sk, and uses the symmetric encryption algorithm to symmetrically encrypt the information msg to obtain Sym, and calculates ssk = sk u (mod n), (Sym, ssk, F, Y) form a digital envelope and send it to the information receiver R0.

[0089] S6, receiving stage;

[0090] The information recipient first processes the digital envelope and then the digital signature to obtain valid plaintext information.

[0091] The specific steps are:

[0092] S601, information receiver R0 calculates sk=ssk v (mod n), get the symmetric key sk, use sk to decrypt Sym, and get the message msg;

[0093] S602, based on public information and signature (F, Y), passed the test Is it true? Verify the validity of the information obtained.

[0094] Based on the above method, a secure communication device based on multiple blind signatures in this embodiment includes: at least one memory and at least one processor;

[0095] The at least one memory is configured to store a machine-readable program;

[0096] The at least one processor is configured to call the machine-readable program to execute a secure communication method based on multiple blind signatures.

[0097] The above-mentioned specific implementation methods are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the above-mentioned specific implementation methods. Any appropriate changes or substitutions made by ordinary technicians in any of the above-mentioned technical fields that comply with the claims of the present invention regarding a secure communication method and device based on multiple blind signatures shall fall within the scope of patent protection of the present invention.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A secure communication method based on multiple blind signatures, characterized in that: The steps are as follows: S1, initialization phase; The key generation center KGC generates a pair of RSA public and private keys (e, d) according to the RSA algorithm, and discloses two cryptographic hash functions H0 and H1, as well as the identity information of each signatory. The information receiver generates a pair of RSA public and private keys (u, v) according to the RSA algorithm. S2, key generation phase; Each signatory generates its own random secret value, encrypts it and sends it to the key generation center KGC. The key generation center KGC aggregates the secret value and collaborates with each signatory to generate their own identity private key. S3, blinding stage; The information sender, i.e. the signature requester, randomly selects a blinding factor a and uses it to blind the plaintext information to obtain bm1, which is then sent to the key generation center KGC. S4, signing stage; The key generation center KGC signs bm1 with the private key d and broadcasts the signature result bm2 to each signatory. Each signatory uses the aggregate secret value and their own identity private key to sign bm2 individually. The information sender collects the individual signature results of the signatories and performs an aggregate signature. S5, unblinding and sending stage; The sender of the information unblinds the blind signature result to obtain the signature result of the plaintext information, encrypts the plaintext information with the randomly generated symmetric key, encrypts the symmetric key with the public key u, and forms a digital envelope with the two encryption results and the signature and sends it to the receiver of the information; S6, receiving stage; The information receiver first processes the digital envelope and then the digital signature to obtain valid plaintext information.

2. A secure communication method based on multiple blind signatures according to claim 1, characterized in that: In step S1, further comprising: S101, the key generation center KGC randomly selects two large prime numbers p1 and q1, and calculates the RSA modulus n = p1 · q1, and the Euler function S102, the key generation center KGC selects a random number e, Meet e and Coprime, calculate d so that Public key (e,n) is made public and private key (d,p1,q1) is kept secret; S103, select two strong anti-collision cryptographic hash functions H0: {0,1} * →Z n * , H1:{0,1} * →{0,1} l , l≤log2n, public H0, H1; S104, Public Signing Party P i IdentityNum i , i = 1, 2, ..., k, a total of k signing parties; S105, the information receiver R0 randomly selects two large prime numbers p2 and q2, and calculates the RSA modulus w = p2 q2, and the Euler function S106, information receiver R o Choose a random number u, Satisfy u and Coprime, calculate v so that The public key (u, w) is made public and the private key (v, p2, q2) is kept secret.

3. A secure communication method based on multiple blind signatures according to claim 2, characterized in that: In step S2, further comprising: S201, Signing Party P i , i=1,2,……,k, select a random number x i ∈Z n , as their respective secret values, calculate x i The inverse element x i -1 , for x i Encrypt to get y i , and y i Send to the key generation center KGC; S202, the key generation center KGC to P i Identity information and P i The secret value y i Encrypt to get sgn i , i = 1, 2, ..., k, and aggregate the secret values ​​of all signatories to obtain Y, and convert (sgn i ,Y) sent to the signing party P i ; S203, Signing Party P i ,i=1,2,……,k,on receiving (sgn i ,Y) after sgn i Calculate the value based on Num i Identity private key ppk i .

4. A secure communication method based on multiple blind signatures according to claim 3, characterized in that: In step S3, further comprising: The sender of the information, that is, the signature requester P0, uses the blinding factor a∈Z n * , calculate the information msg to obtain bm1, and send bm1 to the key generation center KGC.

5. A secure communication method based on multiple blind signatures according to claim 4, characterized in that: In step S4, further comprising: S401, the key generation center KGC performs a private key signature on the blinded information bm1 to obtain bm2, and sends bm2 to each signatory; S402, Signing Party P i Using ppk i Sign bm2 to get z i , and z i Sent to the information sender P0; S403, the information sender P0 aggregates all signatures z i , i=1,2,…,k, and get the blind signature result Z.

6. A secure communication method based on multiple blind signatures according to claim 5, characterized in that: In step S5, further comprising: S501, the message sender P0 unblinds the blind signature result Z and obtains F, (F, Y) which is the signature of the message msg; S502. The information sender P0 randomly generates a symmetric key sk, and uses a symmetric encryption algorithm to symmetrically encrypt the information msg to obtain Sym, and uses the public key u to encrypt sk to obtain the public key ciphertext ssk. (Sym, ssk, F, Y) constitutes a digital envelope and sends it to the information receiver R0.

7. A secure communication method based on multiple blind signatures according to claim 6, characterized in that: In step S6, further comprising: S601, the information receiver R0 uses the private key v to decrypt ssk, obtains the symmetric key sk, and uses sk to decrypt Sym to obtain the information msg; S602: Based on the public information and the signature (F, Y), verify the validity of the information.

8. A secure communication device based on multiple blind signatures, characterized in that: include: at least one memory and at least one processor; The at least one memory is used to store a machine-readable program; The at least one processor is configured to call the machine-readable program to execute the method according to any one of claims 1 to 7.

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