A repudiable multi-recipient authentication method and system

Abstract

This invention relates to a repudiable multi-receiver authentication method and system, comprising: S1, initializing the required public parameters, hash function, key generation organization, and user members; S2, each user member obtains an identity key pair through the public parameters, key generation organization, and identity information, stores the private key locally, and sends the public key to other user members; S3, the sender selects multiple receivers from the user members, constructs intermediate parameters for each receiver and the information to be sent, and generates corresponding ciphertext information using the intermediate parameters and each receiver's identity public key, and sends it to each receiver; S4, each receiver receives the corresponding ciphertext information transmitted by the sender, decrypts the ciphertext information using the receiver's identity key pair, and verifies it. This invention allows multiple receivers to decrypt the message by the sender only once, avoiding repeated encryption of the message by the sender, while protecting the confidentiality and security of the information.

Description

Technical Field

[0001] This invention relates to the field of secure communications, and in particular to a deniable multi-receiver authentication method and system. Background Technology

[0002] With the rapid development of internet communication technology and the computing and storage capabilities of smart devices, a vast amount of information and data exists on the internet. This information may originate from various sources, and the recipient's trust in the data is highly dependent on their level of trust in its source. Ensuring data verifiability is a crucial measure to guarantee that data originates from a trustworthy party. Secondly, in certain special scenarios, data such as personal medical records, internet access logs, and corporate production plans are sensitive data that reflects the privacy and confidentiality of their owners. Therefore, anonymity must be considered during transmission and use to protect the privacy of the data's owner.

[0003] Repudiable authentication encryption technology is a branch of cryptography. Due to its special cryptographic properties, it has important applications in many fields, mainly including interactive repudiable authentication protocols and non-interactive repudiable authentication protocols. During communication, the receiver can verify the true identity of the sender and the true source of the transmitted information. However, the sender can deny having sent the transmitted information. Even if the receiver colludes with a third party, others cannot fully believe the sender's claimed source of the transmitted information. This is because the essence of denial is that the receiver can also generate the transmitted information generated by the sender. Therefore, the sender can claim that the transmitted information received by the receiver is forged by the receiver, thus denying the existence of the communication.

[0004] However, previous work on applying repudiation authentication protocols to real-world scenarios has focused only on their security and anonymity, neglecting the efficiency of the protocols. In the Internet environment where communication technologies and device computing power are developing rapidly, efficiency has become an important factor for many users to consider when evaluating whether a protocol meets their scenario requirements.

[0005] Multi-receiver encryption is a hot research topic in modern cryptography because it allows the sender to encrypt and authenticate a message once and send it to multiple receivers for decryption, thus greatly improving the communication efficiency of the system. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a deniable multi-receiver authentication method and system.

[0007] The objective of this invention is achieved through the following technical solution: This invention provides a deniable multi-recipient authentication method, comprising the following steps: S1. Initialize the public parameters, hash function, key generation mechanism, and members used by the sender and receiver; S2. Each user member obtains an identity key pair through public parameters, the key generation organization, and their own identity information, saves the private key of the identity key pair locally, and sends the public key to other users. S3. The sender selects multiple receivers from the users, constructs intermediate parameters for each receiver and the information to be sent, and generates corresponding ciphertext information using the intermediate parameters and the public key of each receiver's identity, and then sends it to each receiver. S4. Each receiver receives the corresponding ciphertext information transmitted by the sender, uses the receiver's identity key pair to decrypt the ciphertext information to recover the original information, and verifies the recovered original information.

[0008] As a further improvement, in step S1, initializing the common parameters involves first inputting security parameters. Generate two large prime numbers and And respectively, as the addition group of the elliptic curve group Multiplication group The generator and order, choose As The base point and the bilinear pair are determined. .

[0009] As a further improvement, in step S1, initializing the hash function includes determining four hash functions, specifically, This represents mapping binary data of arbitrary length to a group. , used for calculations using the member's public key; Representatives will group The dots in the code are mapped to binary data of a specified length for use in ciphertext encryption and decryption operations. This represents mapping binary data of arbitrary length to an integer field for use in ciphertext parameter operations; Used to encrypt sent messages and allow the recipient to verify the authenticity of the messages, It is an infinitely looping group.

[0010] As a further improvement, in step S1, initializing the key generation mechanism includes randomly selecting a public-private key. Calculate the public key using the public and private keys .

[0011] As a further improvement, in step S2, each user member obtains an identity key pair through public parameters, the key generation organization, and the user member's identity information, including the following steps: S21, Each user selects a random number. As the member's private key, the member's public key is calculated by combining the member's private key. Then the member's public key and the identity of the member Send to the key generation organization; S22, The key generation organization receives the member public key from each user member. and identity Calculate the public key of each member's identity separately. and identity private key And transmit the identity key pair containing the identity public key and identity private key through a secure channel. Return it to the corresponding user member; S23. After each user receives the identity key pair, they verify it using the public key. If the conditions are met, the identity key pair will be accepted.

[0012] As a further improvement, in step S3, intermediate parameters are constructed for each receiver and the information to be sent, and corresponding ciphertext information is generated using the intermediate parameters and the public key of each receiver, including the following steps: S31. The sender selects a random number to generate the first parameter. Then calculate the first parameter of the ciphertext information. ; S32. The sender determines the set of message receivers. and the information to be sent and through a hash function Calculate the second parameter ; S33. Perform the following calculations for each receiver. ; ; ; ; ; ; in, It is the product of the random number chosen by the sender and the public key of the receiver. Represents the set of receivers Member count in, , The total number of members in the receiver set. Indicates the first The recipient's public key. This indicates the sender's private key. express and The bilinear mapping value, Indicates the information to be sent and The result of XORing the hash values. This indicates the sender's public key. This represents the product of the random number chosen by the sender and their own public key. Indicates the first The recipient's member public key, This indicates that the random number chosen by the sender is related to the first... The product of the recipient's member public key, the identity public key, and the system public key. yes Input hash function The result after hashing will As a third parameter; S34. The sender obtains the coefficients according to the following polynomial. As the fourth parameter, ; in, This represents the polynomial constructed by the sender. To represent the unknowns in a polynomial; S35, The sender encapsulates the ciphertext information. And then send them to each recipient separately.

[0013] As a further improvement, in step S4, the encrypted information is decrypted using the receiver's identity key to recover the original information, including the following steps: S41, The receiver uses the first parameter of the ciphertext. and the third parameter And the calculation of the recipient's private key , Then calculate based on the recipient's identity key. , , ;in, Indicates the first The product of each receiver's private key and the first ciphertext parameter sent by the sender. Indicates the first Each recipient member's private key Indicates the first A bilinear mapping value between the recipient's private key and the third ciphertext parameter. No. Recipient's identity private key express Input hash function As a result, express The sum of the results of multiplying the first ciphertext parameter by the receiver's private key. express Input hash function The result; S42, Through Construct the following polynomial by combining the fourth parameter of the ciphertext To calculate : ; in, This represents the polynomial used by the receiver for decryption. S43. The receiver obtains the recovered original message through the following calculation. : ; ; ; ; ; .

[0014] As a further improvement, in step S4, verifying the recovered original information involves the receiver obtaining the recovered original message and then using a hash function. The original message is hashed and then compared with the ciphertext. If they match, the received message is verified; otherwise, the received message is not verified.

[0015] This invention provides a repudiable multi-receiver authentication method, comprising the following steps: S1, initializing the required public parameters, hash function, key generation organization, and user members including sender and receiver; S2, each user member obtains an identity key pair through the public parameters, key generation organization, and their own identity information, locally saves the private key of the identity key pair, and sends the public key to other user members; S3, the sender selects multiple receivers from the user members, constructs intermediate parameters for each receiver and the information to be sent, and generates corresponding ciphertext information using the intermediate parameters and each receiver's identity public key, and sends it to each receiver; S4, each receiver receives the corresponding ciphertext information transmitted by the sender, uses the receiver's identity key pair to decrypt the ciphertext information to recover the original information, and verifies the recovered original information. In multi-receiver encryption, when information needs to be sent, the sender can select multiple receivers according to its needs. For each receiver, intermediate parameters are calculated based on their public key, the message to be sent, and common parameters. Information is then encrypted using these intermediate parameters and each receiver's public key. Each receiver decrypts the received encrypted information without requiring information from other receivers. This allows the sender to encapsulate the message only once, enabling multiple receivers to decrypt and verify it, avoiding repeated encryption and reducing computational overhead. It can be applied to secure group communication, multi-party information sharing, and other scenarios, ensuring that information can only be decrypted by authorized receivers, protecting the confidentiality and security of the information.

[0016] The present invention also provides a deniable multi-receiver authentication system, including any further improvement of the deniable multi-receiver authentication method described above. Since it adopts the above technical content, it should have the same or corresponding technical effects, and therefore will not be described in detail.

[0017] As further improvements, these include a system parameter module, a key generation mechanism, a sending module, a receiving module, and a verification module. The parameter module includes: public parameters required for system initialization, hash functions, public key pairs from the key generation organization, and member information containing the sender and receiver; The key generation mechanism generates identity key pairs based on public key pairs and user member information; The sending module encrypts the message to be sent based on the recipient's public key to form ciphertext information, and then sends the ciphertext information to the recipient. The receiving module receives encrypted information sent by the sender and decrypts and recovers the original message based on the encrypted information and the identity private key. The verification module: The receiver verifies the decrypted original message based on the ciphertext information. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] Combination Figure 1 As shown, this embodiment of the invention provides a deniable multi-recipient authentication method, including the following steps: S1. Initialize the public parameters, hash function, key generation mechanism, and members used by the sender and receiver.

[0021] Specifically, initialize common parameters, which may include, but are not limited to, first inputting security parameters. Generate two large prime numbers and And respectively, as the addition group of the elliptic curve group Multiplication group The generator and order, choose As The base point and the bilinear pair are determined. .

[0022] Initialize the hash function, optionally including, but not limited to, determining four hash functions, among which This represents mapping binary data of arbitrary length to a group. , used for calculations using the member's public key; Representatives will group The dots in the code are mapped to binary data of a specified length for use in ciphertext encryption and decryption operations. This represents mapping binary data of arbitrary length to an integer field for use in ciphertext parameter operations; Used to encrypt sent messages and allow the recipient to verify the authenticity of the messages, It is an infinitely looping group.

[0023] The initial key generation organization can optionally include, but is not limited to, randomly selecting public and private keys. Through public and private keys Calculate the public key .

[0024] Initialization includes user members for both the sender and receiver, setting a unique identity for each user member. With identity information, each user can act as a sender or receiver of information. When acting as a sender, the message to be sent is encrypted into ciphertext and sent to the receiver. When acting as a receiver, the ciphertext is received, decrypted, and the original message is recovered.

[0025] S2. Each user member obtains an identity key pair using public parameters, the key generation organization, and their own identity information. They then locally store the private key of the identity key pair and send the public key to other users. Specifically, optional but not limited to the following steps: S21, Each user selects a random number. As a member's private key, combined with the member's private key Calculate member public key Then the member's public key and use the unique identity of members Send it to the key generation organization.

[0026] S22, The key generation organization, based on the member public key received from each user member... and identity Calculate the public key of each member's identity separately. and identity private key and transmit the identity public key through a secure channel and identity private key identity key pair Return it to the corresponding user member.

[0027] S23. After each user receives the identity key pair, they verify it using the public key. If the conditions are met, the identity key pair will be accepted.

[0028] S3. The sender selects at least one receiver from the users. It should be noted that the receivers in this embodiment of the invention can be selected, but are not limited to multiple, and are also applicable in the case of a single receiver. Intermediate parameters are constructed for each receiver and the information to be sent. The intermediate parameters include four: a random number selected by the sender. Additive group with elliptic curve group The base point Multiplication yields the first parameter Used to construct polynomial parameters when the receiver decrypts the ciphertext. ; For sending messages The second parameter obtained by performing a hash operation The first parameter is used by the receiver to verify the decrypted original message; the sender calculates the first parameter. The random number selected at the time Public key of sender's identity information The third parameter is obtained through calculation and is used by the receiver to construct polynomial parameters when decrypting the ciphertext. The sender obtains the first parameter of the coefficient list based on the polynomial, which is used by the receiver to construct the polynomial when decrypting and recovering the encrypted ciphertext. The sender then generates the corresponding ciphertext information using the four intermediate parameters and each receiver's public key, and sends it to each receiver. The specific steps include: S31. The sender selects a random number. Then calculate the first parameter of the ciphertext information. .

[0029] S32. The sender first determines the information to be sent. and through a hash function Calculate the second parameter Then determine the set of information recipients. ,in, Represents any one receiver in the receiver set. Represents the set of receivers Member count in , This represents the total number of members in the receiver set.

[0030] S33. Perform the following calculations for each receiver. ; ; ; ; ; ; in, It is the product of the random number chosen by the sender and the public key of the receiver. Indicates the first The recipient's public key. This indicates the sender's private key. express and The bilinear mapping value, Indicates the information to be sent and The result of XORing the hash values. This indicates the sender's public key. This represents the product of the random number chosen by the sender and their own public key. Indicates the first The recipient's member public key, Indicates the random number selected by the sender. With the The recipient's member public key Add identity public key Multiply by the system public key The product of the results, yes Input hash function The result after hashing will As a third parameter.

[0031] S34. The sender obtains the coefficients according to the following polynomial. As the fourth parameter, ; in, This represents the polynomial constructed by the sender. This represents the unknowns in a polynomial.

[0032] S35, The sender encapsulates the ciphertext information. And then send them to each recipient separately.

[0033] S4. Each receiver receives the corresponding ciphertext information transmitted by the sender, and uses the receiver's identity key pair to decrypt the ciphertext information and recover the original information. The specific steps include the following: S41, The receiver uses the first parameter of the ciphertext. and the third parameter And the calculation of the recipient's private key , ,in, Indicates the first The product of each receiver's private key and the first ciphertext parameter sent by the sender. This represents the private key of the recipient member. Indicates the first A bilinear mapping value between the recipient's private key and the third ciphertext parameter. No. The recipient's private key is then used to calculate... , , ,in, express Input hash function As a result, express The sum of the results of multiplying the first ciphertext parameter by the receiver's private key. express Input hash function The result afterwards.

[0034] S42, Through Combined with the fourth parameter of the ciphertext Construct the following polynomial To calculate : ; in, This represents the polynomial used by the receiver for decryption.

[0035] S43. The receiver obtains the recovered original message through the following calculation. : ; ; ; ; ; The recovered original information is verified. Specifically, after receiving the recovered original message, each receiver uses a hash function. The original message is hashed and then compared with the second parameter. If they match, the received message is verified; otherwise, it is rejected and the message verification fails.

[0036] This invention provides a repudiable multi-receiver authentication method. In multi-receiver encryption, when information needs to be sent, the sender can select multiple recipients according to its needs. For each recipient, intermediate parameters are calculated based on their public key, the information to be sent, and common parameters. Information encryption is then performed based on these intermediate parameters and each recipient's public key. Recipients decrypt the received encrypted information without needing information from other recipients. This method allows the sender to encapsulate the message only once, enabling multiple recipients to decrypt and verify it, avoiding repeated encryption and reducing computational overhead. It can be applied to secure group communication, multi-party data sharing, and other scenarios, ensuring that data can only be decrypted by authorized recipients, protecting the confidentiality and security of information.

[0037] Therefore, in today's increasingly diverse and frequently interacting internet environment, ensuring secure and fair business cooperation while protecting the privacy of critical information has become a key task for promoting the development of the internet economy. Repudiation authentication can identify the source of information and guarantee its privacy, while multi-receiver encryption improves encryption efficiency. The combination of these two technologies makes it a suitable information security transmission protocol for commercial internet environments where privacy protection is paramount.

[0038] This invention also provides a repudiable multi-receiver authentication system, including any preferred embodiment of a repudiable multi-receiver authentication method, and combinations of further preferred embodiments where there is no conflict. Since the above-described repudiable multi-receiver authentication system is based on the above-described repudiable multi-receiver authentication method, it should have the same or corresponding technical functions and beneficial effects, which will not be elaborated here.

[0039] As a further preferred embodiment, the system mainly includes a system parameter module, a key generation mechanism, a sending module, a receiving module, and a verification module. The parameter module includes: public parameters required for system initialization, hash functions, public key pairs from the key generation organization, and member information containing the sender and receiver; The key generation mechanism generates identity key pairs based on public key pairs and user member information; The sending module encrypts the message to be sent based on the recipient's public key to form ciphertext information, and then sends the ciphertext information to the recipient. The receiving module receives encrypted information sent by the sender and decrypts and recovers the original message based on the encrypted information and the sender's private key.

[0040] The verification module: The receiver verifies the decrypted original message based on the ciphertext information.

[0041] It should be noted that the system's verification module can be selectively configured based on the security requirements of the usage environment.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A repudiable multi-recipient authentication method, characterized in that, Includes the following steps: S1. Initialize the public parameters, hash function, key generation mechanism, and members used by the sender and receiver; S2. Each user member obtains an identity key pair through public parameters, the key generation organization, and their own identity information, saves the private key of the identity key pair locally, and sends the public key to other users. S3. The sender selects multiple receivers from the users, constructs intermediate parameters for each receiver and the information to be sent, and generates corresponding ciphertext information using the intermediate parameters and each receiver's public key and identity public key, and then sends it to each receiver. S4. Each receiver receives the corresponding ciphertext information transmitted by the sender, uses the receiver's identity key pair to decrypt the ciphertext information to recover the original information, and verifies the recovered original information. In step S1, initializing the common parameters involves first inputting the security parameters. Generate two large prime numbers and And respectively, as the addition group of the elliptic curve group Multiplication group The generator and order, choose As The base point and the bilinear pair are determined. Initializing the hash function involves determining four hash functions, among which, This represents mapping binary data of arbitrary length to a group. , used for calculations using the member's public key; Representatives will group The dots in the code are mapped to binary data of a specified length for use in ciphertext encryption and decryption operations. This represents mapping binary data of arbitrary length to an integer field for use in ciphertext parameter operations; Used to encrypt sent messages and allow the recipient to verify the authenticity of the messages, It is an infinite looping group; In step S2, each user member obtains an identity key pair through public parameters, the key generation organization, and the user member's identity information, including the following steps: S21, Each user selects a random number. As the member's private key, the member's public key is calculated by combining the member's private key. Then the member's public key and the identity of the member Send to the key generation organization; S22, The key generation organization receives the member public key from each user member. and identity Calculate the public key of each member's identity separately. and identity private key And transmit the identity key pair containing the identity public key and identity private key through a secure channel. Return it to the corresponding user member; S23. After each user receives the identity key pair, they verify it using the public key. Check if the identity key pair is valid; if valid, accept the identity key pair. In step S3, intermediate parameters are constructed for each receiver and the information to be sent, and corresponding ciphertext information is generated using the intermediate parameters and the public key of each receiver, including the following steps: S31. The sender selects a random number to generate the first parameter. Then calculate the first parameter of the ciphertext information. ; S32. The sender determines the set of message receivers. and the information to be sent and through a hash function Calculate the second parameter ; S33. Perform the following calculations for each receiver. ； ； ； ； ； ； in, It is the product of the random number chosen by the sender and the public key of the receiver. Represents the set of receivers Member count in, , The total number of members in the receiver set. Indicates the first The recipient's public key. This indicates the sender's private key. express and The bilinear mapping value, Indicates the information to be sent and The result of XORing the hash values. This represents the sender's public key. This represents the product of the random number chosen by the sender and their own public key. Indicates the first The recipient's member public key, This indicates that the random number chosen by the sender is related to the first... The product of the recipient's member public key, the identity public key, and the system public key. yes Input hash function The result after hashing will As a third parameter; S34. The sender obtains the coefficients according to the following polynomial. As the fourth parameter, ； in, This represents the polynomial constructed by the sender. To represent the unknowns in a polynomial; S35, The sender encapsulates the ciphertext information. And send them to each recipient separately; In step S4, the encrypted information is decrypted using the receiver's identity key to recover the original information, including the following steps: S41, The receiver uses the first parameter of the ciphertext. and the third parameter And the calculation of the recipient's private key , Then calculate based on the recipient's identity key. , , ;in, Indicates the first The product of each receiver's private key and the first ciphertext parameter sent by the sender. Indicates the first Each recipient member's private key Indicates the first A bilinear mapping value between the recipient's private key and the third ciphertext parameter. No. Recipient's identity private key express Input hash function As a result, express The sum of the results of multiplying the first ciphertext parameter by the receiver's private key. express Input hash function The result; S42, Through Construct the following polynomial by combining the fourth parameter of the ciphertext. To calculate : ； in, This represents the polynomial used by the receiver for decryption. S43. The receiver obtains the recovered original message through the following calculation. : 。 2. The repudiable multi-recipient authentication method according to claim 1, characterized in that, In step S1, initializing the key generation mechanism includes randomly selecting a public and private key. Calculate the public key using the public and private keys .

3. The deniable multi-recipient authentication method according to any one of claims 1 to 2, characterized in that, In step S4, verifying the recovered original information involves the receiver obtaining the recovered original message and then using a hash function. The original message is hashed and then compared with the ciphertext. If they match, the message verification is successful; otherwise, it is rejected and the message verification fails.

4. A repudiable multi-recipient authentication system, characterized in that, A repudiable multi-receiver authentication method as described in any one of claims 1 to 3 includes a system parameter module, a key generation mechanism, a sending module, a receiving module, and a verification module. The parameter module includes: public parameters required for system initialization, hash functions, public key pairs from the key generation organization, and member information containing the sender and receiver; The key generation mechanism generates identity key pairs based on public key pairs and user member information; The sending module encrypts the message to be sent based on the recipient's public key to form ciphertext information, and then sends the ciphertext information to the recipient. The receiving module receives encrypted information sent by the sender and decrypts and recovers the original message based on the encrypted information and the identity private key. The verification module: The receiver verifies the decrypted original message based on the ciphertext information.

Images